Method for manufacturing a secondary battery

Abstract

According to an exemplary embodiment, there is provided a method for manufacturing a secondary battery, the method including the steps of: coating an electrode slurry on an electrode sheet unwound from an electrode roll to form a plurality of land lanes on the electrode sheet, the land lanes having a plurality of uncoated areas therebetween; and forming a plurality of reference points on the electrode sheet, each of the first reference point and the second reference point including a first symbol indicating an orientation of the reference point and a second symbol indicating a corresponding land lane among the plurality of land lanes.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a secondary battery. This application claims the benefit of Korean Application No. 10-2023-0102883 filed on August 7, 2023, and Korean Application No. 10-2024-0077824 filed on June 14, 2024, which are incorporated herein by reference in their entireties. [Background technology]

[0002] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries are widely used as energy sources for a variety of 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. As the driving range of battery electric vehicles (BEVs) has increased to the same level as fuel-powered vehicles, the primary 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 press 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 press process, the electrode can be pressed by a pressure roll. The roll press process can determine the density, performance, and surface quality of the electrode. In the slitting process, the electrode can be cut into multiple electrodes according 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 method for manufacturing a secondary battery with improved traceability. [Means for solving the problem]

[0005] To solve the above-mentioned problems, an exemplary embodiment of the present invention provides a method for manufacturing a secondary battery, the method including the steps of: coating an electrode slurry on an electrode sheet unwound from an electrode roll to form a plurality of land lanes on the electrode sheet, the land lanes having a plurality of uncoated areas therebetween; and forming a plurality of reference points on the electrode sheet, each of the plurality of reference points including a first symbol indicating an orientation of the reference point and a second symbol indicating a corresponding land lane among the plurality of land lanes.

[0006] Each of the plurality of reference points includes a third symbol that indicates an order in which the plurality of reference points are formed.

[0007] The third symbol indicates the tenth digit of the formation order.

[0008] Each of the plurality of reference points further includes a fourth symbol indicating the formation order of the plurality of reference points.

[0009] The fourth symbol indicates one digit of the formation order.

[0010] The first symbol includes an alphabet, and each of the second to fourth symbols includes a number.

[0011] The second symbol follows the first symbol, the third symbol follows the second symbol, and the fourth symbol follows the third symbol.

[0012] The first symbol follows the second symbol, the fourth symbol follows the first symbol, and the third symbol follows the fourth symbol.

[0013] The first symbol further indicates a corresponding land lane among the plurality of land lanes.

[0014] The first symbol indicates the 10-digit number of the corresponding land lane among the plurality of land lanes.

[0015] The second symbol indicates one digit of the corresponding land lane among the plurality of land lanes.

[0016] The plurality of reference points are formed by a dot printing method.

[0017] The plurality of reference points are formed by inkjet printing.

[0018] The plurality of reference points are formed by laser printing.

[0019] The plurality of reference points are formed in the plurality of uncoated portions.

[0020] According to an exemplary embodiment, an electrode is provided, the electrode including a current collector including an electrode tab, a positive electrode active material layer on the current collector, and reference points on the electrode tab, the reference points including a first symbol, a second symbol, a third symbol, and a fourth symbol.

[0021] The first symbol indicates the orientation of the reference point.

[0022] The second symbol indicates the land lane from which the electrode originates.

[0023] The third and fourth symbols each indicate the order in which the reference points are formed.

[0024] The third symbol indicates the tenth digit of the formation order.

[0025] The fourth symbol indicates one digit of the formation order.

[0026] The first symbol is an alphabet, and each of the second to fourth symbols is a number.

[0027] The reference points include the first symbol to the third symbol.

[0028] The reference point includes a first symbol and a second symbol.

[0029] The reference point includes a symbol.

[0030] There is also a data matrix on the electrode tab. [Effects of the Invention]

[0031] According to an exemplary embodiment of the present invention, reference points including symbols indicating orientation are formed in a plurality of uncoated portions of an electrode sheet, thereby enabling the orientation of the reference points to be recognized and improving the accuracy of recognition of the reference points.

[0032] The effects obtained from the exemplary embodiments of the present invention 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]

[0033] [Figure 1] 1 illustrates a secondary battery manufacturing system according to an exemplary embodiment. [Figure 2] 1 illustrates a coating apparatus according to an exemplary embodiment. [Figure 3a] 1 shows a first electrode sheet processed by a coating apparatus. [Figure 3b] Indicates the first reference point. [Figure 3c] Indicates the first reference point. [Figure 3d] Indicates the first reference point. [Figure 3e] Indicates the first reference point. [Figure 3f] Indicates the reference point. [Figure 4]1 illustrates a roll pressing apparatus according to an exemplary embodiment. [Figure 5] FIG. 2 is a plan view showing a second electrode sheet. [Figure 6] FIG. 2 is a plan view showing a second electrode sheet. [Figure 7] 1 illustrates a slitting apparatus according to an exemplary embodiment. [Figure 8] FIG. 4 is a plan view showing a third electrode sheet. [Figure 9] FIG. 4 is a plan view showing a third electrode sheet. [Figure 10] 1 is a flowchart illustrating a method for manufacturing a secondary battery according to an exemplary embodiment. [Figure 11] FIG. 2 is a plan view of a positive electrode according to an exemplary embodiment. [Figure 12] FIG. 11 is a cross-sectional view taken along the line 11I-11I' in FIG. [Figure 13] FIG. 2 is a plan view of a positive electrode according to another exemplary embodiment. [Figure 14] FIG. 2 is a plan view of a positive electrode according to another exemplary embodiment. [Figure 15] FIG. 2 is a plan view of a positive electrode according to another exemplary embodiment. [Figure 16] FIG. 2 is a plan view of a positive electrode according to another exemplary embodiment. [Figure 17] FIG. 2 is a plan view of a positive electrode according to another exemplary embodiment. [Figure 18] FIG. 2 is a plan view of a positive electrode according to another exemplary embodiment. [Figure 19] FIG. 2 is a plan view of an exemplary negative electrode. [Figure 20] FIG. 20 is a cross-sectional view taken along the line 19I-19I′ in FIG. 19. [Figure 21] FIG. 2 is a plan view of an electrode assembly according to an exemplary embodiment. [Figure 22] 21I is a cross-sectional view taken along the line 21I-21I' in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0034] 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.

[0035] 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.

[0036] 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.

[0037] The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and therefore 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.

[0038] (First embodiment) FIG. 1 shows a secondary battery manufacturing system 10 according to an exemplary embodiment.

[0039] Referring to FIG. 1, a secondary battery manufacturing system 10 may include a coating device 100 , a roll pressing device 200 , a slitting device 300 , an EIF 1010 , a server 1020 , and a display device 1030 .

[0040] The secondary battery manufacturing system 10 may be configured to manufacture battery cells (e.g., cylindrical battery cells) by performing a series of roll-to-roll processes. The electrode sheet unwound from the input electrode roll may be processed by any one of the die coater 115 of the coating apparatus 100 (see FIG. 2), the pressure roll 219 of the roll pressing apparatus 200 (see FIG. 4), and the slitting knife 315 of the slitting apparatus 300 (see FIG. 5), and the processed electrode sheet may be wound onto the electrode roll. As such, each of the processes performed by the coating apparatus 100, the roll pressing apparatus 200, and the slitting apparatus 300 to produce electrodes for secondary batteries may be referred to as a roll-to-roll process.

[0041] The coating apparatus 100 may perform a coating process on the electrode sheet. In the coating process, an electrode slurry may be coated on the electrode sheet. The electrode slurry may include an active material, a conductive material, a binder, and a solvent. The electrode slurry may be prepared by dissolving the active material, the conductive material, the binder, etc. in a solvent.

[0042] The roll pressing device 200 may perform a roll pressing process on the electrode sheet. In the roll pressing process, the electrode sheet coated with the electrode slurry may be passed between pressure rolls 219 (see FIG. 4). The roll pressing process may flatten the surface of the electrode sheet and increase the bonding strength between the active material of the electrode sheet and the current collector.

[0043] The slitting device 300 can perform a slitting process on the electrode sheet, which can be divided into a plurality of electrode sheets through the slitting process.

[0044] The electrode roll completed by the slitting device 300 can be processed by a winding device or a notching device, thereby providing a stack-type electrode assembly or a cylindrical electrode assembly.

[0045] If the electrode sheet contains defects, the defects may be discarded at either the roll pressing device 200 or the rewinding stage (not shown).

[0046] The EIF 1010 may be a device for communication between a process PLC of a manufacturing facility and the server 1020. The process PLC 143 of the coating apparatus 100 (see FIG. 2), the process PLC 243 of the roll pressing apparatus 200 (see FIG. 4), and the process PLC 343 of the slitting apparatus 300 (see FIG. 5) can communicate with the server 1020 via the EIF 1010. As a result, data on process events occurring in the coating apparatus 100, the roll pressing apparatus 200, and the slitting apparatus 300 can be transmitted to the server 1020.

[0047] The server 1020 may be configured to generate first to third roll maps each including process event data. The process event data in the roll maps may include a value representing the process event and coordinates matching the value. The coordinates may indicate a position on the electrode sheet. This allows the roll maps to track feedback, feedforward, and the secondary battery manufacturing process, as described below.

[0048] The roll map can be generated on a lot-by-lot basis. A lot is a production unit in a roll-to-roll process, and an example of a lot is an electrode roll (or electrode assembly roll) separated after achieving the target winding length for each process. Similarly, an example of a lot is an electrode roll loaded onto an unwinder for each process. The server 1020 can generate and store a roll map for each process (e.g., a coating process, a roll pressing process, or a slitting process).

[0049] Time series data constructed according to the flow of time in the roll map (i.e., according to the progress of the process) can be associated with coordinate data collected based on the amount of movement of the electrode sheet (i.e., either the amount consumed or the amount input).

[0050] The manufacturing of secondary batteries involves a series of different processes, and leading processes affect subsequent processes. However, if the time series data of a leading process cannot be directly matched with the real-world workpieces, intermediate products, and finished products, it is difficult to reflect the time series data of the leading process in the subsequent process. Hereinafter, the correction of the subsequent process based on the data generated according to the results of the leading process is called feedforward.

[0051] Here, the term "work product" refers to an article provided as a result of each process, such as an electrode sheet, after the coating process, roll pressing process, and slitting process. The term "intermediate product" refers to one of a separator, an electrode, or an assembly thereof (i.e., an electrode assembly) cut by the notching process. The intermediate product may be a structure including a housing and an electrode assembly housed in the housing (in some cases, the structure may further include an electrolyte). The term "product" refers to an article that has been processed to be operable as a secondary battery through an activation process. The above definitions of work product, intermediate product, and product relate to one aspect of the term and do not exclude the usual definitions thereof.

[0052] Process events are generally time-series data because they occur as the process progresses, and thus process event data may include a value representing the event and a time value that is matched to the event.

[0053] For feedforward, time-series data must be associated with the positions of images of workpieces, parts, semi-finished products, and finished products in the real world. Here, feedforward can include controlling processing of the electrode sheet based on a roll map generated in a previous process. The roll map can associate the time-series data with coordinate data including coordinates indicating the positions of images of workpieces, parts, semi-finished products, and finished products in the real world. The roll map can provide matching between the time-series data and workpieces, parts, semi-finished products, and finished products in the real world based on the coordinate data. Thus, generation of the roll map and feedforward based on the roll map can improve the productivity and quality of the secondary battery manufacturing process by quantifying and objectifying aspects of the process that were previously dependent on the discretion of the worker.

[0054] The roll map of a previous lot can also be used to improve the process for subsequent lots, and such an action can be called process feedback. Process feedback using a roll map can include identifying process conditions and process parameters that lead to problems and defects based on the data contained in the roll map.

[0055] Furthermore, as described below, roll maps are cumulatively generated for workpieces, parts, semi-finished products, and finished products of a unit process, thereby enabling tracking of the process history of shipped products (e.g., battery cells, battery modules, or battery packs). As an example, a battery cell may include a cell ID formed on an electrode assembly or a case. The cell ID may include lot number and coordinate information of the electrodes and separator included in the battery cell. In other words, the cell ID may be associated with a roll map of the electrodes and separator included in the battery cell. As a result, if an event such as a quality issue occurs in a battery cell that has already been shipped, historical data on the manufacture of the battery cell can be retrieved based on the cell ID.

[0056] According to an exemplary embodiment, the server 1020 may be a data processing system that supports various activities required to manage the manufacturing of secondary batteries, such as work schedule management, work instructions, quality control, and work performance aggregation. The server 1020 may be, for example, a manufacturing execution system (MES). The server 1020 may be configured to perform input, processing, output, and communication of data required for electrode manufacturing, such as coating, pressing, and slitting processes.

[0057] According to another exemplary embodiment, the server 1020 may be configured to store and process raw measurement data. The server 1020 may continuously monitor the electrode sheet processing based on the measurement data, thereby managing the quality of the electrode sheet processing. According to an exemplary embodiment, the server 1020 may be a statistical process controller (SPC). The server 1020 may collect and analyze manufacturing data in near real time, thereby identifying problem conditions in a timely manner and providing an alarm to an operator before a potential problem occurs.

[0058] According to another example embodiment, the server 1020 may be, for example, a data warehouse, and may store role maps for long periods of time, such as based on product warranty periods.

[0059] According to other exemplary embodiments, the server 1020 may perform all of the functions of the MES, SPC, and data warehouse, or may be provided separately from the MES, SPC, and data warehouse to create the role map.

[0060] FIG. 2 illustrates a coating apparatus 100 according to an exemplary embodiment.

[0061] FIG. 3 a shows a first electrode sheet ES1 processed by the coating apparatus 100 .

[0062] FIG. 3b shows the first reference point DP1.

[0063] Referring to Figures 2 to 3b, the coating apparatus 100 may include an unwinder 111, a rewinder 113, a die coater 115, marking machines 117a and 117b, a controller 119, a first rotary encoder 121, a second rotary encoder 123, an inspector 131, a roll map PLC (Programmable Logic Controller) 141, and a process PLC 143.

[0064] The first electrode roll ER1 may be loaded onto an unwinder 111. The unwinder 111 may be configured to unwind the first electrode sheet ES1 from the first electrode roll ER1. The rewinder 113 may be configured to wind the first electrode sheet ES1 onto the second electrode roll ER2. This allows the first electrode sheet ES1 to move between the unwinder 111 and the rewinder 113.

[0065] The first electrode sheet ES1 is wound around the second electrode roll ER2, and after reaching a predetermined wound length, it can be cut and separated in the transverse direction TD. The separated second electrode roll ER2 is an article that has undergone the coating process, and can be managed by lot, which is the unit of the production process.

[0066] The first rotary encoder 121 may be configured to sense the amount of the first electrode sheet ES1 unwound from the first electrode roll ER1 by the unwinder 111. Thus, the first rotary encoder 121 may be configured to generate an input amount signal UWAS1 indicating the length of the first electrode sheet ES1 unwound by the unwinder 111. The first rotary encoder 121 may be configured to transmit the input amount signal UWAS1 to the roll map PLC 141.

[0067] The second rotary encoder 123 may be configured to sense the amount of the first electrode sheet ES1 wound onto the second electrode roll ER2 by the rewinder 113. Thus, the second rotary encoder 123 may be configured to generate an exhaustion amount signal WAS1 indicating the length of the first electrode sheet ES1 wound by the rewinder 113. The second rotary encoder 123 may be configured to transmit the exhaustion amount signal WAS1 to the roll map PLC 141.

[0068] The die coater 115 may be configured to coat an electrode slurry containing an active material onto the first electrode sheet ES1. When the first electrode sheet ES1 is a positive electrode current collector, the electrode slurry containing a positive electrode active material may be provided on the first electrode sheet ES1. When the first electrode sheet ES1 is a negative electrode current collector, the electrode slurry containing a negative electrode active material may be provided on the first electrode sheet ES1.

[0069] The die coater 115 can form first to fourth ground lanes L1, L2, L3, and L4 (hereinafter referred to as L1 to L4) on the first electrode sheet ES1. The first to fourth ground lanes L1 to L4 are portions of the first electrode sheet ES1 that are coated with an active material.

[0070] The first ground lane L1 and the second ground lane L2 can be formed from the same slit of the die coater 115 and can be connected to each other. The third ground lane L3 and the fourth ground lane L4 can be formed from the same slit of the die coater 115 and can be connected to each other.

[0071] The first ground lane L1, the second ground lane L2, and the third ground lane L3 and the fourth ground lane L4 can be separated by a slitting device 300 (see FIG. 7). That is, the first electrode sheet ES1 including the four ground lanes L1 to L4 can be cut into a plurality of individual electrode sheets ES3a, ES3b (see FIG. 7) including only one of the first ground lane L1 to the fourth ground lane L4 by the slitting device 300 (see FIG. 7).

[0072] Each of the plurality of ground lanes L1 to L4 may extend in the traveling direction MD of the first electrode sheet ES1, and may be spaced apart from each other in the lateral direction TD of the first electrode sheet ES1.

[0073] Each of the first to fourth uncoated regions U1, U2, U3, and U4 (hereinafter referred to as U1 to U4) is a portion of the first electrode sheet ES1 that is not coated with an active material. The first uncoated region U1 and the fourth uncoated region U4 may be located at both ends of the first electrode sheet ES1 in the lateral direction TD. The first uncoated region U1 and the fourth uncoated region U4 may be spaced apart with the first to fourth uncoated region lanes L1 to L4 interposed therebetween. The second uncoated region U2 and the third uncoated region U3 may be located between the second and third uncoated region lanes L2 and L3.

[0074] The first plain portion U1 corresponds to the first ground portion lane L1, and the first plain portion U1 and the first ground portion lane L1 can be included in the same electrode roll after the slitting process is completed. The second plain portion U2 corresponds to the second ground portion lane L2, and the second plain portion U2 and the second ground portion lane L2 can be included in the same electrode roll after the slitting process is completed. The third plain portion U3 corresponds to the third ground portion lane L3, and the third plain portion U3 and the third ground portion lane L3 can be included in the same electrode roll after the slitting process is completed. The fourth plain portion U4 corresponds to the fourth ground portion lane L4, and the fourth plain portion U4 and the fourth ground portion lane L4 can be included in the same electrode roll after the slitting process is completed.

[0075] The technical concept of the present invention will be described below based on a first electrode sheet ES1 including four land lanes L1-L4 and four un-landed areas U1-U4. Based on what has been described herein, a person skilled in the art can easily arrive at a method for generating a process roll map for an electrode sheet including two, three, five or more land lanes and un-landed areas.

[0076] The roll map PLC 141 may be configured to collect coordinate data CD1 of the first electrode sheet ES1 based on the consumed amount signal WAS1 and / or the input amount signal UWAS1 of the first electrode sheet ES1. As an example, the roll map PLC 141 may determine the movement distance of the first electrode sheet ES1 based on the consumed amount signal WAS1 of the first electrode sheet ES1. As a result, the roll map PLC 141 may be configured to determine the position within the first electrode sheet ES1 of the portion of the first electrode sheet ES1 that is being wound by the rewinder 113 at each time an event occurs on the first electrode sheet ES1.

[0077] As another example, the roll map PLC 141 may determine the movement distance of the first electrode sheet ES1 based on the input amount signal UWAS1 of the first electrode sheet ES1, or may determine the movement distance of the first electrode sheet ES1 based on both the consumption amount signal WAS1 and the input amount signal UWAS1. Hereinafter, the technical idea of ​​the present invention will be described with reference to an embodiment in which the roll map PLC 141 collects coordinate data CD1 based on the consumption amount signal WAS1 of the first electrode sheet ES1, as a non-limiting example.

[0078] The coordinate data CD1 may include coordinates that are matched to each portion of the first electrode sheet ES1. That is, each arbitrary point on the first electrode sheet ES1 may be matched to a corresponding coordinate. The coordinates may be, but are not limited to, a one-dimensional quantity in the machine direction MD (or the longitudinal direction of the first electrode sheet ES1) of the first electrode sheet ES1. The coordinates may also be two-dimensional quantities in the machine direction MD and the lateral direction TD of the first electrode sheet ES1.

[0079] According to an exemplary embodiment, the controller 119 may be configured to control the marking machines 117a, 117b based on the coordinate data CD1. According to an exemplary embodiment, the controller 119 may be configured to calibrate the coordinates of the coordinate data CD1 based on the offset lengths of the marking machines 117a, 117b, generate commands MCD for controlling the marking machines 117a, 117b based on the calibrated coordinates, and transmit the commands MCD to the marking machines 117a, 117b.

[0080] Here, the offset length of the marking machines 117a and 117b may be the length of the first electrode sheet ES1 between the portion of the first electrode sheet ES1 sensed by the second rotary encoder 123 and the portion of the first electrode sheet ES1 processed by the marking machines 117a and 117b. The controller 119 may be configured to transmit operation data of the marking machines 117a and 117b (i.e., data on the formation of the first to fourth reference points DP1, DP2, DP3, and DP4 (hereinafter, DP1 to DP4)) to the process PLC 143.

[0081] The marking machines 117a and 117b may be, for example, printing devices. The marking machines 117a and 117b may be configured to form first to fourth reference points DP1 to DP4 on the first electrode sheet ES1 based on a body including a product ID and manufacturing recipe details transmitted from the MES. The marking machines 117a and 117b may be configured to form the first to fourth reference points DP1 to DP4 on the first to fourth uncoated portions U1 to U4.

[0082] The first reference point DP1 may be formed in the first uncoated portion U1, the second reference point DP2 may be formed in the second uncoated portion U2, the third reference point DP3 may be formed in the third uncoated portion U3, and the fourth reference point DP4 may be formed in the fourth uncoated portion U4. The first to fourth reference points DP1 to DP4 may be formed at predetermined intervals on the first electrode sheet ES1.

[0083] Based on the first to fourth reference points DP1 to DP4, the positions of other elements on the first electrode sheet ES1 may be known (may be located). The first to fourth reference points DP1 to DP4 may be used to calibrate coordinate data of elements on a roll map. As an example, in the roll pressing device 200 of FIG. 4, the first to fourth reference points DP1 to DP4 may be used to calibrate the coordinates of the discarded portion of the second electrode sheet ES2 (i.e., the start and end coordinates of the discarded portion of the second electrode sheet ES2) and the coordinates of the seam of the second electrode sheet ES2. As another example, the first to fourth reference points DP1 to DP4 may be used to calibrate the coordinates of the combination of two or more second electrode rolls ER2.

[0084] The marking machine 117a may be fixed, and the marking machine 117b may be movable. The marking machine 117a may be configured to form a first reference point DP1 on a first uncoated portion U1 of the first electrode sheet ES1, which moves in a traveling direction TD, at a fixed position. The marking machine 117b may be configured to move in the lateral direction TD. The marking machine 117b may be configured to form second to fourth reference points DP2, DP3, and DP4 on second to fourth uncoated portions U2, U3, and U4.

[0085] The first to fourth reference points DP1 to DP4 may be repeatedly formed. As a non-limiting example, each of the same first to fourth reference points DP1 to DP4 may be repeated, for example, three times. The first reference point DP1 including the symbol "A101" may be repeated three times in the first uncoated portion U1, the second reference point DP2 including the symbol "A201" may be repeated three times in the second uncoated portion U2, the third reference point DP3 including the symbol "A301" may be repeated three times in the third uncoated portion U3, and the fourth reference point DP4 including the symbol "A401" may be repeated three times in the fourth uncoated portion U4. According to an exemplary embodiment, by repeatedly forming the first to fourth reference points DP1 to DP4, it is possible to prevent the entire reference points from being removed during the partial disposal or notching process of the electrode sheet. The first to fourth reference points DP1 to DP4 may be repeated once, twice, four times, five times, or more times.

[0086] Although the first reference point DP1 and the second reference point DP2 are formed substantially simultaneously, there may be an offset OF1 between the first reference point DP1 and the second reference point DP2 due to tolerances in the marking process. The third reference point DP3 is formed after the formation of the second reference point DP2 is completed, so there may be an offset OF2 between the first reference point DP1 and the third reference point DP3. The offset OF2 may be even larger than the offset OF1. The fourth reference point DP4 is formed after the formation of the third reference point DP3 is completed, so there may be an offset OF3 between the first reference point DP1 and the fourth reference point DP4. The offset OF3 may be even larger than the offset OF2.

[0087] Accordingly, collecting data on the formation of the first to fourth reference points DP1 to DP4 by the marking machines 117a and 117b may include collecting offset data OFD including offsets OF1, OF2, and OF3. The offset data OFD may be collected by the controller 119. The controller 119 may be configured to transmit the offset data OFD to the process PLC 143. The offset data OFD may also be transmitted to the process PLC 143 via the roll map PLC 141.

[0088] According to an exemplary embodiment, each of the first to fourth reference points DP1 to DP4 may include a plurality of symbols. Here, the symbols may refer to symbols, letters, indications, and the like that indicate a certain meaning. As an example, each of the first to fourth reference points DP1 to DP4 may include a first symbol S1 indicating the orientation of the first to fourth reference points DP1 to DP4 and the insertion direction of the electrode rolls (e.g., the insertion direction of the second electrode roll ER2 and the insertion direction of the third electrode roll ER3 in FIG. 2 ), a second symbol S2 indicating the ground portion lane corresponding to the first to fourth reference points DP1 to DP4 among the first to fourth ground portion lanes L1 to L4, and a third symbol S3 and a fourth symbol S4 indicating the formation order of the first to fourth reference points DP1 to DP4.

[0089] As a non-limiting example, the first symbol S1 of each of the first to fourth reference points DP1 may be "A." The first symbol is not limited to alphabets, and each of the first symbols of the first to fourth reference points DP1 may include any symbols, letters, and symbols that can distinguish the orientation of the first symbol. The first symbol S1 may be included in a different set from the second to fourth symbols S2, S3, and S4. For example, if the second through fourth symbols S2, S3, and S4 include Arabic numerals, the first symbol S1 can include any character that can provide orientation information, such as alphabets including Greek, Latin, Mongolian, Armenian, Ngo, Georgian, Braille, Cyrillic, Tifinagh, and Thana, ideographic characters such as Hangul, Syriac, Arabic, and Hebrew abjads, Gujarati, Devanagari, Lao, Malayalam, Burmese, Sinhalese, Ge'ez, Oriya, Canadian First Nations, Kannada, Khmer, Tamil, Thai, Telugu, and Tibetan abjads, Cherokee, and syllabaries such as kana. The first symbol S1 can also be included in the same set as the second through fourth symbols S2, S3, and S4. For example, the first symbol may include a sequence of two or more Arabic numerals, such as 00, 11, 22, and 33 in succession.

[0090] The outer part of the first electrode roll ER1 introduced into the coating apparatus 100 can be wound around the inside of the second electrode roll ER2 (the outer part of the first electrode roll ER1 winds inwards in the second electrode roll ER2). Similarly, the inner part of the first electrode roll ER1 introduced into the coating apparatus 100 can be wound around the outside of the second electrode roll ER2 (the inner part of the first electrode roll ER1 winds outwards in the second electrode roll ER2). The outer part of the second electrode roll ER2 introduced into the roll pressing apparatus 200 of FIG. 4 can be wound around the inside of the third electrode roll ER3 (see FIG. 4). Similarly, the inner part of the second electrode roll ER2 introduced into the roll pressing apparatus 200 of FIG. 4 can be wound around the outside of the third electrode roll ER3 (see FIG. 4). Furthermore, depending on the loading and unwinding methods of the second electrode roll ER2 and the third electrode roll ER3, the left and right of the second electrode sheet ES2 (see FIG. 4) and the third electrode sheet ES3 (see FIG. 7) can be reversed. Here, the running direction MD can be the axis of left and right reversal.

[0091] FIG. 3c shows the first reference point DP1 inverted.

[0092] 3c, in the second electrode sheet ES2 of FIG. 6, the first reference point DP1 to the fourth reference point DP4 may include an inverted first symbol S1. That is, the first symbol S1, "A," is inverted. Based on the inverted orientation of the first symbol S1, the subsequent second to fourth symbols S2, S3, and S4 may be determined to be inverted, thereby allowing the first to fourth symbols S1, S2, S3, and S4 of the first to fourth reference points DP1 to DP4, respectively, to be accurately read.

[0093] 2 to 3b, as another example, in the second electrode sheet ES2 of FIG. 5, the first to fourth reference points DP1 to DP4 may include a non-inverted (i.e., upright) first symbol S1 "A." Based on the non-inverted orientation of the first symbol S1, "A," the subsequent second to fourth symbols S2, S3, and S4 may be determined to be non-inverted, thereby allowing the first to fourth symbols S1, S2, S3, and S4 of the first to fourth reference points DP1 to DP4, respectively, to be accurately read.

[0094] Furthermore, when the first symbol S1 is recognized, the symbol following the first symbol S1 can be determined as the second symbol S2 (i.e., the symbol specifying the corresponding land lane among the first land lane L1 to the fourth land lane L4), the symbol following the second symbol S2 can be determined as the third symbol S3 (i.e., the symbol indicating the tens digit of the formation order), and the symbol following the third symbol S3 can be determined as the fourth symbol S4 (i.e., the symbol indicating the single digit of the formation order). Thus, the second to fourth symbols S2, S3, and S4 of the first to fourth reference points DP1 to DP4 can be determined by the recognition of the first symbol S1 by the reference point sensor 231 (see FIG. 4) and the reference point sensor 331 (see FIG. 7).

[0095] Here, the leading and trailing of symbols are determined based on horizontal writing from left to right, but may be the opposite of the leading and trailing based on the direction of travel MD. That is, at the first reference point DP1, the first symbol S1, "A," leads the second to fourth symbols S2, S3, and S4, "101," but the part of the first plain area U1 where the second to fourth symbols S2, S3, and S4, "101," are formed can be wound by the rewinder 113 earlier than the part of the first plain area U1 where the first symbol S1, "A," is formed.

[0096] As a non-limiting example, the second symbol S2 of each of the first to fourth reference points DP1 to DP4 may indicate a corresponding ground lane among the first to fourth ground lanes L1 to L4. For example, the second symbol S2 of the first reference point DP1 may be "1" representing the first ground lane L1, the second symbol S2 of the second reference point DP2 may be "2" representing the second ground lane L2, the second symbol S2 of the third reference point DP3 may be "3" representing the third ground lane L3, and the second symbol S2 of the fourth reference point DP4 may be "4" representing the fourth ground lane L4.

[0097] The third symbol of each of the first to fourth reference points DP1 to DP4 may represent tens of places in the formation order, and the fourth symbol of each of the first to fourth reference points DP1 to DP4 may represent one place in the formation order. In Figure 3a, the third and fourth symbols of each of the first to fourth reference points DP1 to DP4 may be "01," indicating that the first reference point DP1 is the first reference point formed on the first uncoated portion U1, the second reference point DP2 is the first reference point formed on the second uncoated portion U2, the third reference point DP3 is the first reference point formed on the third uncoated portion U3, and the fourth reference point DP4 is the first reference point formed on the fourth uncoated portion U4.

[0098] However, without being limited to this, the second symbol S2 may include any symbol to indicate the corresponding ground lane among the first ground lane L1 to the fourth ground lane L4, and the third symbol S3 and the fourth symbol S4 may include any symbol to indicate the formation order of the first reference point DP1 to the fourth reference point DP4.

[0099] For example, the alphabets A to I can correspond to the Arabic numerals 0 to 9 as shown in Table 1 below.

[0100] (Second embodiment)

[0101] [Table 1]

[0102] For example, "A101", which is the first to fourth symbols S1, S2, S3, and S4 of the first reference point DP1, can be converted to "ABAB" based on Table 1. As another example, A201, which is the second to fourth symbols S1, S2, S3, and S4 of the second reference point PD2, can be converted to "ACAB" based on Table 1. In the above, an embodiment in which the first to fourth symbols S1, S2, S3, and S4 are arranged in order has been described. However, this is a non-limiting example, and a person skilled in the art can easily arrive at an embodiment in which the first to fourth symbols of the first reference point DP1 to the fourth reference point DP4 are arranged in any permutation.

[0103] (Third embodiment) FIG. 3d shows the first reference point DP1' in a different permutation than FIG. 3b.

[0104] 3d, the second symbol S2 indicating the corresponding land lane among the first land lane L1 to the fourth land lane L4 precedes the first symbol S2, the first symbol S1 indicating the orientation of the reference point follows the second symbol S2, the fourth symbol S4 indicating the first digit of the formation order follows the first symbol S1, and the third symbol S3 indicating the tenth digit of the formation order follows the fourth symbol S4. Any permutation of the first symbol to the fourth symbol S1 includes a total of 24 arrangements, and a person of ordinary skill in the art can easily arrive at the remaining 22 arrangements, excluding those shown in FIGS. 3b and 3d, based on what has been described herein.

[0105] Furthermore, those skilled in the art can easily come up with embodiments in which each of the first to fourth reference points includes an additional symbol for specifying the lane, an embodiment in which three or more symbols are included for specifying the formation order of each of the first to fourth reference points, and an embodiment in which a single symbol specifies the lane and also indicates the orientation of each of the first to fourth reference points. Also, although only one side of the first electrode sheet ES1 is shown in Figure 3a, the coating process can be performed on each of both sides of the first electrode sheet ES1, and the first to fourth reference points DP1 to DP4 can be formed on each of both sides of the first electrode sheet ES1.

[0106] (Fourth embodiment) FIG. 3e shows a first reference point DP'' according to another exemplary embodiment.

[0107] Referring to FIG. 3e, a first reference point DP1″ is similar to the first reference point DP1 of FIG. 3b and may be formed by a dot printing method. The reference points DP may include first to fourth symbols S1′, S2′, S3′, and S4′. The first to fourth symbols S1′, S2′, S3′, and S4′ are substantially the same as the first to fourth symbols S1, S2, S3, and S4 of FIG. 3b, except for the printing method.

[0108] Each of the first to fourth symbols S1', S2', S3', and S4' can include a plurality of dots. The first to fourth symbols S1', S2', S3', and S4' can include a plurality of dots arranged in the shape of a specific symbol. For example, the first symbol S1' can include a plurality of dots arranged in the shape of an "A," the second symbol S2' can include a plurality of dots arranged in the shape of a "1," the third symbol S3' can include a plurality of dots arranged in the shape of a "0," and the fourth symbol S4' can include a plurality of dots arranged in the shape of a "1."

[0109] As an example, the first to fourth symbols S1', S2', S3', and S4' may be formed by inkjet printing. As another example, the first to fourth symbols S1', S2', S3', and S4' may be formed by laser printing.

[0110] (Fifth embodiment) FIG. 3f shows a reference point DP according to another exemplary embodiment.

[0111] Referring to Figure 3f, reference points DP may be formed in the uncoated portions of the electrode sheet, similar to Figure 2. The reference points DP may include first to fourth symbols S1'', S2'', S3'', and S4''.

[0112] The first symbol S1" can indicate the orientation of the reference point DP as well as the ground lane corresponding to the reference point DP. The second symbol S2" can, together with the first symbol S1", indicate the ground lane corresponding to the reference point DP. More specifically, the first symbol S1" can indicate the tens digit of the corresponding ground lane, and the second symbol S2" can indicate the single digit of the corresponding ground lane. The third symbol S3" can indicate the tens digit of the formation order of the reference point DP. The fourth symbol S4" can indicate the single digit of the formation order of the reference point DP.

[0113] Table 2 below shows the correspondence between the first symbol S1 and the second symbol S2 and the land lanes.

[0114] [Table 2]

[0115] Since the first to fourth symbols S1" and S2" of the reference point DP are "F213," the reference point DP can be formed as the 13th in the ungrounded portion corresponding to the 12th landed lane. In Table 2, the alphabets "A, F, R, Y" are presented to indicate the 10 digits of the landed lane, but this is for illustrative purposes only and does not limit the technical spirit of the present invention in any way. The first symbol S1 can also include various symbols, such as other English alphabets that are easily distinguishable in orientation, such as G, J, L, P, Q, and T, and Greek alphabets that are easily distinguishable in orientation, such as Γ (gamma), Δ (delta), Λ (lambda), Π (pi), Ψ (psi), and Ω (omega).

[0116] 1 to 3a, the process PLC 143 may be configured to transmit data on the operation of the marking machines 117a, 117b, including the offset data OD, to the server 1020 (see FIG. 1) via the EIF 1010 (see FIG. 1). The server 1020 (see FIG. 1) may be configured to generate a first roll map of the second electrode roll ER2 processed by the coating apparatus 100 based on the data on the operation of the marking machines 117a, 117b and the data on additional process events.

[0117] Here, the data of the additional process events may include inspection data and measurement data of the first electrode sheet ES1. The measurement data may include a plurality of measurement values ​​expressed as numerical values. For example, the measurement data may include dimensional data of the first electrode sheet ES1, such as thickness and width, data on the amount of coating material loaded on the first electrode sheet ES1, 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, and data on mismatch between the land lane on the upper surface of the first electrode sheet ES1 and the land lane on the lower surface of the first electrode sheet ES1. Here, the loading amount represents the amount of coating material loaded per unit area of ​​the first electrode sheet ES1 and may be the areal density of the coating material.

[0118] The measurement data is processed according to a set method to determine whether the measured portion of the first electrode sheet ES1 is good or bad. If the measured amount of the coating material on the first electrode sheet ES1 (e.g., the loading amount on the first electrode sheet ES1 or the thickness of the first electrode sheet ES1) is within a set range including an upper limit and a lower limit, the corresponding portion of the first electrode sheet ES1 may be determined to be good. If the measured amount of the coating material on the first electrode sheet ES1 (e.g., the loading amount on the first electrode sheet ES1 or the thickness of the first electrode sheet ES1) is smaller than the lower limit or larger than the upper limit, the corresponding portion of the first electrode sheet ES1 may be determined to be bad.

[0119] The measurement data can be collected by instruments. The instruments can include, for example, time delay and integration (TDI) cameras, complementary metal oxide semiconductor (CMOS) image sensors, and time-of-flight (TOF) sensors. The instruments can also include emitters and receivers configured to perform measurements using non-destructive signals such as ultrasound, microwaves, terahertz waves, and infrared. The instruments can also include analog and / or digital sensors such as 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 instruments can 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.

[0120] The measuring device may include a processor configured to generate evaluation data based on the measurement data, and the evaluation data may be collected based on a comparison between measurement values ​​of a plurality of sections within the first electrode sheet ES1 and a set range.

[0121] For example, a measurement (or an average of the measurement values) within a first range can be determined to be normal, a measurement (or an average of the measurement values) within a second range that is even larger than the first range can be determined to be excessive, a measurement (or an average of the measurement values) within a third range that is even larger than the second range can be determined to be very excessive, a measurement (or an average of the measurement values) within a fourth range that is even smaller than the first range can be determined to be insufficient, and a measurement (or an average of the measurement values) within a fifth range that is even smaller than the fourth range can be determined to be very insufficient.

[0122] Here, if the lower limit of the second range is equal to or greater than the upper limit of the first range, the second range is greater than the first range. Similarly, if the upper limit of the fourth range is equal to or less than the lower limit of the first range, the fourth range is smaller than the first range.

[0123] The evaluation values ​​of the evaluation data may be associated with coordinates, for example, each of which may be matched with the start and end coordinates of the portion of the first electrode sheet ES1 for which the evaluation value is calculated.

[0124] The inspection data may be collected by an inspector. The inspector may be configured to inspect the first electrode sheet ES1 to collect inspection data of the first electrode sheet ES1. The inspector may be configured to detect defects, such as surface defects, of the first electrode sheet ES1 based on changes in color and reflectance on the surface of the first electrode sheet ES1. The inspector may be configured to collect inspection data of a portion of the first electrode sheet ES1 that corresponds to (e.g., overlaps) the sensing unit.

[0125] The inspection data collected by the inspector may include process events and judgments regarding the quality of the portions of the first electrode sheet ES1. For example, the inspection data may include data on the appearance of the first electrode sheet ES1 collected by an image-based inspection device such as a vision machine, data on breaks and seams on the first electrode sheet ES1, data on portions of the first electrode sheet ES1 that have been sampled, data on portions of the first electrode sheet ES1 that are scheduled for scrapping, data on the scrapped portions of the first electrode sheet ES1, data on the quality of the coating material and insulating material on the first electrode sheet ES1, data on reference points indicating the position of the first electrode sheet ES1, and defect data such as pinhole defects, crater defects, line defects, crack defects, side ring defects, island defects, fold defects, wrinkle defects, poke defects, and dent defects. The inspector may be any one of a color sensor, a seam sensor, a reference point sensor, and a vision machine.

[0126] The measurement data and test data described above may be time-series data. The measurement data and test data may be temporally ordered. Temporal ordering is a key characteristic of time-series data, which is arranging events in the order in which they occur and arrive for processing. That is, the measurement data and test data may be stored based on the time at which the measurements and tests were performed, and the measurement data and test data may be associated with time. This allows each measurement value of the measurement data to be matched to a time, and each test value of the test data to be matched to a time.

[0127] As an example, the measurement quantity (e.g., the amount of loading on the first electrode sheet ES1 or the thickness of the first electrode sheet ES1) data may include a series of measurement quantity (e.g., the amount of loading on the first electrode sheet ES1 or the thickness of the first electrode sheet ES1) values ​​and time values ​​associated with the series of measurement quantity values. The measurement quantity values ​​and the time values ​​may be matched one-to-one, but are not limited thereto. As another example, the defect data may include a value indicating a defect and a time value associated with the value indicating a defect. Here, indicating a defect means including information regarding at least one of the presence or absence of a defect and the type of defect.

[0128] The roll map can include coordinate-related measurement data and coordinate-related inspection data generated by associating time-series measurement data and inspection data with coordinate data, thereby providing traceability to a previous process during subsequent processes or after a product has been shipped.

[0129] FIG. 4 illustrates a roll pressing apparatus 200 according to an exemplary embodiment.

[0130] 5 and 6 are plan views showing the second electrode sheet ES2.

[0131] Referring to Figures 4 to 6, the roll pressing device 200 may include an unwinder 211, a rewinder 213, a splicing table 215, a scrap port 217, a pressure roll 219, a first rotary encoder 221, a second rotary encoder 223, a reference point sensor 231, a roll map PLC (Programmable Logic Controller) 241, and a process PLC 243.

[0132] The second electrode roll ER2 may be loaded onto the unwinder 211. After being completed in the coating apparatus 100, the second electrode roll ER2 may be transferred to the roll pressing apparatus 200 by a transfer device. The unwinder 211 may be configured to unwind the second electrode sheet ES2 from the second electrode roll ER2. The rewinder 213 may be configured to wind the second electrode sheet ES2 onto the third electrode roll ER3. After the second electrode sheet ES2 is wound onto the third electrode roll ER3 and reaches a winding amount target, the third electrode roll ER3 may be cut in the transverse direction TD and separated. This allows the second electrode sheet ES2 to move between the unwinder 211 and the rewinder 213.

[0133] The first rotary encoder 221 may be configured to sense the amount of the second electrode sheet ES2 unwound from the second electrode roll ER2 by the unwinder 211. Thus, the first rotary encoder 221 may be configured to generate an input amount signal UWAS2 indicating the length of the second electrode sheet ES2 unwound by the unwinder 211. The first rotary encoder 221 may be configured to transmit the input amount signal UWAS2 to the roll map PLC 241.

[0134] The second rotary encoder 223 may be configured to sense the amount of the second electrode sheet ES2 wound onto the third electrode roll ER3 by the rewinder 213. Thus, the second rotary encoder 223 may be configured to generate an exhaustion amount signal WAS2 indicating the length of the second electrode sheet ES2 wound by the rewinder 213. The second rotary encoder 223 may be configured to transmit the exhaustion amount signal WAS2 to the roll map PLC 241.

[0135] The roll map PLC 241 may be configured to collect coordinate data CD2 of the second electrode sheet ES2 based on the consumed amount signal WAS2 and / or the input amount signal UWAS2 of the second electrode sheet ES2. As an example, the roll map PLC 241 may determine the movement distance of the second electrode sheet ES2 based on the consumed amount signal WAS2 of the second electrode sheet ES2. Thus, the roll map PLC 241 may be configured to determine the position within the second electrode sheet ES2 of the portion of the second electrode sheet ES2 being wound by the rewinder 213 at each time an event occurs on the second electrode sheet ES2. Here, the event may include the detection of the first to fourth reference points DP1 to DP4 by the reference point sensor 231 and the processing of the second electrode sheet ES2 by the pressure roll 219.

[0136] As another example, the roll map PLC241 may determine the movement distance of the second electrode sheet ES2 based on the input amount signal UWAS2 of the second electrode sheet ES2, or may determine the movement distance of the second electrode sheet ES2 based on both the consumption amount signal WAS2 and the input amount signal UWAS2. Hereinafter, the technical idea of ​​the present invention will be described with reference to an embodiment in which the roll map PLC241 collects coordinate data CD2 based on the consumption amount signal WAS2 of the second electrode sheet ES2, as a non-limiting example.

[0137] The coordinate data CD2 may include coordinates that are matched to each portion of the second electrode sheet ES2. That is, each arbitrary point on the second electrode sheet ES2 may be matched to a coordinate. The coordinates may be one-dimensional quantities in the direction of travel MD of the second electrode sheet ES2, but are not limited thereto. The coordinates may also be two-dimensional quantities in the direction of travel MD of the second electrode sheet ES2 and the lateral direction TD of the second electrode sheet ES2.

[0138] The reference point sensor 231 may be configured to sense the first to fourth reference points DP1 to DP4 on the second electrode sheet ES2. The reference point sensor 231 may include a sensing unit 231S and a processing unit 231P. The sensing unit 231S and the processing unit 231P may be connected to each other by wire or wirelessly.

[0139] According to an exemplary embodiment, the sensing unit 231S may include an OCR (Optical Character Reader). The sensing unit 231S may be configured to sense the first to fourth reference points DP1 to DP4 to generate a reference point sensing signal DSS1. The sensing unit 231S may be configured to transmit the reference point sensing signal DSS1 to the processing unit 231P.

[0140] According to an exemplary embodiment, the number of sensing units 231S may be less than the number of the first uncoated area U1 to the fourth uncoated area U4. For example, one sensing unit 231S may cover the four uncoated areas U1 to U4. This reduces the cost of constructing the reference point sensor 231.

[0141] The sensing unit 231S may be configured to sense one of the first to fourth reference points DP1 to DP4 at a fixed position. Depending on the direction in which the second electrode roll ER2 is loaded and the direction in which the second electrode sheet ES2 is unwound, the sensing unit 231S may be configured to sense the first reference point DP1 on the first uncoated portion U1 as shown in FIG. 5 or the fourth reference point DP4 on the fourth uncoated portion U4 as shown in FIG. 6.

[0142] The sensing unit 231S may be disposed at a position to sense the second reference point DP2 on the second uncoated portion U2 of Fig. 5 or the third reference point DP3 on the third uncoated portion U3 of Fig. 6. The sensing unit 231S may be disposed at a position to sense the third reference point DP3 on the third uncoated portion U3 of Fig. 5 or the second reference point DP2 on the second uncoated portion U2 of Fig. 6. The sensing unit 231S may be disposed at a position to sense the fourth reference point DP4 on the fourth uncoated portion U4 of Fig. 5 or the first reference point DP1 on the first uncoated portion U1 of Fig. 6.

[0143] The first to fourth reference points DP1 to DP4 may be formed at the same positions on the upper and lower surfaces of the second electrode sheet ES2 in the traveling direction MD. Thus, the positions of the first to fourth reference points DP1 to DP4 on the upper and lower surfaces of the second electrode sheet ES2 may be determined by detecting the first to fourth reference points DP1 to DP4 on either the upper or lower surface of the second electrode sheet ES2.

[0144] The processing unit 231P may be configured to collect reference point data DSD1 based on the reference point sensing signal DSS1 and the coordinate data CD2. The processing unit 231P may be configured to collect the reference point data DSD1 by matching the reference point sensing signal DSS1 generated by reading any one of the first to fourth reference points DP1 to DP4 with the coordinates of the coordinate data CD2. As a result, the reference point data DSD1 may include a value indicating one of the first to fourth coated lanes L1 to L4 corresponding to the detected one among the first to fourth datum points DP1 to DP4, a value indicating the formation order of the detected reference point among the first to fourth reference points DP1 to DP4, and the coordinates of the detected reference point among the first to fourth reference points DP1 to DP4.

[0145] In order to match the reference point sensing signal DSS1 of any one of the first to fourth reference points DP1 to DP4 with the coordinates of the coordinate data CD2, the processing unit 231P may be configured to calibrate the coordinates of the coordinate data CD2. The processing unit 231P may be configured to calibrate the coordinates of the coordinate data CD2 based on the length of the second electrode sheet ES2 between the portion of the second electrode sheet ES2 wound by the rewinder 213 and the portion of the second electrode sheet ES2 sensed by the sensing unit 231S, and match the calibrated coordinates to the reference point sensing signal DSS1.

[0146] The processing unit 231P may be configured to transmit the reference point data DSD1 to the roll map PLC 241. The roll map PLC 241 may be configured to transmit the reference point data DSD1 to the process PLC 243. The process PLC 243 may be configured to transmit the reference point data DSD1 and the additional process event data to the server 1020 (see FIG. 1) via the EIF 1010 (see FIG. 1). The server 1020 (see FIG. 1) may be configured to generate a second roll map of the third electrode roll ER3 processed by the roll pressing device 200 based on the reference point data DSD1 and the additional process event data.

[0147] The process PLC 243 can be configured to control the operation of the unwinder 211, the rewinder 213, the scrap port 217, and the pressure roll 219 based on the reference point data DSD1. The process PLC 243 can be configured to generate signals for operating and interrupting the unwinder 211, the rewinder 213, the scrap port 217, and the pressure roll 219. The signals for operating and interrupting the unwinder 211, the rewinder 213, the scrap port 217, and the pressure roll 219 can be generated based on the body and reference point data DSD1, which includes product ID and manufacturing recipe details.

[0148] The roll pressing apparatus 200 may include additional inspection and measurement devices, similar to the coating apparatus 100 of Fig. 2. When a defect on the second electrode sheet ES2 identified by the defect data in the roll map of the second electrode roll ER2 or the inspection and measurement devices in the roll pressing apparatus 200 approaches the splicing table 215, the process PLC 243 may be configured to generate a signal to slow down the moving speed of the second electrode sheet ES2 or to interrupt the winding and unwinding of the unwinder 211 and the rewinder 213.

[0149] After cutting the start position of the defect on the splicing table 215 (or a position adjacent to the start position of the defect, taking into account a process margin), the scrap port 217 can be configured to wind up the defective portion DES of the second electrode sheet ES2, as represented by the dashed line. After the defective portion DES of the second electrode sheet ES2 has been fully wound up by the scrap port 217, the second electrode sheet ES2 connected to the scrap port 217 and the second electrode sheet ES2 connected to the unwinder 211 can be separated. Then, the portion of the second electrode sheet ES2 connected to the unwinder 211 and the portion of the second electrode sheet ES2 connected to the rewinder 213 can be spliced ​​together to continue the current process. The portion of the second electrode sheet ES2 connected to the unwinder 211 and the portion of the second electrode sheet ES2 connected to the rewinder 213 can be spliced ​​together on the splicing table 215.

[0150] The portion of the second electrode sheet ES2 that has passed through the splicing table 215 can be pressed by a pressure roll 219 and then wound up by a rewinder 213 onto a third electrode roll ER3.

[0151] FIG. 7 illustrates a slitting apparatus 300 according to an exemplary embodiment.

[0152] 8 and 9 are plan views showing the third electrode sheet ES3.

[0153] Referring to Figures 7 to 9, the slitting device 300 may include an unwinder 311, rewinders 313a and 313b, a slitting knife 315, a guide roll 316, a first rotary encoder 321, a second rotary encoder 323a and 323b, a reference point sensor 331, a roll map PLC (Programmable Logic Controller) 341, and a process PLC 343.

[0154] The third electrode roll ER3 may be loaded onto the unwinder 311. After being completed in the roll pressing device 200, the third electrode roll ER3 may be transferred to the slitting device 300 by a transfer device. The unwinder 311 may be configured to unwind the third electrode sheet ES3 from the third electrode roll ER3. The third electrode sheet ES3 may be cut by a slitting knife 315 to form individualized electrode sheets ES3a and ES3b. The individualized electrode sheet ES3a may be referred to as a first individualized electrode sheet, and the individualized electrode sheet ES3b may be referred to as a second individualized electrode sheet. Each of the individualized electrode sheets ES3a and ES3b may include a ground lane. For example, the individualized electrode sheet ES3a may include a first ground lane L1, and the individualized electrode sheet ES3b may include a second ground lane L2. The guide roll 316 can be disposed on the moving path of the individualized electrode sheet ES3b so as to separate the moving paths of the individualized electrode sheet ES3a and the individualized electrode sheet ES3b.

[0155] 7, for ease of illustration, only two individualized electrode sheets ES3a and ES3b are shown, but the separation of the electrode sheets can be determined based on the number of ground lanes on the electrode sheets. For example, because the third electrode sheet ES3 includes the first ground lane L1 to the fourth ground lane L4, the third electrode sheet ES3 can be cut into four individualized electrode sheets.

[0156] The rewinders 313a, 313b can be configured to wind the individualized electrode sheets ES3a, ES3b onto the individualized electrode rolls ER4a, ER4b. The individualized electrode sheets ES3a, ES3b are wound onto the individualized electrode rolls ER4a, ER4b, and after reaching a winding amount target, the individualized electrode rolls ER4a, ER4b can be cut and separated in the transverse direction TD. The individualized electrode roll ER4a may be referred to as a first individualized electrode roll, and the individualized electrode roll ER4b may be referred to as a second individualized electrode roll. The first rotary encoder 321 may be configured to sense the amount of the third electrode sheet ES3 unwound from the third electrode roll ER3 by the unwinder 311. Thus, the first rotary encoder 321 may be configured to generate an input amount signal UWAS3 indicating the length of the third electrode sheet ES3 unwound by the unwinder 311. The first rotary encoder 321 may be configured to transmit the input amount signal UWAS3 to the roll map PLC 341.

[0157] The second rotary encoders 323a and 323b may be configured to sense the amount of the third electrode sheet ES3 wound onto the individualized electrode rolls ER4a and ER4b by the rewinders 313a and 313b. Accordingly, the second rotary encoders 323a and 323b may be configured to generate consumed amount signals WAS3a and WAS3b indicating the lengths of the individualized electrode sheets ES3a and ES3b wound by the rewinders 313a and 313b. The second rotary encoders 323a and 323b may be configured to transmit the consumed amount signals WAS3a and WAS3b to the roll map PLC 341.

[0158] The roll map PLC341 can be configured to collect coordinate data CD3a of the electrode sheet ES3a and coordinate data CD3b of the electrode sheet ES3a based on the input amount signal UWAS3 of the third electrode sheet ES3 and / or the consumption amount signals WAS3a, WAS3b of the individualized electrode sheets ES3a, ES3b.

[0159] For example, the roll map PLC 341 may determine the movement distance of the individualized electrode sheets ES3a and ES3b based on the consumption amount signals WAS3a and WAS3b of the third electrode sheet ES3. Thus, the roll map PLC 341 may be configured to determine the position within the individualized electrode sheets ES3a and ES3b of the portion of the individualized electrode sheets ES3a and ES3b being wound by the rewinders 313a and 313b at each time an event occurs in the individualized electrode sheets ES3a and ES3b. Here, the event within the slitting device 300 may include sensing any one of the first to fourth reference points DP1 to DP4.

[0160] As another example, the roll map PLC 341 may determine the movement distance of the individualized electrode sheets ES3a, ES3b based on the input amount signal UWAS3 of the third electrode sheet ES3, or may determine the movement distance of the individualized electrode sheets ES3a, ES3b based on the consumption amount signals WAS3a, WAS3b and the input amount signal UWAS3, respectively. Hereinafter, the technical idea of ​​the present invention will be described with reference to an embodiment in which the roll map PLC 341 collects coordinate data CD3a, CD3b based on the consumption amount signals WAS3a, WAS3b of the individualized electrode sheets ES3a, ES3b, as a non-limiting example.

[0161] The coordinate data CD3a, CD3b may include coordinates that are matched to each portion of the individualized electrode sheets ES3a, ES3b. That is, each arbitrary point on the individualized electrode sheets ES3a, ES3b may be matched with a coordinate. The coordinates may be, but are not limited to, a one-dimensional quantity in the direction of travel MD of the individualized electrode sheets ES3a, ES3b. The coordinates may also be two-dimensional quantities in the direction of travel MD of the electrode sheets ES3a, ES3b and the lateral direction TD of the individualized electrode sheets ES3a, ES3b.

[0162] The reference point sensor 331 may be configured to sense any one of the first to fourth reference points DP1 to DP4 on the third electrode sheet ES3. The reference point sensor 331 may include a sensing unit 331S and a processing unit 331P. The sensing unit 331S and the processing unit 331P may be connected to each other via a wire or wirelessly.

[0163] According to an exemplary embodiment, the sensing unit 331S may include an OCR. The sensing unit 331S may be configured to sense the first to fourth reference points DP1 to DP4 to generate a reference point sensing signal DSS2. The sensing unit 331S may be configured to transmit the reference point sensing signal DSS2 to the processing unit 331P.

[0164] According to an exemplary embodiment, the number of sensing units 331S may be less than the number of the first uncoated area U1 to the fourth uncoated area U4. For example, one sensing unit 331S may cover the four uncoated areas U1 to U4. This reduces the cost of constructing the reference point sensor 331.

[0165] The sensing unit 331S may be configured to sense one of the first to fourth reference points DP1 to DP4 at a fixed position. Depending on the direction in which the third electrode roll ER3 is loaded and the direction in which the third electrode sheet ES3 is unwound, the sensing unit 331S may be configured to sense the first reference point DP1 on the first uncoated portion U1 as shown in Fig. 8 or the fourth reference point DP4 on the fourth uncoated portion U4 as shown in Fig. 9.

[0166] The sensing unit 331S may be disposed at a position to sense the second reference point DP2 on the second uncoated portion U2 of Fig. 8 or the third reference point DP3 on the third uncoated portion U3 of Fig. 9. The sensing unit 331S may be disposed at a position to sense the third reference point DP3 on the third uncoated portion U3 of Fig. 8 or the second reference point DP2 on the second uncoated portion U2 of Fig. 9. The sensing unit 331S may be disposed at a position to sense the fourth reference point DP4 on the fourth uncoated portion U4 of Fig. 8 or the first reference point DP1 on the first uncoated portion U1 of Fig. 9.

[0167] As described above, the reference point sensor 331 can determine the positions of the first reference point DP1 to the fourth reference point DP4 on either the upper or lower surface of the third electrode sheet ES3 by detecting the first reference point DP1 to the fourth reference point DP4 on either the upper or lower surface of the third electrode sheet ES3.

[0168] The processing unit 331P may be configured to collect reference point data DSD2 based on the reference point sensing signal DSS2 and the coordinate data CD3a, CD3b. The processing unit 331P may be configured to collect the reference point data DSD2 by matching the reference point sensing signal DSS2 generated by reading any one of the first to fourth reference points DP1 to DP4 with the coordinates of the coordinate data CD3a, CD3b. As a result, the reference point data DSD2 may include a value indicating a ground portion lane corresponding to the detected reference point among the first to fourth reference points DP1 to DP4 among the first to fourth ground portions L1 to L4, a value indicating the formation order of the detected reference point among the first to fourth reference points DP1 to DP4, and the coordinates of the detected reference point among the first to fourth reference points DP1 to DP4.

[0169] In order to match the reference point sensing signal DSS2 of any one of the first to fourth reference points DP1 to DP4 with the coordinates of the coordinate data CD3a and CD3b, the processing unit 331P may be configured to calibrate the coordinates of the coordinate data CD3a and CD3b. The processing unit 331P may be configured to calibrate the coordinates of the coordinate data CD3a and CD3b based on the length of the third electrode sheet ES3 between the portion of the third electrode sheet ES3 wound by the rewinder 313 and the portion of the third electrode sheet ES3 sensed by the sensing unit 331S, and match the calibrated coordinates to the reference point sensing signal DSS2.

[0170] The processing unit 331P may be configured to transmit the reference point data DSD2 to the roll map PLC 341. The roll map PLC 341 may be configured to transmit the reference point data DSD2 to the process PLC 343. The process PLC 343 may be configured to transmit the reference point data DSD2 and the additional process event data to the server 1020 (see FIG. 1) via the EIF 1010 (see FIG. 1). The server 1020 (see FIG. 1) may be configured to generate a third roll map of the individualized electrode rolls ER4a, ER4b processed by the slitting apparatus 300 based on the reference point data DSD2 and the additional process event data.

[0171] The process PLC 343 may be configured to transmit the sensed reference point data DSD2 and the additional process event data to the server 1020 (see FIG. 1) via the EIF 1010 (see FIG. 1). The server 1020 (see FIG. 1) may be configured to generate a third roll map of the individualized electrode rolls ER4a, ER4b processed by the slitting apparatus 300 based on the sensed reference point data DSD2 and the additional process event data.

[0172] 1, 2, 4, and 7, the controller 119, the processing units 231P and 331P, the roll map PLCs 141, 241, and 341, the process PLCs 143, 243, and 343, the EIF 1010, and the server 1020 may be implemented using hardware, firmware, software, or a combination thereof. For example, the controller 119, the processing units 231P and 331P, the roll map PLCs 141, 241, and 341, the process PLCs 143, 243, and 343, the EIF 1010, and the server 1020 may include computing devices such as a workstation computer, a desktop computer, a laptop computer, or a tablet computer. The controller 119, processing units 231P, 331P, role map PLCs 141, 241, 341, process PLCs 143, 243, 343, EIF 1010, and server 1020 may include any one of a simple controller, a complex processor such as a microprocessor, a CPU, or a GPU, a processor configured by software, dedicated hardware, and firmware. The controller 119, processing units 231P, 331P, role map PLCs 141, 241, 341, process PLCs 143, 243, 343, EIF 1010, and server 1020 may be implemented by a general-purpose computer or application-specific hardware such as a digital signal processor (DSP), a field programmable gate array (FPGA), or an application-specific integrated circuit (ASIC).

[0173] The server 1020 may include a physical server or a cloud server. The server 1020 may provide data and analysis results to operators through various frameworks. The framework may include a protocol that supports data transmission so that the display device 1030 can visualize the data through a user interface and provide updated visualizations when new data is calculated by the server 1020. The protocol that supports the data transmission may use HTML, JavaScript, and / or JSON.

[0174] The server 1020 may include various APIs (Application Programming Interfaces) for storing data in databases and other data management tools. The APIs may also be used to retrieve data in the databases of various data management systems. The data management systems may provide access to the databases, pull data from the databases, retrieve data, and generate metrics, where metrics are tools for visualizing data. Metrics include measurements generated over time and may be used for application monitoring and generating status alerts.

[0175] The server 1020 may be configured to generate a first roll map of the second electrode roll ER2 completed in the coating apparatus 100, a second roll map of the third electrode roll ER3 completed in the roll pressing apparatus 200, and a third roll map of the individualized electrode rolls ER4a and ER4b completed in the slitting apparatus 300. The first roll map may include offset data OFD, and the second roll map and the third roll map may be generated based on the offset data OFD.

[0176] The server 1020 can transmit a visualization command VC to the display device 1030, and the display device 1030 can visualize the first to third role maps and display the visualized role maps. The first to third role maps can be displayed by the display device 1030. The first to third role maps can be aligned in one direction, which can facilitate tracking of the process history.

[0177] 1 and 4 to 6, the reference point data DSD1 may be generated by detecting one of the first to fourth reference points DP1 to DP4 (e.g., the first reference point DP1). The server 1020 may be configured to generate reference point data representing coordinates of the second to fourth reference points DP2, DP3, and DP4 based on the reference point data DSD1 and the offset data OFD (see FIG. 2). The reference point data of the second to fourth reference points DP2, DP3, and DP4 may include values ​​indicating the formation order of each of the second to fourth reference points DP2, DP3, and DP4, and coordinates matched to the values ​​indicating the formation order.

[0178] According to an exemplary embodiment, the coordinates of the undetected reference points (e.g., the second to fourth reference points DP2, DP3, and DP4) can be calculated by performing an operation between the detected reference point (e.g., the first reference point DP1) and the offset data OFD (see FIG. 2). The operation can include subtraction and addition.

[0179] As shown in FIG. 5, when the first reference point DP1 is detected, the coordinates of the second reference point DP2 can be calculated by subtracting the offset OF1 from the coordinates of the first reference point DP1, the coordinates of the third reference point DP3 can be calculated by subtracting the offset OF2 from the coordinates of the first reference point DP1, and the coordinates of the fourth reference point DP4 can be calculated by subtracting the offset OF3 from the coordinates of the first reference point DP1.

[0180] As shown in FIG. 6, when the fourth reference point DP4 is detected, the coordinates of the first reference point DP1 can be calculated by adding the offset OF3 to the coordinates of the fourth reference point DP4, the coordinates of the second reference point DP2 can be calculated by subtracting the offset OF1 from the coordinates of the first reference point DP1, and the coordinates of the third reference point DP3 can be calculated by subtracting the offset OF2 from the coordinates of the first reference point DP1.

[0181] In this manner, the server 1020 may be configured to generate reference point data for undetected reference points among the first to fourth reference points DP1 to DP4 based on the reference point data DSD1 and offset data OFD (see FIG. 2) for detected reference points among the first to fourth reference points DP1 to DP4. The reference point data DSD1 may be referred to as first reference point data, and the reference point data for undetected reference points among the first to fourth reference points DP1 to DP4 may be referred to as second reference point data. The server 1020 may be configured to generate a third roll map for the third electrode roll ER3 completed by the roll pressing process based on the first reference point data and the second reference point data.

[0182] 1 and 7 to 9, the reference point data DSD2 may be generated by detecting one of the first to fourth reference points DP1 to DP4 (e.g., the first reference point DP1). The server 1020 may be configured to generate reference point data representing coordinates of the second to fourth reference points DP2, DP3, and DP4 based on the reference point data DSD2 and the offset data OFD (see FIG. 2). The reference point data of the second to fourth reference points DP2, DP3, and DP4 may include values ​​indicating the formation order of each of the second to fourth reference points DP2, DP3, and DP4, and coordinates matched to the values ​​indicating the formation order.

[0183] As shown in FIG. 8, when the first reference point DP1 is detected, the coordinates of the second reference point DP2 can be calculated by adding an offset OF1 to the coordinates of the first reference point DP1, the coordinates of the third reference point DP3 can be calculated by adding an offset OF2 to the coordinates of the first reference point DP1, and the coordinates of the fourth reference point DP4 can be calculated by adding an offset OF3 to the coordinates of the first reference point DP1.

[0184] As shown in FIG. 9, when the fourth reference point DP4 is detected, the coordinates of the first reference point DP1 can be calculated by subtracting the offset OF3 from the coordinates of the fourth reference point DP4, the coordinates of the second reference point DP2 can be calculated by adding the offset OF1 to the coordinates of the first reference point DP1, and the coordinates of the third reference point DP3 can be calculated by adding the offset OF2 to the coordinates of the first reference point DP1.

[0185] In this manner, the server 1020 may be configured to generate reference point data for undetected reference points among the first to fourth reference points DP1 to DP4 based on the reference point data DSD2 and offset data OFD for detected reference points among the first to fourth reference points DP1 to DP4. The reference point data DSD2 may be referred to as third reference point data, and the reference point data for undetected reference points among the first to fourth reference points DP1 to DP4 may be referred to as fourth reference point data. The server 1020 may be configured to generate a third roll map of the individualized electrode rolls ER4a and ER4b completed by the slitting apparatus 300 based on the third reference point data and the fourth reference point data.

[0186] The third roll map may include data related to the corresponding ground lane among the first ground lane L1 to the fourth ground lane L4. For example, the third roll map of the singulated electrode roll ER4a may include data indicating the first ground lane L1, and the third roll map of the singulated electrode roll ER4b may include data indicating the second ground lane L2. After singulation by the slitting device 300, each of the singulated electrode rolls ER4a and ER4b includes only a single ground lane. However, because the third roll map includes data indicating the corresponding ground lane, traceability of the secondary battery manufacturing process can be improved.

[0187] When the reference point data DSD2 is generated by sensing the first reference point DP1, the third roll map of the individualized electrode roll ER3a including the first uncoated portion U1 and the first ground portion lane L1 can be generated based on the reference point data DSD2 of the first reference point DP1, the third roll map of the individualized electrode roll ER3b including the second uncoated portion U2 and the second ground portion lane L2 can be generated based on the reference point data DSD2 and the offset data OFD, the third roll map of the individualized electrode roll including the third uncoated portion U3 and the third ground portion lane L3 can be generated based on the reference point data of the third reference point DP3 generated based on the reference point data DSD2 and the offset data OFD, and the third roll map of the individualized electrode roll including the fourth uncoated portion U4 and the fourth ground portion lane L4 can be generated based on the reference point data DSD2 and the offset data OFD.

[0188] 1, 2, 4, and 7, the secondary battery manufacturing system 10 may implement a plug-in architecture together with an API for data acquisition to provide plug-and-play connections for sensors, measuring instruments, and inspection instruments, thereby allowing resources at a particular process step and site to be easily transferred to other processes and sites, or new resources to be easily introduced to each process step and site.

[0189] In some embodiments, the secondary battery manufacturing system 10 may further include a manual input system that allows an operator to input manufacturing data. The secondary battery manufacturing system 10 may allow operator data input using an input tool or computer-based input of manufacturing data, such as scraping an Excel file. The manual input system may be, for example, a Supervisory Control and Data Acquisition (SCADA) HMI (Human-Machine Interface). SCADA typically includes a combination of software and hardware, such as PLCs and remote terminal units (RTUs). The HMI is a screen that supports communication between an operator and the SCADA system and is a key element of the SCADA system. For example, manual input via the HMI may include selecting defect types and reflecting performance at the time of completion.

[0190] In some embodiments, the operations of the controller 119, processing units 231P, 331P, role map PLCs 141, 241, 341, process PLCs 143, 243, 343, EIF 1010, and server 1020 may be embodied as instructions stored on a machine-readable medium that can be read and executed by one or more processors. Here, a machine-readable medium may include any mechanism for storing and / or transmitting information in a form readable by a machine (e.g., a computing device). For example, a machine-readable medium may include read-only memory (ROM), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory, electrical, optical, acoustic, or other forms of radio signals (e.g., carrier waves, infrared signals, digital signals, etc.), and any other signals.

[0191] The controller 119, processing units 231P, 331P, role map PLCs 141, 241, 341, process PLCs 143, 243, 343, EIF 1010, and server 1020 may be configured with firmware, software, routines, and instructions to perform the operations described above or any of the processes described below. For example, the controller 119, processing units 231P, 331P, role map PLCs 141, 241, 341, process PLCs 143, 243, 343, EIF 1010, and server 1020 may be instantiated in memory.

[0192] (Sixth embodiment) FIG. 10 is a flowchart illustrating a method for manufacturing a secondary battery according to an exemplary embodiment.

[0193] 2, 3a, and 10, in step P110, the first electrode sheet ES1 unwound from the first electrode roll ER1 can be coated with electrode slurry so that the first to fourth ground lanes L1 to L4 are formed. The coating of the electrode slurry onto the first electrode sheet ES1 can be performed by a die coater 115 in the coating apparatus 100.

[0194] Next, in step P120, first to fourth reference points DP1 to DP4 may be formed on the first electrode sheet ES1. The first to fourth reference points DP1 to DP4 may be formed by marking machines 117a and 117b.

[0195] Subsequently, in P130, the first electrode sheet ES1 can be wound onto the second electrode roll ER2. The second electrode roll ER2 can be wound by the rewinder 113.

[0196] 4 to 6 and 10, in P140, a reference point (e.g., first reference point DP1) of the second electrode sheet ES2 unwound from the second electrode roll ER2 can be sensed to collect reference point data DSD1. To unwound the second electrode sheet ES2 from the second electrode roll ER2, the second electrode roll ER2 completed in the coating apparatus 100 (see FIG. 2) can be transferred to the roll pressing device 200 and loaded onto the unwinder 211. The second electrode sheet ES2 can be unwound from the second electrode roll ER2 by the unwinder 211.

[0197] Collecting the reference point data DSD1 may include sensing a reference point (e.g., the first reference point DP1) on the second electrode sheet ES2 to generate a reference point sensing signal DSS1, calibrating coordinates of the coordinate data CD2, and matching the calibrated coordinates to the reference point sensing signal DSS1. The collection of the reference point data DSD1 may be performed by the reference point sensor 231. In P140, the second to fourth reference points DP2, DP3, and DP4 may be sensed instead of the first reference point DP1 to collect the reference point data DSD1.

[0198] 1, 4 to 6, and 10, in P150, reference point data for each of the undetected reference points (e.g., the second to fourth reference points DP2, DP3, and DP4) can be generated based on the reference point data DSD1 of the detected reference point (e.g., the first reference point DP1) and the offset data OFD (see FIG. 2). The reference point data for each of the second to fourth reference points DP2, DP3, and DP4 can be generated by the server 1020. Subsequently, a roll map for the third electrode roll ER3 completed by the roll pressing device 200 can be generated based on the reference point data DSD1 of the detected reference point (e.g., the first reference point DP1) and the reference point data for each of the undetected reference points (e.g., the second to fourth reference points DP2, DP3, and DP4).

[0199] Subsequently, in P160, the second electrode sheet ES2 can be wound onto the third electrode roll ER3. The third electrode roll ER3 can be wound by the rewinder 213.

[0200] 1 and 7 to 10, in P170, a reference point (e.g., first reference point DP1) of the third electrode sheet ES3 unwound from the third electrode roll ER3 can be sensed to collect reference point data DSD2. To unwound the third electrode sheet ES3 from the third electrode roll ER3, the third electrode roll ER3 completed in the roll pressing device 200 (see FIG. 4) can be transferred to the slitting device 300 and loaded onto the unwinder 311. The third electrode sheet ES3 can be unwound from the third electrode roll ER3 by the unwinder 311.

[0201] Collecting the reference point data DSD2 may include sensing a reference point (e.g., the first reference point DP1) on the third electrode sheet ES3 to generate a reference point sensing signal DSS2, calibrating the coordinates of the coordinate data CD2, and matching the calibrated coordinates to the reference point sensing signal DSS2. The collection of the reference point data DSD2 may be performed by the reference point sensor 331. In P170, the second to fourth reference points DP2, DP3, and DP4 may be sensed instead of the first reference point DP1 to collect the reference point data DSD1.

[0202] 1, 4 to 6, and 10, in P180, reference point data for each of the undetected reference points (e.g., the second to fourth reference points DP2, DP3, and DP4) can be generated based on the reference point data DSD2 of the detected reference point (e.g., the first reference point DP1) and the offset data OFD (see FIG. 2). The reference point data for each of the second to fourth reference points DP2, DP3, and DP4 can be generated by the server 1020. Subsequently, a third roll map for the individualized electrode rolls ER4a and ER4b completed by the roll pressing device 200 can be generated based on the reference point data DSD2 of the detected reference point (e.g., the first reference point DP1) and the reference point data for each of the undetected reference points (e.g., the second to fourth reference points DP2, DP3, and DP4). One of the third roll maps may include reference point data DSD2 for the first reference point DP1, another of the third roll maps may include reference point data for the second reference point DP2, another of the third roll maps may include reference point data for the third reference point DP3, and another of the third roll maps may include reference point data for the fourth reference point DP4.

[0203] (Seventh embodiment) FIG. 11 is a plan view of a positive electrode EP according to an exemplary embodiment.

[0204] FIG. 12 is a cross-sectional view taken along the line 11I-11I' in FIG.

[0205] 11 and 12, the positive electrode EP can include a positive electrode current collector SP and a positive electrode active material layer CP. The positive electrode EP can be provided by a notching process or a notching and lamination process. The positive electrode EP can be provided by forming positive electrode tabs TP on the individualized electrode rolls ER4a and ER4b shown in FIG. 7 and cutting the electrode sheets unwound from the individualized electrode rolls ER4a and ER4b so that they are separated in the transverse direction for each designed unit length.

[0206] The thickness of the positive electrode current collector SP may range from about 3 μm to about 500 μm. The positive electrode current collector SP may not induce chemical changes in the final secondary battery and may have high conductivity. The positive electrode current collector SP may include, for example, any one of stainless steel, aluminum, nickel, titanium, calcined carbon, and aluminum. The positive electrode current collector SP may also include stainless steel surface-treated with carbon, nickel, titanium, silver, or the like. The surface of the positive electrode current collector SP may include a micro-textured structure to enhance the adhesion of the active material. The shape of the positive electrode current collector SP may include any one of a film, sheet, foil, net, porous material, foam, and nonwoven fabric.

[0207] The positive electrode active material layer CP can be formed by a coating apparatus 100 shown in Fig. 2. The positive electrode active material layer CP can be formed on each of the upper and lower surfaces of the positive electrode current collector SP. Unlike Fig. 12, the positive electrode active material layer CP may be formed on only one of the upper and lower surfaces of the positive electrode current collector SP.

[0208] Each of the positive electrode active material layers CP can include a positive electrode active material. The positive electrode active material is a material capable of undergoing an electrochemical reaction. The positive electrode active material can be a lithium transition metal oxide. Examples of the positive electrode active material include layered compounds such as lithium cobalt oxide (LiCoO2) and lithium nickel oxide (LiNiO2) substituted with one or more transition metals; lithium manganese oxide substituted with one or more transition metals; and lithium manganese oxide with the chemical formula LiNi 1-y M y Lithium nickel-based oxide represented by O2 (where M is any one of Co, Mn, Al, Cu, Fe, Mg, B, Cr, Zn, and Ga, and 0.01≦y≦0.7); Li 1+z Ni 1 / 3 Co 1 / 3 Mn 1 / 3 O2, Li 1+z Ni 0.4 Mn 0.4 Co0.2 Li like O2 1+z Ni b Mn c Co 1-(b+c+d) M d O (2-e) A e (wherein -0.5≦z≦0.5, 0.1≦b≦0.8, 0.1≦c≦0.8, 0≦d≦0.2, 0≦e≦0.2, b+c+d<1, M is any one of Al, Mg, Cr, Ti, Si, and Y, and A is any one of F, P, and Cl); and a lithium nickel cobalt manganese composite oxide represented by the chemical formula Li 1+x M 1-y M' y PO 4-z X z (wherein M is a transition metal, more specifically, any one of Fe, Mn, Co, and Ni; M′ is any one of Al, Mg, and Ti; X is any one of F, S, and N; −0.5≦x≦+0.5; 0≦y≦0.5; and 0≦z≦0.1).

[0209] The positive electrode current collector SP may include a positive electrode tab TP. The positive electrode tab TP may be an uncoated portion remaining after the notching process. The width of the positive electrode tab TP may be different from the width of each positive electrode active material layer CP. The width of the positive electrode tab TP may be narrower than the width of each positive electrode active material layer CP. The positive electrode tab TP may protrude from the positive electrode active material layer CP. The positive electrode tab TP may be used to connect the positive electrodes EP and to connect to an external connection terminal such as an electrode lead.

[0210] 3a, 3b, 11, and 12, a reference point DPP may be located on the positive electrode tab TP. The reference point DPP may be any one of the first to fourth reference points DP1 to DP4. Accordingly, the reference point DPP may include a first symbol S1 indicating the orientation of the first to fourth reference points DP1 to DP4 and the insertion direction of the electrode roll, a second symbol S2 indicating the reference points corresponding to the first to fourth reference points DP1 to DP4 among the first to fourth land portion lanes L1 to L4, and a third symbol S3 and a fourth symbol S4 indicating the formation order of the first to fourth reference points DP1 to DP4.

[0211] (Eighth embodiment) 13 to 18 are plan views of positive electrodes EPa, EPb, EPc, EPd, EPe, and EPf according to other exemplary embodiments.

[0212] Referring to FIG. 13, the positive electrode EPa can be the same as the positive electrode EP in FIG. 12, except for the reference point DPPa.

[0213] 3a, 3b, and 13, a reference point DPPa may be located on the positive electrode tab TP. The reference point DPPa may originate from any one of the first to fourth reference points DP1 to DP4. According to an exemplary embodiment, the reference point DPPa may include only some of the first to fourth symbols S1, S2, S3, and S4. According to an exemplary embodiment, the reference point DPPa may include only the first to third symbols S1, S2, and S3. According to an exemplary embodiment, the reference point DPPa may not include the fourth symbol S4. In this example, the fourth symbol S4 may be removed during the notching process for forming the positive electrode tab TP.

[0214] (Ninth embodiment) Referring to FIG. 14, the positive electrode EPb may be the same as the positive electrode EP in FIG. 12, except for the reference point DPPb.

[0215] 3a, 3b, and 14, a reference point DPPb may be located on the positive electrode tab TP. The reference point DPPb may originate from any one of the first to fourth reference points DP1 to DP4. According to an exemplary embodiment, the reference point DPPb may include only some of the first to fourth symbols S1, S2, S3, and S4. According to an exemplary embodiment, the reference point DPPb may include only the first symbol S1 and the second symbol S2. According to an exemplary embodiment, the reference point DPPb may not include the third symbol S3 and the fourth symbol S4. In this example, the third symbol S3 and the fourth symbol S4 may be removed during the notching process for forming the positive electrode tab TP.

[0216] (Tenth embodiment) Referring to FIG. 15, the positive electrode EPc may be the same as the positive electrode EP in FIG. 12, except for the reference point DPPc.

[0217] 3a, 3b, and 15, a reference point DPPc may be located on the positive electrode tab TP. The reference point DPPc may originate from any one of the first to fourth reference points DP1 to DP4. According to an exemplary embodiment, the reference point DPPc may include only some of the first to fourth symbols S1, S2, S3, and S4. According to an exemplary embodiment, the reference point DPPc may include only the first symbol S1. According to an exemplary embodiment, the reference point DPPc may not include the second to fourth symbols S2, S3, and S4. In this example, the second to fourth symbols S2, S3, and S4 may be removed during the notching process for forming the positive electrode tab TP.

[0218] (Eleventh embodiment) Referring to FIG. 16, the positive electrode EPd can be the same as the positive electrode EP in FIG. 12, except for the reference point DPPd.

[0219] 3a, 3b, and 16, a reference point DPPd may be located on the positive electrode tab TP. The reference point DPPd may originate from any one of the first to fourth reference points DP1 to DP4. According to an exemplary embodiment, the reference point DPPd may include only some of the first to fourth symbols S1, S2, S3, and S4. According to an exemplary embodiment, the reference point DPPd may include only the second to fourth symbols S2, S3, and S4. According to an exemplary embodiment, the reference point DPPd may not include the first symbol S1. In this example, the first symbol S1 may be removed during the notching process for forming the positive electrode tab TP.

[0220] (Twelfth embodiment) Referring to FIG. 17, the positive electrode EPe can be the same as the positive electrode EP of FIG. 12, except for the reference point DPPe.

[0221] 3a, 3b, and 17, a reference point DPPe may be located on the positive electrode tab TP. The reference point DPPe may originate from any one of the first to fourth reference points DP1 to DP4. According to an exemplary embodiment, the reference point DPPe may include only some of the first to fourth symbols S1, S2, S3, and S4. According to an exemplary embodiment, the reference point DPPe may include only the third symbol S3 and the fourth symbol S4. According to an exemplary embodiment, the reference point DPPe may not include the first symbol S1 and the second symbol S2. In this example, the first symbol S1 and the second symbol S2 may be removed during the notching process to form the positive electrode tab TP.

[0222] (Thirteenth embodiment) Referring to FIG. 18, the positive electrode EPf may be the same as the positive electrode EP in FIG. 12, except for the reference point DPPf.

[0223] 3a, 3b, and 18, a reference point DPPf may be located on the positive electrode tab TP. The reference point DPPf may originate from any one of the first to fourth reference points DP1 to DP4. According to an exemplary embodiment, the reference point DPPf may include only some of the first to fourth symbols S1, S2, S3, and S4. According to an exemplary embodiment, the reference point DPPf may include only the fourth symbol S4. According to an exemplary embodiment, the reference point DPPf may not include the first to third symbols S1, S2, and S3. In this example, the first to third symbols S1, S2, and S3 may be removed during the notching process to form the positive electrode tab TP.

[0224] 3a, 3b, and 14 to 18, examples are shown in which the reference points DPPa, DPPb, DPPc, DPPd, DPPe, and DPPf include only some of the first to fourth symbols S1, S2, S3, and S4. Based on what is described herein, a person skilled in the art can easily arrive at an embodiment in which some of the first to fourth symbols S1, S2, S3, and S4 are partially cut off during the formation of the positive electrode tab TP.

[0225] (Fourteenth embodiment) FIG. 19 is a plan view of a negative electrode EN according to an exemplary embodiment.

[0226] FIG. 20 is a cross-sectional view taken along the line 19I-19I' in FIG.

[0227] 19 and 20, the negative electrode EN can include a negative electrode current collector SN and a negative electrode active material layer CN. The negative electrode EN can be provided by a notching process or a notching and lamination process. The negative electrode EN can be provided by forming a negative electrode tab TN on the individualized electrode rolls ER4a and ER4b shown in FIG. 7 and cutting the electrode sheet unwound from the individualized electrode rolls ER4a and ER4b so that the electrode sheet is separated in the transverse direction for each designed unit length.

[0228] The thickness of the negative electrode current collector SN may range from about 3 μm to about 500 μm. The negative electrode current collector SN may not induce chemical changes in the final secondary battery and may have high conductivity. The negative electrode current collector SN may include any one of copper, stainless steel, aluminum, nickel, titanium, sintered carbon, and aluminum-cadmium alloy. The negative electrode current collector SN may also include stainless steel surface-treated with carbon, nickel, titanium, silver, or the like. The surface of the negative electrode current collector SN may include a micro-textured structure to enhance the adhesion of the active material. The shape of the negative electrode current collector SN may include any one of a film, sheet, foil, net, porous material, foam, and nonwoven fabric.

[0229] The negative electrode active material layer CN can be formed by a coating apparatus 100 shown in Fig. 2. The negative electrode active material layer CN can be formed on each of the upper and lower surfaces of the negative electrode current collector SN. Unlike Fig. 20, the negative electrode active material layer CN may be formed on only one of the upper and lower surfaces of the negative electrode current collector SN.

[0230] Each of the negative electrode active material layers CN may contain a negative electrode active material. The negative electrode active material may contain, for example, carbon such as non-graphitizable carbon or graphite-based carbon. The negative electrode active material may contain, for example, Li x Fe2O3(0≦x≦1), Li x WO2(0≦x≦1), Sn x Me 1-x Me' y O z(Here, Me is any one of Mn, Fe, Pb, and Ge, Me' is any one of Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, and halogen; 0 < x ≤ 1; 1 ≤ y ≤ 3; 1 ≤ z ≤ 8), etc. Metal composite oxides can be included. The negative electrode active material can include, for example, any one of lithium metal; lithium alloy; silicon; silicon-based alloy; and tin-based alloy. The negative electrode active material can include, for example, metal oxides such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, and Bi2O5. The negative electrode active material can also include, for example, conductive polymers such as polyacetylene; Li-Co-Ni-based materials, etc.

[0231] The negative electrode current collector SN can include the negative electrode tab TN. The negative electrode tab TN can be the plain part remaining after the notching process. The width of the negative electrode tab TN may be different from the width of each of the negative electrode active material layers CN. The width of the negative electrode tab TN may be even narrower than the width of each of the negative electrode active material layers CN. The negative electrode tab TN can protrude from the negative electrode active material layer CN. The negative electrode tab TN can be used for connection between the negative electrodes EN and connection with external connection terminals such as electrode leads.

[0232] Referring to FIGS. 3a, 3b, 19, and 20, a reference point DPN may be present on the negative electrode tab TN. The reference point DPN may be any one of the first reference point DP1 to the fourth reference point DP4. Thereby, the reference point DPN can include the first symbol to the fourth symbol S1, S2, S3, S4. The reference point DPN can also include only a part of the first symbol to the fourth symbol S1, S2, S3, S4, as shown in FIGS. 13 to 18.

[0233] Based on what is described here, an ordinary technician in the industry can easily reach an embodiment in which the reference point DPN includes only a part of the first symbol to the fourth symbol S1, S2, S3, S4, similar to FIGS. 13 to 18.

[0234] A data matrix DM may also be formed on the negative electrode tab TN. The data matrix DM may be formed by methods such as laser printing and ink printing. According to an exemplary embodiment, the data matrix DM may be a two-dimensional barcode. The data matrix DM may include information about an electrode ID for identifying the negative electrode tab TN. That is, the electrode ID may be read by sensing the data matrix DM with a sensor such as a bar code reader (BCR) or an optical character reader (OCR).

[0235] The electrode ID may include a lot ID indicating the individualized electrode roll ER4a, ER4b from which the negative electrode tab TN (or the negative electrode EN including the negative electrode tab TN) originates, and coordinates indicating the position of the negative electrode tab TN (or the negative electrode EN including the negative electrode tab TN) within the individualized electrode roll ER4a, ER4b. The coordinates may be determined based on a cut count indicating the number of times cutting to form the negative electrode EN has been performed, or may be determined by an encoder configured to sense the amount of unwound material from the individualized electrode roll ER4a, ER4b. The number of cuts may be reset at predetermined time intervals (e.g., every day).

[0236] As described below with reference to FIG. 21 , a negative electrode EN can be combined with a positive electrode EP to provide an electrode assembly EA. Because it is not possible to form a data matrix DM on the positive electrode tab TP of the positive electrode EP, the electrode ID can further include information for identifying the positive electrode EP to be combined with the negative electrode EN. More specifically, the electrode ID can include the lot ID of the individualized electrode roll ER4a, ER4b from which the positive electrode EP is derived, and coordinates indicating the position of the positive electrode EP within the individualized electrode roll ER4a, ER4b. That is, the electrode ID can include a positive electrode lot ID, positive electrode coordinates, negative electrode lot ID, and negative electrode coordinates. The electrode ID can further include additional information for identifying the site and facility where the negative electrode EN and positive electrode EP were produced.

[0237] 19 and 20 show the data matrix DM and the reference points DPN on the same surface TNS1 of the negative electrode tab TN, but this is for illustrative purposes only and does not limit the technical idea of ​​the present invention in any way. The reference points DPN may be on the surface TNS1, and the data matrix DM may be on the surface TNS2 opposite to the surface TNS1.

[0238] (Fifteenth embodiment) FIG. 21 is a plan view of an electrode assembly EA according to an exemplary embodiment.

[0239] FIG. 22 is a cross-sectional view taken along the line 21I-21I' in FIG.

[0240] 21 and 22, the electrode assembly EA may include a positive electrode EP, a negative electrode EN, and a separator SR between the positive electrode EP and the negative electrode EN. The positive electrode EP is substantially the same as that described with reference to FIGS. 11 and 12, and the negative electrode EN is substantially the same as that described with reference to FIGS. 19 and 20.

[0241] The separator SR physically separates the positive electrode EP and the negative electrode EN, thereby preventing a short circuit between them. The separator SR may be configured to provide a path through which lithium ions can move through the electrolyte. The separator SR may have ion conductivity. The separator SR may include any one of polyethylene, polypropylene, a ceramic-coated insulating film, and a safety-reinforced separator (SRS).

[0242] Unlike the illustration in Figure 22, the electrode assembly EA may include two or more positive electrodes EP, two or more separators SR, and two or more negative electrodes EN. In this case, the two or more positive electrodes EP and the two or more negative electrodes EN may be alternately stacked. That is, one of the negative electrodes EN may be located between two adjacent positive electrodes EP, or one of the positive electrodes EP may be located between two adjacent negative electrodes EN. A separator SR may be interposed between the positive electrode EP and the negative electrode EN.

[0243] The present invention has been described in more detail above with reference to 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]

[0244] 10 Secondary battery manufacturing system 100 Coating Equipment 111 Unwinder 113 Rewinder 115 Die Coater 117a marking machine 117b marking machine 119 Controller 121 1st rotary encoder 123 Second rotary encoder 131 Inspection equipment 200 Roll pressing device 211 Unwinder 213 Rewinder 215 Splicing Table 217 Scrapport 219 Pressure Roll 221 1st rotary encoder 223 Second rotary encoder 231 Reference Point Sensor 231P Processing section 231S Sensing unit 241 Role Map 243 Process 300 Slitting Machine 311 Unwinder 313 Rewinder 313a Rewinder 313b Rewinder 315 Slitting Knife 316 Guide Roll 321 1st rotary encoder 323a Second rotary encoder 323b Second rotary encoder 331 Reference Point Sensor 331P Processing section 331S Sensing Unit 341 Role Map 343 Process 1020 Server 1030 Display device

Claims

1. a step of coating an electrode sheet unwound from an electrode roll with an electrode slurry to form a plurality of ground lanes, the step including a plurality of uncoated areas between the plurality of ground lanes; and forming a plurality of reference points on the electrode sheet; 10. A method of manufacturing a secondary battery, wherein each of the plurality of reference points includes a first symbol indicating an orientation of the reference point and a second symbol indicating a corresponding one of the plurality of land lanes.

2. The method of manufacturing a secondary battery according to claim 1 , wherein each of the plurality of reference points includes a third symbol indicating an order in which the plurality of reference points are formed.

3. The method for manufacturing a secondary battery according to claim 2 , wherein the third symbol indicates a ten-digit number of the formation order.

4. The method for manufacturing a secondary battery according to claim 2 or 3, wherein each of the plurality of reference points further includes a fourth symbol indicating the formation order of the plurality of reference points.

5. The method for manufacturing a secondary battery according to claim 4 , wherein the fourth symbol indicates a digit in the formation order.

6. the first symbol comprises an alphabet; The method for manufacturing a secondary battery according to claim 4 , wherein each of the second symbol, the third symbol, and the fourth symbol includes a number.

7. 5. The method of manufacturing a secondary battery according to claim 4, wherein the second symbol follows the first symbol, the third symbol follows the second symbol, and the fourth symbol follows the third symbol.

8. 5. The method of manufacturing a secondary battery according to claim 4, wherein the first symbol follows the second symbol, the fourth symbol follows the first symbol, and the third symbol follows the fourth symbol.

9. The method of manufacturing a secondary battery according to claim 1 , wherein the first symbol further indicates a corresponding land lane among the plurality of land lanes.

10. The method of manufacturing a secondary battery according to claim 1 , wherein the first symbol indicates a tens digit of a corresponding land lane among the plurality of land lanes.

11. The method of manufacturing a secondary battery according to claim 1 , wherein the second symbol indicates a digit of a corresponding land lane among the plurality of land lanes.

12. The method of manufacturing a secondary battery according to claim 1 , wherein the plurality of reference points are formed by a dot printing method.

13. The method for manufacturing a secondary battery according to claim 1 , wherein the plurality of reference points are formed by inkjet printing.

14. The method for manufacturing a secondary battery according to claim 1 , wherein the plurality of reference points are formed by laser printing.

15. The method of manufacturing a secondary battery according to claim 1 , wherein the plurality of reference points are formed in the plurality of uncoated portions.

16. a current collector including an electrode tab; a positive electrode active material layer on the current collector, An electrode having a reference point on the electrode tab.

17. 17. The electrode of claim 16, wherein the reference points include a first symbol, a second symbol, a third symbol, and a fourth symbol.

18. 18. The electrode of claim 17, wherein the first symbol indicates an orientation of the reference point.

19. 18. The electrode of claim 17, wherein the second symbol indicates the land lane from which the electrode originates.

20. The electrode according to any one of claims 17 to 19, wherein the third symbol and the fourth symbol each indicate an order in which the reference points are formed.

21. 21. The electrode of claim 20, wherein the third symbol indicates a tens digit of the formation order.

22. 21. The electrode of claim 20, wherein the fourth symbol indicates a digit in the formation order.

23. The electrode of claim 17, wherein the first symbol is an alphabet, and each of the second to fourth symbols is a number.

24. The electrode of claim 16 , wherein the reference points include first to third symbols.

25. 17. The electrode of claim 16, wherein the reference points include a first symbol and a second symbol.

26. The electrode of claim 16 , wherein the reference point comprises a symbol.

27. 17. The electrode of claim 16, further comprising a data matrix on the electrode tab.

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