Electrode Sheet Connection Method and Electrode Sheet

Abstract

The present technology relates to a method for connecting electrode sheets in a roll-to-roll process, the method comprising: arranging a flexible connecting sheet of a predetermined length between a first electrode sheet and a second electrode sheet; connecting the first electrode sheet to the flexible connecting sheet by attaching one side of the first electrode sheet to one side of the flexible connecting sheet using a first tape; and connecting the second electrode sheet to the flexible connecting sheet by attaching one side of the second electrode sheet to the other side of the flexible connecting sheet using a second tape. In addition, the present technology relates to an electrode sheet manufactured by the method of connecting electrode sheets.

Description

Technical Field

[0001] The present invention relates to a method of connecting electrode sheets, and more particularly, to a method of connecting electrode sheets of a secondary battery in a roll-to-roll process.

[0002] The present invention also relates to an electrode sheet manufactured by the method of connecting electrode sheets.

[0003] This application claims the benefit of priority based on Korean Patent Application No. 10-2020-0148004, filed on November 6, 2020, the entire contents of which are incorporated herein by reference. Background Art

[0004] With the development of technology and the increasing demand for mobile devices, the demand for secondary batteries is also rapidly increasing. Among them, lithium secondary batteries are widely used as an energy source for various electronic products and various mobile devices due to their high energy density, high operating voltage, and excellent storage and life characteristics.

[0005] A lithium secondary battery has a structure in which an electrode assembly for charging and discharging electric energy is built in a case. Electrodes (a positive electrode and a negative electrode) constituting the electrode assembly generate an electric current through ion exchange. Each of the positive electrode and the negative electrode is manufactured as follows: an electrode substrate (electrode sheet) is obtained by applying an electrode paste on the surface of a current collector made of an aluminum or copper film and drying the electrode paste; tabs are processed on the electrode substrate (notching process) and cut into appropriate sizes. Thus, the electrode sheet on which the electrode paste is applied includes a portion coated with the electrode paste (coated portion) and a portion not coated with the electrode paste (uncoated portion). Various processes for battery production, such as tab processing or laser processing, are performed on the uncoated portion. The process of manufacturing and processing the electrode sheet is performed through a roll-to-roll process in which the electrode sheet hung on multiple rollers moves along a predetermined path.

[0006] The electrode sheet is wound around a supply roll and sequentially unwound to undergo a series of manufacturing processes. When the electrode sheet of the supply roll is completely unwound, it is necessary to replace the electrode sheet with a new electrode sheet by replacing the supply roll with a new supply roll. An automatic splicer is an automatic connecting device for continuously operating the machine when the use of one supply roll is completed.

[0007] Figure 1 is a view showing an example of a conventional automatic splicer for connecting electrode sheets between supply rolls in a roll-to-roll process.

[0008] As shown in the figure, the automatic splicer is a device for joining a first web FwA that is unwound from one roll and is almost used up to a second web FwB that is unwound from another roll FrB. The second web FwB is unwound from the roll FrB and moves to the splicing table of the splicing unit via guide rollers 44aB and 44bB. The web moving from the splicing table 45B is joined in the pressure roller 42.

[0009] Figure 2 It is a schematic diagram showing the process of connecting two electrode foils in a roll-to-roll process. Figure 2 (a) thereof is a plan view, and Figure 2 (b) thereof is a side view.

[0010] As shown in the figure, in order to connect a first electrode foil 10 (for example, the electrode foil before replacement) to a second electrode foil 20 (for example, the electrode foil after replacement), a tape 30 is attached to one end of each electrode foil. A connection tag (Tag) 40 for indicating the end of use of the first electrode foil 10 is attached to the end of the first electrode foil 10.

[0011] As Figure 2 shown in the plan view of (a) thereof, the coated portions 11 and 21 coated with electrode paste are located at the lower parts of the first electrode foil 10 and the second electrode foil 20, and the uncoated portions 12 and 22 not coated with electrode paste are located at the upper parts of the first electrode foil 10 and the second electrode foil 20. The other surfaces of the first electrode foil 10 and the second electrode foil 20 also have the same structure. That is, the electrode foil has a structure in which electrode paste is applied to one surface and the other surface of the metal foil.

[0012] Referring to Figure 2 the side view of (b) thereof, the sheet portion of the metal foil is omitted in the drawing, and only the overall appearance of the coated portion coated with electrode paste is shown.

[0013] In Figure 2 the conventional electrode foil connection scheme as in

[0014] , the connection portion (tape attachment portion) of the electrode foil may be disconnected due to stress. That is, in the roll-to-roll process, the electrode foil bends, and the tension applied to the electrode foil is not constant. The tension may vary according to the portion of the electrode foil. Therefore, there may be a portion where the tension is concentrated on the traveling path of the electrode foil. When such a portion becomes the connection portion of the electrode foil, the electrode foil may break at the connection portion. When the connection portion breaks, the defect rate increases and the device operation rate decreases.

[0015] However, in a conventional electrode sheet connection part, two electrode sheets are directly connected by tape. Therefore, the movement path of the meandering movement part cannot be adjusted.

[0016] Therefore, an electrode connection technique is needed to relieve the stress locally applied to the electrode sheet and adjust the path of the meandering movement part in a roll-to-roll process.

[0017] [Prior Art Documents]

[0018] [Patent Documents]

[0019] Korean Patent Publication No. 10-2014-0069900 Summary of the Invention

[0020] Technical Problem

[0021] The present invention is considered to solve at least some of the above problems. For example, one aspect of the present invention provides an electrode sheet connection method capable of relieving stress on the electrode sheet during movement.

[0022] In addition, another aspect of the present invention provides an electrode sheet for relieving stress on the electrode sheet during movement and ensuring a margin when adjusting the meandering movement.

[0023] Technical Solution

[0024] To solve the above problems, a method for connecting electrode sheets in a roll-to-roll process according to the present invention includes: disposing a flexible connection sheet of a predetermined length between a first electrode sheet and a second electrode sheet; connecting the first electrode sheet to the flexible connection sheet by attaching one side of the first electrode sheet to one side of the flexible connection sheet using a first tape; and connecting the second electrode sheet to the flexible connection sheet by attaching one side of the second electrode sheet to the other side of the flexible connection sheet using a second tape.

[0025] In one example, the flexible connection sheet is made of one selected from the group consisting of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), oriented polypropylene (OPP), polyimide (PI), polybutylene terephthalate (PBT), polyester, polyacetal, polyamide, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, polyethylene naphthalene, and flexible silicone.

[0026] Specifically, the length of the flexible connecting piece is in the range of 100 mm to 2000 mm.

[0027] In one example, the first tape is attached only to the portion of the first electrode sheet coated with the electrode paste and not to the portion of the first electrode sheet not coated with the electrode paste, and the second tape is attached only to the portion of the second electrode sheet coated with the electrode paste and not to the portion of the second electrode sheet not coated with the electrode paste.

[0028] In one example, the thickness of the flexible connecting piece may be the same as the thickness of the first electrode sheet and the second electrode sheet or may be less than the thickness of the first electrode sheet and the second electrode sheet.

[0029] In another example, the first electrode sheet or the second electrode sheet may not include a connection tag.

[0030] In another example, the width of the flexible connecting piece may be the same as the width of the first electrode sheet and the second electrode sheet or may be less than the width of the first electrode sheet and the second electrode sheet.

[0031] In a specific example, the width of the flexible connecting piece may be the same as the width of the portions of the first electrode sheet and the second electrode sheet coated with the electrode paste, and the flexible connecting piece may be connected to the first electrode sheet and the second electrode sheet by arranging the flexible connecting piece parallel to the portions of the first electrode sheet and the second electrode sheet coated with the electrode paste so that the width of the flexible connecting piece is opposite to the width of the portions of the first electrode sheet and the second electrode sheet coated with the electrode paste.

[0032] The present invention provides an electrode sheet, comprising: a first electrode sheet; a second electrode sheet; a flexible connecting piece of a predetermined length disposed between the first electrode sheet and the second electrode sheet; a first tape for attaching one side of the first electrode sheet to one side of the flexible connecting piece; and a second tape for attaching one side of the second electrode sheet to the other side of the flexible connecting piece.

[0033] Advantageous Effects

[0034] According to the present invention, by including a flexible connecting piece capable of reducing the stress caused by the tension between the electrode sheets, the possibility of rupture at the connection portion of the electrode sheets can be significantly reduced.

[0035] In addition, according to the present invention, the flexible connecting piece provides a movement margin between the electrode sheets before and after replacement, and a margin for adjusting the zigzag movement can be ensured through this movement margin. Brief Description of the Drawings

[0036] Figure 1 is a diagram showing an example of an automatic splicer in a conventional roll-to-roll process.

[0037] Figure 2 is a schematic diagram showing the process of connecting two electrode sheets in a roll-to-roll process. Figure 2 (a) of is a plan view, and Figure 2 (b) of is a side view.

[0038] Figure 3 is a schematic diagram showing the process of connecting electrode sheets according to an embodiment of the present invention. Figure 3 (a) of is a plan view, and Figure 3 (b) of is a side view.

[0039] Figure 4 is a schematic diagram showing the process of connecting electrode sheets according to another embodiment of the present invention. Figure 4 (a) of is a plan view, and Figure 4 (b) of is a side view.

[0040] Figure 5 is a schematic diagram showing the process of connecting electrode sheets according to still another embodiment of the present invention. Detailed Embodiments

[0041] Hereinafter, the detailed structure of the present invention will be described in detail with reference to the drawings and each embodiment. The embodiments described below are illustrative and are intended to assist in understanding the present invention. For the purpose of assisting in understanding the present invention, the drawings are not shown at an actual scale, and the scales of some components may be exaggerated.

[0042] Since the inventive concept allows for various variations and multiple embodiments, specific embodiments will be shown in the drawings and described in detail herein. However, this is not intended to limit the present invention to the specific forms disclosed, and it should be understood to cover all variations, equivalents, and substitutions included within the spirit and scope of the present invention.

[0043] The object of the present invention is to relieve stress during the roll-to-roll process by arranging flexible connection sheets when connecting electrode sheets. As Figure 2 shown, when electrode sheets are attached without margin and connected by tape, the stress applied during the roll-to-roll process cannot be absorbed. That is, the electrode foils (metal sheets) such as aluminum or copper of the electrode sheets are too hard to be stretched. Thus, when local tension is applied, it will be strongly impacted. Therefore, when performing each process, it is subject to the load of the devices of each process, and the tension of the electrode sheets is concentrated on the electrode sheet connection part, which causes damage to the connection part. In addition, although conventional tapes are made of soft materials, as Figure 2As shown, the tape is only attached to the coated portion to attach the electrode sheet, and it cannot solve the problem of tension concentration in the roll-to-roll process. In addition, although the tape itself is flexible, the tape is attached to the coated portion through the lower adhesive. In this way, the tape cannot absorb stress.

[0044] Therefore, the present invention solves the existing technical problems by arranging a flexible connecting sheet capable of reducing stress by absorbing tension between the electrode sheets.

[0045] (First Embodiment)

[0046] Figure 3 is a schematic diagram showing the process of connecting electrode sheets according to the first embodiment of the present invention. Figure 3 (a) of is a plan view, and Figure 3 (b) of is a side view.

[0047] For ease of explanation, Figure 3 the horizontal direction on the plan view of (a) of is defined as the length direction of the electrode sheet, the flexible connecting sheet, and the tape, and the vertical direction is defined as the width direction.

[0048] To connect the electrode sheets, two electrode sheets are arranged, namely, the first electrode sheet 210 and the second electrode sheet 220. For example, the first electrode sheet 210 may be the electrode sheet before replacement that has been used up, and the second electrode sheet 220 may be the electrode sheet after replacement to be reused. The first electrode sheet 210 is unwound from a supply roll (running roll) (not shown) and the second electrode sheet 220 is unwound from another supply roll (spare roll) (not shown), so as to be positioned at a predetermined position. A flexible connecting sheet 250 of a predetermined length is arranged between the first electrode 210 and the second electrode 220.

[0049] When the sensor senses the connection label 240 at the time point when the first electrode sheet 210 is used up, the process of connecting the first electrode 210 and the second electrode 220 is started. That is, the first electrode sheet 210 is connected to the flexible connecting sheet 250 by attaching one side of the first electrode sheet 210 to one side of the flexible connecting sheet 250 using the first tape 230a.

[0050] After that, the second electrode sheet 220 is connected to the flexible connecting sheet 250 by attaching one side of the second electrode sheet 220 to the other side of the flexible connecting sheet 250 using the second tape 230b. As a result, while there is a flexible connecting sheet 250 between the first electrode sheet 210 and the second electrode sheet 220, the first electrode sheet 210 and the second electrode sheet 220 are connected to each other through the tapes 230a and 230b.

[0051] The arrangement of the first electrode sheet 210, the second electrode sheet 220, and the flexible connection sheet 250, as well as the attachment of the tape, can be manually performed by a person or can be performed using the above-described automatic splicer in an automatic connection scheme.

[0052] As Figure 3 shown in the plan view of (a) of, the coated portions (coated parts) 211 and 221 with electrode paste are located at the lower part in the width direction of the first electrode sheet 210 and the second electrode sheet 220, and the uncoated portions (uncoated parts) 212 and 222 where the electrode paste is not coated are located at the upper part in the width direction of the first electrode sheet 210 and the second electrode sheet 220. The other surfaces of the first electrode sheet 210 and the second electrode sheet 220 also have the same structure. That is, the electrode sheet has a structure in which the electrode paste is applied to one surface and the other surface of the metal foil.

[0053] In Figure 3 (a) of, the uncoated portions 212 and 222 are only formed at the upper part in the width direction of each electrode sheet, but uncoated portions can be formed at the upper and lower parts in the width direction of the coated portions 211 and 221, respectively. This is the case where the coated portion is located between the uncoated portion at the upper part and the uncoated portion at the lower part in the width direction.

[0054] Referring to Figure 3 the side view of (b) of, the sheet portion of the metal foil is omitted in the figure, and only the coated portion and the overall appearance of the electrode sheets 210 and 220 are shown. In addition, since the connection label 240 is removed later, it is not shown in the side view of Figure 3 (b) of.

[0055] A flexible connection sheet that is more flexible than the electrode sheet made of metal foil can be used as the flexible connection sheet 250. Any flexible material that can reduce the local tension concentration in the roll-to-roll process can be used. The flexible connection sheet is made of one selected from the group consisting of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), oriented polypropylene (OPP), polyimide (PI), polybutylene terephthalate (PBT), polyester (PE), polyacetal, polyamide, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, polyethylene naphthalene, and flexible silicon.

[0056] In addition, the length and thickness of the flexible connection piece 250 can be appropriately selected within the range of reducing the stress between the electrode pieces. Electrode pieces have various sizes according to the type of the manufactured electrode unit or battery. Therefore, the length of the flexible connection piece 250 can be determined within a relatively wide range accordingly. Specifically, the length of the flexible connection piece 250 can be within the range of 100 mm to 2000 mm. A 100-mm flexible connection piece can be used for a super-small battery, and a 2000-mm flexible connection piece can be used for a large-sized battery, such as a battery for a vehicle.

[0057] The thickness of the flexible connection piece 250 can be determined in consideration of the material and physical properties of the flexible connection piece and the characteristics of the battery. Here, in terms of reducing stress, it is not preferable that the thickness of the flexible connection piece 250 is greater than the thicknesses of the first electrode piece 210 and the second electrode piece 220. In addition, in the roll-to-roll process, the flexible connection piece 250 is also wound around a roller together with the first electrode piece 210 and the second electrode piece 220. Therefore, when the flexible connection piece is made thicker, stress will concentrate on the flexible connection piece 250 and its adjacent areas. Therefore, preferably, the thickness of the flexible connection piece 250 is the same as the thicknesses of the first electrode piece 210 and the second electrode piece 220.

[0058] More preferably, as Figure 3 shown, the thickness of the flexible connection piece 250 is less than the thicknesses of the first electrode piece 210 and the second electrode piece 220, so that the stress between the electrode pieces can be better absorbed. Specifically, the thickness of the flexible connection piece 250 can be within the range of 10 μm to 30 μm, but this range can be changed according to the type or shape of the battery.

[0059] A known ordinary tape can be used as the adhesive tape for connecting the electrode pieces 210 and 220 to the flexible connection piece 250. A product obtained by applying an acrylic adhesive on a film sheet made of paper, synthetic resin, etc. can be used as the tape. The tape for connecting one side of the first electrode piece 210 to one side of the flexible connection piece 250 is called the first tape 230a, and the tape for connecting one side of the second electrode piece 220 to the other side of the flexible connection piece 250 is called the second tape 230b, but the first tape 230a and the second tape 230b can use the same tape. What matters is not the type of the tape, but as Figure 3 shown, whether the flexible connection piece 250 between the first electrode piece 210 and the second electrode piece 220 extends a predetermined length to reduce stress. In such as Figure 2In the example, the two electrode sheets are in direct contact with each other or have a very small gap therebetween, and the tape is attached to one surface and the other surface. Therefore, it is difficult to relieve or absorb stress. The difference in this embodiment is that a flexible connecting piece 250 having a predetermined length extends between the first electrode sheet 210 and the second electrode sheet 220. The first tape 230a is attached to one side of the flexible connecting piece 250 and the first electrode sheet 210, and the second tape 230b is attached to the other side of the flexible connecting piece 250 and the second electrode sheet 220, thereby connecting the flexible connecting piece 250 to the first electrode sheet 210 and the second electrode sheet 220 (see Figure 3 (b) thereof).

[0060] In addition, as shown in Figure 3 , preferably, the tape is only attached to the coated portions 211 and 221. The uncoated portions 212 and 222 are electrode foils (metal portions), and various processes for battery production, such as tabbing or laser processing, are performed on the uncoated portions. Therefore, since the tape will interfere with the processing on the uncoated portions, the tape is not attached to the uncoated portions 212 and 222. In addition, when the adhesive of the tape flows into the electrode foil portion, it will affect the processing. Therefore, preferably, the tapes 230a and 230b are attached to the coated portions 211 and 221 and the flexible connecting piece 250 with a slight gap from the uncoated portions 212 and 222.

[0061] The tapes 230a and 230b are attached while covering a portion in a certain range near the end of each electrode sheet and a portion in a certain range near the side surface of the flexible connecting piece 250. In the case of a super-small battery, the lengths of the tapes 230a and 230b covering the electrode sheets and the flexible connecting piece can be 30 mm. The lengths of the tapes 230a and 230b can be determined within a range capable of stably attaching the electrode sheets 210 and 220 to the flexible connecting piece 250. Here, the flexible connecting piece 250 extends a predetermined length to relieve stress, and the lengths of the tapes 230a and 230b are less than the length of the flexible connecting piece 250. The lengths of the tapes 230a and 230b are determined within an appropriate range for connection between the sheets, and the flexible connecting piece 250 is installed to relieve or absorb stress. Therefore, each length can be determined considering the purpose, and there is no specific relationship between the lengths of the tapes 230a and 230b and the length of the flexible connecting piece 250. However, the length of the flexible connecting piece can correspond to 3 to 10 times the lengths of the tapes 230a and 230b.

[0062] When a flexible connection piece 250 is disposed between the first electrode piece 210 and the second electrode piece 220 and they are attached using tapes 230a and 230b, the adhesive force is increased as an additional effect. That is, the adhesive force is higher when the electrode pieces are attached to the flexible connection piece 250 using tapes 230a and 230b compared to when the first electrode piece 210 and the second electrode piece 220 are directly bonded by tapes. Therefore, since the adhesive force of the attachment portion between the flexible connection piece 250 and the tapes 230a and 230b is greater than the adhesive force of the attachment portion between the electrode piece and the tape, the overall adhesive force is increased.

[0063] (Second Embodiment)

[0064] Figure 4 is a schematic diagram showing a process of connecting electrode pieces according to a second embodiment of the present invention.

[0065] In this embodiment, the Figure 3 connection label 240 is removed. Generally, the connection label 240 indicates the end of use of the first electrode piece 210, and the portion to which the connection label 240 is attached is the connection portion between the two electrode pieces. The connection label 240 can be recognized with the naked eye and its color can be recognized by a color sensor. However, conventional color sensors sometimes cannot recognize the connection label 240 due to low sensitivity. If the connection label 240 is still attached even during the battery assembly process after the connection of the electrode pieces, it may cause product defects.

[0066] In this embodiment, such a connection label 240 is removed, and the connection portion of the first electrode piece and the second electrode piece is composed only of the flexible connection piece 250 and the tapes 230a and 230b. Since the flexible connection piece 250 extends a predetermined length, it is easy to recognize with the naked eye. In addition, since the flexible connection piece 250, particularly a sheet made of a synthetic resin such as PET, has excellent light transmittance, the detection efficiency is excellent when sensed by an optical sensor (transmissive optical sensor).

[0067] Therefore, in the present invention, the flexible connection piece 250 is sensed by a sensor or the like without the connection label 240. In this case, the time point of the end of use of the electrode piece and the electrode connection portion can be easily recognized.

[0068] (Third Embodiment)

[0069] Figure 5 is a schematic diagram showing a process of connecting electrode pieces according to a third embodiment of the present invention.

[0070] This embodiment is different from the first embodiment in that the width of the flexible connection piece 250 is smaller than the widths of the first electrode piece 210 and the second electrode piece 220. That is, inFigure 3 In the first embodiment, the flexible connection piece 250 extends to the metal foil portions corresponding to the uncoated portions 212 and 222. In this case, the width of the flexible connection piece 250 is the same as the width of the electrode piece. In Figure 5 it, the width of the flexible connection piece 250 is the same as the width of the coated portions 211 and 221.

[0071] The electrode piece is composed of an uncoated portion formed only of metal foil and a coated portion coated with electrode paste. Thus, compared with the coated portion, tension is not significantly applied to the uncoated portion. Therefore, the flexible connection piece 250 can be made to connect only the coated portions 211 and 221 as in Figure 5 . In addition, in Figure 3 the structure, the adhesive leaking from the tapes 230a and 230b can flow into the uncoated portions 212 and 222 through the flexible connection piece 250. Therefore, preferably, the width of the flexible connection piece 250 is limited to the width of the coated portions 211 and 221. In addition, in Figure 3 it, the flexible connection piece 250 is not attached to the uncoated portions 212 and 222. They just contact each other. Therefore, when the electrode piece is wound, the ends of the flexible connection piece 250 contacting the uncoated portions 212 and 222 may bend, and if such bent portions are wound, stress imbalance may be caused.

[0072] Therefore, as in the third embodiment, preferably, the width of the flexible connection piece 250 is smaller than the widths of the first electrode piece 210 and the second electrode piece 220. In particular, the width of the flexible connection piece 250 is the same as the widths of the coated portions 211 and 221.

[0073] The present invention has been described with reference to the embodiments. The present invention also relates to an electrode piece manufactured by a method of connecting electrode pieces.

[0074] The electrode piece 200 of the present invention includes: a first electrode piece 210; a second electrode piece 220; a flexible connection piece 250 of a predetermined length disposed between the first electrode piece 210 and the second electrode piece 220; a first tape 230a for attaching one side of the first electrode piece 210 to one side of the flexible connection piece 250; and a second tape 230b for attaching one side of the second electrode piece 220 to the other side of the flexible connection piece 250. Since the electrode piece 200 of the present invention includes the flexible connection piece 250 extending a predetermined length between the first electrode piece 210 and the second electrode piece 220, the flexible connection piece 250 reduces local tension concentration, thereby reducing the stress applied to the electrode piece 200.

[0075] In addition, during the processes before and after replacing the electrode sheets, the flexible connection sheet 250 can ensure the operating margin between the processes and the margin when adjusting the zigzag movement.

[0076] In addition, the electrode sheet connection part can be easily identified through the flexible connection sheet 250 without a connection label.

[0077] The width of the flexible connection sheet 250 can be the same as or less than the widths of the first electrode sheet 210 and the second electrode sheet 220.

[0078] When the width of the flexible connection sheet 250 is less than the widths of the first electrode sheet 210 and the second electrode sheet 220, preferably, the width of the flexible connection sheet 250 is the same as the widths of the coating parts 211 and 221. In this case, as Figure 5 shown, the flexible connection sheet 250 is connected to the first electrode sheet 210 and the second electrode sheet 220 by arranging the flexible connection sheet 250 parallel to the coating parts 211 and 221 of the first electrode sheet 210 and the second electrode sheet 220 such that the width of the flexible connection sheet 250 is opposite to the widths of the coating parts 211 and 221 of the first electrode sheet 210 and the second electrode sheet 220.

[0079] Above, the present invention has been described in more detail through the drawings and examples. Therefore, the embodiments described in this application and the configurations described in the drawings are only the most preferred embodiments of the present invention and do not represent all the technical concepts of the present invention. It should be understood that various equivalents and deformations may exist to replace them when submitting this application.

[0080] (Reference numeral description)

[0081] 10, 210: First electrode sheet

[0082] 11, 211: Coating part

[0083] 12, 212: Uncoated part

[0084] 20, 220: Second electrode sheet

[0085] 21, 221: Coating part

[0086] 22, 222: Uncoated part

[0087] 30: Tape

[0088] 230a: First tape

[0089] 230b: Second tape

[0090] 40, 240: Connection label

[0091] 250: Flexible connecting piece.

Claims

1. A method for connecting electrode sheets in a roll-to-roll process, the method comprises: arranging a flexible connecting sheet of a predetermined length between a first electrode sheet and a second electrode sheet; connecting the first electrode sheet to the flexible connecting sheet by attaching one side of the first electrode sheet to one side of the flexible connecting sheet using a first tape; and connecting the second electrode sheet to the flexible connecting sheet by attaching one side of the second electrode sheet to the other side of the flexible connecting sheet using a second tape, wherein the length of the flexible connecting sheet is in the range of 100 mm to 2000 mm.

2. The method according to claim 1, wherein the flexible connecting sheet is made of one selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, oriented polypropylene, polyimide, polybutylene terephthalate, polyester, polyacetal, polyamide, polyethersulfone, polyphenylene ether, polyphenylene sulfide, polyethylene naphthalene, and flexible silicon.

3. The method according to claim 1, wherein the first tape is attached only to the portion of the first electrode sheet coated with electrode paste and not to the portion of the first electrode sheet not coated with electrode paste, and the second tape is attached only to the portion of the second electrode sheet coated with electrode paste and not to the portion of the second electrode sheet not coated with electrode paste.

4. The method according to claim 1, wherein the thickness of the flexible connecting sheet is the same as the thickness of the first electrode sheet and the second electrode sheet.

5. The method according to claim 1, wherein the thickness of the flexible connecting sheet is less than the thickness of the first electrode sheet and the second electrode sheet.

6. The method according to claim 1, wherein the first electrode sheet or the second electrode sheet does not include a connection label.

7. The method according to claim 1, wherein the width of the flexible connecting sheet is the same as the width of the first electrode sheet and the second electrode sheet.

8. The method according to claim 1, wherein the width of the flexible connecting sheet is less than the width of the first electrode sheet and the second electrode sheet.

9. The method according to claim 8, wherein the width of the flexible connecting sheet is the same as the width of the portions of the first electrode sheet and the second electrode sheet coated with electrode paste, wherein the flexible connecting sheet is connected to the first electrode sheet and the second electrode sheet by arranging the flexible connecting sheet parallel to the portions of the first electrode sheet and the second electrode sheet coated with electrode paste such that the width of the flexible connecting sheet is opposite to the width of the portions of the first electrode sheet and the second electrode sheet coated with electrode paste.

10. An electrode sheet, comprises: a first electrode sheet; a second electrode sheet; a flexible connecting sheet of a predetermined length arranged between the first electrode sheet and the second electrode sheet; a first tape for attaching one side of the first electrode sheet to one side of the flexible connecting sheet; and a second tape for attaching one side of the second electrode sheet to the other side of the flexible connecting sheet.

11. The electrode sheet according to claim 10, wherein the width of the flexible connection sheet is the same as the widths of the first electrode sheet and the second electrode sheet.

12. The electrode sheet according to claim 10, wherein the width of the flexible connection sheet is the same as the widths of the portions of the first electrode sheet and the second electrode sheet coated with the electrode paste, wherein the flexible connection sheet is connected to the first electrode sheet and the second electrode sheet by arranging the flexible connection sheet parallel to the portions of the first electrode sheet and the second electrode sheet coated with the electrode paste such that the width of the flexible connection sheet faces the widths of the portions of the first electrode sheet and the second electrode sheet coated with the electrode paste.

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