JP2008066050A - Method for producing electrode plate for lithium secondary battery - Google Patents

Abstract

An electrode plate manufacturing intermediate member in which a plurality of stripe-shaped active material layer forming portions and strip-shaped connecting portions interposed therebetween are formed on both surfaces of a base material is transferred efficiently. Provided is a method for producing an electrode plate for a lithium secondary battery capable of producing a high-quality tabless electrode plate while effectively preventing deformation while rolling.
An electrode plate manufacturing intermediate member in which a coating pattern having a plurality of stripe-shaped active material layer forming portions and an active material uncoated portion is formed on both surfaces of a substrate is continuously provided. In the active material uncoated portions 4, the linear through-cuts 32 extending in the width direction are positioned at both ends thereof separated from the edge of the active material layer forming portion 2 by a predetermined distance L. The electrode plate production intermediate member 7 is rolled while being continuously transferred, and the electrode plate production intermediate member 7 after the rolling process is predetermined along the longitudinal direction and the width direction. Cut along each cutting imaginary line and separate into individual plates.
[Selection] Figure 2

Description

  The present invention relates to a manufacturing method capable of manufacturing a tabless positive electrode plate and a negative electrode plate for a lithium secondary battery with high productivity and high quality.

  In recent years, portable and cordless electronic devices such as AV devices, personal computers, and portable communication devices have been rapidly promoted. As a driving power source for these electronic devices and other electronic devices, high energy density and load characteristics are achieved. There is a need for an excellent sealed battery. In particular, lithium secondary batteries are attracting attention because they have various features such as high energy density and output voltage, long storage life, and excellent weight reduction.

  In particular, a lithium secondary battery used as a drive power source for an electric drive device or an electric vehicle is required to have a high rate discharge performance, but the resistance of the nonaqueous electrolyte used in the lithium secondary battery is higher than that of an aqueous electrolyte. Therefore, in order to obtain the above-described high rate discharge performance, it is necessary to increase the area of the positive and negative electrodes to increase the opposing area between the positive and negative electrodes, which are constituent elements of the electrode group. Therefore, a lithium secondary battery requires an extremely thin strip-shaped electrode plate as compared with the electrode plate of an aqueous battery, and in general, an active material coating is applied to a base material made of metal foil to form an active material layer forming portion. The electrode plate provided with is used.

  A conventional positive electrode plate and negative electrode plate for a lithium secondary battery are provided with an active material layer forming part and an active material uncoated part extending in the width direction of the base material on the base material. A structure in which lead pieces are joined by welding means has been generally used. However, in recent lithium secondary batteries, there is no tab piece (lead) having a feature that can achieve higher capacity and higher output. Less) type electrode plates tend to be used.

  As shown in FIG. 8, the tabless positive electrode plate and the negative electrode plate form an active material layer forming portion 2 excluding a region along one side edge in the width direction of the base material 1 having a band shape. A region along one side edge is formed as a band-like connecting portion 3 in which the active material is not coated and the base material 1 is exposed. When the electrode plate group is formed by winding the positive electrode plate and the negative electrode plate formed in the shape of FIG. 8 in a spiral shape with a separator interposed therebetween, the strip-shaped connecting portions 3 of the positive electrode plate and the negative electrode plate are Since it protrudes from the group main body in a direction perpendicular to the winding direction, when assembling the lithium secondary battery, the strip-shaped connecting portions 3 on the positive electrode side and the negative electrode side of the electrode plate group are arranged on the positive electrode side and the negative electrode side. The current collector is electrically connected to the current collector, and the current collector is electrically connected to, for example, the positive electrode side sealing member and the negative electrode side battery case, respectively. Since this tabless type electrode plate group is electrically connected without using lead pieces, the high-rate discharge characteristics are improved as the internal resistance of the battery is reduced, and the discharge characteristics at a large current can be improved. There are advantages.

  Generally, the tabless type electrode plate is manufactured by one of two types of manufacturing methods described below. In the first manufacturing method, a base material made of a metal foil is passed through a tank in which an active material paint is stored, and an active material paint is applied to both sides of the base material while the active material paint is applied on both sides of the base material. By stripping off the material paint, a predetermined amount of active material paint is applied to the entire surface of both sides of the substrate, and after this active material paint is dried to form an active material layer forming part, the active material layer forming part is , Rolled by a press process such as a roll press, and further, a part of the active material layer forming part is removed in a predetermined pattern to form the above-described band-shaped connecting part, and finally cut along a predetermined cutting virtual line Thus, it is manufactured through a process of separating into individual electrode plates. As the removal means of the active material layer forming portion, a trimming means using a fourth harmonic YAG laser, an excimer laser, or the like, an active solvent is partially removed by using an organic solvent to break the bond between the particles of the active material. A peeling means for eluting the material layer forming portion or a peeling means for peeling off the masking material previously attached to the substrate to peel the active material layer forming portion is used.

  In the second manufacturing method, a striped active material coating is applied to one surface of a substrate by applying a slurry-like active material paint using a coating apparatus while transferring the substrate made of metal foil in the horizontal direction. After forming the material coated part and the side edge part of this or a band-shaped active material uncoated part located between them, the active material coated part is dried to be an active material layer forming part, The active material layer forming portion is pressed and rolled with a large pressure, and finally manufactured through a process of separating into individual electrode plates by cutting along a predetermined virtual cutting line.

  As described above, the tabless type electrode plate increases the active material density to increase the contact area of the active material particles and improves the binding force of the active material layer forming part to the base material in any manufacturing method. It is manufactured through a rolling process aimed at achieving the above. However, in this rolling process, due to the difference in thickness between the active material layer forming part and the active material uncoated part, the tensile stress in the longitudinal direction is generated in the base material in the active material layer forming part, resulting in a defective deformation. There is a problem that is likely to occur. Various means have been proposed for suppressing the occurrence of deformation associated with rolling.

  For example, in a hydrogen storage alloy electrode plate used as a negative electrode of an alkaline storage battery, a plurality of parallel grooves extending along the band-shaped width direction are formed in an active material layer forming portion provided by application of an active material having low fluidity. By forming gaps by the slits at a constant pitch along the longitudinal direction, the active material layer forming part is divided at regular intervals along the longitudinal direction, and means for rolling in this state is known (for example, patents) Reference 1). In this rolling step, the surplus active material is filled in the gap, so that it is possible to prevent the surplus active material from becoming excessive and causing a wavy deformation due to a large pressure generated locally.

  In another alkaline storage battery, the base material is formed into a shape capable of three-dimensional current collection by arranging strip-like projections alternately projecting in both directions, and the active material retention capability is increased and the projections are not formed. By forming the plain part of the formation along the longitudinal edge of the base material in parallel with the longitudinal direction and improving the tensile strength with respect to the longitudinal direction of the base material, deformation during rolling can be generated. It has been proposed to form a belt-like connecting portion by removing the coated active material forming portion on the plain portion, which has a lower active material retention capability than the projection formation location (see, for example, Patent Document 2). reference).

On the other hand, in the electrode plate for a lithium secondary battery, a strip-shaped active material coating portion and a strip shape along the side edge portion are formed on one surface of the strip-shaped base material through a process based on the second manufacturing method described above. The active material uncoated part is formed, and then the active material uncoated part is extended in the width direction of the base material from the side end of the active material uncoated part and the active material layer forming part. By forming a plurality of parallel slits reaching the boundary portion at a constant pitch along the longitudinal direction and rolling in this state, it is possible to prevent undulations, wrinkles, etc. from occurring in the active material uncoated portion Has been proposed (see, for example, Patent Document 3). That is, in the case where the slit is not provided, the active material layer forming portion is formed in the base material because no compressive force is applied to the active material uncoated portion thinner than the active material layer forming portion in the rolling process. A tensile stress in the longitudinal direction is generated in the part, and this tensile stress concentrates strain at the boundary between the active material layer forming part and the active material uncoated part, and undulations and wrinkles occur. Since it acts to relieve stress, it is possible to prevent the occurrence of waviness and wrinkles.
Japanese Patent Laid-Open No. 9-147853 Japanese Patent Laid-Open No. 2002-15741 JP 2000-208129 A

  By the way, in the first manufacturing method of the tabless type electrode plate, the active material paint is applied to the entire surface of the base material and then dried, that is, the whole is rolled in a substantially identical thickness state. No deformation occurs due to the pressure difference due to the above-described wall thickness difference. However, the process of scraping off the active material paint once applied to both sides of the base material to form a band-like connecting portion is required, so that productivity cannot be improved, and more processes are required. Therefore, there is a problem that the manufacturing cost is high.

  On the other hand, in the second manufacturing method, since the active material layer forming portion and the strip-shaped connecting portion are formed on the substrate with a stripe-like coating pattern extending in the longitudinal direction in parallel with each other by the coating apparatus, the strip-shaped connecting portion is formed. There is an advantage that an active material paint scraping process for forming is unnecessary, but in the rolling process, deformation due to a difference in compressive force due to a difference in thickness between the active material layer forming part and the active material uncoated part. In addition to the inconvenience that occurs, it is difficult to match each coating pattern formed by coating twice on one side and the other side of the substrate with high accuracy without misalignment. There is a problem that it is difficult to obtain a plate.

  Moreover, conventionally, in order to prevent the occurrence of deformation in the rolling process described above, an active material uncoated portion for forming a strip-shaped connecting portion on one side in the width direction of the active material layer forming portion is formed, And by rolling in a state where a dummy active material uncoated part is formed on the other side, by applying a tensile force in the longitudinal direction from the active material uncoated part to both ends of the active material layer forming part, respectively. In order to prevent the occurrence of deformation and to remove the dummy active material uncoated part by cutting after the rolling process, etc., this means that the tensile stress in the longitudinal direction is applied to the active material layer forming part. As a result, it is not possible to solve the problem that wrinkles or wavy deformation is likely to occur at the boundary between the active material layer forming part and the active material uncoated part.

  Accordingly, the applicant of the present application is a manufacturing method capable of manufacturing a tabless type electrode plate capable of high rate discharge in a lithium secondary battery with high productivity and high accuracy, and a manufacturing apparatus capable of faithfully embodying this manufacturing method. Devised. The details of this manufacturing method will be described later with reference to FIGS. 5 and 6. However, in brief, a belt-like base material made of metal foil is transferred along a vertical transfer path, and both surfaces of the base material are transferred. A plurality of slit-shaped discharge ports of discharge nozzles are arranged at a predetermined pitch in the width direction of the substrate, and a pair of discharge nozzles facing each other on both sides of the substrate are mutually matched. The active material paint is discharged from each discharge nozzle, and a plurality of active material layer forming parts are located on both sides of the base material with an active material uncoated part between them. Simultaneously formed in a stripe-shaped coating pattern, dried after the active material layer forming part is pressed and rolled, the substrate is cut at a predetermined pitch in the longitudinal direction, and the active material uncoated part is elongated. Cut along imaginary lines along the direction, individually Those undergoing a process of separating the plates.

  In this manufacturing method, on both surfaces of the substrate, a plurality of stripe-shaped active material layer forming portions can be simultaneously formed with a coating pattern parallel to each other with an active material uncoated portion interposed therebetween, Productivity is greatly improved since only one coating is required and a scraping process of the coated active material layer forming portion is not required. In addition, when simultaneously forming a plurality of active material layer forming portions on both sides of the substrate with a stripe-shaped coating pattern, the same number of discharge nozzles as the active material layer forming portions to be formed correspond to the coating pattern. Since each of the discharge nozzles is positioned in the opposite arrangement that exactly matches, the position accuracy of the coating pattern by the plurality of active material layer forming portions formed on both surfaces of the substrate is Since it is mechanically determined based on the arrangement of the discharge nozzles, it is extremely stable, and it is possible to obtain a high-quality tabless electrode plate.

  However, in order to commercialize this method for producing a lithium secondary battery electrode plate and to produce a tabless high-quality electrode plate with high productivity and high accuracy, problems still need to be solved. Yes. That is, while the plurality of stripe-shaped active material layer forming portions formed on both surfaces of the base material and the belt-like connecting portions interposed therebetween are continuously transferred and efficiently rolled, It is necessary to devise a means for effectively preventing the deformation caused by the difference in the elongation ratio of the base material due to the thickness difference between the layer forming part and the active material uncoated part. If deformation occurs in this rolling process, winding deviation may occur when winding in a spiral shape, and the electrode plate group may have a bamboo slab shape, or the roundness of the electrode plate group may vary. Therefore, a high-quality tabless type electrode plate group cannot be formed.

  In order to solve the above-described problems, the techniques of Patent Document 1 and Patent Document 2 are related to alkaline storage batteries, and are applied to deformation preventing means in the rolling process of the electrode plate for lithium secondary batteries. I can't. Further, the technique of Patent Document 3 is parallel to each other and extends in the width direction of the band-shaped substrate from the side end of the active material uncoated part and reaches the boundary between the active material uncoated part and the active material layer forming part. A plurality of slits are formed at a constant pitch along the longitudinal direction, but the active material uncoated part interposing such slits between two adjacent active material layer forming parts in the form of stripes Therefore, when separated into individual electrode plates through a cutting process, the band-shaped connecting part obtained by cutting the active material uncoated part is separated in the longitudinal direction by the remaining slits. Insufficient strength and no reliable electrical connection to the current collector. Since the electrode plate of Patent Document 3 is of a type in which a lead piece is connected to a strip-like connecting portion obtained by cutting an active material uncoated portion, even if a slit remains in the manufactured electrode plate, there is a considerable inconvenience. Does not occur.

  The present invention has been made in view of the above problems, and is an electrode plate manufacturing in which a plurality of stripe-shaped active material layer forming portions and strip-shaped connecting portions interposed therebetween are formed on both surfaces of a substrate. High quality tabless type electrode plate is produced by effectively preventing the deformation caused by the difference in the partial elongation rate of the base material while efficiently transporting and rolling the intermediate member continuously An object of the present invention is to provide a method for producing an electrode plate for a lithium secondary battery.

  In order to achieve the above object, a manufacturing method of an electrode plate for a lithium secondary battery of the invention according to claim 1 includes a plurality of stripe-shaped active material layer forming portions extending along the longitudinal direction of a belt-like substrate. While continuously transferring the electrode plate production intermediate member in which the coating pattern having the active material uncoated part located between each of these active material layer forming parts is formed on both surfaces of the base material, In each active material uncoated part, a linear through-cut extending in the width direction is arranged with respect to the longitudinal direction in such an arrangement that both end parts thereof are separated from the edge of the active material layer forming part by a predetermined distance. A through-cut forming step formed at a constant pitch, a rolling step of continuously rolling the electrode plate manufacturing intermediate member after the through cut forming step, and a length of the electrode plate manufacturing intermediate member after the rolling step Each predetermined cut along the direction and width Is characterized by undergoing a cutting step of separating by cutting in phantom individual electrode plates, the.

  According to a second aspect of the present invention, in the cutting step of the method for manufacturing an electrode plate for a lithium secondary battery according to the first aspect of the present invention, each active material uncoated portion is formed in each of the through-cuts formed therein. It cuts along two cutting imaginary lines which connect both ends.

  According to a third aspect of the present invention, in the through-cut forming step of the manufacturing method of the electrode plate for a lithium secondary battery according to the first or second aspect of the present invention, a through-hole having a long hole shape is used instead of the straight through-cut. It is to be formed.

  In the first aspect of the present invention, while continuously transferring the electrode plate manufacturing intermediate member, the through-cuts are formed at a constant pitch in the longitudinal direction in the active material uncoated portion of the electrode plate manufacturing intermediate member prior to the rolling step. The active material uncoated part, because of the penetration through which can be easily deformed by pressing in the longitudinal direction by penetrating, it is easy to extend in the longitudinal direction, so in the next rolling step, When the active material uncoated part is subjected to a tensile force in the longitudinal direction generated in the active material layer forming part of the base material, the base material is deformed into a long hole shape while the straight through-cut is deformed. Since the length of the active material layer forming portion is substantially the same as that of the active material layer forming portion in the longitudinal direction, distortion is likely to occur due to the concentration of tensile stress at the boundary between the active material layer forming portion and the active material uncoated portion. To extend the active material uncoated area Ri can be absorbed, it is hardly deformed electrode plate manufacturing intermediate member after the rolling process.

  Therefore, the present invention can simultaneously apply a coating pattern having a plurality of stripe-shaped active material layer forming portions and an active material uncoated portion interposed between them in a state in which both sides of the substrate are accurately matched. Since the problem of rolling while continuously transporting the formed electrode plate manufacturing intermediate member can be solved and a tabless type electrode plate without distortion can be obtained efficiently, the above electrode plate It becomes possible to effectively put into practical use the manufacturing process with a coating device that can efficiently manufacture intermediate members, and to manufacture high-quality tabless electrode plates with high productivity and high accuracy. .

  In the invention of claim 2, by cutting the active material uncoated part with two cutting imaginary lines connecting both ends of each through cut, all the formation points of the through cut in the active material uncoated part are excluded. Since the portion remaining along each side edge of the active material layer forming portion on both sides of the active material uncoated portion is a strip-shaped connecting portion, the strip-shaped connecting portion has a trace of a through-cut formed in the manufacturing process. It does not remain at all, and has a strong waist that allows a good electrical connection to the current collector when a spiral electrode plate group is constructed and incorporated into a battery.

  In the invention of claim 3, since the long hole-like through cut is formed in the active material uncoated part, the base material of the active material uncoated part can be further extended in the longitudinal direction, and the active material uncoated In addition to being able to more reliably suppress stress concentration at the boundary between the working part and the active material layer forming part, when rolling while applying tension in the rolling direction to the electrode plate production intermediate member Even if it exists, there exists an advantage which there is no possibility that a tear etc. may generate | occur | produce at the both ends of a penetration cut.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram schematically showing an entire manufacturing apparatus that embodies a method for manufacturing a lithium secondary battery electrode plate according to an embodiment of the present invention. As shown in FIG. A plurality of striped active material layer forming portions 2 are arranged in parallel to each other on both surfaces of a strip-like base material 1 such as an aluminum foil or a copper foil with an active material uncoated portion 4 interposed therebetween. The electrode plate manufacturing intermediate member 7 on which a coating pattern extending in the longitudinal direction is continuously rolled. That is, since this rolling step is intended for rolling the electrode plate manufacturing intermediate member 7 according to the above-mentioned proposal of the present applicant, the electrode plate manufacturing intermediate is performed prior to the description of the embodiment of the present invention. The manufacturing process of the member 7 is demonstrated referring FIG. 5 and FIG.

  5 and 6 are a front view and a plan view of a coating apparatus for manufacturing the above-described electrode plate manufacturing intermediate member 7. The base material 1 is transported upward in the vertical plane, and coating dies 8 having the same structure are installed on both sides of the transport path of the base material 1. As shown in FIG. 6, the coating die 8 has a multi-row nozzle structure in which four discharge nozzles 9 are arranged at predetermined intervals along the width direction of the substrate 1 being conveyed in the vertical direction, that is, the horizontal direction. Have. In addition, the coating die 8 presses and compresses the paste-like active material paint 12 supplied into the chamber chamber 11 through the paint supply pipe 10 by the operation of a pump from a paint tank (not shown), After equalizing the pressure applied to the active material paint 12 throughout the chamber chamber 11, a predetermined amount of the active material paint 12 is discharged from the slit-like discharge ports (not shown) of the four discharge nozzles 9. Then, the base material 1 is coated.

  Since the coating die 8 equalizes the pressure applied to the active material paint 12 throughout the chamber chamber 11 as described above, the same amount can be obtained at substantially the same discharge pressure from any of the four discharge nozzles 9. The active material paint 12 is discharged, and the active material paint 12 is applied to the substrate 1 with substantially the same coating pressure. Therefore, all of the active material layer forming portions 2 in FIG. 2 provided by application of the active material paint 12 discharged from the four discharge nozzles 9 are formed with substantially the same coating thickness.

  Further, the two coating dies 8 are set and installed in a state in which each of the four discharge nozzles 9 of each of the coating dies 8 is positioned in an opposing arrangement that matches each other with high accuracy. Therefore, the active material layer forming portions 2 formed in stripes by four on both surfaces of the base material 1 by the active material paint 12 discharged from each discharge nozzle 9 are matched with each other with high accuracy on both surfaces of the base material 1. Since the position accuracy of the coating pattern on both surfaces of the substrate 1 can be mechanically stabilized by matching the opposing positions of the discharge nozzles 9 of the two coating dies 8, it is long. Can continue to be maintained for a period of time.

  Prior to the start of coating, the two coating dies 8 are moved toward and away from the substrate 1 via the die slider 6 so that the discharge port of the discharge nozzle 9 is relative to the substrate 1. They are positioned so as to face each other with a predetermined gap. The thickness of the active material layer forming portion 2 to be formed on the substrate 1 is set by the gap between the discharge port of the discharge nozzle 9 and the substrate 1.

  On the other hand, on one side and the other side of the substrate 1 to be transferred, five pieces are respectively provided at two locations adjacent to the coating position where the discharge nozzle 9 of the coating die 8 is disposed on the upper side and the lower side. The upper presser roll 13 and the lower presser roll 14 are pressed. As shown in FIG. 6, the portions of the substrate 1 to which the rolls 13 and 14 are pressed are located between the portions where the active material paint 12 is applied by the discharge nozzles 9, that is, the active material paint 12. The unrolled active material uncoated portion 4, and the two rolls 13 and 14 facing each other on both sides of the base material 1 are positioned at relative positions accurately matching each other, so that the base material 1 is placed on both sides. By pinching from the side, the occurrence of vibration of the base material 1 due to transfer or coating of the active material paint 12 is suppressed. That is, for each portion where the active material coating 12 is to be applied on the substrate 1, a total of four portions, which are both sides in the width direction adjacent above and below this portion, are sandwiched by a pair of rolls 13 and 14 from both sides. By providing the shake preventing means to be applied, simultaneous application of the active material coating 12 to each of the four positions on both sides of the base material 1 can be performed stably.

  As described above, a plurality of active material layer forming portions 2 (four cases are exemplified in this embodiment) on both surfaces of the base material 1 and a plurality (three cases in this embodiment) interposed between them. The electrode plate manufacturing intermediate member 7 in which the active material uncoated portion 4 is formed is wound on a reel or the like after the active material layer forming portion 2 is dried through the drying device. In this coating apparatus, as clearly shown in FIG. 2 (a), four active material layer forming portions 2 and three active material uncoated portions 4 are formed on both sides of the base material 1 in a stripe shape parallel to each other. Since it can be formed simultaneously with the coating pattern, compared with the conventional manufacturing method, one coating and only one coating are necessary for the one surface and the other surface of the base material 1 while the conventional coating method requires two coatings. In this manufacturing method, the scraping-off process of the coated active material paint 12 is not required, so that the productivity in the process of forming the electrode plate manufacturing intermediate member 7 is greatly improved by about 2 to 3 times.

  Returning to FIG. 1, the uncoiler 17 around which the electrode plate production intermediate member 7 formed as described above is wound is installed on the supply side, and the electrode plate production intermediate member 7 wound around the uncoiler 17 is The accumulator 18 having the brake unit 18 a is sequentially fed out and fed to the rotary cutter 19. By this rotary cutter 19, through-cuts to be described later extending in the width direction of the substrate 1 are each active material uncoated portion 4. On the other hand, the active material layer forming part 2 is compressed to a predetermined thickness by passing between the pair of rolling rolls 21 and 22 in the rolling press part 20, and finally the recoiler 23. Rolled up.

  Next, the details of the rotary cutter 19 will be described with reference to FIG. As shown in FIGS. 2A and 2C, the rotary cutter 19 is provided in an arrangement in which the electrode plate manufacturing intermediate member 7 transported in the horizontal direction by the two guide rolls 30 and 31 is sandwiched from below and above. A reference roll 24 and a cutter unit roll 27 are provided. The reference roll 24 has a large-diameter ring portion 28 for supporting the two active material uncoated portions 4 provided on the electrode plate manufacturing intermediate member 7 from below. That is, the large-diameter ring portion 28 is formed with a diameter larger than the roll body of the reference roll 24 by an amount corresponding to the coating thickness of the active material layer forming portion 2 of the electrode plate manufacturing intermediate member 7. The base material 1 of the active material uncoated part 4 is supported from below by entering between the two active material layer forming parts 2 adjacent to the roll body that supports the layer forming part 2 from below.

  On the other hand, as shown in FIG. 5C, the cutter unit roll 27 has eight cutter units 26 attached so that the cutter blades 29 protrude outward, and each cutter blade 29 is radially outward. It arrange | positions at equal intervals in the peripheral part by the arrangement | positioning which protrudes toward the direction. The cutter blade 29 has a shape in which a sharp blade edge extends linearly as shown in FIG. Therefore, the cutting edge of each cutter blade 29 is sequentially cut into the base material 1 of each active material uncoated portion 4 supported from below by the large-diameter ring portion 28 of the reference roll 24 as the cutter unit roll 27 rotates. As a result, as shown in FIGS. 4A and 4B, linear through cuts 32 extending in the width direction of the substrate 1 are formed at a constant pitch in the longitudinal direction.

  As shown in FIG. 6D, the cutter unit 26 has a configuration in which the attachment position of the cutter blade 29 is finely adjusted and then detachably fixed with a plurality of fixing screws 34. FIG. As shown in FIG. 4, the cutter blade 29 is placed at a position separated by a predetermined distance L from the side edges of the two active material layer forming portions 2 adjacent on both sides of the active material uncoated portion 4, and both ends of the linear blade edge are It is fixed by fine adjustment in advance to the matching positioning state. The predetermined distance L corresponds to the width of the strip-like connecting portion 3 of the electrode plate to be formed described with reference to FIG. Further, as shown in FIG. 4D, the cutter unit 26 is high in a relative position where the blade edge accurately contacts the outer peripheral surface of the large-diameter ring portion 28 when the cutter blade 29 is opposed to the reference roll 24. Positioned and fixed with accuracy. Thereby, the linear penetration cut | interruption 32 formed in the base material 1 of the active material uncoated part 4 will penetrate the base material 1 reliably.

  FIG. 3 shows a perspective view of the rolling press section 20, and the electrode plate manufacturing intermediate member 7 in which the linear through cuts 32 are formed in the base material 1 of each active material uncoated section 4 by the rotary cutter 19 as described above. Passes between the pair of rolling rolls 21, 22, whereby the active material layer forming portion 2 is pressed from above and below and compressed to a predetermined thickness set by the gap between the rolling rolls 21, 22. At this time, the formation part of the active material layer formation part 2 in the base material 1 is extended in the longitudinal direction by the tensile force by the pressure by both the rolling rolls 21 and 22 being directly applied through the active material layer formation part 2. However, due to the difference in wall thickness between the active material layer forming part 2 and the active material uncoated part 4, the pressure applied by the rolling rolls 21 and 22 is directly applied to the part where the active material uncoated part 4 is formed in the substrate 1. Hardly participates.

  However, the active material uncoated portion 4 has a straight through-cut 32 that can be easily deformed by pressurization in the longitudinal direction due to the penetration, and is easily extended in the longitudinal direction. Therefore, the active material uncoated portion 4 has a linear shape as shown in FIG. 3 when a tensile force in the longitudinal direction generated in the formation portion of the active material layer forming portion 2 in the base material 1 is applied. The electrode plate manufacturing intermediate member 7 is subjected to a rolling process because it is extended in the longitudinal direction by substantially the same dimension as the formation portion of the active material layer forming portion 2 in the base material 1 while deforming the through cut 32 into a long hole shape. Later deformation hardly occurs. In other words, in the rolling step, the formation of the active material layer forming portion 2 is performed by forming a straight through cut 32 in advance of the forming portion of the active material uncoated portion 4 in the base material 1 prior to the rolling step. Since it is set in a state where it can extend substantially the same dimension as the portion, distortion is likely to occur due to concentration of tensile stress at the boundary portion between the active material layer forming portion 2 and the active material uncoated portion 4. Is absorbed by the extension of the portion where the active material uncoated portion 4 is formed in the substrate 1. On the other hand, in the conventional rolling process, since the active material uncoated part hardly extends in the longitudinal direction, the active material layer forming part is caused by the longitudinal tensile stress generated in the active material layer forming part in the base material. As a result of the concentration of strain at the boundary between the active material and the uncoated part of the active material, wrinkles and wavy deformation occurred at the boundary.

  FIG. 4 is a front view showing the electrode plate manufacturing intermediate member 7 after the rolling process, and the entire plate is almost uniformly extended with respect to the shape before rolling and is elongated in the longitudinal direction. There is no deformation. The electrode plate manufacturing intermediate member 7 is divided into electrode plates shown in FIG. 8 by being cut along a virtual cutting line indicated by a two-dot chain line. The two active material uncoated portions 4 are cut at two cutting imaginary lines connecting both ends of each linear through cut 32, so that all the portions where the linear through cut 32 is formed are excluded. Thus, the portions remaining along the side edges of the active material layer forming portions 2 on both sides become the band-shaped connecting portions 3 in FIG. Therefore, the strip-shaped connecting portion 3 has no trace of the linear through-cut 32 formed in the manufacturing process, and is excellent for the current collector when constituting a spiral electrode plate group and incorporating it into a battery. It has a strong waist that can be electrically connected to. That is, the linear through-cut 32 formed in the manufacturing process is extended in the width direction of the base material from the side end of the active material uncoated portion disclosed in Patent Document 3 described above, and is not coated with the active material. It can be said that the slit reaching the boundary between the working part and the active material layer forming part is completely different in its purpose and function.

  The manufacturing apparatus of this embodiment includes an electrode plate manufacturing intermediate member 7 manufactured by the coating apparatus shown in FIGS. 5 and 6, that is, a plurality of stripe-shaped active material layer forming portions 2 and an active material interposed therebetween. While the electrode plate production intermediate member 7 formed simultaneously with the coating pattern having the uncoated portion 4 precisely matched to both surfaces of the substrate 1 is continuously transferred, the extension of the substrate 1 It is possible to perform rolling while significantly suppressing the occurrence of distortion due to the difference in rate. As described above, this manufacturing apparatus eliminates the problems in rolling the electrode plate manufacturing intermediate member 7 obtained by the coating apparatus shown in FIGS. 5 and 6 and efficiently rolls the tabless system without distortion. Therefore, it is possible to effectively put the manufacturing process using the coating apparatus into practical use, and it is possible to manufacture a high-quality tabless electrode plate with high productivity and high accuracy. .

  FIG. 7A is a perspective view showing a cutter blade 33 used in a manufacturing apparatus that embodies a manufacturing method according to another embodiment of the present invention, and FIG. It is a front view which shows the electrode plate manufacture intermediate member 7 in which the through-cut 37 of this was formed. The cutter blade 33 has a cutting edge capable of forming a long hole-shaped through cut 37, and the long hole-shaped through cut 37 is formed on the active material uncoated portion 4 on both sides of the active material layer forming portion 2. It is formed at a position separated by a certain distance L with respect to the edge. In the case where such a long hole-shaped through cut 37 is formed, the base material 1 of the active material uncoated portion 4 can be further extended in the longitudinal direction. In addition to being able to more reliably suppress the stress concentration at the boundary with the material layer forming part 2, the rolling is performed while applying tension in the rolling direction to the electrode plate manufacturing intermediate member 7. However, there is an advantage that tearing or the like may not occur at both ends of the long hole-like through cut 37.

  According to the method for manufacturing an electrode plate for a lithium secondary battery according to the present invention, while continuously transferring the electrode plate manufacturing intermediate member, prior to the rolling step, the active material uncoated portion in the electrode plate manufacturing intermediate member Since the through-cuts are formed at a constant pitch in the longitudinal direction and the active material uncoated part is made easy to extend in the longitudinal direction, rolling is performed, so the active material uncoated part has a long through-cut line. By deforming into a hole shape, it is extended in the longitudinal direction by substantially the same length as the base material of the active material layer forming portion, and deformation hardly occurs in the electrode plate production intermediate member after the rolling process. Therefore, in the manufacturing method of the present invention, a coating pattern having a plurality of stripe-shaped active material layer forming portions and an active material uncoated portion interposed therebetween is accurately matched to both surfaces of the substrate. Since the problem of rolling while continuously transporting the electrode plate production intermediate member formed at the same time in the state can be eliminated, and a tabless method electrode plate without distortion can be obtained efficiently, It is possible to effectively put into practical use a manufacturing process by a coating apparatus that can efficiently manufacture the above-mentioned electrode plate manufacturing intermediate member, and to manufacture a high-quality tabless electrode plate with high productivity and high accuracy. It becomes possible.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram which showed simply the whole manufacturing apparatus which actualized the manufacturing method of the electrode plate for lithium secondary batteries which concerns on one embodiment of this invention. The rotary cutter in a manufacturing apparatus same as the above is shown, (a) is a perspective view, (b) is an explanatory view of a straight through-cut formed in an active material uncoated part, (c) is a longitudinal sectional view, (d) Is an enlarged view showing a part of (c) in detail, (e) is a partial perspective view of the cutter blade The perspective view which shows the rolling press part in a manufacturing apparatus same as the above. Front view showing the electrode plate production intermediate member rolled in the same rolling press section The front view which shows the coating apparatus provided as a pre-process of one embodiment same as the above Plan view showing the same coating equipment (A) is a partial perspective view of the cutter blade used for the manufacturing apparatus which actualized the manufacturing method of the electrode plate for lithium secondary batteries which concerns on other embodiment of this invention, (b) is other implementation of this invention. The front view which shows the electrode plate manufacturing intermediate member which formed the long hole-shaped through-cut with the cutter blade used for the manufacturing apparatus which actualized the manufacturing method of the electrode plate for lithium secondary batteries which concerns on the form of this (A) is a front view of an electrode plate manufactured by the same manufacturing apparatus, (b) is a side view of an electrode plate manufactured by the same manufacturing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material 2 Active material layer formation part 4 Active material uncoated part 7 Electrode board production intermediate member 32 Straight through-cut 37 Long hole-like through-cut L Predetermined distance

Claims (3)

The coating pattern having a plurality of stripe-shaped active material layer forming portions extending along the longitudinal direction of the band-shaped base material and the active material uncoated portions positioned between the respective active material layer forming portions is While continuously transferring the electrode plate manufacturing intermediate member formed on both surfaces of the base material, linear through-cuts extending in the width direction are formed in the active material uncoated portions, and both end portions thereof are the active portions. A through-cut forming step of forming at a constant pitch with respect to the longitudinal direction in an arrangement located at a predetermined distance from the edge of the material layer forming portion;
A rolling step of rolling while continuously transferring the electrode plate production intermediate member after the through-cut formation step;
A cutting step of cutting the electrode plate production intermediate member after the rolling step into individual electrode plates by cutting each predetermined cutting virtual line along the longitudinal direction and the width direction;
The manufacturing method of the electrode plate for lithium secondary batteries characterized by passing through.   2. The lithium secondary battery according to claim 1, wherein in the cutting step, each active material uncoated portion is cut along two cutting imaginary lines respectively connecting both end portions of each through cut formed in the active material uncoated portion. A method for producing an electrode plate for a secondary battery.   3. The method for producing an electrode plate for a lithium secondary battery according to claim 1, wherein, in the through-cut forming step, an elongated through-cut is formed instead of the straight through-cut.

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