Method for producing electrode

Abstract

The invention relates to a method for producing an electrode from an electrode-continuous web (9), comprising: a coating process in which the electrode-continuous web (9) is coated with an electrode coating (5); and a cutting process in which the uncoated region (11) is cut, in particular while forming the arrester flag (7). The method has a marking process in which an uncoated region (11) of the electrode-continuous web (9) is marked for product tracking in the case of origin certification or quality complaints. According to the invention, the marking process is an imprint process in which a continuous imprint pattern (19), which is void-free and varied in the production direction (F), is imprint as a mark into the uncoated region (11) of the electrode-continuous web (9).

Description

Technical Field

[0001] The invention relates to a method for producing an electrode according to the preamble of claim 1 and to a process arrangement according to claim 10 . Background Art

[0002] In the electrode / diaphragm stack of a battery cell, electrode sheets (i.e. anode sheets and cathode sheets) are stacked alternately with diaphragm sheets. The corresponding electrode sheets have a current arrester formed by aluminum foil or copper foil. The current arrester is usually coated with an electrode coating on both sides. In addition, the current arrester has a laterally protruding uncoated arrester flag.

[0003] Such electrode sheets are produced in this type of battery cell production as follows: First, a foil-shaped electrode continuous web is provided. The electrode continuous web is then subjected to a coating process, in which the electrode continuous web is coated with an electrode coating. A cutting process is then carried out, in which the uncoated areas of the electrode continuous web are cut while forming discharger flags. In a further process sequence, separation is carried out, in which the coated and cut electrode continuous web is separated into electrode sheets.

[0004] Web materials are processed in the production of battery cells. They are aluminum and copper foils that are coated into electrode rolls that are several thousand meters long. The coating is carried out in two rounds: first the upper side of the web is coated, then the lower side. In the further manufacturing process, electrode sheets are cut from the web and battery cells are constructed. For product tracking in the case of proof of origin or quality complaints ("track and trace"), it is advantageous to identify the individual electrode sheets in the battery cell and to be able to associate them with the electrode roll with the recorded material and manufacturing parameters.

[0005] According to a first known solution, after coating, colored spray marks are printed onto the web in the uncoated area of ​​the foil using an inkjet printer (inkjet) in a running process, and more precisely at regular intervals (e.g. every meter) or only when anomalies occur (error marks). These marks are detected in a subsequent production step by means of a sensor system.

[0006] According to a second known solution, after coating, a mark is inscribed on the web by means of a laser in the uncoated area of ​​the foil in a running process, and more precisely at regular intervals (e.g. every meter) or only in the event of anomalies (error marks). This mark is detected in a subsequent production step by means of a sensor system.

[0007] According to a third known solution, after coating, an adhesive marker (such as a label) is adhered to the web in the uncoated area of ​​the foil during the ongoing process and, more precisely, when an anomaly occurs (error marking), this marking is detected in a subsequent production step by means of a sensor system.

[0008] All three solutions known from the prior art have in common that the marking is applied only after the second coating run. Thus, the production can only be traced back to after the second coating run. Therefore, information about the first coating run and the foil is lost. Before this, the marking cannot be applied, because the uncoated area on which the marking can be made is only visible after the coating. Another disadvantage is that the marking on the web is carried out at intervals rather than without gaps. For example, if every new meter is marked, many individual sheets within a meter remain without marking. It is not possible to shorten the spacing in order to mark each individual sheet, because it is not clear at the time of marking where the individual sheets are cut. In addition, there are special disadvantages:

[0009] In inkjet printer solutions, the sprayed markings require time to dry and can become smudged or unreadable during further processing. Ink is a foreign substance that should neither get onto the electrode coating in order not to trigger negative chemical reactions in the battery cells nor remain on uncoated areas of the foil, since here the individual sheets are welded to one another and the welds are weakened by foreign substances. Inkjet printers are maintenance-intensive, can become clogged, and the print heads must be cleaned regularly. In addition, high operating costs result from ink consumption and low fail-safety, since, for example, an empty ink tank or clogged lines lead to incorrect or missing markings.

[0010] Laser solutions require high operating costs due to the requirements for worker protection because of the laser. In addition, the material removal from the web results in uncontrolled emission of metal particles, which remain on the electrode coating and can cause short circuits in the battery cells. In addition, there are high equipment costs due to the laser source and the suction device, and high energy costs due to the laser source. In addition, laser solutions are sensitive to changes in production parameters such as the web speed, because the heat input for branding the mark also changes when the web is running slowly or quickly.

[0011] When using adhesive markers, such as labels (third solution), these markers cannot be installed in the battery cells, but they must be removed again. Weakly attached markers may fall off during further processing. Markers protruding from the electrode roll may be bent or torn off during further processing. In addition, high operating costs are generated due to the consumption of labels, and the failure safety is low, because, for example, an empty label roll leads to missing markings.

[0012] An electrode arrangement for a battery cell is known from US 2012 / 0295145 A1. A method for producing an electrode sheet is known from WO 2013 / 018254 A1. Summary of the invention

[0013] The object of the present invention is to provide a method and a process arrangement by means of which an operationally reliable product tracking is achieved in comparison with the prior art.

[0014] This object is achieved by the features of claim 1 or claim 10. Preferred developments are disclosed in the dependent claims.

[0015] The invention is based on a production method in which an electrode continuous web is coated with an electrode coating in a coating process. This is followed by a cutting process, in which the uncoated areas of the electrode continuous web are cut off, in particular when forming arrester flags. The method also has a marking process, in which the uncoated areas of the electrode continuous web are marked. The marking can be used to trace the product, and more precisely in the case of proof of origin or quality complaints. According to the characterizing part of claim 1, the marking process is implemented as an embossing process. In the embossing process, a continuous, gap-free, changing embossing pattern in the production direction is embossed as a marking into the uncoated areas of the electrode continuous web before the cutting process, in particular also before the coating process.

[0016] According to the invention, an uncoated aluminum or copper foil is provided with a void-free mark in the absence of foreign matter. The void-free mark is continuously embossed onto the foil using an embossing roller. The molded structure has a depth of less than 1 μm and does not affect the mechanical stability of thin foils up to 4 μm. The mark that varies in the longitudinal direction of the web is produced by a combination of different patterns on the embossing roller and different diameters on the upper and lower sides of the web. The arrangement and diameter of the embossing roller are designed so that this combination is repeated only after an entire electrode roll (for example after 10,000 m). The embossing roller is connected to a rotary encoder that detects the position of the embossing roller and the current position of the web. The mark can be derived from the position of the embossing roller and the position of the web can therefore be inferred. A sensor device (such as a camera) can decode the mark.

[0017] The core of the invention is that the marking is not done with foreign substances (such as ink, labels), but by embossing. In addition, the marking is gap-free, i.e. continuous. In addition, the marking varies in the longitudinal direction of the web by a combination of geometric patterns on the upper and lower sides of the foil.

[0018] By way of example, a plurality of embossing rollers can be embossed with different diameters and can be arranged above and below the web in different patterns and on a plurality of tracks. The web is moved by the embossing rollers. The embossing rollers are connected to a rotary encoder which detects the current rotational position of the embossing rollers. In addition, the current position of the web is detected via a deflection drum connected to the rotary encoder. The rotary encoder sends a signal to a control device which associates the current embossing roller position with the current web position and stores it. In a subsequent production step, a camera detects the embossed pattern on the web. The camera is connected to a control device in which possible pattern combinations are stored. The position of the embossing roller and the current web position are inferred from the detected pattern.

[0019] Important aspects of the invention are emphasized again in detail below: Thus, in one technical implementation, a database, an optical sensor and a comparator module are provided for product tracking. In the database, an embossing pattern or parameters associated therewith that vary in the longitudinal direction of the web are stored as a function of the longitudinal position of the web. With the aid of the optical sensor, the embossing pattern embossed into the electrode-continuous web can be optically detected in sections in the image at a later process time. In the comparator module, the optically detected image can be compared with the sections of the embossing pattern stored in the database. In the case of agreement, the longitudinal position of the embossing pattern section is associated with the optically detected image, thereby enabling product tracking.

[0020] The embossing tool used in the embossing process can preferably be a roller unit with at least one embossing roller. During the embossing process, the embossing roller rolls on the uncoated area of ​​the electrode-continuous web. The embossing roller has an embossing profile at the periphery, which during the embossing process is embossed into the uncoated area of ​​the electrode-continuous web while forming an embossed pattern.

[0021] When detecting and storing the embossing pattern in the database, it is of great significance to reduce the computing cost and the equipment cost. Therefore, it is preferably possible to abandon the reading of the image data of the embossing pattern into the database, which will be accompanied by a high memory requirement. Instead, parameters related to the embossing pattern can be read into the database, such as the rotational position of at least one embossing roller related to the embossing pattern. For this purpose, the embossing roller has a rotary encoder, which is connected to the control unit signal of the embossing roller. The rotational position of the embossing roller is related to the current longitudinal position of the web, at which the current embossing process is carried out. In addition, the rotational position of the embossing roller is related to the embossing pattern-section currently produced in the embossing process. Therefore, the embossing pattern-section related thereto can be derived from the rotational position of the embossing roller in a simple manner. In this context, instead of the embossing pattern, the rotational position of the embossing roller can be stored in the database as a parameter related thereto.

[0022] Preferably, the roll unit has at least one embossing roll pair, through the roll gap of which the uncoated region of the electrode-continuous web is guided. It is particularly advantageous here that the roll unit has a plurality of embossing roll pairs arranged in a row. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] An embodiment of the present invention is described below with reference to the accompanying drawings.

[0024] in:

[0025] Figures 1 to 8 Different views are shown in each case, based on which the production method according to the invention is explained. DETAILED DESCRIPTION

[0026] exist Figure 1 1 shows an electrode sheet 1 produced by the method according to the invention, which is a component of an electrode / separator stack (not shown) of a battery cell. The electrode sheet 1 is constructed with a central current arrester foil 3 (for example an aluminum foil or a copper foil), which is coated on both sides with an electrode coating 5. The current arrester foil 3 is extended laterally outward with an uncoated arrester flag 7.

[0027] The electrode sheet 1 is made of a substrate-foil web 10 ( Figure 2 ). The substrate-foil web is first guided in an uncoated state through a marking station M (described later) Figure 2 ). Then in ( Figure 2The substrate foil web 10 is divided into a total of four electrode continuous webs 9 at longitudinal cutting lines 15 (shown in FIG. 1 ). The electrode continuous webs 9 are subjected to a coating process, wherein each electrode continuous web 9 is coated with an electrode coating 5 on its upper side and on its lower side. Alternatively, the substrate foil web 10 can also be subjected to a coating process. After passing through the marking station M, Figure 2 The substrate-foil web 10 is transferred via a deflection reel 13 to the next process station.

[0028] exist Figure 5 , a web section of an already coated electrode-continuous web 9 is shown. Accordingly, the electrode-continuous web 9 has, at its right longitudinal edge side, an uncoated region 11 extending in the manufacturing direction F, in which a three-track embossing pattern 19 is embossed, by way of example. The electrode-continuous web 9 thus provided is subjected to a cutting process. In the cutting process, the cutting lines 36 ( Figure 5 ) Cut the electrode continuous web 9. Here, the arrester flags 7 are punched out in the coating-free regions 11 of the electrode continuous web 9. In addition, the electrode sheets 1 are separated from the electrode continuous web 9.

[0029] exist Figure 2 and Figure 3 In the marking station M depicted in FIG. 1 , the regions 11 of the substrate foil web 10 that remain uncoated after the electrode coating are marked with an embossing pattern 19 in an embossing process. Figure 5 The marking can be performed on one side or on both sides. The embossed pattern 19 enables product tracking in the case of origin certification or quality complaints of the manufactured electrode sheet 1 .

[0030] According to the invention, the marking (i.e. the embossing pattern) is carried out without foreign matter, so that the chemical reaction of the battery cell is not negatively affected. Welding can also be carried out directly at the marked location, and more precisely without weakening the weld due to foreign matter. Coating can also be carried out directly at the marking without negative interaction.

[0031] In the embodiment shown, the roller unit 17 ( Figure 2 ) The embossed pattern 19 is embossed into the uncoated area 11 ( Figure 5 ). The embossed pattern 19 is in the non-coated area 11 ( Figure 5 ) in each of which extends continuously and without gaps in the manufacturing direction F. In addition, the embossed pattern 19 changes along the manufacturing direction F. Figure 2 In the embodiment, the roller unit 17 consists of a total of four embossing roller pairs 21, 22, 23, 24 arranged one after the other in the production direction F. Figure 3In the embodiment of the present invention, the roller unit 17 has, by way of example, only three roller pairs 22, 24, 26. On each of the embossing rollers, an embossing contour 30 is formed on the outer circumference, which embosses an embossing pattern 19 into the coating-free region 11 during the embossing process.

[0032] exist Figure 2 In the embodiment, the embossing roller pairs 21 to 24 and the deflection drum 13 each have a rotary encoder 20, which is signal-connected to an electronic control unit 25, with the aid of which the embossing roller can be controlled. The rotational position D1(x) to D4(x) of the embossing roller is detected with the aid of the rotary encoder 20. The rotational position D1(x) to D4(x) of the embossing roller is related to the current longitudinal position x of the web, at which the current embossing process is carried out. The longitudinal position x of the web is detected with the aid of the rotary encoder 20 of the deflection drum 13. In addition, the rotational position D1(x) to D4(x) of the embossing roller is related to the embossing pattern segment A(x) currently embossed during the embossing process ( Figure 8 ). Thus, for each longitudinal position x of the web, the associated embossing pattern section A(x) can be derived from the rotational positions D1 (x) to D4 (x) of the roller pairs 21 to 24 .

[0033] according to Figure 2 In order to perform product tracking, a database 27, an optical sensor 29 and a comparator module 31 are provided. The embossing pattern 19 and / or the rotational positions D1(x) to D4(x) of the roller pairs 21 to 24 that vary in the longitudinal direction of the web and / or the rotational positions D1(x) to D4(x) associated therewith are read into the database 27 by the electronic control unit 25 according to the corresponding longitudinal position x of the web and stored there in a table, such as Figure 7 As described in Figure 7 In the embodiment, the web longitudinal positions x1 to x5, the embossing patterns 19 according to the web longitudinal positions x1 to x5 and the rotational positions D1 (x) to D4 (x) of the roller pairs 21 to 24 associated therewith are stored in a table.

[0034] exist Figure 1 In the electrode sheet 11 shown in , product tracking is performed by way of example. For this purpose, the arrester flag 7 of the electrode sheet 11 is optically detected as an image B by means of an optical sensor 29. The image B is directed to a comparator module 31. In addition, the data x, D1(x) to D4(x) and / or the embossing pattern 19 stored in the database 27 are read into the comparator module 31.

[0035] As from Figure 8As is known from , in the comparator module 31 the image B is compared with the segment A(x) of the embossing pattern 19 stored in the database 27 (or the parameters D1(x), D2(x), D3(x), D4(x) associated therewith). Figure 8 In the example, image B is made to coincide with the embossed pattern segment A(x4). Based on the detected coincidence of image B with the embossed pattern segment A(x4), the web-direction position x4 is associated with the optically detected image B. In this way, the web-direction position of image B is identified, which is required for product tracking.

[0036] exist Figure 7 In the database 27 shown in FIG. 1 , by way of example, both the embossing pattern 19 and the rotational positions D1 (x) to D4 (x) of the embossing roller pairs 21 to 24 are stored as parameters associated with the embossing pattern 19 .

[0037] In the embodiment shown, the embossing pattern is implemented in three tracks, wherein each track is constructed of strips spaced apart from each other and extending in the longitudinal direction. Alternatively, the embossing pattern 19 can also be implemented in any other way. In addition, the number of tracks can also be selected arbitrarily. By way of example, the marking station M can be integrated in the coating device. Alternatively, the marking station M can be integrated during the foil manufacturing, or implemented as a separate device. The optical sensor 29 can be, by way of example, a line scan camera, or implemented by a comparison sensor.

[0038] List of reference numerals:

[0039] 1 electrode sheet

[0040] 3-Current Arrester - Foil

[0041] 5. Electrode coating

[0042] 7 Discharger flag

[0043] 9 electrodes - continuous web

[0044] 10Substrate - Foil Web

[0045] 11 Uncoated area

[0046] 13 Deflection reel

[0047] 15 Longitudinal cutting section

[0048] 17 roller unit

[0049] 19 Embossed pattern

[0050] 20 Rotary encoder

[0051] 21 to 24 embossing roller pairs

[0052] 25 Electronic Control Units

[0053] 27 Database

[0054] 29 optical sensors

[0055] 30 embossing profile

[0056] 31 Comparator Module

[0057] 36 cutting line

[0058] x-direction web position

[0059] D1(x), D2(x), D3(x), D4(x) Rotational position of the stamping roller

[0060] B-picture

[0061] FManufacturing direction

[0062] A(x) Imprint pattern-section

[0063] M Mark Station

Claims

1. A method for producing an electrode from an electrode-continuous web (9) having - a coating process, wherein the electrode-continuous web (9) is coated with an electrode coating (5), - a cutting process, in which the coating-free regions (11) are cut off, in particular when forming arrester flags (7), wherein: The method comprises a marking process, in which the uncoated areas (11) of the electrode-continuous web (9) are marked for product tracking in the case of proof of origin or quality complaints, characterized in that the marking process is an embossing process, in which a continuous, gap-free and variable embossing pattern (19) is embossed as a mark into the uncoated areas (11) of the electrode-continuous web (9).

2. The method according to claim 1, characterized in that The marking process is carried out before the cutting process, in particular before the coating process.

3. The method according to claim 1 or 2, characterized in that: For product tracking, the following are provided: - a database (27) in which embossing patterns (19) varying in the longitudinal direction of the web or parameters associated therewith (D1(x), D2(x), D3(x), D4(x)) are stored as a function of the longitudinal position (x); an optical sensor (29) which optically detects the embossing pattern (19) in sections in an image at a later process time; and a comparator module (31) which compares the optically detected image (B) with a section (A(x)) of the embossed pattern (19) stored in said database (27), And in the case of agreement, the longitudinal position (x) of the embossed pattern section (A(x)) is associated with the optically detected image (B).

4. The method according to claim 1, 2 or 3, characterized in that: The embossing tool used in the embossing process is a roller unit (17) with at least one embossing roller (21 to 24), which rolls on the uncoated area (5) of the electrode-continuous web (9), and in particular the embossing roller (21 to 24) has an embossing profile (30) at the periphery, which is embossed into the uncoated area (11) of the electrode-continuous web (9) while forming the embossing pattern (19) during the embossing process.

5. The method according to claim 4, characterized in that The embossing rollers (21 to 24) have a rotary encoder (20) which is connected to a control unit (25) for controlling the embossing rollers (21 to 24) by signals.

6. The method according to claim 5, characterized in that The rotational position of the embossing roller (21 to 24) is related to the current longitudinal position (x) of the web, in which the current embossing process is carried out, and / or the rotational position (D1(x), D2(x), D3(x), D4(x)) of the embossing roller (21 to 24) is related to the embossing pattern segment (A(x)) currently embossed during the embossing process, so that the embossing pattern segment (Ax)) associated therewith can be derived from the rotational position (D1(x), D2(x), D3(x), D4(x)) of the embossing roller (21 to 24).

7. The method according to claim 6, characterized in that In addition to the embossing pattern (19) or instead of the embossing pattern (19), the rotational positions (D1(x), D2(x), D3(x), D4(x)) of the embossing rollers (21 to 24) are stored in the database (27) as parameters associated therewith.

8. The method according to claim 5, 6 or 7, characterized in that: The roller unit (17) has at least one, in particular a plurality of, embossing roller pairs (21 to 24) arranged one after the other in a row, and the uncoated region (11) of the electrode continuous web (9) is guided through the roller gap of the embossing roller pairs (21 to 24).

9. The method according to any one of the preceding claims, characterized in that The cutting process is followed by a separation process in which the coated electrode continuous web (9) is separated into electrode sheets (1).

10. A process arrangement for carrying out the method according to any of the preceding claims.

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