Method for checking a quality of an electrode-separator assembly while it is being produced

Abstract

The invention relates to a method for checking test criteria of an electrode-separator assembly (1), ESA, having ESA sheets (10) comprising the separator sheets (13), anode sheets (11) and cathode sheets (12). According to the method, positions of different relevant regions of the ESA sheets are determined using purely optical means and thus stacking errors can be detected already during the production of an ESA (1).

Description

[0001] Description

[0002] Method for testing the quality of an electrode-separator assembly under manufacture

[0003] The invention relates to a method for testing the quality of an electrode separator assembly (ESV) under production.

[0004] An ESV comprises alternating anode and cathode sheets, each with a separator layer between them. This separator layer is typically formed by individual separator sheets. The electrochemical performance of a battery cell comprising the ESV depends significantly on the overlap of the ESV sheets, i.e., the electrode sheets and separator sheets. This performance decreases more rapidly with less electrode sheet overlap at the edge of the ESV. In addition, direct contact between an anode and cathode sheet caused by incorrect placement in the ESV can cause a short circuit and battery cell failure. Furthermore, imprecise stacking of the ESV sheets results in inhomogeneous voltage peaks during the charging process, allowing pure lithium to deposit on the anode. These deposits form dendrites that can pierce the separator sheet.

[0005] Typically, the anode blade of an ESV is circumferentially slightly larger than the cathode blade to ensure complete coverage of the anode and cathode despite deposition inaccuracies and size and geometry variations of the blades.

[0006] There is a constant effort to reduce this anode overhang in order to save material.

[0007] This means that increasing demands are placed on the deposition accuracy of the ESV stacking process. Furthermore, the stacking process is a bottleneck in battery cell production, making it desirable to shorten production times. However, as process speed increases, deposition accuracy decreases. For further optimization and development of stacking processes, the position, i.e., the position and orientation of the ESV sheets in the ESV must be measured after completion. The position of the electrode sheets in the ESV is determined using computed tomography (CT) imaging techniques. However, this has the disadvantage that certain materials of the anodes or cathode sheets (coating or substrate) do not exhibit CT contrast and thus remain invisible in the CT image.

[0008] Furthermore, the use of CT systems requires complex radiation protection measures, so that the integration of a CT system into a production line entails significantly increased complexity.

[0009] In addition, the acquisition and evaluation of CT data is time-consuming and leads to a slowdown of the production process in a series production line, since each ESV must be examined after completion according to predefined test criteria.

[0010] A simple visual inspection during production, particularly after an ESV sheet has been deposited, can lead to incorrect results in the finished ESV, since the storage device that stacks the ESV sheets can itself contribute to the subsequent slipping of ESV sheets that have already been deposited, e.g. due to transverse forces that the storage device exerts on the ESV sheets that have already been deposited.

[0011] On the one hand, this can lead to each ESV sheet being successively slightly offset relative to the previous ESV sheet, which can result in a crooked stack of all ESV sheets. Another source of error, which also cannot be remedied with a simple visual inspection, is the acute slippage or incorrect placement of an individual ESV sheet relative to the other ESV sheets and the workpiece carrier, which occurs after placement.

[0012] In addition, the formation of steps, in which ESV sheets of the same type are deposited successively shifted in one direction, is a problem that is not detected with known purely optical systems.

[0013] DE 10 2022 124 784 A1 discloses a system designed and configured for stacking ESV sheets. The system features various sensors but cannot resolve the aforementioned problems.

[0014] KR 102023 0 101 723 and DE 102022 102 764 A1 each disclose systems for partially optically checking the placement of ESV sheets in an ESV stack. However, neither system is designed to overcome the aforementioned disadvantages. The present invention is based on the object of eliminating these disadvantages and providing a fast, inexpensive, and reliable method for checking the position of the ESV sheets in an ESV stack.

[0015] The object is achieved according to the invention by a method according to claim 1. Advantageous embodiments are given in the subclaims.

[0016] A first aspect of the invention relates to a method for testing test criteria of an electrode-separator assembly (ESV), with ESV sheets comprising the following types of ESV sheets, separator and electrode sheets, the latter selected from the group comprising anode and cathode sheets, comprising the following steps: a) After each deposit of an ESV sheet on the ESV and in particular before depositing a further ESV sheet, determining a plurality of positions of selected regions of the deposited ESV sheet, wherein at least the positions which are determined again in the following steps b) to d) are included in the plurality of positions, wherein the positions in a deposit plane of the ESV sheet are determined based on a first optical image in plan view, obliquely or perpendicular to the deposit plane; b) After depositing all ESV sheets on the ESV, determining a position of the separator sheets along an x-direction,along which a first edge of the ESV extends, based on a second optical image of a first side view of the ESV; c) After all ESV sheets have been deposited on the ESV, determining a position of the anode sheets along the x-direction and a y-direction of the ESV, wherein the y-direction extends along a second edge of the ESV, based on a third optical image comprising a second and third side view of the ESV, d) After all ESV sheets have been deposited on the ESV, determining a position of an outer contour line of conductor lugs of the electrode sheets, wherein the position with respect to the y-direction is determined based on a fourth optical image of the ESV of at least parts of the deposit plane, wherein in step a) it is checked for each ESV sheet whether the ESV sheet lies within a tolerance range assigned to the type of ESV sheet, wherein in steps b) to d) it is checked,whether the ESV meets at least some predefined test criteria even after all ESV sheets have been filed. This test is positive if all positions determined in steps b) to d) continue to lie within the assigned tolerance range for the respective position and the type of ESV sheet, and negative if not all positions determined lie within the assigned tolerance range.

[0017] According to the invention, steps b) to d) ensure that the predefined test criteria are met even after all ESV sheets have been filed.

[0018] The method according to the invention makes it possible to determine the position of the ESV sheets during stacking of the ESV and to determine immediately after the last ESV sheet has been deposited whether the ESV sheets have changed their position after depositing, e.g. have slipped, shifted or twisted, or whether they continue to lie within the assigned tolerance ranges, so that the predefined test criteria for the ESV are met even after all ESV sheets have been deposited.

[0019] In step a), essentially a large number of positions at selected areas, such as corners or edges of each individual ESV sheet, are determined, while the subsequent steps b) to d) serve to identify subsequently occurred deviations in the position and to estimate to what extent the position or position of the ESV sheets still fulfills the predefined test criteria.

[0020] The procedure can be carried out exclusively with optical imaging devices, so that a time-consuming computed tomography examination can be omitted if the optical examination does not reveal any abnormalities, ie if the predefined test criteria are met after filing all ESV sheets.

[0021] The predefined inspection criteria are, on the one hand, geometric criteria that define tolerance ranges for the ESV sheets within which each ESV sheet must lie, and, on the other hand, the inspection criteria also concern an order of the ESV sheets in the ESV and a position with respect to a workpiece carrier on which the ESV is stacked.

[0022] A change in the order of the ESV sheets after they have been deposited is not expected, so such a test criterion does not need to be verified using steps b) to d). A deviation from the correct stacking order would already be detected in step a), and the process could be aborted. However, steps b) to d) check at least one position parameter for each ESV sheet, so that a subsequent change in position can be determined based on these checks.

[0023] Thus, step b) checks the corner positions and, if applicable, selected edge positions of the separator sheets, step c) the position of at least some corners of the anode sheets, and step d) the position of the conductor lugs of the anode and cathode sheets.

[0024] In particular, in steps b) and c), the position of only one corner of the ESV sheets can be determined or several, in particular the positions of all four corners of the ESV sheets can be determined.

[0025] This allows for the detection of changes in the position of the ESV blades that have subsequently occurred and, in addition, for checking further test criteria that relate to a variable derived from the position of the ESV blades, such as the spacing of the edges of the electrode blades from one another along the deposition plane.

[0026] The electrode sheets have an active area coated with an active material. In particular, the active areas of the electrode sheets are essentially rectangular. The electrode sheets themselves also have conductor tabs that can break this rectangular geometry.

[0027] For the sake of better readability, reference is made below to rectangular electrode sheets, whereby this is to be understood in relation to the active areas, or in relation to the electrode sheets without taking the conductor lugs into account.

[0028] Without loss of generality, a first edge of the electrode sheet extends along an x-direction after placement and a second edge along a y-direction, provided the electrode sheet has been correctly placed on the ESV.

[0029] The x and y directions correspond in particular to an alignment of the workpiece carrier.

[0030] In particular, the conductor lug is arranged on one of the second edges of the electrode sheet. The tolerance range assigned to the ESV sheets is essentially a region that has a predetermined position and size relative to the workpiece carrier. In particular, the tolerance ranges are identical for the same type of ESV sheets.

[0031] According to one embodiment of the invention, it is provided that the separator sheets are connected along the y-direction and are integrally enclosed in a separator band, wherein the separator band is alternately folded over at the second edges of the ESV and thus forms the separator sheets between the electrode sheets of the ESV.

[0032] This embodiment allows the use of a continuous separator belt in which the separator blades are ultimately connected to one another in one piece.

[0033] This embodiment may require that the first, second, and / or third side views be taken from the first edge side.

[0034] 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.

[0035] According to this embodiment, the separator belt ultimately winds along a vertical axis of the ESV between the electrode sheets.

[0036] A separator tape has the advantages, among others, that fewer cuts are necessary and, on the other hand, an overlap of the electrode sheet is always guaranteed, at least along one edge.

[0037] Alternatively, the separator sheets can also be provided as individual, non-contiguous rectangular separator sheets that are stacked individually.

[0038] According to a further embodiment of the invention, the tolerance range assigned to the ESV sheet is determined based on a limited storage area assigned to the respective type of ESV sheet, wherein the tolerance range assigned to the respective ESV sheet is spaced from the edges of the corresponding storage area by a predefined value, in particular symmetrically, in particular such that the tolerance range comprises at most 90%, in particular at most 80%, in particular at least 70%, of the corresponding part of the storage area. This provides a tolerance range that is slightly smaller than the maximum permissible storage area for the ESV sheets. This allows it to be assumed with certainty, based on the visual inspections, that an ESV whose test criteria are still considered to be met according to steps b) to d), that the ESV was manufactured according to the specifications.

[0039] According to a further embodiment of the invention, it is provided that in step a) for each type of ESV sheet, for each position that is determined for a selected area of ​​the ESV sheet, an associated storage field is determined, which is indicative of at least the most diverse determined positions of the same selected area of ​​the already stored ESV sheets of this type, and in particular records all determined positions of the same selected areas of the already stored ESV sheets, wherein the storage field is set in relation to the tolerance range, so that the check as to whether the positions determined in steps b) to d) lie in the respective associated tolerance ranges is carried out relative to the storage field and the tolerance range set in relation thereto, wherein the check is positive if the determined positions lie within the tolerance range and negative if not.

[0040] This means that the extent to which the positions determined in steps b), c), and d) are still within the tolerance ranges is determined depending on a relative position to each other, so that no external marker or a reference coordinate system with respect to the workpiece carrier is required.

[0041] Although steps b) to d) in particular cannot fully determine the position of the respective ESV sheet, these steps are sufficient to detect a change in the position of the ESV sheet after all ESV sheets have been deposited.

[0042] According to a further embodiment of the invention, it is provided that if the determined positions are within the storage area and outside the assigned tolerance range, the ESV is subjected to a CT test.

[0043] This means that if the optical evaluation in steps b) to d) indicates that the ESV has been manufactured within the specifications, but only just, i.e. close to the permitted limits, this can be verified using a separate CT test so that the ESV can be further processed if necessary. According to a further embodiment of the invention, before step a) and before placement on the ESV, a geometry and, if applicable, a position of the ESV sheet to be deposited is determined using an upstream optical image, wherein if the determined geometry of the ESV sheet lies within a component tolerance assigned to this size, a correction vector is determined which is designed such that the ESV sheet is deposited centrally on the ESV by a depositing device based on the determined geometry.

[0044] This allows each ESV sheet to be placed as centrally as possible, i.e., centrally along a common vertical axis of the ESV. This means that the correction vector is determined specifically with regard to the dimensions and position of the ESV sheet, so that the ESV sheet is ideally placed centrally on the ESV.

[0045] The component tolerance should always be within the tolerance range for the ESV. At most, the component tolerance can correspond to the tolerance range for the ESV sheet.

[0046] In particular, if the separator sheets are included in a separator band, this embodiment may be limited to the electrode sheets only, or the correction vector for the separator band may be determined only along the x-direction.

[0047] According to a further embodiment of the invention, if the determined geometry of the ESV sheet is not within the assigned component tolerance and the ESV sheet is an electrode sheet or a single separator sheet, the ESV sheet is sorted out and is not placed on the ESV stack.

[0048] This embodiment advantageously allows for determining whether an ESV sheet to be deposited falls within a manufacturing tolerance before it is deposited. If this is not the case, depositing it on the ESV could result in non-fulfillment of the predefined inspection criteria, which would ultimately require the ESV to be rejected or subjected to further, delaying testing.

[0049] According to a further embodiment of the invention, the predefined test criteria of the ESV are fully determined based on the positions of the ESV sheets determined in step a). This means that if there were no risk of a subsequent change in the position of the ESV sheets after the ESV sheet has been deposited, this information would be sufficient to achieve quality assurance in ESV production.

[0050] However, since this is often not the case, the further test steps b) to d) are carried out according to the invention.

[0051] According to a further embodiment of the invention, the ESV is sorted out of the production line and / or subjected to a computer tomography examination if the determined position of the ESV sheet in step a) is not within the assigned tolerance range.

[0052] This embodiment allows for immediate detection of an incorrect placement of the ESV sheet on the ESV and for the process to be aborted or verified by a CT scan.

[0053] If necessary, a correction vector for subsequent ESV sheet filings can be determined from the failed filing.

[0054] According to a further embodiment of the invention, the test criteria are selected from the group consisting of:

[0055] First test criterion: Corner areas that form the corners of the separator sheets must be located in a predefined storage area for separator sheets in the x and y directions;

[0056] Second test criterion: All outer corners of the anode leaves must lie in a predefined storage area for anode leaves in the x and y directions;

[0057] Third test criterion: All outer corners of cathode sheets must lie in a predefined storage area for cathode sheets in the x and y directions;

[0058] Fourth test criterion: The sequence of the ESV sheets on the ESV must be an alternating sequence of anode and cathode sheets, each with a separator sheet arranged between them;

[0059] Fifth test criterion: A distance between the separator blades and the anode blades must be greater than a predefined minimum distance along the x and y directions;

[0060] Sixth test criterion: A distance between the cathode blades and the anode blades must be greater than a predefined minimum distance along the x- and y-direction; Seventh test criterion: a layer of the ESV blades and the layer of a workpiece carrier of the ESV have the same orientation and the ESV blades are arranged centrally on the workpiece carrier.

[0061] In particular, the predefined review criteria include all review criteria listed in this group. If not all ESV sheets are stored on the ESV, the predefined review criteria are checked against the ESV sheets already stored.

[0062] With regard to the first test criterion, it is particularly important to note that, if the separator blades are enclosed in a separator belt, the corner regions are formed, for example, by the edges of the separator belt where the separator belt bends from the storage plane along the vertical axis. In a photograph oriented toward the storage plane, this edge can be clearly identified. Thus, these edges and the edges of the separator belt form corner regions for each separator blade, based on which the corners of the respective separator blade can be determined.

[0063] According to a further embodiment of the invention, it is provided that the determined position of the separator sheets from step b) is used to check whether at least the first test criterion is also met after deposition of all ESV sheets, and / or wherein the determined position of the anode sheets from step c) is used to check whether at least the second test criterion is also met after deposition of all ESV sheets, and / or wherein the determined position of the outer contour line of the arrester lugs from step d) is used to check whether at least the second and third test criteria are also met after deposition of all ESV sheets.

[0064] According to a further embodiment of the invention, the ESV is fed to a further manufacturing step if compliance with the test criteria has been verified after storage by steps b) to d), in particular without a computed tomographic review of the test criteria being carried out.

[0065] In particular, only if all dimensions are within the assigned tolerance ranges is a computed tomographic examination of the ESV omitted with regard to at least some of the predefined test criteria.

[0066] According to a further embodiment of the invention, if at least one variable corresponding to the determined position of the separator blades, the determined position of the anode blades, and / or the determined position of the outer contour line of the arrester lugs is not within the respective assigned tolerance range, the ESV is subjected to a computer tomographic examination of at least some of the or all of the predefined test criteria before the ESV is either sorted out or fed to a further production step.

[0067] This embodiment allows an ESV, which probably does not meet all the test criteria based on the results of the optical inspection of the test criteria, to be examined more thoroughly with regard to the test criteria by means of a computed tomography examination.

[0068] According to a further embodiment of the invention, the ESV is moved along a vertical extension direction before depositing an ESV sheet such that the deposit plane is always at the same height.

[0069] According to a further aspect of the invention, an optical ESV inspection system is provided which is configured to carry out the method according to the first aspect of the invention, wherein the system has at least the following components: a computer, a storage device which is configured to store the ESV sheets on a workpiece carrier and is controlled by a control unit, a first optical recording system which is configured to record the ESV with a view of the storage plane in order to create the first and / or the fourth optical recording, a second optical recording system which is configured to record the ESV in a first side view in order to create the second optical recording, a third optical recording system which is configured to record the ESV in a second and third side view in order to create the third optical recording.

[0070] According to a further aspect of the invention, a computer program is provided that comprises computer program code which, when executed on a computer, in particular when executed on the computer of the system, causes the computer to perform the method according to the invention. In the context of this specification, a computer program is understood in particular to mean a computer program product, i.e., a computer program code stored on a non-transitory storage medium that can be executed on a computer or at least one processor and, when executed, performs the method according to the invention.

[0071] The invention is explained below with reference to the embodiments shown in the accompanying drawings.

[0072] It shows

[0073] Fig. 1 : schematic representation of deposition errors in the production of ESVs;

[0074] Fig. 2: schematic representation of the storage areas of an ESV;

[0075] Fig. 3: Geometries of the ESV blades;

[0076] Fig 4: Position changes of one type of ESV blades between the process steps:

[0077] Fig. 5: Relationship between various areas and surfaces for quality assurance; Fig. 6: Schematic representation of a first optical recording system; Fig. 7: Schematic representation of a second optical recording system; Fig. 8: Schematic representation of a third optical recording system; Fig. 9: Schematic representation of a fourth optical recording system.

[0078] Fig. 1 shows an ESV 1 comprising a plurality of stacked ESV sheets 10, each having a rectangular active area (relative to an xy plane perpendicular to the stacking direction z). The ESV 1 extends along a vertical axis, which, without restriction of generality, runs along a z-direction. The ESV sheets 10 extend along an x- and y-direction.

[0079] The ESV sheets 10 are selected from the group: electrode sheet, separator sheet 13. The group of electrode sheets comprises anode sheets 11 and cathode sheets 12. The ESV sheets are stacked alternately on top of one another: a separator sheet 13 followed by an electrode sheet 11, 12. The electrode sheets 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 all around in the xy plane than the active areas of the cathode sheets 12. The separator sheets 13 are larger all around in the xy plane than the anode sheets. Each electrode sheet 11, 12 has a collector tab 11-1, 12-1, which are arranged on opposite sides of the ESV 1 depending on the type of electrode sheet. The ESV blades 10 are arranged on a workpiece carrier 2, which is part of the ESV 1. In Fig.1A shows an ideally stacked ESV 1 in which the ESV blades 10 are all stacked exactly centrally along the vertical axis h. In comparison, Fig. 1B shows a deposition error of the first type in which a slight transverse force (indicated by the arrow K pointing diagonally towards the ESV) causes a successive translational displacement along the x-direction during deposition, so that the ESV extends diagonally along the vertical axis, which is indicated by arrow 100. Fig. 1C shows a deposition error of the second type. Here, immediately after deposition, due to an acute transverse force K, a single ESV blade 10, in the example an anode blade 11, was deposited individually offset (arrow 101) to the center p of the ESV 1. The preceding ESV blades 10 and also the subsequent ESV blades 10 are again deposited centrally on the ESV 1.

[0080] Fig. 1D shows a type three error, in which a lateral jump (indicated by arrow 102) occurred along the x-direction, and all ESV sheets 10 deposited thereafter were shifted by this amount. ESV 1 has one step.

[0081] Fig. 2 shows a section of the three storage areas 21, 22, 23 assigned to the respective types of ESV sheets. The ESV sheets 10 should be arranged with their corners and edges in the assigned storage areas 21, 22, 23 to ensure the desired performance of the ESV 1. The section represents a fourth corner area (of four corner areas) of the ESV 1. The other corner areas are designed in an analogous manner (not shown).

[0082] The storage area 23 for the separator blades 13 extends furthest outward relative to the center of the ESV 1. Along the x and y directions, this storage area 23 has an ideal nominal position SE4N(x), SE4N(y) for the separator blades in the x and y directions. The storage area 23 extends symmetrically around these nominal positions, indicating a maximum deviation up to which a deposited separator blade still lies within the desired manufacturing tolerance of the ESV, and thus within the storage area.

[0083] The width Sd(x), Sd(y) of this support surface 21 around the respective nominal position SE4N(x), SE4N(y) is typically in the sub-millimeter range.

[0084] Further inward, the support surface 21 runs in a similar manner, representing the manufacturing tolerance for the placement of the anode sheets 11. The support surface 22 for the cathode sheets 12 is also shown. Both support surfaces 21, 22 indicate a nominal position for the respective electrode sheet and, symmetrically surrounding, a range of maximum tolerated deviation. The widths – Ad(x) and Ad(y) or Kd(x) and Kd(y) – of these support surfaces 21, 22 are also in the sub-millimeter range.

[0085] The storage areas 21, 22, and 23 are spaced apart from one another, with the storage areas being selected such that a minimum distance dSA(x), dSA(y), dAK(x), dAK(y) or a minimum overlap is not undercut between the storage areas; this minimum distance is also in the sub-millimeter range. All relevant ESV sheets 10 must be stored within the respective storage areas 21, 22, and 23 in order to produce the ESV 1 within the manufacturing tolerance.

[0086] The boundaries of the storage areas are designated using the nomenclature explained below:

[0087] X1-X2-X3 (x / y)

[0088] X1 designates the storage area for the respective type of ESV sheet. X1 is selected from the letters

[0089] - S for the storage area for the separator sheets,

[0090] - A for the storage area for the anode leaves,

[0091] - K for storage area for the cathode leaves.

[0092] X2 designates the respective corner of the storage area and thus also the corner of the respective ESV sheet. X2 is selected from the letter-index combinations:

[0093] E1 for the first corner,

[0094] E2 for the second corner,

[0095] E3 for the third corner,

[0096] E4 for the fourth corner,

[0097] In particular, the corner designation runs clockwise around the storage area / ESV sheet.

[0098] X3 denotes the limit or nominal position of the respective storage area. X3 is selected from the letters

[0099] - U for the outer boundary of the storage area;

[0100] - L for the inner boundary of the storage area;

[0101] - N for the nominal position for the respective ESV sheets - typically running centrally between U and L. (x / y) specifies the respective limit or nominal position of the storage area with respect to the x- or y-direction and can take the letters x to specify the limit or nominal position along the x-direction or y to specify the limit or nominal position along the y-direction.

[0102] For example, SE4L(x) denotes the inner boundary of the storage area assigned to the separator blades along the x-direction, see also Fig. 2.

[0103] Similarly, distances can be specified with respect to these limits.

[0104] In Figs. 3A to C, it is shown schematically and by way of example which parameters can be used to determine a geometry of the electrode sheets 11, 12 (Fig. 3A + 3B) and the separator sheets 13 (Fig. 30).

[0105] To determine the geometry, the lengths 11, 12 and the widths b1, b2 of the edges of the respective ESV sheet 10 are determined, for example, optically and assigned to them. A rectangular geometry is assumed, with the exception of the conductor lugs 11-1, 12-1 of the electrode sheets 11, 12. This rectangular geometry essentially corresponds to the active areas 11-2, 12-2 of the electrode sheets 11, 12. If a separator sheet 13 is involved, the conductor lugs and the active area are omitted.

[0106] To determine the geometry, the corner positions E1, E2, E3, E4 of the ESV sheet 10 are determined using an optical image.

[0107] The distances 11, 12, b1, b2 between the determined corner positions E1, E2, E3, and E4 are also determined in this step. The edges can also be designated as ae1e2 for the edge of the anode sheet between corners E1 and E2, ae2e3 for the edge of the anode sheet between corners E2 and E3, ae3e4 for the edge of the anode sheet between corners E3 and E4, and ae4e1 for the edge of the anode sheet between corners E4 and E1.

[0108] Similarly, the edges of the electrode sheet can be designated as ke1e2 for the edge of the cathode sheet between the corners E1 and E2, ke2e3 for the edge of the cathode sheet between the corners E2 and E3, ke3e4 for the edge of the cathode sheet between the corners E3 and E4, ke4e1 for the edge of the cathode sheet between the corners E4 and E1.

[0109] Nevertheless, the edges of the separator sheet can be designated as se1e2 for the edge of the separator sheet between the corners E1 and E2, se2e3 for the edge of the separator sheet between the corners E2 and E3, se3e4 for the edge of the separator sheet between the corners E3 and E4, se4e1 for the edge of the separator sheet between the corners E4 and E1.

[0110] The edges belonging to the electrode sheets 11, 12, or the separator sheets are designated by the enclosing corners and the ESV sheet type.

[0111] For example, ae2e3 denotes the edge of the anode sheet (a for anode) that extends between corners E2 and E3. Similarly, se1e2 denotes the edge of the separator sheet (s for separator) that extends between corners E1 and E2.

[0112] The edges that extend between vertices E1 and E2, and between vertices E3 and E4, are the edges along the x-direction. The edges that extend between vertices E4 and E1, and between vertices E2 and E3, are the edges along the y-direction.

[0113] Furthermore, the y-positions of the edge positions AF1, AF2, KF1, KF2 of the conductor lugs of the anode and cathode sheets 11, 12 can be determined.

[0114] For each ESV sheet 10, the four corners E1, E2, E3, and E4 are determined. If a separator sheet 13 is involved, one or more x-positions M1, M2, M3, and M4 of the edges of the separator sheet 13, as well as their distance from each other, are also determined in the area of ​​the conductor tabs of the electrode sheets.

[0115] This geometry determination takes place before storage on the ESV 1.

[0116] In particular, determining the x-position(s) of the edges of the separator sheet 13 proves to be advantageous, since these edges in the area of ​​the collector tab can be determined without a doubt as soon as the separator sheet 13 has been placed on an electrode sheet 11, 12. This is due to the fact that an electrode sheet 11, 12 lying beneath the separator sheet 13 with the collector tab 11-1, 12-1 covers all separator sheets 3 lying beneath this electrode sheet in the area of ​​the collector tab 11-1, 12-1, so that when determining the edges M1, M2, M3, M4 of the separator sheet from an optical image, the correct edge is reliably used as the basis and not erroneously the edge of a separator sheet 13 arranged further down in the ESV.As soon as this edge position M1, M2, M3, M4 of the separator sheet has been determined in the ESV 1, the position of the opposite edge and the position of the corners of the separator sheet can be determined based on the previously determined length of the separator sheet.

[0117] The corners E1, E2, E3, E4 of the electrode sheets 11, 12 can be unequivocally identified immediately after being deposited on an underlying and circumferentially protruding separator sheet 13. Based on some or all of the corner positions and the previously determined geometry of the respective electrode sheet 11, 12, the position, i.e., in particular, the orientation and position in the ESV 1, can be determined.

[0118] Due to inevitable length and position variations when picking up ESV sheets 10 of the same type by a gripping unit of the storage device, a correction vector can be determined for each ESV sheet, designed so that the ESV sheet is placed centrally on the ESV. If it becomes apparent during geometry determination that an ESV sheet is outside the manufacturing tolerance due to its geometry, this ESV sheet can be rejected.

[0119] The total of the determined dimensions, i.e., the corner positions E1, E2, E3, E4, and, if applicable, the edge positions M1, M2, M3, M4, can be summarized for each type of ESV blade using an ESV blade tolerance zone. The ESV blade tolerance zone encompasses the length and shape variations of the ESV blades due to manufacturing reasons (see also Fig. 4A).

[0120] In contrast to the support surface 21, 22, 23, which sets a maximum and minimum limit regarding the lateral positioning of the ESV blade 10 in the ESV, the ESV blade tolerance field is formed from the determined measured values ​​for the respective size. This means that the tolerance field of all determined measured values ​​for the size must lie entirely within the support surface 21, 22, 23 or, as far as the visual inspection is concerned, even within the tolerance range for the ESV to be considered manufactured according to the permitted specification. The ESV blade tolerance field records the values ​​of the size, at least relative to one another.

[0121] Immediately after depositing an ESV sheet onto the ESV, and in particular before depositing another ESV sheet, the corner positions E1, E2, E3, E4 and, if applicable, certain edge positions M1, M2, M3, M4 of the ESV sheet and thus the position of the ESV sheet are determined (test step a). Since the deposit never occurs 100% at the location where it is intended, a deposit field results that depends on the deposit accuracy. The deposit field can be determined for each determined position (e.g., corner and edge positions) of the ESV sheet 10. This deposit field 51 must lie completely within the tolerance range assigned to the type of ESV sheet so that the ESV is considered to be within the specified manufacturing tolerance.

[0122] This manufacturing tolerance is specified based on various test criteria.

[0123] The tolerance range of the ESV sheet depends on the type of ESV sheet; i.e. whether it is an anode, cathode or separator sheet (cf. Fig. 2).

[0124] The previously described is illustrated in Fig. 4. Fig. 4A shows the measured corner positions of the anode blades for two corners, E1, E2 of a common edge of the respective anode blade 11, in the example positions of the first and second corners of the anode blades 11, before placement on the ESV 1. The length variation of the anode blades 11 reflects the component tolerance in the form of the ESV blade tolerance field 50. The totality of all determined corner positions assigned to this first edge (black and hatched dots) in the tolerance field 50 defines the ESV blade tolerance field 50 to the left and right of the anode blades 11. All first and second corners E1, E2 of the anode blades 11 lie in the ESV blade tolerance fields 50 if they are aligned centrally to one another. For this reason, the ESV blade tolerance fields 50 for the first and second corner positions E1, E2 on the left and right are also symmetrical.

[0125] In an optical detection and inspection step (inspection step a), after placement on the ESV 1 and in particular before placement of another ESV sheet, the positions of the corners E1, E2 and, if applicable, selected edge positions of the just-deposited anode sheet 11 are determined again. For this purpose, the corresponding positions of the deposited ESV sheet 10, here, for example, the anode sheet 11, in a placement plane are determined based on a first optical image of at least parts of the placement plane of the ESV 1, i.e., for example, in a top view, obliquely, or directly perpendicular to the placement plane of the ESV; see Fig. 4B.

[0126] The storage plane extends particularly along the x and y directions.

[0127] The positions thus determined (black and hatched circles) are now checked with regard to predefined test criteria, including determining whether the stored ESV sheet 10 lies within the tolerance range 52 of the tolerance range 52 assigned to this type of ESV sheet 10, but also whether the sequence of the ESV sheets, as far as they have already been stored, is correct.

[0128] The recording of the ESV sheet size followed by the recording of the ESV sheet position can be used to calculate the storage accuracy of the manufacturing process.

[0129] The difference between the position of the ESV sheet and the ESV sheet size can be used as a measure of stacking accuracy. The value thus determined can also be used for the acceptance of the stacking process, which must achieve a defined stacking accuracy.

[0130] The known values ​​also make it possible to differentiate between the positioning accuracy of the process in a translational x and y direction and in a rotational direction.

[0131] In addition, the storage field 51 is determined for each type of ESV sheet from the totality of all determined positions and in particular for each position of characteristic areas, such as corners and certain edges, of the stored ESV sheets determined in this context; Fig. 4B.

[0132] This storage area 51 is schematically illustrated in Fig. 4B with respect to the position of a plurality of anode blades for the corner positions along the first edge. Compared to the ESV blade tolerance area 50, some anode blades 11 are shifted after storage with respect to the corner positions (highlighted by hatching) and protrude beyond the ESV blade tolerance area 50. This is illustrated in Fig. 4B.

[0133] Analogously, these ESV sheet tolerance fields 50 and storage fields 51 are also determined for the separator sheets, the cathode sheets and the corresponding sizes (not shown).

[0134] In an ideal, error-free placement, the positions of the anode blades 11 would be at the same location in the placement field 51 as in the ESV blade tolerance field 50. Due to placement inaccuracies, it regularly happens that the anode blade 11 (despite the correction vector) is placed slightly offset from the center of the workpiece carrier and thus may protrude from the ESV blade tolerance field 50. The large number of corner positions thus recorded with respect to an ESV center defines the storage field 51, which is usually larger than the ESV blade tolerance field 50. In addition to determining the storage fields 51 for each type of ESV blade 10, for each deposited anode blade 10 (and similarly for the other types of ESV blades), a check is carried out to determine whether the positions of the respective ESV blade 10 lie within the tolerance range 52 assigned to the type of ESV blade 10.If the position is not within tolerance range 52, the production of the ESV can be aborted.

[0135] Ideally, the determined storage field 51 lies completely within the tolerance range 52, so that a difference range 53 (see Fig. 5A) between the storage field 51 and the tolerance range 21, 22, 23 for which the respective determined position can be determined.

[0136] A change in the position of individual or multiple ESV sheets that has occurred after all ESV sheets 10 have been deposited is reflected in a subsequent check - test steps b) to d) - in particular in that the position of the size (e.g. the corner position(s) of one or more corners of the deposited ESV sheet or an edge position) in the respective deposit field 51 is changed in at least one of these subsequent checks, at least relative to the determined positions of the other ESV sheets (of the same type) or a mean nominal position in the deposit field (see Fig. 4G).

[0137] If such a change occurs, it can be checked to what extent the deviating position still falls within the difference range 53.

[0138] If the checked position does not lie within this difference range 53, this size is no longer within the tolerance range 52 assigned to it.

[0139] Whether an ESV sheet 1 has slipped after the last ESV sheet has been placed on the ESV compared to the position determined immediately after placement is determined by means of a large number of optical images, each of which is taken from different directions on the ESV.

[0140] It should be noted that a subsequent change in the position of the ESV sheets 10 is determined in particular in reference to the determined storage field 51. This makes it possible to check, independent of the coordinate system, whether all ESV sheets 10 are in the expected position and whether there has been a deviation with regard to the positions in the storage field 51. This means that for each ESV sheet 10, the corresponding measured value is determined in relation to the storage field 51. Precisely because the determination of the positions of the ESV sheets 10 after all ESV sheets 10 have been deposited on the ESV 1, in particular by recording various side views, it is advantageous to use the storage fields 51 as a reference (in contrast to a workpiece carrier-related coordinate system), since here in particular a relative positioning of the ESV sheets is checked, so that referencing to an external or workpiece carrier-related coordinate system can be omitted.

[0141] In Fig. 5A and 5B the relationship between the storage field 51 and the associated tolerance range 52 is shown schematically.

[0142] Fig. 5A shows the storage area 51 for the position of a corner for the separator sheets. The storage area 51 is located inside and extends by a nominal value for the separator corner positions determined in test step a) for the second corner of the separator sheets.

[0143] The corner positions were determined as part of the determination of the position of the separator sheets immediately after each separator sheet was deposited in test step a) and were combined to form the deposit field 51.

[0144] The tolerance range is determined relative to the predefined support surface 23 for the separator blades. The support surface 23 for the separator blades extends furthest outward in Fig. 5A.

[0145] For example, the tolerance range 52 can be defined such that it has a minimum distance from the boundaries of the storage area 23. This distance can be specified as a percentage or in absolute units. The desired distance from the boundaries can be determined based on the system characteristics, a subsequent evaluation of data from previously produced ESV stacks, or similar statistical considerations.

[0146] From the comparison of the storage field 51 with the assigned tolerance range 52 for the corner positions of the separator blades 13, the difference range 53 is determined, which does not necessarily have to be positioned symmetrically around the storage field 51.

[0147] The outermost area indicates the area that lies outside the difference area 53 and thus also outside the tolerance area 52. The tolerance area 52 itself is therefore divided into the storage area 51 and the difference area 53. All corner positions of the second corner E2 of the separator sheets determined in a verification step that lie within the tolerance area 52, i.e., the storage area 51 and the difference area 53, meet at least one of the predefined test criteria.

[0148] With regard to the separator blade 13 cited as an example, this downstream check of the corner position falls into the test step b), determining a position of the separator blades 13 along an x-direction, along which a first edge of the ESV extends, based on a second optical image of a first side view of the ESV.

[0149] As already described, the edge can be used to determine the position of the separator blade in the ESV.

[0150] In general, in the stacking process, the electrode sheets 11, 12 and separator sheets 13 are successively combined to form an ESV stack.

[0151] In the same or similar manner, after all ESV sheets have been placed on the ESV, test steps c) and d) are performed. In step c), after all ESV sheets have been placed on the ESV, a position of the anode sheets 11 along the x-direction and the y-direction of the ESV 1 is determined using a third optical image comprising a second and third side view of the ESV. The second and third side views depict at least a second edge of the anode sheets 11.

[0152] A side view is particularly considered to be a picture taken along the x and / or y direction of the ESV 1. This means, in particular, not along the z direction. This means that here the position of the anode blades is recorded at least along an x ​​and y direction using the second and third side views, which capture the ESV from different angles. This can be done, for example, by determining at least one corner position of one or two corners opposite one side of the ESV using the second and third side views. Based on the previously determined storage field 51 and the associated difference range 53 of this corner(s), it is determined whether the anode blades 11 are still within the tolerance range 52 for the anode blades 11.

[0153] A special feature to note in test step c) is that in this step changes in the position of the anode blades can only be determined towards the outer limit of the support surface 23 or the tolerance range 52, since a shift towards the inner limit cannot be determined with certainty, so that the test is limited to a shift towards the outer limits of the support surface. The diagram from Fig. 5A is therefore modified for the anode blades 11 and shown in Fig. 5B. If the anode blades 11 are still within the tolerance range 52 for the anode blades, at least one further test criterion would be considered fulfilled. The same applies to test steps b) and d), the successful testing of which means that at least one further test criterion is considered fulfilled.

[0154] In test step d), after all ESV sheets have been deposited on the ESV 1, a position of an outer contour line AF1, AF2, KF1, KF2 of conductor lugs 11-1, 12-1 of all anodes or cathode sheets is determined, wherein the position with respect to the y-direction is determined using a fourth optical image of the ESV of at least parts of the deposit plane.

[0155] The outer contour line is the line resulting from determining the edge AF1, AF2, KF1, KF2 (see Fig. 1A and Fig. 1B) of the conductor lug 11-1, 12-1 positioned furthest along the y-direction.

[0156] This means that two outer contour lines can be determined for the anode blades 11. The same applies to the cathode blades.

[0157] The storage plane can be recorded by looking at the ESV 1 from above. In step d), only the y-position of the electrode blades is determined to be essentially unchanged. A check along the x-direction does not appear to be reliable, as the conductor lugs often bend along the x-direction due to their length, and determining the x-position would lead to inaccurate measurement results or require more complex evaluation procedures.

[0158] Since only the outer contour line can be determined with certainty, the only thing that can be determined is whether all anode 11 or all cathode 12 blades are still within tolerance range 52 with regard to their position along the y-direction. If the outer contour line lies outside the assigned tolerance range, it is typically possible to determine which of the electrode blades is outside the tolerance range. Such a test would have to and could be performed using CT scans, a 3D scanner, or lateral radiography.

[0159] In summary, and with regard to possible stacking errors of the first, second, and third types, it can be said that a displacement of one or more ESV sheets after additional ESV sheets have been deposited on the displaced ESV sheets cannot be detected by test step a). Therefore, test steps b) to d) are intended to identify and quantify displacements of this type, so that it can be determined using a purely optical measurement method whether the finished ESV is manufactured within the specifications. Figs. 6A and 6B schematically illustrate how the position of a just-deposited anode sheet 11 on the ESV is determined using an optical ESV inspection system.

[0160] For this purpose, Fig. 6A shows a side view and Fig. 6B a top view (along the z-direction). These diagrams show how the corner positions E1 to E4 of the anode sheet 11 are determined based on the intersection points of edge lines. For this purpose, one or more line segments 311 are determined at the edges of the anode sheet 11, the intersection points of which determine the corner positions E1 to E4 and also an edge position / edge coordinate of the anode sheet. Furthermore, in the area of ​​the arrester lug, the y-position AF1, AF2 of the arrester lug 11-1 is determined using a line segment 311 on both sides of the arrester lug 11-1.

[0161] For this purpose, the inspection system comprises a first optical recording system 301 configured to record the ESV 1 with a view of the storage plane 400, i.e., in particular, along the z-direction, in order to create the first optical image. For this purpose, the first optical recording system 301 comprises two cameras 301-1 and light sources 301-2 assigned to the cameras, which illuminate the ESV 1 in a top view in the direction of the cameras.

[0162] Each of the cameras 301-1 is configured to record an opposite side of the anode sheet 11. Furthermore, reference markers R1, R2 are arranged in the recording areas 301-3 of the cameras 301-1, i.e., the field of view 301-3 of the cameras 301-1, which allow the positions to be determined relative to a common coordinate system, e.g., with the origin at the center of the workpiece carrier 2. Due to the separator sheet 13 arranged beneath the anode sheet 11, the edges and corners of the underlying electrode sheets 11, 12 are not visible to the cameras 301-1, thus ensuring reliable determination of these measured variables.

[0163] The first optical recording system 301 can also be configured to create the recordings required in test step d).

[0164] In principle, it may be desirable to use different optical systems for test steps a) and d), since test steps a) and d) do not have completely the same requirements.

[0165] In test step a) only the storage plane needs to be in focus, so that a shallow depth of field is necessary or advantageous.

[0166] In test step d), a high depth of field is advantageous, as a height of the ESV 1 must be sharply imaged in the z-direction. For optimal selection of the optical components, it may therefore be advantageous to use two different systems 301 and 304 for test steps a) and d).

[0167] Figs. 7A and 7B show how, in test step b), the corner positions—here, for example, the first corner E1—of the separator blades 13 are determined using a second optical recording system 302. For this purpose, up to four cameras 302-1 are provided, each of which records the corner regions E1 of the separator blades 13 in a first side view along the y-direction (along the x-direction is also possible, of course). It is also possible to use only one camera 302-1. However, rotational deviations cannot be covered in this case. Implementation with at least three cameras 302-1 is therefore advantageous. Each camera 302-1 is assigned a light source 302-2, which projects light at a 45° angle from the direction of the camera 302-1 onto the ESV 1. This configuration allows for a particularly high-contrast recording in which the corners and edges of the separator blades 13 are clearly visible.Based on the images, an x-position of the separator blades 13 (shown as a black circle at the end of the separator blades 13 in Fig. 7B) can be easily determined. If necessary, the x-positions of the electrode blades 11, 12 can also be determined based on these images.

[0168] Using the images, it can then be determined for each corner E1 to E4 whether all determined positions lie within the assigned tolerance range 52, i.e., in the storage area 51 or in the difference range 53. For this reason, no external reference markers are necessary in the recording areas of the cameras 302-1 of the second optical recording system 302, since the absolute determination with respect to a workpiece carrier-centered coordinate system is not necessary for the reasons stated above.

[0169] Fig. 8 schematically illustrates the third optical recording system 303. The third optical recording system 303 is configured to record the ESV 1 in a second side view as part of testing step c). At least two cameras, in particular four cameras 303-1 of the third recording system 303 are configured to record the ESV blades 10 along the xy plane at a 45° angle to a first side of the ESV 1. Each camera 303-1 is assigned a light source 303-2, which illuminates the ESV 1 opposite to the viewing direction of the camera 303-1. This configuration allows information about the x and y positions of the corners of the anode blades 11 to be determined.

[0170] Here, too, no external reference marker is necessary to determine the extent to which the anode blades 11, with their corners and edges, still lie within the assigned tolerance range 52. Fig. 9 shows the fourth optical recording system 304 in a side view, illustrating the execution of test step d). Furthermore, in this example, the illumination with the light sources 304-2 assigned to the cameras 304-1 is carried out opposite to the recording direction. The two cameras 304-1 of the fourth recording system record the conductor lugs 11-1; 12-1 of the anode blades 12 and the cathode blades 12, respectively, at least in some areas (see boxes 304-3). In the images of the conductor lugs 11-1, 12-1 of the cathode sheets 12 and anode sheets 11, only one outer contour line 11-3, 12-3 of the totality of all conductor lugs 11-1, 12-1 of the same type of electrode sheet 11, 12 can be reliably determined.Using the example of the anode blades 11, up to two lines 11-3 are determined, which correspond to the arrester lug edge positioned furthest along and opposite the y-direction. If this "lowest" and "top" edge in 11-3 lies within the assigned tolerance range, it can be assumed that the anode blades 11 are correctly arranged along the y-direction in the ESV 1. The same applies to the cathode blades 12.

[0171] In one variant of the invention, the separator sheets are formed in one piece in the form of a separator strip, wherein the separator strip runs along the z-direction in serpentine lines between the electrode sheets through the ESV. In this case, the recording directions of the cameras may need to be adjusted. In particular, the cameras of the second recording system should then record along the x-direction if the separator strip snakes through the ESV with respect to the y-direction. Likewise, care must be taken to ensure that the third recording system is then also rotated by 90° (and thus records the ESV essentially from the x-direction, not the y-direction (see Fig. 8)), so that the separator strip does not cover the anode sheets.

[0172] Finally, it is noted that the test steps b) to d) can be performed individually or all together during the stacking process in order to detect misplacements or storage trends in the ESV at an early stage, so that the ESV can either be rejected early or corrected in a timely manner, e.g., by adjusting the correction vector.

[0173] ESV 1

[0174] Workpiece carrier 2

[0175] ESV Sheet 10

[0176] Anode sheet 11

[0177] Cathode sheet 12

[0178] Separator sheet 13

[0179] Arrester lug 11-1, 12-1

[0180] Active areas 11-2, 12-2

[0181] Outer contour line of the anode conductor lugs 11-3

[0182] Outer contour line of the cathode conductor lugs 12-3

[0183] Storage area for anode leaves 21

[0184] Storage area for cathode sheets 22

[0185] Storage area for separator sheets 23

[0186] Shear force K

[0187] Vertical axis h x-direction x y-direction y z-direction z

[0188] Filing errors of the first kind 101

[0189] Filing error of the second kind 102

[0190] Filing error type 3 103 x-position of the edge of the separator sheet M1, M2, M3, M4

[0191] Corners of the ESV sheet E1, E2, E3, E4

[0192] Lengths of ESV sheet 11, I2

[0193] Widths of the ESV sheet b1, b2

[0194] Middle of the ESV p

[0195] Tolerance field 50

[0196] Storage field 51

[0197] Tolerance range 52 Difference range 53

[0198] First optical recording system 301

[0199] Camera 301-1

[0200] Light source 301-1

[0201] Field of view 301-3

[0202] Reference position markers R1, R2

[0203] Second optical recording system 302

[0204] Cameras 302-1

[0205] Light source 302-2

[0206] Third optical recording system 303

[0207] Camera 303-1

[0208] Light source 303-2

[0209] Fourth optical recording system 304

[0210] Viewing area 304-3

[0211] Edge lines anode sheet 311

[0212] Storage level 400

Claims

Patent claims 1. A method for testing test criteria of an electrode-separator assembly (1) (ESV) with ESV sheets (10) comprising the following types of ESV sheets (10), separator (13) and electrode sheets (11, 12), the latter selected from the group comprising anode (11) and cathode sheets (12), comprising the following steps: a) After depositing an ESV sheet (10) on the ESV (1), determining a plurality of positions of selected regions of the deposited ESV sheet (10), wherein at least the positions which are determined again in the following steps b) to d) are included in the plurality of positions, wherein the positions in a deposit plane (400) of the ESV sheet are determined on the basis of a first optical image in plan view; b) After depositing all ESV sheets (10) on the ESV (1), determining a position of the separator sheets (13) along an x-direction (x) along which a first edge of the ESV (1) extends,based on a second optical image of a first side view of the ESV (1); c) After placing all ESV sheets (10) on the ESV (1), determining a position of the anode sheets (11) along the x-direction (x) and a y-direction (y) of the ESV (1), wherein a second edge of the ESV (1) extends along the y-direction (y), using a third optical image comprising a second and third side view of the ESV (1), d) After placing all ESV sheets (10) on the ESV (1), determining a position of an outer contour line (11-3, 12-3) of conductor lugs (11-1, 12-1) of the electrode sheets (11, 12), wherein the position with respect to the y-direction is determined using a fourth optical image of the ESV 1 in a top view of the ESV (21), wherein in step a) for each ESV sheet (10) it is checked whether the ESV sheet (10) lies in a tolerance range (52) assigned to the type of ESV sheet (10), wherein in steps b) to d) it is checked,whether the ESV (1) meets at least some predefined test criteria even after all ESV sheets (10) have been filed, whereby this test is positive if all positions determined in steps b) to d) continue to lie within the assigned tolerance range (52), and negative if not all positions determined lie within the assigned tolerance range (52).

2. The method according to claim 1, characterized in that the separator sheets (13) are connected along the y-direction (y) and are enclosed in a separator band, wherein the separator band is alternately folded over at the second edges of the ESV (1) and thus forms the separator sheets between the electrode sheets (11, 12) of the ESV (1).

3. The method according to claim 1 or 2, characterized in that the tolerance range (52) assigned to the ESV sheet (10) is determined on the basis of a limited storage area (21, 22, 23) assigned to the type of the respective ESV sheet (10), wherein the tolerance range (52) assigned to the respective ESV sheet (10) is spaced from the edges of the corresponding storage area (21, 22, 23) by a predefined value, in particular such that the tolerance range comprises at most 90%, in particular at most 80%, in particular at least 70%, of the corresponding part of the storage area (21, 22, 23).

4. The method according to claim 3, characterized in that in step a) for each type of ESV sheet (10) for each position which is determined for a selected area of ​​the ESV sheet (10), an associated storage field (51) is determined, which is indicative of at least the most diverse determined positions of the same selected area of ​​the already stored ESV sheets (10) of this type, wherein the storage field (51) is set in relation to the tolerance range (52) so that the check as to whether the positions determined in steps b) to d) lie in the respective associated tolerance ranges (52) is carried out relative to the storage field (51) and the tolerance range (52) set in relation thereto, wherein the check is positive if the determined positions lie in the tolerance range (52) and negative if not.

5. The method according to one of the preceding claims, characterized in that before step a) and before depositing on the ESV (1), a geometry of the ESV sheet (10) to be deposited is determined on the basis of an upstream optical recording, wherein, if the determined geometry of the ESV sheet (10) lies within a component tolerance assigned to this size, a correction vector is determined which is designed such that the ESV sheet is deposited centrally on the ESV (1) by a depositing device based on the determined geometry.

6. The method according to claim 5, wherein if the determined geometry of the ESV sheet (10) is not within the assigned component tolerance and the ESV sheet (10) is an electrode sheet (11, 12) or a single separator sheet (13), the ESV sheet (10) is sorted out and is not placed on the ESV (1).

7. The method according to one of the preceding claims, characterized in that the predefined test criteria of the ESV (1) are completely determined on the basis of the determined positions of the selected areas of the ESV sheets (10).

8. The method according to one of the preceding claims, characterized in that if the determined positions of the selected areas of the ESV sheet (10) in step a) are not within the assigned tolerance range (52) for the ESV sheet (10), the ESV (1) is sorted out of a production line.

9. The method according to any one of the preceding claims, wherein the test criteria are selected from the group consisting of: First test criterion: Corner areas which form corners of the separator blades (13) must be located in the x and y directions in a predefined storage area (23) for separator blades (13); Second test criterion: All outer corners of the anode sheets (11) must lie in a predefined support area (21) for anode sheets (11) in the x and y directions; Third test criterion: All outer corners of the cathode sheets (12) must lie in a predefined support area (22) for cathode sheets (12) in the x and y directions. Fourth test criterion: The sequence of the ESV sheets (10) on the ESV must have an alternating sequence of anode and cathode sheets (11, 12) between each of which a separator sheet (13) is arranged; Fifth test criterion: A distance between the separator blades (13) and the anode blades (12) must be greater than a predefined minimum distance along the x and y directions; Sixth test criterion: A distance between the cathode sheets (12) and the anode sheets (11) must be greater than a predefined minimum distance along the x and y directions; Seventh test criterion: a position of the ESV blades (1) and the position of a workpiece carrier (2) of the ESV (1) have the same orientation and the ESV blades (10) are arranged centrally on the workpiece carrier (2).

10. The method according to claim 9, characterized in that the determined position of the separator sheets (13) from step b) is used to check whether at least the first test criterion is also met after all ESV sheets (10) have been deposited, and / or wherein the determined position of the anode sheets (11) from step c) is used to check whether at least the second test criterion is also met after all ESV sheets (10) have been deposited, and / or wherein the determined position of the outer contour line (11-3, 12-3) of the arrester lugs (11-1, 12-2) from step d) is used to check whether at least the second and third test criteria are also met after all ESV sheets (10) have been deposited.

11. An optical ESV inspection system comprising at least the following components: a computer comprising a computer program with computer program code, a storage device configured to deposit the ESV sheets (10) onto a workpiece carrier (2) and to be controlled by a control unit, a first optical recording system (301) configured to record the ESV (1) with a view of the storage plane (400) in order to create the first and / or the fourth optical recording, a second optical recording system (302) configured to record the ESV (1) in a first side view in order to create the second optical recording, a third optical recording system (303) configured to record the ESV (1) in a second and third side view in order to create the third optical recording, characterized in that the computer program code, when executed on the computer,the ESV test system is caused to carry out the method according to one of the preceding claims., 12. A computer program comprising computer program code which, when executed on a computer, causes the system according to claim 11 to carry out the method according to any one of claims 1 to 10.

Images