Secondary battery manufacturing apparatus and method for manufacturing secondary batteries using the same

Abstract

According to an exemplary embodiment of the present invention, there is provided a secondary battery manufacturing apparatus including: a dancer roll configured to change a travel path of an electrode sheet, a cutter configured to cut the electrode sheet adjacent to the dancer roll into a first electrode sheet and a second electrode sheet, and a waste winder configured to wind up a defective portion of the first electrode sheet.

Description

[Technical Field]

[0001] The present invention relates to a secondary battery manufacturing apparatus and a method for manufacturing a secondary battery using the same. This application claims the benefit of Korean Application No. 10-2023-0103309, filed on August 8, 2023, which is incorporated herein by reference in its entirety. [Background technology]

[0002] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries are widely used as energy sources for various wireless devices such as handsets, laptops, and wireless vacuum cleaners. In recent years, improvements in energy density and economies of scale have dramatically reduced the manufacturing cost per unit capacity of secondary batteries, and as the driving range of battery electric vehicles (BEVs) has increased to the same level as fuel-powered vehicles, the main use of secondary batteries has shifted from mobile devices to mobility.

[0003] Secondary batteries are manufactured through an electrode process, an assembly process, and an activation process. Among these processes, the electrode process is the most crucial process for determining the yield and performance of the battery cell. The electrode process can include a coating process, a roll pressing process, and a slitting process. In the coating process, active materials and insulating materials can be applied to the surface of a current collector. In the roll pressing process, the electrode can be pressed by a pressure roll. The roll pressing process can determine the density, performance, and surface quality of the electrode. In the slitting process, the electrode can be cut into multiple electrodes to correspond to the design of the battery cell. Summary of the Invention [Problem to be solved by the invention]

[0004] The problem to be solved by the technical idea of ​​the present invention is to provide a secondary battery manufacturing apparatus with improved productivity and a method for manufacturing a secondary battery using the same. [Means for solving the problem]

[0005] According to an exemplary embodiment of the present invention for solving the above-mentioned problems, there is provided a secondary battery manufacturing apparatus including: a dancer roll configured to change the running path of an electrode sheet; a cutter configured to cut the electrode sheet adjacent to the dancer roll into a first electrode sheet and a second electrode sheet; and a waste winder configured to wind up a defective portion of the first electrode sheet.

[0006] The dancer roll is configured to move in a direction perpendicular to the running direction of the electrode sheet.

[0007] The dancer roll is configured to move in a direction perpendicular to the lateral direction of the electrode sheet.

[0008] The dancer roll changes the path of the electrode sheet while maintaining the tension of the electrode sheet.

[0009] The secondary battery manufacturing apparatus further includes a nip bar configured to fix the electrode sheet.

[0010] The dancer roll is disposed below the electrode sheet, and the dancer roll lengthens the travel path of the electrode sheet.

[0011] The dancer roll is disposed above the electrode sheet, and the dancer roll lengthens the travel path of the electrode sheet.

[0012] The secondary battery manufacturing apparatus further includes a tape attacher configured to connect the first electrode sheet and the second electrode sheet.

[0013] According to an exemplary embodiment, there is provided a method for manufacturing a secondary battery, the method including: a step of changing a travel path of an electrode sheet by moving a dancer roll, wherein the electrode sheet is unwound from a first electrode roll by an unwinder and wound onto a second electrode roll by a rewinder; a step of cutting the electrode sheet so that the electrode sheet is separated into a first electrode sheet and a second electrode sheet, wherein the first electrode sheet is connected to the first electrode roll and the second electrode sheet is connected to the second electrode roll; and a step of winding up a defective portion of the first electrode sheet so that the defective portion of the first electrode sheet is discarded.

[0014] The movement of the dancer roll lengthens the travel path of the electrode sheet.

[0015] While the dancer roll is moving, the electrode sheet is unwound from the electrode roll.

[0016] The method further includes the step of fixing the electrode sheet with a nip bar before cutting the electrode sheet.

[0017] Before the electrode sheet is fixed by the nip bar, the unwinding onto the electrode roll is interrupted.

[0018] The method further includes joining the first electrode sheet and the second electrode sheet to provide a rejoined electrode sheet.

[0019] The method further includes restoring the travel path of the reconnected electrode sheets.

[0020] The dancer roll is moved from a standby position to a working position so that the travel path of the electrode sheet is changed, and the dancer roll is moved from the working position to the standby position so that the travel path of the reconnected electrode sheet is changed. [Effects of the Invention]

[0021] According to an exemplary embodiment of the present invention, defective portions of an electrode sheet can be removed by automated equipment without the intervention of an operator, thereby ensuring the safety of operators and improving the reliability and productivity of secondary battery manufacturing.

[0022] The effects that can be obtained from the exemplary embodiments of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood from the following description by a person having ordinary skill in the art to which the exemplary embodiments of the present disclosure belong. In other words, unintended effects accompanying the implementation of the exemplary embodiments of the present disclosure can also be derived from the exemplary embodiments of the present disclosure by a person having ordinary skill in the art. [Brief explanation of the drawings]

[0023] [Figure 1] 1 illustrates a secondary battery manufacturing apparatus according to an exemplary embodiment. [Figure 2] 1 is a flowchart illustrating a method for manufacturing a secondary battery according to an exemplary embodiment. [Figure 3] 1 is a diagram illustrating a method for manufacturing a secondary battery according to an exemplary embodiment; [Figure 4] 1 is a diagram illustrating a method for manufacturing a secondary battery according to an exemplary embodiment; [Figure 5] 1 is a diagram illustrating a method for manufacturing a secondary battery according to an exemplary embodiment; [Figure 6] 1 is a diagram illustrating a method for manufacturing a secondary battery according to an exemplary embodiment; [Figure 7] 1 is a diagram illustrating a method for manufacturing a secondary battery according to an exemplary embodiment; [Figure 8] 1 illustrates a secondary battery manufacturing apparatus according to an exemplary embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Before that, the terms and words used in the specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as meanings and concepts that are consistent with the technical idea of ​​the present invention, based on the principle that an inventor can appropriately define the concepts of terms to best describe his own invention.

[0025] Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and there may be various equivalents and modifications that can replace them at the time of this application.

[0026] Furthermore, in the description of the present invention, if it is determined that a detailed description of related publicly known structures or functions may obscure the gist of the present invention, the detailed description will be omitted.

[0027] Since the embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, the shapes and sizes of components in the drawings may be exaggerated, omitted, or shown in a schematic manner for clearer explanation. Therefore, the sizes and proportions of each component do not completely reflect the actual sizes and proportions.

[0028] (First embodiment: secondary battery manufacturing apparatus) FIG. 1 shows a secondary battery manufacturing apparatus 100 according to an exemplary embodiment.

[0029] Referring to FIG. 1 , the secondary battery manufacturing apparatus 100 may include an unwinder 111, a rewinder 113, a processing tool 115, a dancer roll 120, a guide roll 131, a nip bar 133, a cutter 140, a waste winder 150, a tape applicator 160, and a controller 170.

[0030] The secondary battery manufacturing apparatus 100 can be configured to perform processes for manufacturing secondary batteries. In the secondary battery manufacturing apparatus 100, an electrode process is performed on an electrode sheet ES unwound from a first electrode roll ER1 by an unwinder 111, and the electrode sheet ES can be rewound onto a second electrode roll ER2 by a rewinder 113. This allows the electrode process to be a roll-to-roll process.

[0031] Hereinafter, the direction of movement of the electrode sheet ES (i.e., the longitudinal direction) will be referred to as the machine direction MD, and the direction parallel to the electrode sheet ES and perpendicular to the machine direction MD will be referred to as the transverse direction (TD). The transverse direction TD may also be the width direction of the electrode sheet ES. The directions perpendicular to both the machine direction MD and the transverse direction TD will be referred to as the vertical direction VD.

[0032] The electrode sheet can be processed by the processing tool 115. In one example, the processing tool 115 can include a die coater, and an electrode slurry can be coated onto the electrode sheet. In another example, the processing tool 115 can include a pressure roll, and a roll pressing process can be performed on the electrode sheet coated with the electrode slurry. In another example, the processing tool 115 can include a splicing die and a scrap port, and a portion of the electrode sheet can be scrapped. In another example, the processing tool 115 can include a slitter, and the electrode sheet can be separated into multiple electrode sheets having smaller widths.

[0033] The coating process is a process of applying a coating material, such as an electrode slurry, onto an electrode sheet. The electrode slurry may include an electrode active material, a conductive material, a binder, and a solvent. The electrode active material, the conductive material, and the binder may be dissolved in a solvent to provide the electrode slurry. In the coating process, an insulating layer may be further coated on the boundary of the land lane of the electrode sheet. Here, the land lane is the portion of the electrode sheet coated with the electrode slurry.

[0034] The roll pressing process is a process in which an electrode sheet coated with electrode slurry is passed between opposing pressure rolls, which can flatten the electrode surface and increase the bonding strength between the active material and the current collector.

[0035] To increase the production volume (e.g., GWh) per line of a secondary battery production facility, a wide electrode sheet ES is subjected to a coating process and a roll pressing process. In a subsequent slitting process, the wide electrode sheet ES can be cut according to the specifications of the battery cell. The slitting process is an optional process and may be omitted depending on the specifications of the battery cell to be finally manufactured.

[0036] The dancer roll 120 can be configured to change the travel path of the electrode sheet ES. When the electrode sheet ES includes a defective portion, the dancer roll 120 can change the path of the electrode sheet ES to easily remove the defective portion. The dancer roll 120 can be configured to move in the vertical direction VD. In one example, the dancer roll 120 disposed below the electrode sheet ES can push the electrode sheet ES upward. The dancer roll 120 can be moved in the travel direction MD and the lateral direction TD to accommodate equipment maintenance and changes to the travel path of the electrode sheet ES.

[0037] Here, up and down are relative concepts, and unless otherwise defined, the direction away from the bottom surface of the site where the secondary battery manufacturing apparatus 100 is installed is defined as the up direction, and the direction approaching the bottom surface of the site where the secondary battery manufacturing apparatus 100 is installed is defined as the down direction. Also, when a first element is below a second element, it means that the first element is closer to the bottom surface of the site where the secondary battery manufacturing apparatus 100 is installed than the second element.

[0038] As the dancer roll 120 moves, the electrode sheet ES can be moved while being pushed by the dancer roll 120 and maintaining tension. In other words, while the dancer roll 120 is moving, the unwinding of the electrode sheet by the unwinder 111 and the winding of the electrode sheet by the rewinder 113 can continue.

[0039] The guide rolls 131 can define a moving path of the electrode sheet ES. Although not shown in detail, the secondary battery manufacturing apparatus 100 can include additional guide rolls for defining the moving path of the electrode sheet ES. By arranging the additional guide rolls, the traveling path of the electrode sheet ES can be designed and the tension of the electrode sheet ES can be maintained while the electrode sheet ES is being processed.

[0040] The nip bar 133 may be configured to pressurize the electrode sheet ES to fix the electrode sheet ES. The nip bar 133 may be configured to move three-dimensionally based on the electrode sheet ES, including in the vertical direction VD. The nip bar 133 may pressurize the electrode sheet ES after the travel of the electrode sheet ES is interrupted.

[0041] The cutter 140 can be configured to cut the electrode sheet ES. The cutter 140 can cut the electrode sheet ES into a first electrode sheet ES1 (see FIG. 4) and a second electrode sheet ES2 (see FIG. 4). The cutter 140 can cut the portion of the electrode sheet ES between the nip bar 133 and the dancer roll 120, for example.

[0042] The waste winder 150 can be configured to wind up the defective portion of the first electrode sheet ES1 (see FIG. 4) for disposal of the defective portion of the first electrode sheet ES1 (see FIG. 4).

[0043] The tape applicator 160 can be configured to apply a seam (e.g., tape) to the first electrode sheet ES1 (see FIG. 4) and the second electrode sheet ES2 (see FIG. 4) to connect the first electrode sheet ES1 (see FIG. 4) and the second electrode sheet ES2 (see FIG. 4).

[0044] The controller 170 can be configured to control the operation of the unwinder 111, rewinder 113, processing tools 115, dancer roll 120, nip bar 133, cutter 140, waste winder 150, and tape applicator 160. The controller 170 can be a PLC (Programmable Logic Controller). A PLC is a specialized form of microprocessor-based controller that uses programmable memory to store instructions and implements functions such as logic, sequencing, timing, counting, and arithmetic to control machines and processes. PLCs are easy to operate and program.

[0045] The secondary battery manufacturing apparatus 100 may include a first rotary encoder configured to sense the input amount of the electrode sheet based on the rotation amount of the unwinder 111, and a second rotary encoder configured to sense the consumed amount of the electrode sheet based on the rotation amount of the rewinder 113. The first rotary encoder may generate an input amount signal and may be configured to transmit the input amount signal to the controller 170. The second rotary encoder may generate a consumed amount signal and may be configured to transmit the consumed amount signal to the controller 170.

[0046] The controller 170 may be configured to receive the input amount signal and the consumed amount signal from the rotary encoder. The controller 170 may have defect data collected from the tester. The defect data may include a value indicating the defect and a coordinate value corresponding to the defect. The controller 170 may control elements of the secondary battery manufacturing apparatus 100 based on the movement distance of the electrode sheet ES. For example, the controller 170 may be configured to generate a signal to move the dancer roll 120 when a defective portion of the electrode sheet ES approaches the dancer roll 120.

[0047] The secondary battery manufacturing apparatus 100 may further include a measuring instrument and an inspection instrument. Defect data indicating a defect in the electrode sheet ES may be collected by the measuring instrument and the inspection instrument. The defect in the electrode sheet may be determined by the inspection instrument and the measuring instrument included in the current process (i.e., the secondary battery manufacturing apparatus 100), or may be a defect known in a previous process.

[0048] Measuring instruments and inspectors may include a sensing unit and a processing unit. The sensing unit may be configured to generate a measurement signal or an inspection signal. It may include a time delay and integration (TDI) camera, a complementary metal oxide semiconductor (CMOS) image sensor, a time of flight (TOF) sensor, etc. The sensing unit may also include an emitter and a receiver configured to perform measurements using non-destructive signals such as ultrasound, microwaves, terahertz waves, and infrared rays. The sensing unit may also include analog and / or digital sensors such as color sensors, biosensors, chemical sensors, composition sensors, current and / or power meters, air quality sensors, gas sensors, Hall effect sensors, brightness level sensors, and light sensors. The sensing unit may also include pressure sensors, temperature sensors, ultrasonic sensors, proximity sensors, door status sensors, motion tracking sensors, humidity sensors, visible light sensors, infrared sensors, and cameras. In some cases, the inspector may include only the sensing unit.

[0049] The measuring device can be configured to collect measurement data, and the inspector can be configured to collect inspection data. The raw measurement data can include a profile of a physical quantity based on scanning. For example, the measurement data can include thickness data and data on the loading amount of a coating material on the electrode sheet. As a non-limiting example, the measuring device can include a web gauge and a thickness meter from Thermofisher Scientific. A determination value indicating a defect in the electrode sheet ES can be determined by performing a calculation (e.g., a comparison calculation) on the measurement data with a range indicating a normal value.

[0050] For example, if a measured amount of coating material on the electrode sheet ES (e.g., the loading amount on the electrode sheet ES or the thickness of the electrode sheet ES) is within a set range including an upper limit and a lower limit, the corresponding portion of the electrode sheet ES can be determined to be good. If the measured amount of coating material on the electrode sheet ES (e.g., the loading amount on the electrode sheet ES or the thickness of the electrode sheet ES) is less than the lower limit or greater than the upper limit, the corresponding portion of the electrode sheet ES can be determined to be bad.

[0051] As another example, a measurement value (or representative value) within a first range can be determined to be normal, a measurement value (or representative value) within a second range that is even larger than the first range can be determined to be excessive, and a measurement value (or representative value) within a third range that is even smaller than the first range can be determined to be deficient.

[0052] The inspection data may include judgments and process events related to the quality of portions of the electrode sheet. For example, the inspection data may include data on the appearance of the electrode sheet collected by an image-based inspection device such as a vision machine, dimensional data such as the width of the insulating material provided on the coating material and the overlap width between the coating material and the insulating material, mismatch data between the land lane on the upper surface of the electrode sheet and the land lane on the lower surface of the electrode sheet, data on breaks and seams in the electrode sheet, data on portions of the electrode sheet that were sampled, data on portions of the electrode sheet scheduled for scrapping, data on the scrapped portions of the electrode sheet, data on the quality of the coating material and insulating material on the electrode sheet, data on reference points indicating the position of the electrode sheet, and defect data such as pinhole defects, crater defects, line defects, crack defects, side ring defects, Ireland defects, fold defects, wrinkle defects, poke defects, and dent defects. The reference points may be formed at predetermined intervals on the electrode sheet, and the positions of other elements on the electrode sheet may be known based on the reference points. The inspector may be any one of a color sensor, a seam sensor, a fiducial sensor, and a vision machine.

[0053] (Second embodiment: manufacturing method) FIG. 2 is a flowchart illustrating a method for manufacturing a secondary battery according to an exemplary embodiment.

[0054] 3 to 7 are diagrams illustrating a method for manufacturing a secondary battery according to an exemplary embodiment.

[0055] 2 and 3, at P110, the travel path of the electrode sheet ES can be changed. The dancer roll 120 moves from the standby position SBP (see FIG. 1) to the working position WP, thereby changing the travel path of the electrode sheet ES. Changing the travel path of the electrode sheet ES can lengthen the travel path of the electrode sheet ES, which can facilitate cutting the electrode sheet with the knife and winding up the cut portion of the electrode sheet.

[0056] In this example, the dancer roll 120 can rise to change the travel path of the electrode sheet ES, and the electrode sheet ES can include a portion that has been pushed up by the dancer roll 120. At P110, the dancer roll 120 can be moved while the electrode sheet ES continues to travel. That is, while the dancer roll 120 is moving, the electrode sheet ES can be unwound from the first electrode roll ER1 by the unwinder 111 and wound onto the second electrode roll ER2 by the rewinder 113.

[0057] Subsequently, at P120, the electrode sheet ES can be fixed. To fix the electrode sheet ES, the nip bar 133 can be moved to a position where the electrode sheet ES can be fixed. Since the nip bar 133 fixes the electrode sheet ES, the running of the electrode sheet ES can be interrupted before the nip bar 133 applies pressure to the electrode sheet ES. In other words, before the electrode sheet ES is fixed by the nip bar 133, the unwinding of the electrode sheet ES by the unwinder 111 and the winding of the electrode sheet ES by the rewinder 113 can be interrupted.

[0058] 2 and 4, in P130, the electrode sheet ES can be cut into a first electrode sheet ES1 and a second electrode sheet ES2. The first electrode sheet ES1 can be connected to a first electrode roll ER1. The second electrode sheet ES2 can be connected to a second electrode roll ER2. The first electrode sheet ES1 and the second electrode sheet ES2 can be separated in the running direction MD (i.e., the longitudinal direction). The first electrode sheet ES1 can include a defective portion.

[0059] 2 and 5, at P140, the defective portion of the first electrode sheet ES1 can be discarded. To discard the defective portion of the first electrode sheet ES1, a waste winder 150 can approach the dancer roll 120 or the first electrode sheet ES1. To discard the defective portion of the first electrode sheet ES1, the defective portion of the first electrode sheet ES1 can be wound by the waste winder 150. Based on the known position of the defective portion of the first electrode sheet ES1, the waste winder 150 can wind the first electrode sheet ES1 a sufficient number of rotations to wind up the defective portion of the first electrode sheet ES1. To remove the defective portion of the first electrode sheet ES1, the waste winder 150 can be controlled by the controller 170 (see FIG. 1).

[0060] 2 and 6, in P150, the first electrode sheet ES1 and the second electrode sheet ES2 can be connected to provide a reconnected electrode sheet RES. The first electrode sheet ES1 and the second electrode sheet ES2 can be connected by a tape applicator 160. This allows the connection of the first electrode sheet ES1 and the second electrode sheet ES2 to also be automated, eliminating operator intervention from discarding defective portions of the electrode sheet ES (see FIG. 1) to reconnecting them.

[0061] 2, 6, and 7, the travel path of the reconnected electrode sheet RES can be restored at P160. To restore the travel path of the reconnected electrode sheet RES, the dancer roll 120 can be moved from the working position WP to the standby position SBP.

[0062] FIG. 8 shows a secondary battery manufacturing apparatus 101 according to an exemplary embodiment.

[0063] Referring to FIG. 8 , the secondary battery manufacturing apparatus 101 may include an unwinder 111, a rewinder 113, a processing tool 115, a dancer roll 120, a guide roll 131, a nip bar 133, a cutter 140, a waste winder 150, a tape applicator 160, and a controller 170.

[0064] 8, the secondary battery manufacturing apparatus 101 is substantially the same as the secondary battery manufacturing apparatus 100, except that a dancer roll 120 is disposed above the electrode sheet ES, and a guide roll 131 and a nip bar 133 are disposed below the electrode sheet ES. As a result, the dancer roll 120 can be moved downward to change the travel path of the electrode sheet ES. Also, the nip bar 133 can be moved upward to fix the electrode sheet ES.

[0065] The present invention has been described in more detail above through the drawings and embodiments, etc. However, the configurations shown in the drawings or embodiments in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, and therefore, there may be various equivalents and modifications that can replace them at the time of filing this application. [Explanation of symbols]

[0066] 100 Secondary battery manufacturing equipment 111 Unwinder 113 Rewinder 115 Processing equipment 120 Dancer Roll 131 Guide Roll 133 Nip Bar 140 Cutter 150 Waste Winder 160 Tape Applicator 170 Controller ER1 First electrode roll ER2 Second electrode roll ES electrode sheet ES1 First electrode sheet ES2 Second electrode sheet MD running direction RES electrode sheet SBP standby position TD Lateral VD vertical direction WP working position

Claims

1. a dancer roll configured to change the travel path of the electrode sheet; a cutter configured to cut the electrode sheet adjacent to the dancer roll into a first electrode sheet and a second electrode sheet; a waste winder configured to wind up a defective portion of the first electrode sheet.

2. The secondary battery manufacturing apparatus according to claim 1 , wherein the dancer roll is configured to move in a direction perpendicular to a running direction of the electrode sheet.

3. The secondary battery manufacturing apparatus according to claim 2 , wherein the dancer roll is configured to move in a direction perpendicular to a lateral direction of the electrode sheet.

4. The secondary battery manufacturing apparatus according to claim 1 , wherein the dancer roll changes the path of the electrode sheet while maintaining tension on the electrode sheet.

5. The secondary battery manufacturing apparatus according to claim 1 , further comprising a nip bar configured to fix the electrode sheet.

6. the dancer roll is disposed below the electrode sheet; and 6. The secondary battery manufacturing apparatus according to claim 1, wherein the travel path of the electrode sheet is lengthened by the dancer roll.

7. the dancer roll is disposed on top of the electrode sheet; and 6. The secondary battery manufacturing apparatus according to claim 1, wherein the travel path of the electrode sheet is lengthened by the dancer roll.

8. The apparatus of claim 1 , further comprising a tape attacher configured to connect the first electrode sheet and the second electrode sheet.

9. a step of changing a travel path of an electrode sheet by moving a dancer roll, wherein the electrode sheet is unwound from a first electrode roll by an unwinder and wound onto a second electrode roll by a rewinder; cutting the electrode sheet so that the electrode sheet is separated into a first electrode sheet and a second electrode sheet, the first electrode sheet being connected to the first electrode roll and the second electrode sheet being connected to the second electrode roll; A method for manufacturing a secondary battery, comprising: winding up the defective portion of the first electrode sheet so as to discard the defective portion of the first electrode sheet.

10. The method for manufacturing a secondary battery according to claim 9 , wherein the movement of the dancer roll lengthens a travel path of the electrode sheet.

11. The method for manufacturing a secondary battery according to claim 9 , wherein the electrode sheet is unwound from the first electrode roll while the dancer roll is moving.

12. The method for manufacturing a secondary battery according to claim 9 , further comprising the step of fixing the electrode sheet with a nip bar before cutting the electrode sheet.

13. The method for manufacturing a secondary battery according to claim 12 , wherein unwinding onto the second electrode roll is interrupted before the electrode sheet is fixed by the nip bar.

14. 14. The method for manufacturing a secondary battery according to claim 9, further comprising the step of connecting the first electrode sheet and the second electrode sheet to provide the reconnected electrode sheets.

15. The method for manufacturing a secondary battery according to claim 14 , further comprising the step of restoring the running path of the reconnected electrode sheets.

16. The dancer roll is moved from a standby position to a working position so that the travel path of the electrode sheet is changed; and The method for manufacturing a secondary battery according to claim 14 , wherein the dancer roll is moved from the working position to the waiting position so as to change the traveling path of the reconnected electrode sheets.

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