Optical method for determining the position and / or the geometry of an electrode sheet in an electrode-separator assembly

Abstract

The invention relates to an optical method for determining the position and / or the geometry of an electrode sheet in an electrode-separator assembly. The method according to the invention involves using the evaluation of optical images (100) during the stacking of an electrode-separator assembly (1) (ESV) to determine the location and position of relevant regions of electrode and separator sheets (13, 14) during the stacking process. The positions (E) and coordinates (14-4) determined in this way can then be used in a completed ESV (1) to detect changes in position of individual electrode sheets (14) and / or separator sheets (13) in the ESV (1) even after they have been laid down. As a result, this method allows inline quality control to be carried out by means of purely optical imaging means, which significantly accelerates and simplifies the stacking process of an ESV on a production line.

Description

[0001] Description

[0002] Optical method for determining a position and / or a geometry of an electrode sheet in an electrode-separator assembly

[0003] The invention relates to an optical method for determining a position and / or a geometry of an electrode sheet in an electrode-separator assembly, ESV, according to claim 1, as well as a computer program for carrying out the method.

[0004] US 2014 0027643 A1 discloses an optical method in which the position of the electrode sheets of an ESV is recorded by a camera in a top view, specifically whenever an ESV sheet, i.e., an electrode sheet or a separator sheet, is deposited on the ESV to be manufactured. Based on the camera image, at least three corners of the electrode sheet or separator sheet last deposited on the ESV are then determined, and from this, the relative positioning of the electrode and separator sheets in the ESV is determined.

[0005] This method can be used to determine inline whether the ESV sheets were correctly aligned immediately after filing.

[0006] However, a situation can arise in which, for example, transverse forces exerted on the ESV relative to the stacking direction of the ESV by an electrode sheet depositing device cause individual or multiple already deposited ESV sheets to slip. This cannot be optically detected using the aforementioned prior art because the electrode sheets overlap.

[0007] The present invention is based on the object of determining additional reference points of the ESV sheets so that precise position and geometry information of the ESV sheets can be determined during the stacking process. In particular, the method according to the invention can at least partially detect any slippage of ESV sheets below the last deposited ESV sheet, so that the depositing accuracy and subsequent position changes of the ESV sheet can be determined quickly and reliably during the ESV manufacturing process using a purely optical imaging method.

[0008] A first aspect of the invention relates to an optical method for determining a position and / or a geometry of an electrode sheet in an electrode-separator assembly, ESV, wherein the electrode sheet has a rectangular target geometry with respect to an active area and a collector tab arranged on a collector edge of the electrode sheet, wherein the method comprises at least the following steps:

[0009] - Selecting an electrode sheet from the group consisting of: anode sheet, cathode sheet,

[0010] - Placing the selected electrode sheet onto a separator sheet of the ESV along an x- and y-axis, optically recording corners of the electrode sheet and at least partially the conductor tab at the conductor edge of the electrode sheet, determining the corner positions of the electrode sheet assigned to the corners in a storage plane of the electrode sheet from the optical image, determining an edge coordinate of the conductor tab with respect to the y-axis in a storage plane of the electrode sheet from the optical image,

[0011] - Based on the determined corner positions and the edge coordinates of the arrester lug, determine a position in the ESV and / or a geometry of the electrode sheet in the storage plane.

[0012] The invention is based on essentially rectangular active regions of the electrode sheets. The active region of an electrode sheet typically consists of a coated region of the electrode sheet. This region is essentially rectangular. The electrode sheet also has a conductor lug that protrudes on one side of the electrode sheet. In the following, reference is made to rectangular electrode sheets, whereby this is to be understood as the active region of the electrode sheet. Without limiting its general validity, the underlying coordinate system is a Cartesian coordinate system. The z-axis of the coordinate system extends essentially along a stacking direction of the ESV, i.e. a vertical axis of the ESV.

[0013] Typically, the coordinate system is aligned with respect to an ESV carrier on which the ESV sheets are stacked. Ideally, a first edge of the rectangular electrode sheets (more precisely, the active regions of the electrode sheets) or separator sheets is aligned along the x-axis, and a second edge of the ESV sheets is aligned along the y-axis, i.e., the main axes of the rectangular active regions are aligned along the x- and y-axes.

[0014] The cathode leaves and the anode leaves differ particularly with regard to their deposition orientation in that the conductor lugs are arranged on opposite sides, in particular along the x-axis opposite sides of the ESV.

[0015] The side of the electrode sheet on which the conductor tab is located is called the conductor edge. The optical image can be captured using one or more cameras, so the optical image can be composed of one or more image areas. The optical image can be saved as a digital file structure and further processed.

[0016] In particular, the optical image comprises obliquely opposite (i.e., in particular diagonally opposite) corners of the electrode sheet; more precisely, the active area. In some embodiments, only two diagonally opposite corners of the electrode sheet are captured.

[0017] The invention provides that in addition to the corners and their position, at least one y-coordinate is determined with respect to the conductor lug.

[0018] In some embodiments, two y-coordinates are determined with respect to the arrester lug, namely a first y-coordinate with respect to a first edge of the arrester lug and a second y-coordinate with respect to a second edge of the arrester lug.

[0019] The conductor lug has two edges that extend essentially along the x-axis from the electrode blade. Determining the y-coordinate of at least one or both of these edges provides additional information that allows for a more precise determination of the orientation of the electrode blade in the ESV.

[0020] Since the arrester lugs are not completely covered by the separator sheets, reference can be made to the determined y-edge coordinate of the arrester lug, even if another separator sheet and another electrode sheet have already been placed on the ESV.

[0021] This allows any subsequent slippage or change in position of electrode blades in the ESV to be detected using an optical recording system arranged in a top view.

[0022] The term "optical" in this context is to be understood in particular as a distinction from computed tomography methods. This means that the term "optical" is used in the context of the present invention, in particular, for imaging methods whose wavelength lies in the visible, ultraviolet, and / or infrared spectral range, i.e., in particular in the wavelength range between 200 nm and 1,500 nm.

[0023] The determined corner positions and the edge coordinate(s) of the electrode sheet are assigned to the electrode sheet and, in particular, saved.

[0024] In the context of the present invention, the term "position" particularly encompasses a position and orientation of the electrode sheet with respect to the coordinate system or relative to another reference system. According to one embodiment of the invention, the separator sheets of the ESV are connected along a y-direction, which extends in particular along the y-axis, and are integrally enclosed in a separator strip. The separator strip is alternately folded over at two opposite edges of the ESV, thus forming the separator sheets between the electrode sheets of the ESV.

[0025] This embodiment allows the use of a continuous separator belt in which the separator blades are ultimately connected to one another in one piece.

[0026] Alternatively or additionally, the separator tape can also be semi-transparent, so that it can be seen on the optical images, but the electrode sheets behind it also remain visible.

[0027] According to this embodiment, the separator belt ultimately winds along the stacking direction of the ESV between the electrode sheets.

[0028] One of the advantages of a separator tape is that an overlap of the electrode sheet is always guaranteed, at least along one edge of the separator sheet.

[0029] Alternatively, the separator sheets can also be provided as individual, non-contiguous rectangular separator sheets that are stacked individually.

[0030] According to a further embodiment of the invention, the edge coordinate of the conductor lug is determined with at least the following steps:

[0031] Determining a straight edge line of an edge of a separator sheet which is arranged below the electrode sheet and protrudes below the electrode sheet with respect to the collector edge of the electrode sheet,

[0032] Determining a curved or angled edge line of the conductor edge of the electrode sheet in an area of ​​the conductor lug in which the conductor edge forms a corner to the conductor lug,

[0033] Determining an intersection point of the straight edge line of the edge of the separator blade and the curved or angled edge line of the conductor edge,

[0034] Assigning a y-coordinate of the crossing point to the edge coordinate of the arrester lug, In particular assigning an x-coordinate of the crossing point to an edge point of the arrester lug.

[0035] This embodiment is advantageous in many ways.

[0036] One problem with determining edge lines is that low contrast with the surroundings / background makes the determination difficult or even impossible.

[0037] To determine the y-coordinate of the collector tab edge, this embodiment uses the intersection of two edge lines that reliably exhibit a high contrast or a comparatively high contrast change, namely the edge line of an underlying separator sheet (the separator sheet exhibits a high contrast with the background) and the edge line of the electrode sheet in the collector tab region, the edge line of the collector edge. The edge line in the collector tab region is curved or angled, so that this line extends partially along the y-axis (in the active region) and then changes direction so that it extends essentially along the x-axis, forming the collector tab.

[0038] In the area of ​​the edge line that overlaps with the separator sheet, the edge line exhibits high contrast; this is particularly evident in the area parallel to the y-axis. Further along the x-axis, the contrast abruptly deteriorates at the moment the electrode sheet no longer overlaps with the separator sheet.

[0039] The edge line of the collector edge intersects (as projected onto the deposition plane) the edge line of the separator sheet precisely at the point where the contrast abruptly deteriorates. This intersection point can therefore be determined with high reliability and accuracy. While the x-coordinate of this intersection point is essentially determined by the position of the separator sheet, the y-coordinate directly provides information about the position of the electrode sheet.

[0040] If this electrode sheet is subsequently covered by another separator sheet or another electrode sheet, this y-coordinate can still be determined or verified because the subsequently deposited electrode sheet has a conductor lug that is opposite to that of the electrode sheet arranged below it along the x-axis.

[0041] According to a further embodiment of the invention, it is provided that on a side of the electrode sheet opposite the conductor edge, an edge coordinate of the separator sheet lying below the electrode sheet (and projecting above it) is determined with respect to the x-axis.

[0042] Here, too, the invention advantageously makes use of areas of the optical recording with large contrast changes in order to ensure safe and reliable determination of position and orientation information of the separator sheet.

[0043] According to a further embodiment of the invention, in order to determine the edge coordinate of the separator sheet, in particular exclusively in a region of the separator sheet in which the conductor lug of an electrode sheet lying beneath the separator sheet protrudes, a straight edge line of the edge of the separator sheet is determined along the edge of the separator sheet and an x-coordinate of the edge line of the separator sheet is assigned to the edge coordinate of the separator sheet.

[0044] In this area, it is ensured that the determined edge line actually belongs to the separator sheet below and not to a separator sheet located further down that protrudes further from the ESV in the x-direction.

[0045] In this area, separator sheets arranged further down are not visible in plan view because they are covered by the conductor lug of the electrode sheet.

[0046] This means that this embodiment allows a reliable determination and assignment of the x-coordinate of the separator edge to the separator blade.

[0047] The terms "below," "further down," and the like are to be understood particularly with reference to the stacking order. Within the meaning of the invention, ESV sheets stacked earlier are arranged further down in the ESV than ESV sheets stacked later.

[0048] This means that the terms “below” and “above” are to be understood relative to a stack chronology and not necessarily with regard to a position in space.

[0049] According to a further embodiment of the invention, determining each corner position of the electrode sheet comprises at least the following steps: o Determining straight edge lines of two edges of the electrode sheet which form the corner of the electrode sheet, o Extrapolating the straight edge lines to an intersection point in the deposition plane, o Assigning the intersection point to the respective corner position.

[0050] This method for determining the intersection point is particularly precise because it does not attempt to determine a possibly rounded corner position directly, but rather by extending the edge lines that form the corner.

[0051] According to a further embodiment of the invention, it is provided that at least one or more, in particular all, of the straight edge lines is / are determined with at least the following steps:

[0052] In the optical recording, along the edge or part of the edge of the electrode sheet or the separator sheet, determining points, in particular more than 10 points in the storage plane, which lie on the edge, wherein the points are in particular equidistant from one another along the edge, determining a regression line through the points, assigning the regression line to the straight edge line of the respective edge.

[0053] It should be noted that in this embodiment, straight edge lines are meant in particular one or more of the following edge lines:

[0054] The straight edge lines of two edges of the electrode sheet, which form the corner of the electrode sheet.

[0055] The straight edge line of the edge of a separator sheet.

[0056] In particular, the regression line, especially this embodiment, corresponds to the extrapolation of the edge line.

[0057] According to a further embodiment of the invention, the optical images of the ESV sheets are processed with at least the following filters before determining the straight and / or curved or angled edge lines:

[0058] Filtering, in particular binarizing the or each optical image by means of a statistical threshold filter applied to the respective optical image,

[0059] - Applying an edge filter to the or each filtered optical image.

[0060] The edge filter may include a Sobel edge filter.

[0061] The statistical threshold filter is configured, in particular, to determine a threshold value depending on the intensity distribution of the optical image. Below this threshold, a first value is assigned to an intensity value of a pixel of the optical image, and above this threshold, a second value is assigned. In this way, even with intensity distributions that vary between images, filtering and, in particular, binarization can always be performed, allowing the edge lines to be robustly determined.

[0062] According to a further embodiment of the invention, an actual geometry of the electrode sheet and / or the separator sheet is determined using a first optical recording system, wherein the actual geometry comprises information about the edge lengths of the edges of the active region of the electrode sheet and / or the edge lengths of the edges of the separator sheet, in particular wherein the first recording system detects the electrode sheet and / or the separator sheet before it is placed on the ESV.

[0063] This information can then be used to determine the position of the ESV leaves in the ESV based on the information obtained about the corners and coordinates of the ESV leaves.

[0064] In a further embodiment of the invention, it is provided that the optical image of the ESV sheet deposited on the ESV is created by a second optical recording system, wherein the second recording system comprises two image sensors, each of which captures opposite non-overlapping regions of the ESV in the deposit plane, in particular in a top view, in which two corners of the electrode sheets and the conductor lugs are at least partially encompassed, in particular not necessarily a center and / or a middle of the electrode sheet, wherein each region further comprises a stationary structure which is not connected to the ESV, the position of which relative to one another has been determined, wherein by means of the stationary structures, based on a determined magnification of the optical image and based on the determined corner positions and / or edge coordinates, the position of the electrode sheet and / or the position of the separator sheet on the ESV is determined, in particular without,that the entire ESV sheet is captured in the images of the image sensors.

[0065] This embodiment allows the use of a dedicated imaging system for opposite sides of the ESV sheets along the x-axis, resulting in improved image quality. To allow the images to be correlated, the stationary structures in the optical image are correlated. This also allows the distances between the opposite sides of the ESV sheet along the x-axis to be determined without the entire ESV sheet being optically scanned.According to a further embodiment of the invention, it is provided that the stationary structures have at least two edges that converge to form a corner, wherein a determined corner position of the corner is used as a reference coordinate to determine the corner positions of the electrode sheet, the corner positions of the connection region of the conductor lug, and / or the edge coordinate of the separator sheet in relation to the center of the ESV, so that the position of the electrode sheet and / or the position of the separator sheet is determined in relation to a center of the ESV.

[0066] The determination of the corner positions of the corners of the structures can be carried out analogously to the determination of the corner positions of the electrode sheets.

[0067] According to a second aspect of the invention, a computer program is disclosed, the computer program comprising computer program code which, when executed on a computer, causes the computer to carry out the method according to the invention.

[0068] In the context of the specification, a computer program is understood to mean, in particular, a computer program product that is stored on a non-transitory, computer-readable storage medium.

[0069] The invention is explained below with reference to the embodiments shown in the accompanying drawings.

[0070] It shows

[0071] Fig. 1 : various stacking faults in an ESV;

[0072] Fig. 2: Determination of straight edge lines to determine the corner position of an electrode sheet;

[0073] Fig. 3: schematic representation for determining further prominent positions in the stacking process;

[0074] Fig. 4: Determination of a starting point of a conductor lug, as well as

[0075] Fig. 5: Determination of an x-coordinate of an edge of a separator sheet.

[0076] Fig. 1 shows an ESV 1 comprising a plurality of ESV sheets 11, 12, 13 stacked on top of one another, which have a rectangular active region (relative to a plane perpendicular to the stacking direction z along an xy plane). The ESV 1 extends along a vertical axis (z-axis), which runs along a z-direction without restriction of generality. The ESV sheets 11, 12, 13 extend along an x- and y-direction (x- and y-axis). The ESV sheets 11, 12, 13 are selected from the group: electrode sheet 14, separator sheet 13. The group of electrode sheets 14 comprises anode sheets 11 and cathode sheets 12. The ESV sheets are stacked alternately on top of one another: a separator sheet 13 and subsequently an electrode sheet 11, 12. The electrode sheets 14 are also laid down alternately; an anode sheet 11 followed by a cathode sheet 12 with a separator sheet 13 in between.The active areas of the anode sheets 11 are larger in the x-y plane than the active areas of the cathode sheets 12. The separator sheets 13 are larger in the x-y plane than the anode sheets. Each electrode sheet 11, 12, 14 has a conductor lug 11-1, 12-1, 14-1, which, depending on the type of electrode sheet, are arranged on opposite sides along the x-axis of the ESV 1.

[0077] The ESV blades 13, 14 are arranged on a workpiece carrier 2, which is part of the ESV 1. Fig. 1A shows an ideally stacked ESV 1, in which the ESV blades 13, 14 are all stacked exactly along the vertical axis h, centrally with respect to a center p of the workpiece carrier. In comparison, Fig. 1B shows a placement error of the first type, in which a slight transverse force (indicated by the arrow k pointing obliquely towards the ESV) causes a successive translational displacement along the x-direction during placement, so that the ESV extends obliquely along the vertical axis h, which is indicated by arrow 101. Fig. 1C shows a placement error of the second type. Here, immediately after deposition, due to an acute transverse force k, a single ESV sheet, in the example an anode sheet 11, was deposited individually offset (arrow 102) to the center p of the ESV 1.The previous ESV sheets 13, 14 and also the following ESV sheets 13,14 are again placed in the middle of the ESV 1.

[0078] Fig. 1D shows a third type of error, in which a lateral jump (indicated by arrow 103) occurred along the x-direction, and all ESV sheets 13, 14 deposited thereafter are shifted by this amount. The ESV 1 has a step. The invention aims to detect the aforementioned errors using purely optical means, particularly during the stacking process of the ESV 1. This is explained by way of example with reference to the following figures.

[0079] In Fig. 2, panel A) shows a region of an optical image 100 that encompasses a corner of an electrode sheet 14. Whether this is an anode sheet 11 or a cathode sheet 12 is initially irrelevant. The electrode sheet 14 is deposited on an underlying separator sheet 13, which projects circumferentially beyond the electrode sheet 14 and has a comparatively high intensity (compared to the electrode sheet 14 lying on top) in the optical image 100. As a result, the edges of the electrode sheet 14 that enclose the corner 14-2 of the electrode sheet 14 are clearly visible. Also shown is the position E of the corner of the electrode sheet 14 to be determined using two extrapolated straight lines g1, g2 applied to the edges. The determination of the position E of the corner is described below.

[0080] To determine the position E of corner 14-2, in a first step, the image 100 is processed using a threshold filter so that the edges of the electrode sheet 14 lie within the threshold range. The resulting image is shown in panel B.

[0081] If the image 100 has a sufficiently high contrast, the application of a threshold filter can be omitted.

[0082] The edges of the electrode sheet 14 are determined using an edge filter, see Fig. 2, panel C).

[0083] This assigns a first value to the detected edges in the image and a second value to all other areas.

[0084] In order to determine a straight edge line g1, g2 of the electrode sheet 14, a plurality of points P are determined along each edge line g1, g2 that lie on the edge.

[0085] A regression line is drawn through the multitude of points P. This results in two regression lines g1, g2 being determined – one along the edge in the x-direction and another along the edge in the y-direction. The intersection point of these regression lines g1, g2 is assigned to the corner position E of the electrode sheet 14.

[0086] In this way, further corner positions E of the electrode sheet 14 can be determined in other areas of the optical recording 100 or in other optical recordings, so that a position and / or a location of the electrode sheet 14 in a storage plane can be determined based on the positions E.

[0087] Fig. 3 shows schematically how further positions 14-4, E, ES of relevant areas can be determined by means of essentially the same method as described for Fig. 2.

[0088] Thus, Fig. 3 shows a stationary structure 15 with two edges that converge to form a corner, wherein the corner position E of the corner of the structure 15 is determined using the same method steps as described for Fig. 2. Here, too, straight edge lines g4, g5 are determined in order to determine a corner position ES of the structure 15. The corner position ES of the stationary structure 15 can then be used as a reference coordinate in order to determine the corner positions E of the electrode sheet 14, the corner positions 14-4 of the connection region of the conductor lug 14-1, and / or the edge coordinate of the separator sheet (not shown) in relation to the center of the ESV, so that the position of the electrode sheet 14 and / or the position of the separator sheet 13 is determined in relation to a center of the ESV 1.

[0089] Fig. 3 also shows the determination of an edge line g8 of the arrester lug, which can be used to determine a starting point 14-4 (also referred to as a corner in the context of the specification) of the arrester lug 14-1 on the electrode sheet and / or a y-coordinate of the arrester lug. To determine the starting point 14-4 of the arrester lugs 14-1, as explained with reference to Fig. 2, the straight edge lines g8, g2 are determined at the corresponding points on the electrode sheet 14 in order to then assign the intersection point of the regression lines to the starting point. The starting point can also be used to determine only the y-coordinate of the arrester lug 14-1.

[0090] The determination of the starting point 14-4 of the arrester lug 14-1 can alternatively be carried out using the method steps shown in Fig. 4, whereby the starting point 14-4 is thereby assigned an alternative, but robustly determined position.

[0091] Fig. 4 Panel A) shows a section of an optical image 100 of the conductor lug 14-1. The brightest area corresponds to the separator sheet located under the electrode sheet.

[0092] 13. The separator sheet 13 is separated on the right hand side by the electrode sheet

[0093] 14, with the conductor lug 14-1 of the electrode sheet 14 extending to the left over the separator sheet 13 in the lower region of the optical image 100. First, analogous to Fig. 2, the image is filtered, if necessary, with a threshold filter (see Fig. 4, panel B). Then, an edge filter as described above is also applied to the filtered image.

[0094] In the next step (see Fig. 4 Panel C), a straight edge line g6 is determined along an edge (in this case the left-hand edge) of the separator sheet 13, which extends along the y-direction, to which a corresponding regression line is assigned.

[0095] Likewise, a curved edge line g7 is determined along an edge line extending along the electrode sheet edge 14. This curved or angled edge line g7 of the conductor edge 14-3 of the electrode sheet 14 is determined in an area of ​​the conductor lug 14-1 in which the conductor edge 14-3 forms a corner 14-4 with the conductor lug 14-1.

[0096] The advantage of this is the high contrast change along this line g7, since the underlying separator sheet 13 has a high contrast compared to the electrode sheet 14.

[0097] The intersection point of the curved or angled edge line g7 with the regression line g6 then determines the edge coordinate 14-4 of the conductor lug 14-1 along the y-direction. An x-coordinate can also be determined from the intersection point, although this is of lesser importance for the method.

[0098] Finally, Fig. 5 shows how an x-coordinate of an edge of the separator sheet 13 can be reliably determined in the region of the conductor lug 14-1 of an electrode sheet 14, which lies below a separator sheet 13.

[0099] In Fig. 5 Panel A) an optical recording 100 is shown schematically, which covers this area.

[0100] In the lower part of the recording 100 there are two edges 13-1, 13-1 1of separator sheets can be seen, with the edges 13-1, 13-1" extending along the y-direction. One of the separator sheets lies beneath an electrode sheet, and the other separator sheet 13 lies upon the electrode sheet. In the active region, the electrode sheet is completely concealed by the overlying separator sheet 13, with the collector tab 14-T of the electrode sheet extending to the right-hand edge of the image in the central region of the optical recording 100. The collector tab 14-T covers the underlying separator sheet, so that in the region of the collector tab 14-T, only the edge 13-1 of the overlying separator sheet 13 is visible.

[0101] This enables a robust automated detection of the edge of the separator sheet 13, provided that its determination is restricted to the area of ​​the conductor lug 14-T of the underlying electrode sheet.

[0102] Furthermore, in Fig. 5 (Panel A), another conductor lug 14-1" of an electrode blade located further down in the ESV can be partially seen offset along the y-axis. This type of offset, which is ultimately observed in every ESV, is one reason why determining the conductor lug edge as described in Fig. 4 is particularly advantageous.

[0103] Here, too, as already explained, the straight edge line g3 of the edge of the separator sheet 13 can be determined using a threshold filter, edge filter, and regression line (see Fig. 5, Panel B). Using the regression line g3, the x-coordinate of the separator sheet 13 can be determined, e.g., by assigning a mean or a single x-value to the regression line g3 in the area of ​​the conductor lug 14-T of the electrode sheet.

[0104] Instead of determining a regression line, in this case a plurality of points P along the edge line can also be determined, and an average value of these can be assigned to the x-coordinate of the separator sheet 13.

[0105] The method according to the invention makes it possible to determine the location and position of relevant areas of the electrode and separator sheets in a reliable and robust manner based on the evaluation of optical images 100 when stacking an ESV.

[0106] These positions and coordinates determined in this way can then be used in a completed ESV 1 to determine changes in the position of individual electrode sheets 14 and / or separator sheets 13 in the ESV 1 even after they have been deposited.

[0107] This method allows inline quality control to be carried out using purely optical recording devices, which significantly accelerates and simplifies the stacking process of an ESV in a production line.

[0108] List of reference symbols

[0109] ESV 1

[0110] Workpiece carrier 2

[0111] Anode sheet 11

[0112] Cathode sheet 12

[0113] Separator sheet 13

[0114] Edge of the separator sheet 13-1, 13-T,

[0115] Electrode sheet 14

[0116] Conductor lug 11-1, 12-1, 14-1, 14-1', 14-1“

[0117] Corner of the electrode sheet 14-2

[0118] Conductor edge 14-3

[0119] Corner position of the arrester lug 14-4 opposite side of the arrester edge 14-5 stationary structure 15

[0120] Optical recording 100

[0121] First Offset Type 101

[0122] Second offset type 102

[0123] Third offset type 103

[0124] Corner position of the electrode sheet E

[0125] Corner position of the fixed structure ES straight edge line / regression lines g1 - g6 and g8 curved edge line g

[0126] Stacking direction h

[0127] Force k

[0128] Points on the edge P

[0129] Middle of the ESV

Claims

Patent claims 1. An optical method for determining a position and / or a geometry of an electrode sheet (11, 12, 14) in an electrode-separator assembly (1), ESV, wherein the electrode sheet (11, 12, 14) has a rectangular target geometry with respect to an active area and a conductor lug (11-1, 12-1, 14-1) arranged on a conductor edge (14-3) of the electrode sheet (11, 12, 14), the method comprising at least the following steps: Selecting an electrode sheet (11,12,14) from the group consisting of: anode sheet (11), cathode sheet (12), Placing the selected electrode sheet (14) on a separator sheet (13) of the ESV along an x- and y-axis, optically recording corners (14-2) of the electrode sheet (14) and at least partially the conductor lug (11-1,12-1,14-1) on the conductor edge (14-3) of the electrode sheet (14), Determining corner positions (E) of the electrode sheet (14) assigned to the corners (14-2) in a storage plane of the electrode sheet (14) from the optical recording (100), Determining an edge coordinate (14-4) of the arrester lug (14-1) with respect to the y-axis in a storage plane of the electrode sheet (14) from the optical image, Based on the determined corner positions (E) and the edge coordinate (14-4) of the arrester lug (14-1), determining a position in the ESV (1) and / or a geometry of the electrode sheet (11, 12, 14).

2. The method according to claim 1, wherein the edge coordinate (14-4) of the conductor lug (14-1) is determined with at least the following steps: Determining a straight edge line (g1) of an edge of a separator sheet which is arranged below the electrode sheet and protrudes below the electrode sheet (14) with respect to the collector edge (14-3) of the electrode sheet (14), Determining a curved or angled edge line (g7) of the conductor edge (14-3) of the electrode sheet (14) in a region of the conductor lug (14-1) in which the conductor edge (14-3) forms a corner to the conductor lug (14-4), Determining a crossing point (14-4) of the straight edge line (g6) of the separator sheet (13) and the curved edge line (g7) of the conductor edge (14-3), assigning a y-coordinate of the crossing point (14-4) to the edge coordinate of the conductor lug (14-1).

3. The method according to one of the preceding claims, wherein on a side (14-5) of the electrode sheet (14) opposite the collector edge (14-3), an edge coordinate of the separator sheet (13) lying beneath the electrode sheet (14) is determined with respect to the x-axis.

4. The method according to claim 3, wherein for this purpose, in a region of the separator sheet (13) in which the conductor lug (14-T) of an electrode sheet lying under the separator sheet (13) protrudes, a straight edge line (g3) of the separator sheet (13) is determined along the edge (13-1) of the separator sheet (13) and an x-coordinate of the edge line (g3) of the separator sheet (13) is assigned to the edge coordinate of the separator sheet (13).

5. The method according to claim 1, wherein determining each corner position (E) of the electrode sheet (11, 12, 14) comprises at least the following steps: o Determining straight edge lines (g1, g2) of two edges of the electrode sheet (11, 12, 14) which form the corner (14-2) of the electrode sheet (11, 12, 14), o Extrapolating the straight edge lines (g1, g2) to an intersection point in the deposition plane, o Assigning the intersection point to the respective corner position (E).

6. The method according to one of the preceding claims, characterized in that at least one or more of the straight edge lines (g1, g2, g3, g4, g5, g6, g8) is / are determined with at least the following steps: Determine along the edge or part of the edge points (P) in the support plane that lie on the edge, Determine a regression line through these points (P), assign the regression line to the straight edge line (g1,g2,g3,g4,g5,g6,g8) of the respective edge.

7. The method according to one of the preceding claims, characterized in that the optical recording before determining the rectilinear (g1, g2, g3, g4, g5, g6, g8) and / or curved (g7) edge lines can be processed with at least the following filters: Filtering the optical image (100) by means of a statistical threshold filter applied to the optical image (100), - Applying an edge filter to the filtered optical image (100).

8. The method according to one of the preceding claims, wherein an actual geometry of the electrode sheet (11, 12, 14) and / or of the separator sheet (13) is determined using a first optical recording system, wherein the actual geometry comprises information about the edge lengths of the edges of the active region of the electrode sheet (11, 12, 14) and / or the edge lengths of the edges of the separator sheet (13).

9. The method according to claim 8, wherein the optical image is created by a second optical recording system, wherein the second recording system comprises two image sensors, each detecting opposite non-overlapping regions of the ESV (1), in which two corners of the electrode sheets (11, 12, 14) and the conductor lugs (11-, 12-1, 14-1) are at least partially enclosed, wherein each region further comprises a stationary structure (15) whose position relative to one another has been determined, wherein the position of the electrode sheet (11, 2, 14) and / or the position of the separator sheet (13) on the ESV (1) is determined by means of the stationary structures (15), based on a determined magnification of the optical image and based on the determined corner positions (E) and / or edge coordinates.

10. The method according to claim 9, wherein the stationary structures (15) have at least two edges which converge to form a corner (ES), wherein a determined corner position of the corner (ES) is used as a reference coordinate to determine the corner positions (E) of the electrode sheet (11, 12, 14), the edge coordinate (14-4) of the conductor lug (14-1), and / or the edge coordinate of the separator sheet (13) in relation to the center (p) of the ESV (1), so that the position of the electrode sheet (11, 12, 14) and / or the position of the separator sheet (13) in relation to a center of the ESV (1) is determined.

11. A computer program comprising computer program code which, when executed on a computer, causes the computer to carry out the method according to any one of the preceding claims.

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