Method for identifying location of electrode sheet within electrode / separator composite

Abstract

To provide a method for identifying the location of an electrode sheet within an electrode / separator composite, as well as a system and a computer program for implementing the method.SOLUTION: A method for identifying the location of an electrode sheet within an electrode / separator composite ESV includes the steps of: optically imaging the electrode sheet at one or more imaging regions; identifying at least one region of the geometry of a base material and at least one region of coating on both faces; stacking the electrode sheet to form the ESV; detecting at least one of two components of first and second types of the electrode sheet by computed tomography; identifying the geometry at least in part based on a computed tomography image; aligning with the geometry identified from the computed tomography image; and determining the location of the coating on both faces of the base material.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a method for determining the position of an electrode sheet within an electrode / separator composite, as well as a system and a computer program for carrying out said method.

[0002] To manufacture the cells, the continuous electrode foil needs to be cut to form the current collector contours, which is done by a process known as laser cutting (notching).

[0003] Further cuts are then made transversely to the direction of the laser cut to produce the individual electrode sheets. Each electrode sheet has a substrate and a coating on both sides of the substrate. During laser cutting, it is common to cut in the uncoated contact areas of the anode or cathode sheets, partly due to higher process speeds and also due to achievable cut edge properties or safety requirements. Cutting in the active area, i.e. in the area of ​​the coating, can result in burrs and dross. If these reach the cell in the subsequent process, they can cause short circuits due to separator penetration or dendrite growth.

[0004] For this reason, it is a preferred variant to cut the substrate of the anode and cathode, rather than the active material. The uncoated areas of the electrode sheets are colloquially called "bare shoulders".

[0005] In a subsequent lamination process, the anode sheet, cathode sheet and separator are interlaced to form an electrode / separator composite (ESV).

[0006] The positional accuracy of the electrode sheets in the ESV is a quality criterion for the process capability of the lamination machine and a product feature related to the safety and functionality of the ESV. All corner areas of the electrode sheets must have a defined distance from each other and within a defined tolerance range. The electrochemical performance of the battery cell degrades more quickly during operation the smaller the overlap between the electrodes. Furthermore, improper positioning will cause a short circuit and failure of the battery cell due to direct contact between the anode and cathode.

[0007] In practice, the circumference of the anode (negative electrode) of one compartment is somewhat larger than that of the cathode (positive electrode) in order to achieve perfect overlap of the anode and cathode with less positional accuracy.

[0008] Current efforts are aimed at reducing this anode overhang to conserve material.

[0009] This means that the requirements for positional accuracy are increasing for the lamination process. Furthermore, since the lamination process is a bottleneck in the production of battery cells, its process speed must be increased in the future. However, as the process speed increases, the positional accuracy decreases. Therefore, the position of the electrodes in the laminated composite must be measured for further optimization and development of the lamination process.

[0010] The position of the electrode sheets within the ESV is determined by computed tomography, but this has the disadvantage that certain materials (coatings or substrates) of the anode or cathode sheets do not exhibit CT contrast and thus remain invisible in the CT images.

[0011] The problem underlying the present invention is to improve the detection and identification of position and thus the position accuracy, process capability and overlay evaluation criteria, so that components that are not visible in the CT data of the electrode sheet can be taken into account in the evaluation.

[0012] This problem is solved according to the invention by a method according to claim 1, a system according to claim 12 and a computer program according to claim 13. Advantageous configurations are given in the dependent claims.

[0013] A first aspect of the invention relates to a method for determining the position, in particular the 3D position, of an electrode sheet in an electrode / separator composite ESV, the electrode sheet having at least two components, namely a substrate and a coating on both sides of this substrate, in particular in the active area of ​​the electrode sheet, in particular the substrate of the electrode sheet being uncoated at least in the contact connection area, the electrode sheet comprising at least one electrode sheet of a first type and a second electrode sheet of a second type, i.e. in particular an anode sheet as the first type and a cathode sheet as the second type, made from different substrates and different coating materials, - optically imaging at least a portion of each electrode sheet, in particular the uncoated contact connection areas of the substrate and the active areas coated on both sides; - determining for each electrode sheet at least one region of the geometry of the substrate and at least one region of the geometry of a coating on both sides of the substrate based on the optical images; - marking each electrode sheet with an index so that a correspondence can be made within the ESV between the geometry determined for each electrode sheet from the optical image and the type of electrode sheet; - stacking electrode sheets to form an ESV; - detecting in a computed tomography (CT) image at least one of two components of a first type of electrode sheet in the ESV and at least one of two components of a second type of electrode sheet in the ESV; - determining, at least in part, the geometry of each detected component based on the computed tomography images; - aligning and in particular scaling the respective geometries from the optical images with the geometries determined from a computed tomography image of the electrode sheet in the ESV, in particular so as to coincide the positions of the geometries from both images; - determining the position of the substrate of each electrode sheet and the coating on both sides of this substrate, determining the position in the ESV of all components of the electrode sheets of the ESV by determining the position of components not detected in the computed tomography images from the joint / mutually aligned geometry of the optical images; The present invention relates to a method comprising the steps of:

[0014] The present invention allows missing information or geometry in computed tomography (CT) data of a substrate or a coating on a substrate to be easily and reliably supplemented, thereby providing important information for determining process capability and / or product quality for each ESV.

[0015] The coating of the substrate consists of at least one coating material, which may be different for the two types of electrode sheets.

[0016] Missing information in the CT data concerns the materials used in the ESV, since some coating or substrate materials show no or little CT contrast, and therefore these layers remain invisible in the CT images, so the geometry of these invisible layers is not taken into account when determining process capability and product quality.

[0017] The present invention therefore proposes to supplement this missing information based on previously acquired optical data, which requires that each electrode sheet be completely detected already before they are stacked.

[0018] The electrode sheets can then be re-identified in the CT data and the optically detected geometries associated with the respective substrates and coatings.

[0019] The location of the electrode sheet, substrate and / or coating on the substrate is specified, particularly by its three-dimensional location within the ESV associated with the electrode sheet, and particularly by its orientation relative to an ESV containment device such as a frame.

[0020] In the context of this document, geometry means in particular the outer contour that detects the boundaries of each element.

[0021] According to a further embodiment of the invention it is proposed that for the first type of electrode sheet the coating of the electrode sheet is not detectable by computed tomography and for the second type of electrode sheet the substrate is not detectable by computed tomography.

[0022] In this context, the term "not detected" means, inter alia, that the signal-to-noise ratio (SNR) is too low to show appreciable contrast in the CT data to allow the geometry of the coating or substrate to be determined accurately enough. The low SNR is due to the low or no absorption of the respective materials in the wavelength range used in CT imaging.

[0023] Typically, at least one material of the coating or substrate is "invisible" in the ESV, i.e., not detectable, in the CT data.

[0024] The process steps of optical imaging, processing the optical image to identify the geometry and marking the electrode sheets may each be performed during the step of stacking the electrode sheets to form the ESV, which in this case ensures particularly efficient processing.

[0025] According to a further embodiment of the invention, each electrode sheet has a double-sided coating in the active area, the substrate of the electrode sheet being uncoated at least in the contact connection area.

[0026] According to a further embodiment of the invention, it is proposed that each electrode sheet extends in an xy plane formed by the x and y axes of a Cartesian coordinate system associated with that electrode sheet, and in a z axis indicating along the stacking direction of the ESV stack.

[0027] According to a further embodiment of the invention, it is proposed that the contact-connection area of ​​each electrode sheet extends into the boundary area of ​​the electrode sheet and that the active area of ​​the electrode sheet extends following the contact-connection area along a transition edge, the position of the transition edge for each electrode sheet being determined on the basis of an aligned geometry of at least the optical images, in so far as the position of the transition edge can be detected in the CT data or alternatively or additionally can be determined on the basis of the CT data.

[0028] For determining process capability and product quality, this transition edge is important because it allows the degree of misalignment, relative twist and overlap of the electrode sheets to be determined.

[0029] According to a further embodiment of the invention, the contact connection regions form outer edges of the electrode sheets, and the location of the outer edge for each electrode sheet within the ESV is determined based on the aligned geometry of at least the optical images.

[0030] The contact connection area is also called "bare shoulder" by those skilled in the art. The contact connection area is typically located in the outer area of ​​the electrode sheet, which ensures that the contact can be made.

[0031] The specification of the outer edge therefore corresponds to the outer delimitation of the electrode sheet in the contact connection area, i.e. in the area of ​​the bare shoulder.

[0032] According to a further embodiment of the invention, for each electrode sheet, the position of a stumpf. edge of the electrode sheet in the ESV is determined based on the aligned geometry of at least the optical images, this stumpf. edge corresponding to the edge of the electrode sheet that is located opposite the contact connection area.

[0033] The abutment edge includes in particular the edge of the substrate as well as the edge of the coating on both sides, which ideally all have the same position. However, in some designs, a step along a second transition edge in the region of the abutment edge may be provided so that the substrate protrudes slightly beyond the coating on both sides. Correspondingly, this additional step must be taken into account in this case in order to determine the overlap and positional accuracy of the active areas.

[0034] In particular, based on the positions of the transition edges, outer edges and butt edges for each electrode sheet, the position of each electrode sheet can be determined with high accuracy, so that the position accuracy and therefore process capability and product quality can be precisely determined.

[0035] According to a further embodiment of the invention, an overlap criterion for the active areas of the electrode sheet, in particular along the xy plane, is determined, for which purpose a first offset is determined by the determined positions of the transition edges of the electrode sheet and the determined positions of the butt edges of the electrode sheet: the maximum deviation of the positions of the transition edges of the electrode sheets of the first type relative to one another, in particular along the xy plane, in particular along the x and / or y direction, the maximum deviation of the positions of the transition edges of the electrode sheets of the second type relative to one another, in particular along the xy plane, in particular along the x and / or y direction, the maximum deviation of the positions of the butt edges of the electrode sheets of the first type relative to each other, in particular along the xy plane, in particular along the x and / or y direction, the maximum deviation of the positions of the butt edges of the electrode sheets of the second type relative to each other, in particular along the xy plane, in particular along the x and / or y direction, a minimal deviation, in particular along the xy plane, in particular along the x and / or y direction, of the position of the transition edge of the electrode sheet of the first type relative to the position of the butt edge of the electrode sheet of the second type; - a minimal deviation of the position of the transition edge of the electrode sheet of the second type relative to the position of the butt edge of the electrode sheet of the first type, in particular along the xy plane, in particular along the x and / or y direction It is proposed that a first deviation of one or more of the following is identified:

[0036] The overlay metric is determined by inspecting how much these deviations are within predefined tolerances. Based on these deviations, process capability and / or product quality can be determined. Since these deviations provide information about the location of the electrode sheets along the xy plane within the ESV, it can be determined for each electrode sheet whether its active area is within the tolerances and / or whether the electrode sheet is within the corner / edge tolerances for the first or second type electrode sheets. Based on this determination, process capability and product quality can be determined.

[0037] The deviation can be determined, for example, in the form of an interval.

[0038] According to a further embodiment of the invention, the positional accuracy of the electrode sheet, in particular with respect to the xy-plane, is determined, for which purpose, depending on the determined positions of the outer edges of the electrode sheet and on the determined positions of the butt edges of the electrode sheet, a second deviation is determined, namely: the maximum deviation of the positions of the outer edges of the electrode sheets of the first type relative to one another, in particular along the xy plane, in particular along the x and / or y directions, the maximum deviation of the positions of the outer edges of the electrode sheets of the second type relative to one another, in particular along the xy plane, in particular along the x and / or y directions, the maximum deviation of the positions of the butt edges of the electrode sheets of the first type relative to each other, in particular along the xy plane, in particular along the x and / or y direction, the maximum deviation of the positions of the butt edges of the electrode sheets of the second type relative to each other, in particular along the xy plane, in particular along the x and / or y direction, a minimal deviation, in particular along the xy plane, in particular along the x and / or y direction, of the position of the outer edge of the electroded sheet of the first type relative to the position of the butt edge of the electroded sheet of the second type; - a minimum deviation of the position of the outer edge of the electroded sheet of the second type relative to the position of the butt edge of the electroded sheet of the first type, in particular along the xy plane, in particular along the x and / or y direction A second deviation of one or more of the following is identified:

[0039] In particular, the positional accuracy is determined from said deviations, in particular by checking whether these deviations are within predefined tolerance ranges.

[0040] In this case, the maximum and minimum displacements are determined from the amount of displacement of all electrode sheets for each edge.

[0041] According to a further embodiment of the present invention, it is proposed that the position of the transition edge includes a first position of the transition edge for a first surface of the coating on both sides of the electrode sheet and a second position of the transition edge for a second surface of the coating on both sides of the electrode sheet, the second surface being opposite to the first surface along the stacking direction, and the first and second positions of the transition edge are identified based on an aligned geometry of at least the optical images.

[0042] This allows the transition edges to be determined in a face-selective manner, and deviations in the position of these edges relative to one another can be taken into account in the subsequent evaluation steps.

[0043] According to a further embodiment of the invention, it is proposed that the position of the transition edge is determined from an average value of the first and second positions of the transition edge or that the first or second position of the transition edge is associated with the position of the transition edge in order to determine the first deviation.

[0044] According to a further embodiment of the present invention, it is proposed that each deviation for each electrode sheet is identified for two corner regions of the electrode sheet that are located opposite each other along the y-axis, in particular along the y-axis only, a tolerance range is pre-set for each of these deviations, and for each corner and the determined and associated deviations of these corners, it is determined whether at least one of the determined and associated deviations is outside the tolerance range associated with this at least one deviation, and in particular if at least one of the deviations is outside the tolerance range associated with this at least one deviation, the ESV is classified as defective.

[0045] Based on the determined deviation, it is then determined whether the ESV must potentially be discarded if it does not meet certain quality criteria.

[0046] According to a further embodiment of the present invention, it is proposed that the transition edge of at least one electrode sheet extends at an incline, in particular along the y-axis, whereby the first deviation in the position of the inclined extending transition edge is of a different magnitude for each of the two corner regions.

[0047] According to a further embodiment of the present invention, it is proposed that the position of the transition edge of multiple electrode sheets corresponds to an average value from all positions of the transition edge determined for each electrode sheet, so that this position remains robustly identifiable with respect to peeling or rough transition edge extensions.

[0048] This aspect allows for the specification of edge extensions that are robust to roughness and small edge defects.

[0049] According to a further embodiment of the invention it is proposed that the position of the transition edge of the first type electrode is determined exclusively from the optical image.

[0050] This allows the transition edges to be located with particularly high accuracy, especially since these edges are not detected or are only poorly detected in the CT data and therefore cannot be recognized or are only poorly recognized.

[0051] According to a further embodiment of the invention it is proposed that the position of the outer edge of the electroded sheet of the second type is determined solely from the optical image.

[0052] This allows the outer edges to be located with particularly high accuracy, especially since these edges are not detected or are only poorly detected in the CT data and therefore cannot be or can only be poorly recognized.

[0053] According to a further aspect of the invention, there is provided a system for identifying quality and process parameters of an ESV, comprising: - an optical detection unit configured to perform optical imaging of the electrode sheet from a first side and a second side of the electrode sheet; - an ESV stacking device configured to stack electrode sheets to form an ESV, the system being configured to mark each electrode sheet with an index so that correspondence of each electrode sheet is performed within the ESV from an optical image; and - a computed tomography imaging device configured to generate a three-dimensional image of the ESV stack; In a system having at least A system is proposed, characterized in that it comprises a computer configured to control the components of the system via an interface and to implement the method of any of the previously described embodiments.

[0054] According to a further aspect of the invention, a computer program is proposed, comprising a computer program code for causing a computer to carry out the method according to the invention when said computer program is executed on a computer, in particular a computer of a system.

[0055] In the context of this document, the term computer program also means in particular a computer program product, i.e. a computer program code stored on a non-transitory storage medium.

[0056] The invention will now be described with reference to the embodiments shown in the accompanying drawings. [Brief description of the drawings]

[0057] [Figure 1] FIG. 1 illustrates an embodiment of a system for implementing the method according to the present invention. [Diagram 2] FIG. 2 is an exemplary cross-sectional view along the xz plane of one region of a CT image. [Diagram 3] FIG. 2 is a schematic diagram showing a first type electrode sheet. [Figure 4] FIG. 4 is a schematic diagram showing a second type of electrode sheet. [Diagram 5] FIG. 1 is a schematic diagram showing a cross section of an ESV with identification of electrode sheet misalignment. [Figure 6] FIG. 2 is a schematic diagram showing first type electrode sheets having different edge extensions.

[0058] In Fig. 1A) a side view of an electrode sheet 10 is shown diagrammatically together with the optical detection unit of the system. The optical detection unit comprises two line cameras 1-1, 1-2, which are offset along the z-axis with respect to a corresponding coordinate system, for optically detecting one side of the electrode sheet 10 to be imaged. The electrode sheet 10 extends along the xy-plane and is moved along the y-direction (into or out of the drawing plane).

[0059] A light source 3-1, 3-2 is assigned to each camera, and illuminates one side of the electrode sheet 10 to ensure consistent imaging conditions.

[0060] The electrode sheet 10 includes a substrate 10S extending along the xy plane. Both sides of the substrate 10S are covered with coatings 10B, which also extend along the xy plane. The substrate 10S and the coatings 10B on both sides are made of different materials.

[0061] As the electrode sheet 10 moves, the line cameras 1-1, 1-2 detect in at least one imaging area the geometry of the coating 10B on both sides as well as the geometry of the visible, i.e. uncoated, part of the substrate 10S (also called bare or naked shoulder). In the context of this specification, the coated part of the electrode sheet 10 is also called the active area, whereas the uncoated part forming the naked shoulder of the electrode sheet 10 is called the contact connection area.

[0062] In Fig. 1B) a view of the same scene as in Fig. 1A) is shown. In Fig. 1B) a transition edge 2 of the electrode sheet 10 can be seen, which extends along the y-axis. The transition edge 2 is the edge that occurs at the boundary of the coating 10B to the active area. The line cameras 1-1, 1-2 detect at least this area, but also many other areas, while the electrode sheet 10 is moved along the y-axis.

[0063] In FIG. 1C) the determined optical image of the area of ​​the transition edge 2 detected by one line camera is shown. Not only the transition edge 2 but also the outer edge 1 of the substrate 10S is detected at a number of points along the y direction. On the basis of these points the edge extension is determined, for example by linear interpolation. In this way the edge extension of the transition edge 2 and of the outer edge 1 can be determined for both sides of the electrode sheet 10. The edge extension of the outer edge 1 is identical for both sides. These images allow the main parts of the geometry of the electrode sheet 10 to be determined.

[0064] In FIG. 1D) the edge extension of the transition edge 2 is shown. This edge extension 2 has a large roughness. For this reason, it is advantageous to detect the transition edge 2 at multiple points along the y-axis, since this allows the extension or the interpolated extension of the transition edge 2 to be better determined.

[0065] Additionally and in parallel with this, an optical measurement of the complete electrode sheet geometry may be performed, for example by determining the length (in the x-direction) and width (in the y-direction).

[0066] This can be achieved by means of a further camera assembly (not shown) with a light source, which for example also comprises two correspondingly arranged line cameras, in order to detect in particular the butt edge of the electrode sheet 10 opposite the contact connection area along the x-axis, and to detect the geometry of the electrode sheet rotated by 180° in the xy-plane.

[0067] Similarly, by determining the transition edge 2 on both sides, any misalignment between the coatings on both sides of an electrode sheet 10 can be identified and taken into account in subsequent evaluations.

[0068] By optically detecting a number of regions of the electroded sheet 10, the geometry of the electroded sheet 10 can be determined, at least with respect to the critical edge extensions, based on the optical images.

[0069] The imaged electrode sheets 10 are then integrated into an ESV stack, which is stacked substantially along the z-direction. The ESV 4 comprises a first type of electrode sheet 10 and a second type of electrode sheet 10. These are typically the electrode sheets forming the anode, i.e. the anode sheets, and the electrode sheets forming the cathode, i.e. the cathode sheets.

[0070] In order to be able to later associate the electrode sheets 10 in the stack with the optical images, the electrode sheets 10 are indexed, based on which the position can be ascertained, for example by number.

[0071] The ESV stack is detected in three dimensions, at least in part, by a computed tomography imaging device.

[0072] In Figure 2, a CT image of one region of the ESV4 stack is shown in cross section along the xz plane. Shown are the outer edge regions of the anode sheet 10A (numbered 14-10) and their maximum offset along the x direction based on the determined outer edges 1A-10, 1A-12 of the electrode sheet 10. Similarly, the maximum offset along the x direction is shown for the transition edge of the cathode sheet 10K (also numbered 14-10).

[0073] These deviations are then compared to tolerance ranges that indicate the tolerance for electrode sheet deviation or position. If the deviations are within the tolerance range, the ESV 4 meets predefined quality criteria. If not, the ESV 4 is potentially classified as defective.

[0074] In Fig. 3, a first type electrode sheet 10A is shown, and in Fig. 4, a second type electrode sheet 10K is shown. In Fig. 3, two schematic cross-sectional views of an exemplary anode sheet 10A are shown, along with the butt edges 3, 3A, the transition edges 2, 2A and the outer edges 1, 1A of the anode sheet 10A. The anode sheet 10A includes a coating 10A-B on both sides and a substrate 10A-S. The material of the coating 10A-B, e.g., graphite, is not detected in the CT image and is therefore invisible or difficult to recognize in the CT image of the ESV. In contrast, the material of the substrate 10A-S, e.g., copper, exhibits a sufficiently high CT contrast that the substrate is visible in the CT image of the ESV.

[0075] Similarly, FIG. 4 shows two schematic cross-sectional views of an exemplary cathode sheet 10K. The cathode sheet includes a double-sided coating 10K-B and a substrate 10K-S. FIG. 4 also shows the butt edges 3, 3K, the transition edges 2, 2K and the outer edges 1, 1K of the cathode sheet 10K. The material of the substrate 10K-S, e.g., aluminum, is not detected in the CT image and is therefore invisible or difficult to recognize in the CT image of the ESV. In contrast, the material of the coating 10K-B, e.g., lithium, exhibits a sufficiently high CT contrast that the double-sided coating 10K-B is visible in the CT image of the ESV.

[0076] 5 shows a schematic cross-sectional view of ESV4 taken along the xz plane, where, to avoid unnecessarily complicating the illustration, ESV4 simply includes three anode sheets 10A-1, 10A-2, and 10A-3 and three cathode sheets 10K-1, 10K-2, and 10K-3.

[0077] 5, anode sheets 10A-1, 10A-2, 10A-3 and cathode sheets 10K-1, 10K-2, 10K-3 are stacked rotated 180° relative to one another in the xy plane, so that outer edges 1A-1, 1A-3 and 1K-1, 1K-3 face opposite each other in the x direction. In the ESV4, a separator layer S is further disposed between the electrode sheets.

[0078] As explained with respect to Figures 3 and 4, the substrate of the cathode sheet and the coating of the anode sheet are not visible in the CT images, so selected edges or geometries of the electrode sheets can only be determined or mapped based on optical data.

[0079] In this embodiment, the nomenclature of each edge follows the following logic.

[0080] The first number identifies the edge, specifically the outer edge (1), the transition edge (2) and the butt edge (3).

[0081] The next letter identifies the type of electrode sheet, in this example, anode (A) or cathode (B). The final number indicates its position within the ESV. The further up the electrode sheet is located, the lower the number.

[0082] Thus, "2A-3" refers to the transition edge of the lowermost disposed anode sheet of all the anode sheets in the illustrated ESV, and "1K-1" refers to the outer edge of the uppermost cathode sheet.

[0083] As can be seen from FIG. 5, the transition edges 2A-1, 2A-3 of the anode sheets 10A-1, 10A-3 and the outer edges 1K-1, 1K-3 of the cathode sheets can only be determined on the basis of the associated optical data.

[0084] For this purpose, the geometry of the optical image is aligned and possibly scaled with the geometry of the electrode sheets in the ESV4 determined from the computed tomography images. Since at least one geometry for each electrode sheet is visible in the CT images, i.e. the geometry of the substrate or the geometry of the coating, a transformation is determined for each electrode sheet, on the basis of which the geometry determined from the optical image is made to coincide with the geometry determined from the CT data. In this case, for the geometries that are only detected in the optical images, the transformation corresponding to the electrode sheet is applied, so that it can be assumed that the geometries and positions of all substrates and coatings are determined very well.

[0085] Here, in order to determine various quality evaluation criteria of the ESV, in particular the offset of different edges of the electrode sheet relative to one another in the xy plane, in particular along the x direction, is important.

[0086] Similarly, twist relative to the stack axis or other electrode sheets can be determined.

[0087] For example, to identify quality criteria for process capability, the following intervals or deviations: - D1-1: Maximum deviation between the outer edges 1A-1, 1A-3 of the anode sheets 10A-1, 10A-3 D2-1: the minimum offset of the outer edge 1A-3 of the anode sheet 10A-3 relative to the butt edge 3K-1 of the cathode sheet 10K-1, i.e. the minimum offset of all offsets of the outer edges of the anode sheets relative to the butt edges of the cathode sheets. - D3: Maximum deviation between the butt edges 3K-1 and 3K-3 of the cathode sheets - D4-1: Maximum deviation between the outer edges 1K-1 and 1K-3 of the cathode sheet D5-1: The minimum offset of the outer edge 1K-3 of the cathode sheet 10K-3 relative to the butt edge 3A-1 of the anode sheet 10A-1. - D6: Maximum deviation of the butt edges 3A-1, 3A-3 of the anode sheets 10A-1, 10A-3 from each other is required.

[0088] The outer edges 1K-1, 1K-3 of the cathode sheets 10K-1, 10K-3 can then only be determined from the optical image, and thus, despite the lack of information on the location of these edges from the CT data, the method according to the invention allows the determination of the offsets D4-1 and D5-1 and thus a quality criterion for the process capability.

[0089] Based on the determined deviations, the position of each electrode sheet 10 in the ESV 4, i.e., in particular position and orientation information, can be determined. Advantageously, the deviations for determining the process capability are determined for at least each corner region of the electrode sheet 10. That is to say, each edge is determined at least at two points located in the boundary region of the electrode sheet 10, in particular located on the outside (along the y-axis). A predefined tolerance range is preferably associated with each deviation for determining the process capability for each corner region, and each deviation is preferably within this tolerance range. The process capability provides information, in particular, about how regularly and precisely the outer regions of the electrode sheet 10 are arranged in the ESV 4.

[0090] In addition to process capability, a quality metric in the form of an overlap metric that provides information regarding the overlap area of ​​the active regions of the electroded sheet 10 can also be specified.

[0091] The overlap area corresponds in particular to the intersection of all active areas of the electroded sheets projected onto the xy plane.

[0092] To identify the overlap criteria, the following deviations from the electrode sheet geometry are considered in particular: - D1-2: Maximum deviation of the transition edges 2A-1, 2A-3 of the anode sheets 10A-1, 10A-3 from each other D2-2: the minimum offset of the transition edge 2A-3 of the anode sheet 10A-3 relative to the butt edge 3K-1 of the cathode sheet 10K-1, i.e. the minimum offset of all the offsets of the transition edges of the anode sheet relative to the butt edges of the cathode sheets. - D3: Maximum deviation between the butt edges 3K-1 and 3K-3 of the cathode sheets - D4-2: Maximum deviation between the transition edges 2K-1 and 2K-3 of the cathode sheet D5-2: The minimum deviation of the transition edge 2K-3 of the cathode sheet 10K-3 relative to the butt edge 3A-1 of the anode sheet 10A-1 - D6: Maximum deviation of the butt edges of the anode sheets from each other is required.

[0093] The transition edges 2A-1, 2A-3 of the anode sheet are then only identifiable from the optical image, and thus, despite the lack of information on the location of these edges from the CT data, the method according to the invention allows the determination of the offsets D1-2 and D2-2 and thus the determination of the overlap criterion.

[0094] Based on the offset thus identified, the position of each electrode sheet within the ESV 4, that is, in particular, position and orientation information, can be determined.

[0095] Advantageously, the above-mentioned deviations for determining the overlap criterion are determined for at least each corner region of the electrode sheet, i.e. each edge is identified at least two points located in the boundary region of the electrode sheet, in particular located on the outside (along the y-axis). Each deviation for determining the overlap criterion is preferably associated with a tolerance range, in particular predefined (different from the tolerance range of the positional accuracy / process capability), for each corner region, and each deviation is preferably within this tolerance range.

[0096] By determining at least two corner regions, edge extensions that extend at an angle with respect to the y-axis can also be taken into account (see FIG. 6B).

[0097] Subsequent use of the ESV depends on whether the overlap criteria are met, i.e., whether all deviations in all corner regions are within the expected tolerance ranges.

[0098] Regarding the transition edge of the electrode sheet, various situations may be considered:

[0099] Since the double-sided coating can be detected on both sides of the substrate by the imaging device, a transition edge 2A-1a, 2A-1b can be determined for each side. In order to associate the transition edge with the electrode sheet, for example an average value 2A-1 of both transition edges, i.e. the average extension of the edges, can be applied for further processing (see FIG. 6A).

[0100] Alternatively, in a subsequent processing step of the method, both edges are taken into account, for example the smaller of the two resulting active area overlap areas is used to determine a quality criterion. [Explanation of symbols]

[0101] 1 Outer edge of electrode sheet 1-1,1-2 Line Camera 1A, 1A-1, 1A-3, 1A-10, 1A-12 Outer edge of first type electrode sheet 1K, 1K-1, 1K-3 Outer edge of second type electrode sheet 2. Transition edge of electrode sheet 2A, 2A-1, 2A-3 Transition edge of first type electrode sheet 2A-1a, 2A-1b One side of the transition edge 2K, 2K-1, 2K-3, 2K-10, 2K-14 Transition edge of second type electrode sheet 3 Butt Edge 3-1,3-2 Light source 3A, 3A-1, 3A-3 First type electrode sheet butt edge 3K, 3K-1, 3K-3 Butt edge of second type electrode sheet 4. ESV 10 Electrode sheet 10A, 10A-1, 10A-2, 10A-3 Type 1 electrode sheet 10B Coating of electrode sheet 10K, 10K-1, 10K-2, 10K-3 Type 2 electrode sheet 10A-B Coating of first type electrode sheet 10A-S Type 1 electrode sheet substrate 10K-B Type 2 electrode sheet coating 10K-S Type 2 electrode sheet substrate 10S Electrode sheet base material 100 Movement direction D1-1 Maximum deviation between the outer edges of the first type electrode sheets D1-2 Maximum deviation between transition edges of first type electrode sheets D2-1 Minimum deviation of the outer edge of the first type electrode sheet relative to the butt edge of the second type electrode sheet D2-2 Minimum deviation of the transition edge of the first type electrode sheet relative to the butt edge of the second type electrode sheet D3 Maximum deviation between the butt edges of the second type electrode sheets D4-1 Maximum deviation between the outer edges of the second type electrode sheets D4-2 Maximum deviation between transition edges of second type electrode sheets D5-1 Minimum deviation of the outer edge of the second type electrode sheet relative to the butt edge of the first type electrode sheet D5-2 Minimum deviation of the transition edge of the second type electrode sheet relative to the butt edge of the first type electrode sheet D6 Maximum deviation of the butt edges of the first type electrode sheets S separator layer

Claims

1. A method for identifying the position of an electrode sheet (10) in an electrode / separator composite ESV (4), said electrode sheet (10) having at least two components, namely a substrate (10S) and a coating (10B) on both sides of said substrate (10S), said electrode sheet (10) comprising at least one electrode sheet of a first type (10A) and an electrode sheet of a second type (10K); - optically imaging each electrode sheet (10, 10A, 10K) at least in part in one or more imaging areas; - determining, based on the optical image, at least one region of the geometry of said substrate (10S) and at least one region of the geometry of said double-sided coating (10B) of said substrate (10S); - marking each electrode sheet (10, 10A, 10K) with an index so that a correspondence can be made within the ESV (4) between each electrode sheet (10, 10A, 10K) and the geometry determined for each electrode sheet (10, 10A, 10K) from the optical image; - stacking said electrode sheets (10, 10A, 10K) to form an ESV (4); - detecting in a computed tomography image at least one of the two components of the electrode sheet (10A) of the first type in the ESV (4) and at least one of the two components of the electrode sheet (10K) of the second type in the ESV (4); - determining, at least in part, the geometry of each of said detected components based on said computed tomography images; - aligning each of the geometries from the optical images with the geometries determined from the computed tomography images of the electrode sheets (10, 10A, 10K) in the ESV (4); - determining the position of the substrate (10S) of each electrode sheet (10, 10A, 10K) and the coatings on both sides of said substrate (10S), determining the position in the ESV (4) of all components of the electrode sheets of the ESV (4) by determining the position of components not detected in the computed tomography images from the aligned geometry of the optical images; A method comprising:

2. 2. The method according to claim 1, characterized in that, for the first type of electrode sheet (10A), the coating (10B) of the electrode sheet (10A) is not detected by computer tomography and, for the second type of electrode sheet (10K), the substrate (10S) is not detected by computer tomography.

3. 3. The method according to claim 1 or 2, characterized in that each electrode sheet has said double-sided coating in the active area, and the substrate (10S) of the electrode sheet (10) is uncoated at least in the contact connection area.

4. 4. The method of claim 3, characterized in that the contact connection area of ​​each electrode sheet (10, 10A, 10K) extends into the boundary area of ​​the electrode sheet, the active area of ​​the electrode sheet (10, 10A, 10K) extends following the contact connection area along a transition edge (2, 2A, 2K), and the position of the transition edge (2, 2A, 2K) for each electrode sheet (10, 10A, 10K) is determined based on at least the aligned geometry of the optical image.

5. 5. The method according to claim 3 or 4, characterized in that the contact connection areas form outer edges (1, 1A, 1K) of the electrode sheets (10, 10A, 10K), and the position of the outer edges (1, 1A, 1K) for each electrode sheet (10, 10A, 10K) in the ESV (4) is determined based on at least the aligned geometry of the optical images.

6. 6. The method according to claim 3, further comprising: determining, for each electrode sheet (10, 10A, 10K), a position of a butt edge (3, 3A, 3K) of the electrode sheet (10, 10A, 10K) in the ESV (4) based on the aligned geometry of at least the optical images, the butt edge (3, 3A, 3K) corresponding to an edge of the electrode sheet (10, 10A, 10K) located opposite the contact connection area.

7. An overlap criterion for the active areas of the electrode sheet (10, 10A, 10K) is determined, for which purpose, the determined positions of the transition edges (2, 2A, 2K) of the electrode sheet (10, 10A, 10K) and the determined positions of the butt edges (3, 3A, 3K) of the electrode sheet (10, 10A, 10K) are used to determine a first offset, namely: the maximum deviation (D1-2) of the positions of the transition edges (2A) of the first type of electrode sheets (10A), the maximum deviation (D4-2) of the positions of the transition edges (2K) of the second type of electrode sheets (10K), the maximum deviation (D6) of the positions of the butt edges (3A) of the first type of electrode sheets (10A), the maximum deviation (D3) of the positions of the butt edges (3K) of the second type of electrode sheet (10K), the minimum deviation (D2-2) of the position of the transition edge (2A) of the first type electrode sheet (10A) relative to the position of the butt edge (3K) of the second type electrode sheet (10K), the minimum deviation (D5-2) of the position of the transition edge (2K) of the second type electrode sheet (10K) relative to the position of the butt edge (3A) of the first type electrode sheet (10A); The method according to at least claims 4 and 6, characterized in that a first deviation of one or more of the following is determined.

8. The positional accuracy of the electrode sheet (10, 10A, 10K) is determined, and for this purpose, the following second deviation, i.e., the maximum positional deviation (D1-1) between the outer edges (1A) of the first type of electrode sheet (10A), the maximum positional deviation (D4-1) between the outer edges (1K) of the second type of electrode sheet (10K), the maximum deviation (D6) of the positions of the butt edges (3A) of the first type of electrode sheets (10A), the maximum deviation (D3) of the positions of the butt edges (3K) of the second type of electrode sheet (10K), the minimum deviation (D2-1) of the position of the outer edge (1A) of the first type electrode sheet (10A) relative to the position of the butt edge (3K) of the second type electrode sheet (10K), the minimum deviation (D5-1) of the position of the outer edge (1K) of the second type electrode sheet (10K) relative to the position of the butt edge (3A) of the first type electrode sheet (10A); The method according to at least claims 5 and 6, characterized in that one or more of the second deviations are determined.

9. 9. The method according to claim 1, wherein the position of the transition edge (2, 2A, 2K) includes a first position of the transition edge (2, 2A, 2K) on a first side of the double-sided coating (10B) of the electrode sheet (10, 10A, 10K) and a second position of the transition edge (2, 2A, 2K) on a second side of the double-sided coating (10B) of the electrode sheet (10, 10A, 10K), and the first and second positions of the transition edge (2, 2A, 2K) are determined based on at least the aligned geometry of the optical images.

10. Each of the deviations (D1-1, D1-2, D2-1, D2-2, D3, D4-1, D4-2, D5-1, D5-2, D6) for each of the electrode sheets (10, 10A, 10K) is specified for two corner regions located opposite each other along the y-axis of the electrode sheets (10, 10A, 10K), and a tolerance range is set in advance for each of the deviations (D1-1, D1-2, D2-1, D2-2, D3, D4-1, D4-2, D5-1, D5-2, D6), and each of the corners and the deviations (D1-1, D1-2, D2-1, D2-2, D3, D4-1, D4-2, D5-1, and determining whether at least one of the determined and associated deviations (D1-1, D1-2, D2-1, D2-2, D3, D4-1, D4-2, D5-1, D5-2, D6) is outside the tolerance range associated with the at least one deviation, and if at least one of the deviations (D1-1, D1-2, D2-1, D2-2, D3, D4-1, D4-2, D5-1, D5-2, D6) is outside the tolerance range associated with the at least one deviation, the ESV (4) is classified as defective.

11. The method according to claims 7 and 9, characterized in that the transition edge (2, 2A, 2K) of at least one electrode sheet (10, 10A, 10K) extends at an incline along the y-axis, whereby the first deviation in the position of the transition edge (2, 2A, 2K) extending at an incline is of a different magnitude for each of two corner regions and is identified and evaluated separately.

12. 12. The method according to claim 1, characterized in that the position of the transition edge (2A) of the first type electrode sheet (10A) is determined only from the optical image and / or the position of the outer edge of the second type electrode sheet (10K) is determined only from the optical image.

13. A system for identifying quality and process parameters of an ESV (4), comprising: an optical detection unit configured to perform an optical imaging of the electrode sheet (10, 10A, 10K) from a first side and from a second side of said electrode sheet; an ESV stacking device configured to stack the electrode sheets (10, 10A, 10K) to form an ESV (4), the system being configured to mark each electrode sheet (10, 10A, 10K) with an index, whereby a correspondence between each electrode sheet (10, 10A, 10K) is established within the ESV from the optical image; a computed tomography device configured to generate a three-dimensional image of the ESV stack; In a system having 13. A system comprising a computer configured to control the components of the system via an interface and to carry out the method according to any one of claims 1 to 12.

14. A computer program comprising computer program code for causing a computer to carry out a method according to any one of claims 1 to 12 when the computer program is executed on a computer, in particular a system according to claim 13.

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