Method for determining the orientation of an electrode plate in an electrode-membrane composite

Abstract

The invention relates to a method for determining the orientation of an electrode sheet in an ESV, the electrode sheet having a substrate and a coating on both sides of the substrate, the electrode sheet comprising electrode sheets of a first and a second type, the method comprising the following steps: recording the electrode sheet in a recording range; determining geometrical regions of the substrate and the coating on both sides thereof from the optical photograph; the electrode plates are stacked into an ESV; in the computed tomography picture, obtaining components of the first type of electrode plate and components of the second type of electrode plate in a computed tomography mode; determining a geometry of the component from the computed tomography photograph; aligning the geometry in the optical photograph with the geometry determined from the computed tomography photograph; the orientation of the substrate of the electrode sheet and of the coating on both sides thereof is determined, and the orientation of the component that is not acquired in the computed tomography photograph is determined from the geometry of the optical photograph, thereby determining the orientation of the component of the electrode sheet in the ESV.

Description

Technical Field

[0001] The invention relates to a method for determining the position of an electrode sheet in an electrode-diaphragm assembly and to a system and a computer program for carrying out the method. Background Art

[0002] In order to produce the cells, the arrester contour must be cut into the continuous electrode film. This is performed by means of a process called laser cutting (grooving).

[0003] Next, another cut is made transverse to the direction of the laser cutting to form a single electrode sheet. Each electrode sheet has a substrate and a coating on both sides of the substrate. During laser cutting, the cutting should usually be carried out in the uncoated contact area of ​​the anode sheet or cathode sheet. On the one hand, this is due to the faster process speed, and on the other hand, it is due to the achievable cutting edge characteristics or safety requirements. If cutting is carried out in the active area (i.e., in the area of ​​the coating), burrs and weld nodules may be generated. If it reaches a single cell in a subsequent process, this may cause a short circuit due to piercing the diaphragm or due to dendrite growth.

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

[0005] In the subsequent stacking process, anode sheets, cathode sheets and separators are combined alternately to form an electrode-separator composite (ESV).

[0006] The placement accuracy of the electrode sheets in the ESV is a quality criterion for the process capability of the stacking machine and is a safety- and function-critical product feature of the ESV. All corner areas of the electrode sheets must have a defined distance relative to one another and lie within a defined tolerance band. During operation, the electrochemical properties of the battery cell decrease more rapidly with decreasing electrode coverage. In addition, direct contact between anode and cathode in the event of incorrect placement can trigger short circuits and failures of the battery cell.

[0007] Currently, the anode (negative) of a compartment is slightly larger in circumference than the cathode (positive) so that complete coverage of anode and cathode is achieved despite imprecise placement.

[0008] Current efforts are to reduce this overhang of the anode in order to save material.

[0009] This means that the stacking process places increased demands on the placement accuracy. In addition, the stacking process is a bottleneck in the production of battery cells, so its process speed must be increased in the future. However, the placement accuracy decreases with increasing process speed. Therefore, in order to further optimize and develop the stacking process, the placement of the electrodes in the stacking complex must be measured.

[0010] The position of the electrode plates in the ESV is determined by means of a computed tomography imaging method. However, a disadvantage here is that certain materials of the anode or cathode plates (coating or substrate) do not provide CT contrast and therefore remain invisible in the CP image. Summary of the invention

[0011] The object of the present invention is to improve the detection and determination of the orientation and thus of the placement accuracy, process capability and coverage criterion in such a way that components that are not visible in the CT data of the electrode sheet can be taken into account in the evaluation.

[0012] According to the invention, this object is achieved by a method for determining the orientation of an electrode sheet in an electrode-diaphragm assembly, a system for determining the quality and process parameters of an electrode-diaphragm assembly, and a computer program.

[0013] A first aspect of the invention relates to a method for determining the orientation, in particular the 3D orientation, of an electrode sheet in an electrode-separator assembly ESV, wherein the electrode sheet comprises at least two components, namely a substrate and a coating on both sides of the substrate, in particular in the active region of the electrode sheet, in particular wherein the substrate of the electrode sheet is uncoated at least in the contact region, wherein the electrode sheet comprises at least one electrode sheet of a first and a second type, namely in particular an anode sheet as a first type and a cathode sheet as a second type, which are made of different substrate materials and different coating materials, wherein the method comprises the following steps:

[0014] - at least partially optically recording each electrode sheet, in particular the uncoated contact area together with the substrate and the active area coated on both sides;

[0015] - for each electrode sheet, determining at least one region of the geometric shape of the substrate and at least one region of the geometric shape of the coating on both sides of the substrate from the optical photograph;

[0016] - indexing of each electrode sheet, so that in the ESV each electrode sheet can be associated with the geometry and type of electrode sheet determined therefor in the optical image;

[0017] - Stacking electrode sheets into ESV;

[0018] - in a computed tomography image, at least one of the two components of the electrode sheet of the first type in the ESV and at least one of the two components of the electrode sheet of the second type in the ESV are acquired by means of computed tomography (CT);

[0019] - at least partially determining the geometry of the corresponding acquired component based on the computed tomography image;

[0020] - aligning and, in particular, scaling the corresponding geometrical shapes in the optical image with the geometrical shapes of the electrode pads in the ESV determined from the computed tomography image, in particular so that the orientation of the geometrical shapes in both images is consistent;

[0021] - Determine the orientation of the substrate of each electrode sheet and its coating on both sides, wherein the orientation of the components not captured in the computed tomography image is determined from the said or co-aligned / jointly aligned geometry of the optical image, thereby determining the orientation of all components of the electrode sheet of the ESV in the ESV.

[0022] The invention makes it possible in a simple and reliable manner to supplement the information missing in the computed tomography (CT) data about the geometry of the substrate or its coating, thereby obtaining important information for determining the process capability and / or the product quality of each ESV.

[0023] The coating of the substrate consists of at least one coating material, which can be different for the two types of electrode sheets.

[0024] The missing information in the CT data is related to the materials used in ESV, because some coating materials or substrate materials have no or only low CT contrast. Accordingly, these layers remain invisible in the CT images, so that the geometry of these invisible layers cannot be included in the determination of process capability and product quality.

[0025] Now, the present invention proposes to supplement the missing information based on previously acquired optical data. To do this, each electrode sheet needs to be completely acquired before stacking.

[0026] Subsequently, the electrode sheets are again identified in the CT data and the optically acquired geometry can be associated with the corresponding substrate and coating.

[0027] The position of the electrode sheet, the substrate and / or its coating is determined in particular by the three-dimensional position and orientation associated with the electrode sheet in the ESV, in particular with respect to an ESV receiving device, such as a frame.

[0028] In the context of this description, a geometric shape is understood to mean in particular an outer contour including the boundaries of the respective element.

[0029] According to a further embodiment of the invention, it is provided that in the case of an electrode sheet of the first type the coating of the electrode sheet is not recorded by means of a computed tomography scan and in the case of an electrode sheet of the second type the substrate is not recorded by means of a computed tomography scan.

[0030] In this context, the expression “not acquired” means, in particular, that the signal-to-noise ratio SNR is too low to produce an evaluable contrast in the CT data, from which the geometry of the coating or substrate can be determined with sufficient accuracy. The low SNR is due to the absorption capacity of the corresponding material, which absorbs only slightly or not at all in the wavelength range used in the CT recordings.

[0031] Typically, in ESV, at least one material of the coating or substrate is not "visible" in the CT data, that is, not acquired.

[0032] The process step of optical imaging, its processing for determining the geometry and indexing of the electrode sheets can also be carried out during the stacking of the electrode sheets to form an ESV, so that a particularly efficient processing is ensured here.

[0033] According to a further embodiment of the invention, each electrode sheet has a coating on both sides in the active region and the substrate of the electrode sheet is uncoated at least in the contact region.

[0034] According to another embodiment of the invention, it is provided that each electrode sheet extends in an xy plane associated with the electrode sheet, which plane extends through the x and y axes of a Cartesian coordinate system and is spanned by a z axis which points in the stacking direction of the ESV stack.

[0035] According to another embodiment of the invention, it is provided that the contact region of each electrode sheet extends in the edge region of the electrode sheet and the active region of the electrode sheet extends next to the contact region along the transition edge, wherein the orientation of the transition edge is determined for each electrode sheet at least based on the aligned geometry of the optical image. If the orientation of the transition edge is acquired in the CT data, the orientation of the transition edge can alternatively or additionally be determined based on the CT data.

[0036] The transition edges are very important for determining process capability and product quality, since they can determine the degree of deflection, relative twist and overlap of the electrode sheets.

[0037] According to a further embodiment of the invention, it is provided that the contact region forms an outer edge of the electrode lug, wherein the orientation of the outer edge in the ESV is determined for each electrode lug at least on the basis of the aligned geometry of the optical recording.

[0038] In the professional world, the contact region is also referred to as a “bare shoulder.” The contact region is usually located mostly at the outer region of the electrode sheet, thereby ensuring the ability to connect.

[0039] The determination of the outer edge thus corresponds to the outer boundary of the electrode sheet in the region of the contact area (ie the bare shoulder).

[0040] According to another embodiment of the invention, for each electrode sheet, the orientation of the blunt edge of the electrode sheet in the ESV is determined at least based on the aligned geometry of the optical recording, wherein the blunt edge corresponds to the edge of the electrode sheet opposite the contact region.

[0041] In this case, the blunt edge includes in particular both the edge of the substrate and the edges of the coating on both sides, which ideally have the same orientation. However, in some designs, a stepping along the second transition edge can also be achieved in the region of the blunt edge, so that the substrate protrudes slightly beyond the coating on both sides. This additional stepping must then be taken into account in order to determine the overlap and placement accuracy of the active areas.

[0042] In particular, the orientation of each electrode sheet can be determined with high accuracy based on the orientation of its transition edges, outer edges and blunt edges, so that the placement accuracy and thus the process capability and product quality can be precisely determined.

[0043] According to another embodiment of the invention, provision is made for a coverage criterion of the active area of ​​the electrode sheet to be determined, in particular along the xy plane, wherein for this purpose one or more of the following first offsets are determined with the aid of the determined orientation of the transition edge of the electrode sheet and the determined orientation of the blunt edge of the electrode sheet:

[0044] a maximum deviation of the orientation of the transition edges of the electrode sheets of the first type, in particular along the xy plane, in particular along the x and / or y direction,

[0045] a maximum deviation of the orientation of the transition edges of the electrode sheets of the second type, in particular along the xy plane, in particular along the x and / or y direction,

[0046] a maximum deviation of the orientation of the blunt edge of the electrode sheets of the first type, in particular along the xy plane, in particular along the x and / or y direction,

[0047] a maximum deviation of the orientation of the blunt edge of the electrode sheets of the second type, in particular along the xy plane, in particular along the x and / or y direction,

[0048] a minimum offset of the orientation of the transition edge of the electrode sheet of the first type relative to the orientation of the blunt edge of the electrode sheet of the second type, in particular along the xy plane, in particular along the x and / or y direction,

[0049] A minimum offset of the orientation of the transition edge of the electrode laminae of the second type relative to the blunt edge of the electrode laminae of the first type, in particular along the xy plane, in particular along the x and / or y direction.

[0050] The coverage criterion is determined by checking to what extent the deviations are within a predefined tolerance range. Based on these deviations, the process capability and / or the product quality can be determined. These deviations provide information about the orientation of the electrode sheet in the ESV along the xy plane, so that it can be determined for each electrode sheet whether the electrode sheet is within the tolerance range with its active area and / or whether the electrode sheet is within the tolerance range of the corners / edges of the first or second type of electrode sheet. Based on this determination, the process capability and the product quality can be determined.

[0051] For example, the offset may be determined as a distance.

[0052] According to another embodiment of the invention, the placement accuracy of the electrode sheet, in particular the electrode sheet with respect to the xy plane, is determined, wherein for this purpose one or more of the following second offsets are determined with the aid of the determined orientation of the outer edge of the electrode sheet and the determined orientation of the blunt edge of the electrode sheet:

[0053] a maximum deviation of the orientation of the outer edges of the electrode sheets of the first type, in particular along the xy plane, in particular along the x and / or y direction,

[0054] a maximum deviation of the orientation of the outer edges of the electrode sheets of the second type, in particular along the xy plane, in particular along the x and / or y direction,

[0055] a maximum deviation of the orientation of the blunt edge of the electrode sheets of the first type, in particular along the xy plane, in particular along the x and / or y direction,

[0056] a maximum deviation of the orientation of the blunt edge of the electrode sheets of the second type, in particular along the xy plane, in particular along the x and / or y direction,

[0057] a minimum offset of the orientation of the outer edges of the electrode sheets of the first type relative to the orientation of the blunt edges of the electrode sheets of the second type, in particular along the xy plane, in particular along the x and / or y direction,

[0058] A minimum offset of the orientation of the outer edges of the electrode laminae of the second type relative to the orientation of the blunt edges of the electrode laminae of the first type, in particular along the xy plane, in particular along the x and / or y direction.

[0059] In particular, the placement accuracy is determined from the mentioned offset, in particular by checking whether the offset lies within a predefined tolerance range.

[0060] In this case, a maximum deflection and a minimum deflection are determined from the set of deflections of all electrode strips about the corresponding edge.

[0061] According to another embodiment of the present invention, the orientation of the transition edge includes a first orientation of the transition edge on a first side of the coating for both sides of the electrode sheet and a second orientation of the transition edge on a second side of the coating for both sides of the electrode sheet opposite to the first side along the stacking direction, wherein the first and second orientations of the transition edge are determined at least based on the aligned geometry of the optical photograph.

[0062] This allows the transition edges to be determined in a side-selective manner and deviations in their orientation can be taken into account in a further evaluation step.

[0063] According to another embodiment of the invention, it is provided that the orientation of the transition edge is determined from an average value of the first and second orientations of the transition edge, or that the first or second orientation of the transition edge is linked to the orientation of the transition edge for determining the first offset.

[0064] According to another embodiment of the present invention, it is provided that, for two corner areas of the electrode sheet along the y-axis, in particular for two corner areas which are opposite to each other only along the y-axis, each offset of each electrode sheet is determined, wherein a tolerance range is preset for each of the offsets, wherein, for each corner and its determined and associated offsets, it is determined whether at least one of the determined and associated offsets is outside the tolerance range associated therewith, and in particular, if at least one of the offsets is outside the tolerance range associated therewith, the ESV is associated with a defective product.

[0065] In this way, it can be determined on the basis of the determined deviation whether the ESV must be sorted out if necessary if it does not meet a certain quality criterion.

[0066] According to a further embodiment of the invention, it is provided that the transition edge of at least one electrode sheet runs obliquely, in particular along the y-axis, so that the first offset with respect to the orientation of the obliquely running transition edge is not of the same magnitude in each of the two corner regions.

[0067] According to a further embodiment of the invention, it is provided that the orientation of the transition edges of the electrode strips corresponds to an average value of all orientations of the transition edges determined for the respective electrode strip, so that the orientation remains robustly determinable with respect to offset or rough transition edge courses.

[0068] This aspect makes it possible to determine an edge course which is robust with respect to roughness and small edge defects.

[0069] According to a further embodiment of the invention, it is provided that the position of the transition edge of the electrode of the first type is determined solely from the optical image.

[0070] As a result, transition edges can be determined with particularly high accuracy, in particular because these edges are not or are only poorly detected in the CT data and are therefore not recognizable or can only be recognized poorly in the CT data.

[0071] According to a further embodiment of the invention, it is provided that the orientation of the outer edges of the electrode sheets of the second type is determined solely from the optical image.

[0072] As a result, outer edges can be determined with particularly high accuracy, in particular because these edges are not or are only poorly detected in the CT data and are therefore not recognizable or can only be recognizable poorly in the CT data.

[0073] According to another aspect of the invention, a system for determining quality and process parameters of an ESV is provided, which has at least the following components:

[0074] an optical acquisition unit, which is configured to take optical photographs of the electrode sheet from a first side and a second side of the electrode sheet,

[0075] - an ESV stacking device configured to stack electrode sheets into an ESV, wherein the system is configured to index each electrode sheet so as to achieve an association of each electrode sheet in the optical photograph in the ESV,

[0076] a computer tomography imaging device, which is configured to produce a three-dimensional image of the ESV stack,

[0077] The system comprises a computer which is designed to control the components of the system via an interface and to carry out the method according to any of the preceding claims.

[0078] According to another aspect of the invention, a computer program is provided, which comprises a computer program code, which, when executed on a computer, in particular when executed on a computer of the system, causes the computer to execute the method according to the invention.

[0079] In the context of the present description, a computer program is also understood to mean in particular a computer program product, ie a computer program code stored on a non-transitory storage medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] The present invention is explained below based on the embodiments shown in any of the figures.

[0081] in:

[0082] Figure 1 An embodiment of a system for carrying out the method according to the invention is shown;

[0083] Figure 2 An exemplary cross section along the xz plane of a region of a CT image is shown;

[0084] Figure 3 A schematic diagram showing an electrode sheet of a first type is shown;

[0085] Figure 4 shows a schematic diagram of an electrode sheet of a second type;

[0086] Figure 5 a schematic diagram showing a cross section through an ESV in which the deflection of an electrode sheet is determined; and

[0087] Figure 6 Schematic diagrams of electrode sheets of a first type having different edge profiles are shown. DETAILED DESCRIPTION

[0088] exist Figure 1 A) schematically shows a side view of an electrode patch 10 together with the optical acquisition unit of the system. The optical acquisition unit comprises two line scan cameras 1-1, 1-2, which are offset along the z-axis with respect to an associated coordinate system and thus optically acquire the corresponding side of the electrode patch 10 to be recorded. The electrode patch 10 extends along the xy plane and moves along the y direction (inwards or outwards in the image plane).

[0089] Each camera is associated with a light source 3 - 1 , 3 - 2 which illuminates the electrode sheet 10 on the respective side in order to ensure that identical recording conditions are maintained.

[0090] The electrode sheet 10 includes a substrate 10S extending along the xy plane and covered on both sides with a cover layer 10B also extending along the xy plane. The substrate 10S and the cover layers 10B on both sides are made of different materials.

[0091] When the electrode sheet 10 moves, the line scan cameras 1-1, 1-2 capture both the geometry of the coating 10B on both sides and the geometry of the visible (that is, uncoated) part of the substrate 10S (which is also referred to as bare shoulders or exposed shoulders) at least within the shooting range. In the context of this specification, the coated part of the electrode sheet 10 is also referred to as the active area, while the uncoated part of the electrode sheet 10 (which forms the exposed shoulders) is referred to as the contact area.

[0092] exist Figure 1 B) shows the Figure 1A) is a top view of the same scene, in which the transition edge 2 of the electrode sheet 10 extending along the y-axis can be seen. The transition edge 2 is the edge that occurs at the edge of the coating 10B to the active area. When the electrode sheet 10 is displaced along the y-axis, the line scan cameras 1-1, 1-2 capture at least this area, but in particular also a plurality of other areas.

[0093] exist Figure 1 C) shows a determined optical photograph of the area of ​​the transition edge 2 captured by the line scan camera. The transition edge 2 but also the outer edge 1 of the substrate 10S is captured at multiple locations along the y direction. Depending on the location, the edge direction is determined by, for example, linear interpolation. In this way, the edge direction of the transition edge 2 and the outer edge 1 can be determined for both sides of the electrode sheet 10, wherein the edge direction of the outer edge 1 is the same for both sides. Through the photograph, the main part of the geometric shape of the electrode sheet 10 can be obtained.

[0094] exist Figure 1 D) shows the edge course of a transition edge 2 with a higher degree of roughness. For this reason, it is advantageous to detect the transition edge 2 at a plurality of locations along the y-axis, since this allows an improved determination of the course or interpolated course of the transition edge 2 .

[0095] Additionally, an optical measurement of the entire electrode sheet geometry can be performed in parallel, for example by determining the length (in the x-direction) and the width (in the y-direction).

[0096] This can be done, for example, by means of a further camera assembly (not shown) together with a light source, which camera assembly, for example, also comprises two correspondingly arranged line scan cameras. In this way, in particular, the blunt edges of the electrode sheet 10 can be captured along the x-axis relative to the contact area. This enables the acquisition of the geometry of the electrode sheet arranged rotated 180° in the xy plane.

[0097] Likewise, an offset of the two coatings on the electrode sheet 10 can possibly be determined via both sides of the transition edge 2 , which can be taken into account in the further evaluation.

[0098] The optically acquired region of the electrode sheet 10 allows the geometry of the electrode sheet 10 to be determined from the optical image, at least with regard to the critical edge course.

[0099] Subsequently, the photographed electrode sheets 10 are assembled into an ESV stack substantially stacked along the z direction. Here, the ESV 4 comprises a first and a second type of electrode sheets 10. These are usually electrode sheets forming anodes (i.e., anode sheets) and electrode sheets forming cathodes (i.e., cathode sheets).

[0100] In order to be able to subsequently associate the electrode sheets 10 with the optical photographs in the stack, the electrode sheets 10 are indexed in this respect, so that the stacking position can be determined from the index, for example by means of a number.

[0101] The ESV stack is acquired three-dimensionally at least partially with the aid of a computed tomography recording device.

[0102] exist Figure 2 CT images of a region of an ESV4 stack are shown in a cross-sectional view along the xz plane. The outer edge regions of anode plates 10A (numbered from 14 to 10) are shown, as well as the maximum deviations of the anode plates along the x direction according to the determined outer edges 1A-10, 1A-12 of the electrode plates 10. Likewise, the maximum deviations of the transition edges of cathode plates 10K (likewise numbered from 14 to 10) along the x direction are shown.

[0103] These deviations are then compared with a tolerance range that describes the tolerance for the deviation or orientation of the electrode sheet. If the deviation is within the tolerance range, the ESV 4 meets the predefined quality standard. If this is not the case, the ESV 4 is optionally classified as a defective product.

[0104] exist Figure 3 and Figure 4 The first and second types of electrode sheets 10A and 10K are shown in FIG. Figure 3 2 shows two schematic cross-sectional views of an anode sheet 10A, wherein the blunt edge 3.3A, the transition edge 2.2A and the outer edge 1.1A of the anode sheet 10A are also shown. 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 captured in the CT image and is therefore not visible or difficult to identify in the CT image of the ESV. On the contrary, the material of the substrate 10A-S (e.g., copper) provides a sufficiently high CT contrast so that the substrate is visible in the CT image of the ESV.

[0105] Similarly, in Figure 4 2 shows two schematic cross-sectional views of a cathode plate 10K by way of example. The cathode plate comprises a coating 10K-B on both sides and a substrate 10K-S, wherein the blunt edge 3.3K, the transition edge 2.2K and the outer edge 1.1K of the cathode plate 10K are also shown here. The material of the substrate 10K-S (e.g., aluminum) is not captured in the CT image and is therefore not visible or difficult to identify in the CT image of the ESV. On the other hand, the material of the coating 10K-B (e.g., lithium) provides a sufficiently high CT contrast so that the coating 10K-B on both sides is visible in the CT image of the ESV.

[0106] exist Figure 5A schematic cross section through an ESV 4 along the xz plane is shown in . In this case, the ESV 4 comprises only three anode sheets and three cathode sheets 10A-1, 10A-2, 10A-3, 10K-1, 10K-2, 10K-3, in order not to unnecessarily complicate the illustration.

[0107] So external Figure 5 , anode sheets 10A-1, 10A-2, 10A-3 and cathode sheets 10K-1, 10K-2, 10K-3 are stacked in an xy plane rotated 180° relative to one another, so that outer edges 1A-1, 1A-3, 1K-1, 1K-3 point in opposite x directions. In ESV4, a separator layer S is also arranged between the electrode sheets.

[0108] Because about Figure 3 and Figure 4 As described, the substrate of the cathode sheet and the coating of the anode sheet are not visible in the CT images, so that only selected edges or geometries of the electrode sheet can be determined or correlated based on the optical data.

[0109] In this example, the edges are named according to the following logic:

[0110] The first digit specifies the edge, ie in particular the outer edge (1), the transition edge (2) and the blunt edge (3).

[0111] The following letter determines the type of electrode sheet, here anode (A) or cathode (K). The last number indicates the position in the ESV. The further up the electrode sheet is arranged, the smaller the number.

[0112] Thus, "2A-3" denotes the transition edge of the anode sheet arranged lowest among all the anode sheets in the ESV shown. "1K-1" denotes the outer edge of the cathode sheet arranged highest.

[0113] As from Figure 5 It is known from the drawings that the transition edges 2A-1, 2A-3 of the anode strips 1A-1, 1A-3 and the outer edges 1K-1, 1K-3 of the cathode strips can be determined only on the basis of the associated optical data.

[0114] For this purpose, the geometry of the optical image is aligned with the geometry of the electrode sheet determined from the computed tomography image in the ESV4 and, if necessary, scaled. Since for each electrode sheet at least one geometry (the geometry of the substrate or the geometry of the coating) is visible in the CT image, a transformation can be determined for each electrode sheet, according to which the geometry determined from the optical image can be made consistent with the geometry determined from the CT data, wherein the corresponding transformation for the electrode sheet is applied to the geometry acquired only in the optical image, so that the geometry and orientation of all substrates and coatings can be considered to be very well determined.

[0115] In order to determine the various quality criteria of an ESV, the offset of the various edges of the electrode sheets relative to one another in the xy plane, in particular along the x direction, is now particularly relevant.

[0116] Likewise, the twist of the electrode sheets relative to the stack axis or to other electrode sheets can be determined.

[0117] For example, to determine the quality criteria for process capability, the following distances or offsets are determined:

[0118] - D1-1: maximum deviation of the outer edges 1A-1, 1A-3 of the anode sheets 10A-1, 10A-3 relative to each other;

[0119] - D2-1: the smallest offset of the outer edge 1A-3 of the anode strip 10A-3 relative to the blunt edge 3K-1 of the cathode strip 10K-1, ie the smallest offset of all offsets of the outer edge of the anode strip relative to the blunt edge of the cathode strip.

[0120] - D3: Maximum offset of the blunt edges 3K-1, 3K-3 of the cathode strip relative to one another.

[0121] - D4-1: Maximum deflection of the outer edges 1K-1, 1K-3 of the cathode strips.

[0122] - D5-1: Minimum offset of the outer edge 1K-3 of the cathode strip 10K-3 relative to the blunt edge 3A-1 of the anode strip 10A-1.

[0123] - D6: Maximum deviation of the blunt edges 3A-1, 3A-3 of the anode sheets 10A-1, 10A-3 relative to each other.

[0124] The outer edges 1K-1, 1K-3 of the cathode sheets 10K-1, 10K-3 can only be determined from the optical image. Therefore, despite the lack of information about the length of these edges from the CT data, the method according to the invention still allows the determination of the offsets D4-1 and D5-1 and thus of the quality criterion of the process capability.

[0125] Based on the offsets determined in this way, the position of each electrode sheet 10 in the ESV4 can be determined, that is, in particular information on the position and orientation. In an advantageous manner, the above-mentioned offsets for determining the process capability are determined at least for each corner region of the electrode sheet 10, that is, each edge is determined at at least two locations of the electrode sheet 10 that are located in the edge region, in particular located on the outside (along the y-axis). For each corner region, each of the above-mentioned offsets for determining the process capability is associated with, in particular, a predefined tolerance range, within which the corresponding offset should lie. The process capability provides information, in particular, about the extent to which the outer regions of the electrode sheet 10 are regularly and precisely arranged in the ESV4.

[0126] In addition to the process capability, a quality criterion in the form of a coverage criterion can also be determined, which provides information about the coverage area of ​​the active region of the electrode sheet 10 .

[0127] In this case, the coverage area corresponds in particular to the intersection of all active regions of the electrode sheets projected onto the xy plane.

[0128] In order to determine the coverage criterion, the following deviations are determined, inter alia, from the electrode sheet geometry:

[0129] - D1-2: maximum deviation of the transition edges 2A-1, 2A-3 of the anode sheets 10A-1, 10A-3 relative to each other;

[0130] - D2-2: the smallest offset of the transition edge 2A-3 of the anode strip 10A-3 relative to the blunt edge 3K-1 of the cathode strip 10K-1, ie the smallest offset of all offsets of the transition edge of the anode strip relative to the blunt edge of the cathode strip.

[0131] - D3: Maximum offset of the blunt edges 3K-1, 3K-3 of the cathode strip relative to one another.

[0132] - D4-2: Maximum deflection of the transition edges 2K-1, 2K-3 of the cathode strip.

[0133] - D5-2: Minimum offset of the transition edge 2K-3 of the cathode strip 10K-3 relative to the blunt edge 3A-1 of the anode strip 10A-1.

[0134] - D6: Maximum deviation of the blunt edges of the anode sheet relative to each other.

[0135] The transition edges 2A-1, 2A-3 of the anode sheet can be determined only from the optical image. The method according to the invention therefore makes it possible to determine the offsets D1-2 and D2-2 and thereby the overlay criterion, despite the lack of information on the length of these edges from the CT data.

[0136] From the deflections determined in this way, the position of each electrode patch in the ESV 4 can be determined, ie, in particular information about the position and orientation.

[0137] Advantageously, the above-mentioned offsets for determining the overlay criterion are determined at least for each corner region of the electrode sheet, that is, each of the above-mentioned edges is determined at at least two locations of the electrode sheet that are located in the edge region, in particular located on the outside (along the y-axis). For each corner region, each of the above-mentioned offsets for determining the overlay criterion is associated with a tolerance range, in particular a predefined tolerance range (different from the tolerance range of the placement accuracy / process capability), within which the corresponding offset should lie.

[0138] The determination in at least two corner regions also takes into account the course of the edges which run obliquely with respect to the y-axis, see Figure 6 B.

[0139] The further use of the ESV may depend on whether a coverage criterion is met, ie whether all offsets in all corner regions are within a set tolerance range.

[0140] Regarding the transition edge of the electrode sheet, the following different situations can be considered.

[0141] Since the coating on both sides of the substrate can be captured by the recording device, the transition edge 2A-1a, 2A-1b can be determined for each side. In order to associate the electrode sheet with the transition edge, for example, the average value 2A-1 of the two transition edges (i.e., the average direction of the edge) can be used for further processing, see Figure 6 A.

[0142] Alternatively, both edges are taken into account in a further processing step of the method, so that, for example, the smaller of the two resulting active region coverage areas is used in order to determine the quality criterion.

[0143] Reference numerals list

[0144] 1. The outer edge of the electrode

[0145] 1-1,1-2 line scan camera

[0146] 1A, 1A-1, 1A-3, 1A-10, 1A-12 The outer edge of the first type of electrode sheet

[0147] 1K, 1K-1, 1K-3 The outer edge of the second type of electrode

[0148] 2 Transition edge of electrode sheet

[0149] 2A, 2A-1, 2A-3 Transition edge of the first type of electrode sheet

[0150] 2A-1a, 2A-1b One side of the transition edge

[0151] 2K, 2K-1, 2K-3, 2K-10, 1K-14 Transition edge of the second type of electrode sheet

[0152] 3 Blunt edges

[0153] 3-1,3-2 Light source

[0154] 3A, 3A-1, 3A-3 Blunt edge of the first type of electrode sheet

[0155] 3K, 3K-1, 3K-3 blunt edges of the second type of electrode

[0156] 4ESV

[0157] 10 electrodes

[0158] 10A, 10A-1, 10A-2, 10A-3 The first type of electrode sheet

[0159] 10B electrode coating

[0160] 10K, 10K-1, 10K-2, 10K-3 Second type of electrode

[0161] 10A-B Coating of the first type of electrode sheet

[0162] 10A-S The first type of electrode sheet substrate

[0163] 10K-B Second type electrode sheet coating

[0164] 10K-S Second type of electrode sheet substrate

[0165] 10S electrode substrate

[0166] 100 Movement direction

[0167] D1-1 Maximum deviation of the outer edges of the first type of electrode sheets relative to each other

[0168] D1-2 Maximum offset of transition edges of electrode sheets of the first type relative to each other

[0169] D2-1 Minimum offset of the outer edge of the first type of electrode sheet relative to the blunt edge of the second type of electrode sheet

[0170] D2-2 Minimum offset of the transition edge of the first type of electrode sheet relative to the blunt edge of the second type of electrode sheet

[0171] D3 Maximum offset of the blunt edges of the second type of electrode sheets relative to each other

[0172] D4-1 Maximum deviation of the outer edges of the second type of electrode sheets relative to each other

[0173] D4-2 Maximum offset of transition edges of electrode sheets of the second type relative to each other

[0174] D5-1 Minimum offset of the outer edge of the second type electrode sheet relative to the blunt edge of the first type electrode sheet

[0175] D5-2 Minimum offset of the transition edge of the second type of electrode sheet relative to the blunt edge of the first type of electrode sheet

[0176] D6 Maximum offset of the blunt edges of the first type of electrode sheets relative to each other

[0177] S diaphragm layer

Claims

1. A method for determining the orientation of an electrode sheet (10) in an electrode-separator assembly (ESV) (4), wherein: The electrode sheet (10) has at least two components, namely, a substrate (10S) and coatings (10B) on both sides of the substrate (10S), wherein the electrode sheet (10) comprises at least one first and second type of electrode sheet (10A, 10K), wherein the method comprises the following steps: - optically recording each electrode sheet (10, 10A, 10K) at least partially in one or more recording ranges; - determining at least one area of ​​the geometric shape of the substrate (10S) and at least one area of ​​the geometric shape of the coating (10B) on both sides of the substrate (10S) based on the optical photograph; - indexing each electrode sheet (10, 10A, 10K) so that a link between each electrode sheet (10, 10A, 10K) and a geometry determined therefor in the optical photograph can be realized in the ESV (4); - stacking the electrode sheets (10, 10A, 10K) into an ESV (4); - in a computed tomography image, at least one of the two components of an electrode sheet (10A) of a first type in the ESV (4) and at least one of the two components of an electrode sheet (10K) of a second type in the ESV (4) are acquired by means of a computed tomography scan; - at least partially determining the geometry of the corresponding acquired component from the computed tomography; - aligning the corresponding geometrical shape in the optical photograph with the geometrical shape of the electrode sheet (10, 10A, 10K) in the ESV (4) determined from the computed tomography photograph; - Determining the orientation of the substrate (10S) of each electrode sheet (10, 10A, 10K) and the coatings on both sides thereof, wherein the orientation of the components not captured in the computed tomography photograph is determined from the aligned geometry of the optical photograph, thereby determining the orientation of all components of the electrode sheets of the ESV (4) in the ESV (4).

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

3. The method according to claim 1 or 2, characterized in that: Each electrode sheet has the coating on both sides in the active area, and the substrate (10S) of the electrode sheet (10) is uncoated at least in the contact area.

4. The method according to claim 3, characterized in that: The contact area of ​​each electrode sheet (10, 10A, 10K) extends in the edge area of ​​the electrode sheet, and the active area of ​​the electrode sheet (10, 10A, 10K) extends immediately following the contact area along the transition edge (2, 2A, 2K), wherein for each electrode sheet (10, 10A, 10K), the orientation of the transition edge (2, 2A, 2K) is determined at least according to the aligned geometry of the optical photograph.

5. The method according to claim 3 or 4, characterized in that: The contact region forms an outer edge (1, 1A, 1K) of the electrode sheet (10, 10A, 10K), wherein the orientation of the outer edge (1, 1A, 1K) in the ESV (4) is determined for each electrode sheet (10, 10A, 10K) at least based on the aligned geometry of the optical image.

6. The method according to any one of claims 3 to 5, characterized in that For each electrode sheet (10, 10A, 10K), the orientation of a blunt edge (3, 3A, 3K) of the electrode sheet (10, 10A, 10K) in the ESV (4) is determined at least based on the aligned geometry of the optical photograph, wherein the blunt edge (3, 3A, 3K) corresponds to the edge of the electrode sheet (10, 10A, 10K) that is opposite the contact region.

7. The method according to at least one of claims 4 and 6, characterized in that A coverage criterion for the active area of ​​the electrode sheet (10, 10A, 10K) is determined, wherein for this purpose one or more of the following first offsets are determined with the aid of the determined orientation of the transition edge (2, 2A, 2K) of the electrode sheet (10, 10A, 10K) and the determined orientation of the blunt edge (3, 3A, 3K) of the electrode sheet (10, 10A, 10K): - a maximum deviation (D1-2) of the orientation of the transition edge (2A) of the electrode sheet (10A) of the first type, - a maximum deviation (D4-2) of the orientation of the transition edge (2K) of the electrode sheet (10K) of the second type, - a maximum deviation (D6) of the orientation of the blunt edge (3K) of the electrode sheet (10K) of the first type, - a maximum deviation (D3) of the orientation of the blunt edge (3K) of the electrode sheet (10K) of the second type, - a minimum offset (D2-2) of the orientation of the transition edge (2A) of the electrode sheet (10A) of the first type relative to the orientation of the blunt edge (3K) of the electrode sheet (10K) of the second type, - a minimum offset (D5-2) of the orientation of the transition edge (2K) of the electrode sheet (10K) of the second type relative to the orientation of the blunt edge (3A) of the electrode sheet (10A) of the first type.

8. The method according to at least one of claims 5 and 6, characterized in that The placement accuracy of the electrode sheet (10, 10A, 10K) is determined, wherein for this purpose one or more of the following second offsets are determined with the aid of the determined orientation of the outer edge (1, 1A, 1K) of the electrode sheet (10, 10A, 10K) and the determined orientation of the blunt edge (3, 3A, 3K) of the electrode sheet (10, 10A, 10K): - a maximum deviation (D1-1) of the orientation of the outer edge (1A) of the electrode sheet (10A) of the first type, - a maximum deviation (D4-1) of the orientation of the outer edge (1K) of the electrode sheet (10K) of the second type, - a maximum deviation (D6) of the orientation of the blunt edge (3A) of the electrode sheet (10A) of the first type, - a maximum deviation (D3) of the orientation of the blunt edge (3K) of the electrode sheet (10K) of the second type, - a minimum offset (D2-1) of the orientation of the outer edge (1A) of the electrode sheet (10A) of the first type relative to the orientation of the blunt edge (3K) of the electrode sheet (10K) of the second type, - a minimum offset (D5-1) of the orientation of the outer edge (1K) of the electrode sheet (10K) of the second type relative to the orientation of the blunt edge (3A) of the electrode sheet (10A) of the first type.

9. The method according to any one of the preceding claims, characterized in that The orientation of the transition edge (1, 1A, 1K) includes a first orientation of the transition edge (1, 1A, 1K) on a first side of the coating (10B) on both sides of the electrode sheet (10, 10A, 10K) and a second orientation of the transition edge (2, 2A, 2K) on a second side of the coating (10B) on both sides of the electrode sheet (10, 10A, 10K), wherein the first and second orientations of the transition edge (2, 2A, 2K) are determined at least based on the aligned geometry of the optical photograph.

10. The method according to claim 8, characterized in that For two corner regions of the electrode sheet (10, 10A, 10K) that are opposite to each other along the y-axis, each offset (D1-1, D1-2, D2-1, D2-2, D3, D4-1, D4-2, D5-1, D5-2, D6) of each electrode sheet (10, 10A, 10K) is determined, wherein a tolerance range is preset for each of the offsets (D1-1, D1-2, D2-1, D2-2, D3, D4-1, D4-2, D5-1, D5-2, D6), wherein for each corner and its determined and associated offset (D1-1, D1-2, D2- 1, D2-2, D3, D4-1, D4-2, D5-1, D5-2, D6), determining whether at least one of the determined and associated offsets (D1-1, D1-2, D2-1, D2-2, D3, D4-1, D4-2, D5-1, D5-2, D6) is outside a tolerance range associated therewith, wherein if at least one of the offsets (D1-1, D1-2, D2-1, D2-2, D3, D4-1, D4-2, D5-1, D5-2, D6) is outside a tolerance range associated therewith, the ESV (4) is associated with a defective product.

11. The method according to claims 7 and 9, characterized in that A transition edge (2, 2A, 2K) of at least one electrode sheet (10, 10A, 10K) extends obliquely along the y-axis, so that for each of the two corner regions a first offset with respect to the orientation of the obliquely extending transition edge (2, 2A, 2K) is not of equal magnitude and is determined and evaluated separately.

12. The method according to any one of the preceding claims, characterized in that The orientation of the transition edge (2A) of the electrode sheet (10A) of the first type is determined only from the optical photograph, and / or it is characterized in that the orientation of the outer edge of the electrode sheet (10K) of the second type is determined only from the optical photograph.

13. A system for determining quality and process parameters of an ESV (4), wherein: The system has the following components: an optical acquisition unit, which is configured to take optical photographs of the electrode sheet (10, 10A, 10K) from a first side and a second side of the electrode sheet, - an ESV stacking device configured to stack the electrode sheets (10, 10A, 10K) into an ESV (4), wherein the system is configured to index each electrode sheet (10, 10A, 10K) so as to achieve an association of each electrode sheet (10, 10A, 10K) in the optical photograph in the ESV, a computer tomography recording device, which is configured to produce a three-dimensional image of the ESV stack, The system comprises a computer which is designed to control the components of the system via an interface and to carry out the method according to any one of the preceding claims.

14. A computer program comprising a computer program code which, when executed on a computer, in particular when executed on a computer of a system according to claim 13, causes the computer to perform the method according to any one of claims 1 to 12.

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