Device and method for sensor-based inspection of an object

Abstract

A device for sensor-based inspection of a physical object, especially a planar or ribbon-shaped physical object, comprises: a transportation apparatus for transporting a physical object to be inspected along a transportation path; an image sensor system having at least one image sensor for image sensor-based capture of the object while the latter is moved continuously relative to the image sensor system along the transportation path by means of the transportation apparatus; an illumination apparatus for illuminating a respective surface of the object to be inspected, in a wavelength range that is detectable by the image sensor system, with the result that the image sensor system can perform an image sensor-based capture at least of portions of the surface within such an illuminated surface region; and a shielding apparatus for shielding the image sensor system from radiation that does not originate from the illumination apparatus. In this case, the image sensor system comprises a number N, with N ≥ 1, of digital line cameras, each with a plurality K of camera pixels arranged in a line, with the lines of the line cameras in each case extending across, in particular orthogonal to, the transportation path. The device or a method performable therewith can be used in particular for inspecting electrodes, or preliminary stages thereof, for galvanic elements.

Description

[0001] DEVICE AND METHOD FOR SENSOR-BASED INSPECTION

[0002] OF AN OBJECT

[0003] The present invention relates to a device and a method for sensor-based inspection of physical objects, wherein in particular (at least macroscopically) substantially flat surfaces of the objects can be inspected, such as surfaces of plate- or strip-shaped objects. The invention also relates to the specific use of the device and / or method for inspecting an electron substrate of an electrode for a galvanic element or a coating of such an electron substrate with an anode or cathode material.

[0004] When manufacturing or using a wide variety of physical objects, i.e., objects that occupy space and mass, especially intermediate or final products of industrial production processes, it is important to ensure the high quality of the objects. These quality requirements can particularly relate to the integrity or purity of one or more surfaces of the object. An example of such objects are electrodes for galvanic elements, such as lithium-ion batteries, which are used in a variety of electronic devices and, in particular, in the context of electromobility for supplying energy to vehicles, such as cars, or for temporarily storing electrical energy in stationary systems.It is particularly important that the electrodes are largely free of contaminants, because in addition to reducing the performance of the galvanic element, such contaminants, especially particulate contaminants, could potentially lead to electrical short circuits and thus to the failure of the galvanic element and even to dangerous situations.

[0005] In existing solutions, as part of the quality assurance process, factory-assembled batteries, which may contain one or more galvanic elements, are tested for electrical short circuits. This test is performed in a stationary state, i.e., when the battery being tested is stationary relative to the test fixture used to perform the test.

[0006] The present invention is based on the object of providing an improved solution for the quality control of physical objects, in particular electrodes for galvanic elements or precursors thereof. This object is achieved according to the teaching of the independent claims. Various embodiments and further developments of the invention are the subject of the dependent claims.

[0007] A first aspect of the solution presented here concerns a device for sensor-based inspection of a physical object, in particular a plate-shaped or strip-shaped object. The device comprises:

[0008] (i) a transport device, in particular with one or more conveyor belts, for transporting a physical object to be inspected along a transport path;

[0009] (ii) an image sensor system with at least one image sensor for at least partially capturing the object by image sensor means, while the object is moved continuously, ie without stopping but not necessarily at a constant speed, relative to the image sensor system by the transport device along the transport path;

[0010] (iii) an illumination device for illuminating a respective surface of the object to be inspected, in particular a macroscopically flat surface, in a wavelength range detectable by the image sensor system, in particular in the visible range (VIS) of the electromagnetic spectrum, so that the image sensor system can image-sensor-capture the surface in such an illuminated surface area, at least in sections; and

[0011] (iv) a shielding device for shielding the image sensor from radiation not originating from the illumination device, in particular in the wavelength range;

[0012] The image sensor system has a number N, with N > 1, of digital line scan cameras, each with a plurality of camera pixels arranged in a line, wherein the lines of the line scan cameras each run transversely, in particular orthogonally, to the transport path.

[0013] The term "physical object," as used herein, refers to something that occupies space and mass. Accordingly, a mass-bearing industrial product is a physical object. This includes, in particular, an electrode for a galvanic cell, in particular a lithium-ion cell or battery, or a precursor of such an electrode, a catalyst-coated membrane, a gas diffusion layer, or a membrane-electrode assembly (MEA) as a precursor to a fuel cell.

[0014] The term “line scan camera”, as used herein, is understood to mean an image sensor or a camera of a digital camera type which has a digital image resolution of M x K camera pixels, where (i) M > 1000 ■ K and K < 256 , and / or (ii) M > K with K = 1. M denotes the number of camera pixels per line and K the number of lines. In particular, a line scan camera can therefore only have a single (K = 1) radiation-sensitive line (line sensor) - in contrast to the two-dimensional sensor which has a large number of lines. The camera pixels can each have a plurality of sub-pixels for different colors, e.g. according to the RGB color model or another color model.

[0015] The terms "comprises," "includes," "includes," "has," "has," "with," or any other variation thereof, as used herein, are intended to cover non-exclusive inclusion. For example, a method or apparatus that includes or has a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or that are inherent in such a method or apparatus.

[0016] Furthermore, unless explicitly stated otherwise, "or" refers to an inclusive "or" and not an exclusive "or." For example, a condition A or B is satisfied by one of the following conditions: A is true (or present) and B is false (or absent), A is false (or absent) and B is true (or present), and both A and B are true (or present).

[0017] The terms "a" or "an" as used herein are defined as "one or more." The terms "another" and "another," and any other variations thereof, are defined as "at least one other."

[0018] The term "plurality" as used herein shall mean "two or more".

[0019] The term “configured” or “set up” to fulfil a specific function (and respective variations thereof), as used here where appropriate, is to be understood that a relevant device or component thereof is already in a design or setting in which it can perform the function or is at least adjustable – i.e. configurable – so that it can perform the function after being set accordingly. The configuration can be carried out, for example, by appropriately setting parameters of a process sequence or of switches or the like for activating or deactivating functionalities or settings. In particular, the device can have a plurality of predetermined configurations or operating modes, so that configuration can be carried out by selecting one of these configurations or operating modes.

[0020] A device according to the solution enables sensor-based inspection of a physical object while it is continuously transported by the transport device. The object therefore does not have to be stopped at a special station and then set in motion again. Instead, the elimination of such stops during the inspection process allows for short throughput times and thus process efficiency. Furthermore, if the object is a device, such as a galvanic cell or an entire battery with several such cells, the entire device does not have to be completed in order to inspect components of such a device, especially electrodes. Rather, it is possible to inspect intermediate products at the stage of production. If they are identified as defective, they can be sorted out without the device having to be completed.This reduces the overall material consumption required for series production of such devices, since when a defect is detected, only the identified component needs to be rejected or repaired, rather than a completed device. Overall, the solution contributes to the early detection of manufacturing errors in a particularly efficient manner, thus enabling quality defects to be addressed.

[0021] However, not only advantages in terms of efficiency can be achieved, but in particular the combined use of the special image sensor technology with N line scan cameras, the lighting device and the shielding device also makes it possible to achieve a high image quality and resolution, so that even very small defects, for example the smallest particles present on the surface to be inspected, can be detected particularly well.This is particularly due to the fact that line scan cameras can generally achieve a particularly high effective resolution, the illumination device provides good lighting conditions and, in particular, the possibility of clearly recognizable shadows cast by disturbances to be detected (particularly particles present on a surface), and the shielding device ensures that the images delivered by the image sensors are particularly low-noise, since disruptive influences from radiation not originating from the illumination device are at least largely removed.

[0022] These advantages are particularly evident when using the device according to the solution in the context of electrode production for galvanic elements, where it is important to avoid even small defects, in particular particles on the electrodes, or, if necessary, to detect them in good time during an inspection of the electrodes or of precursors thereof, before the galvanic cell is completed using the electrodes. Furthermore, the problem regularly arises, particularly in the production of such electrodes, that processes are used in which there is a possibility or risk that small particles, in particular small carbon particles, will be released. This can occur particularly when punching the electrodes from a larger substrate, when applying layered cathode or anode material (e.g., carbon powder) to a base electrode substrate (e.g.,This may be the case during subsequent calendering of such applied layers. In particular, the situation may arise where very small particles, especially black carbon particles, on an object surface of essentially the same color (e.g., a calendered carbon layer) are to be detected during inspection.

[0023] In the following, various exemplary embodiments of the device are described, each of which, unless expressly excluded or technically impossible, can be combined with each other as well as with the other aspects of the present solution described.

[0024] In some embodiments, the transport device is configured to move the object relative to the image sensor system in such a way that—particularly in the case of a plate-shaped, cuboid-shaped, or strip-shaped object—at least two opposing sides of the object can be image-sensored simultaneously or sequentially by the image sensor system. The image sensor system can, in particular, have one or more line-scan cameras separately for each of the two sides to be detected. This makes it possible to inspect both sides with the same device.

[0025] In some embodiments, the transport device comprises: (i) a first conveyor device (which may in particular comprise a vacuum conveyor belt) configured to transport the object lying down, while a first side of the object is at least partially detected by the image sensor system; and (ii) a second conveyor device (which may in particular comprise a vacuum conveyor belt) configured to transport the object hanging, while a second side of the object opposite the first side is at least partially detected by the image sensor system.For example, the transport device can be configured to initially transport the object lying down on the first conveyor, inspecting the first side. Then, in a transfer area, transfer the object to the second conveyor, for example, by suction on the underside of the second conveyor, and then inspect the now freely accessible second side from below. This eliminates the need to turn the object, yet still achieves a very efficient, time-saving, inspection process for both sides.

[0026] In some other embodiments, the transport device comprises a turning device for turning the object, which is configured to turn the object between at least partial image sensor detection of a first side of the object and at least partial image sensor detection of a second side of the object opposite the first side. This makes it possible, in particular, to manage with an image sensor located on only one side of the transport device despite inspection from both sides. This allows for particularly compact device designs, in particular with a low overall height, to be implemented.

[0027] In some other embodiments, the transport device comprises two conveyor devices separated from one another by a gap (which may in particular each comprise a vacuum conveyor belt), each of which is configured to transport the object lying down or hanging. The image sensor system is configured here to image-sensor the two opposite sides of the object, while a section of the object to be image-sensored on both sides passes through the gap during operation of the transport device. The two sides can thus be inspected, in particular, simultaneously or in partially overlapping inspection periods, which is particularly advantageous with regard to high process efficiency and a high achievable throughput.

[0028] In some embodiments, the device further comprises a singulation device arranged upstream of the image sensor system in relation to the transport path for singulating the object from a starting object, in particular a starting substrate, such as a sheet, a plate, or a strip. Thus, the inspection can be carried out on the basis of already singulated objects, which is particularly advantageous if the object is turned during the process flow or in preparation for the individual removal of objects identified as defective during inspection. Particularly in these embodiments comprising singulation, the transport device can also be configured such that it pauses the transport before subsequently feeding the next singulated object to the image sensor system for inspection.

[0029] In some embodiments, the transport device comprises a transport table, which is arranged upstream of the separating device with respect to the transport path and has at least two asynchronously operating fixing devices, each movable along the direction of the transport path, for temporarily fixing the object on the transport table. The device is configured to control the movements of the fixing devices in a coordinated manner such that they interact to feed the starting object step by step to the separating device, enabling the object to be separated from the starting object in each step while the starting object remains stationary relative to the transport device.

[0030] In some embodiments, the device further comprises a cleaning device for cleaning the object, which is arranged upstream of at least one of the line scan cameras of the image sensor system with respect to the transport path, in particular arranged between the separating device and the image sensor system with respect to the transport path. This not only allows unwanted defects on the object surface to be inspected to be detected, but also, in particular in advance, reduces the occurrence of such defects, particularly in the case of defects caused by loose particles on the surface.

[0031] In some embodiments, the image sensor system is configured such that at least one of its line scan cameras has an optical axis, the direction of which forms a fixed or variable, in particular temporally variable, acute angle with respect to a support surface provided on the transport device for recording the object during image sensor detection. <p mit <p < 90° definiert. Aufgrund des spitzen Winkels <p ist es insbesondere möglich, ein die Bildqualität potenziell störendes Erfassen von am Objekt bei orthogonaler Einstrahlung reflektiertem Streulicht, insbesondere von anderen Strahlungsquellen als der Beleuchtungseinrichtung, weitgehend zu vermeiden.In general terms, this can be expressed as follows: the optical axis(es) of the line scan camera(s) are or will be aligned in such a way that they are not coaxial with an illumination direction defined by the illumination direction and / or a main direction of incidence of radiation from another illumination source. Furthermore, due to the acute angle < >, any shadows cast by the object can be more easily captured and used for subsequent image analysis to more easily identify defects on the inspected object surface indicated by the shadow. In the case of variable angle adjustment <p kann zudem das Sichtfeld der zumindest einen Zeilenkamera, insbesondere dynamisch, variiert werden, insbesondere in Abhängigkeit von einer Transportgeschwindigkeit, mit der die Transporteinrichtung das zu inspizierende Objekt transportiert.Thus, a surface section of the object can be captured by image sensors from different observation directions during its inspection, which in particular makes it possible to determine, depending on the varying angle, <p auftretende Variationen im erfassten Bildmaterial zu detektieren und auszuwerten, insbesondere im Hinblick auf erst anhand dieser Variationen erkennbaren Störungen.

[0032] In some embodiments, the image sensor system comprises at least one mirror and is configured such that at least one of the line scan cameras has an optical axis directed toward the mirror, so that the line scan camera can image-sensor-capture a mirror image of at least a portion of the object generated by the mirror. This enables particularly compact, particularly flat designs, since the extension of the image sensor system in a direction orthogonal to the transport direction can be kept particularly small.

[0033] In some embodiments, the image sensor system comprises, in addition to the N line-scan cameras, at least one further camera whose field of view extends beyond the cumulative field of view of the N line-scan cameras in a direction transverse, in particular orthogonal, to the transport direction. This makes it possible, in particular, to also inspect those areas, in particular projections, of an object that extend beyond the cumulative field of view of the N line-scan cameras. Especially in the case of electrodes, in particular for lithium-ion cells, such electrodes often each have a so-called conductor lug for conducting current from the electrode, which extends laterally as a projection beyond the electrochemically active surface of the electrode.If such electrodes are transported through the transport device in such a way that the collector tabs extend away from the active surface of the electrode in a direction transverse to, in particular orthogonal to, the transport direction, the collector tabs can be inspected by means of the additional camera even if they extend completely or partially beyond the cumulative field of view of the N line scan cameras. In particular, it is thus possible to inspect any transitions between an electrode coating and the collector tab. In many cases, the collector tab is completely uncoated (i.e. not coated with the active material of the electrode) and a coating edge lies at the transition between the collector tab and the electrode. In particular, not only particles can be detected as disturbances, but also, for example, coating defects and flaking of the coating.

[0034] In some embodiments, the image resolution of at least one of the line scan cameras is at least 6.8 μm per pixel, preferably at least 2.0 μm per pixel. This allows even very small defects, in particular particles, with dimensions of comparable size (e.g., a defect is imaged on at least one pixel) to be captured and detected by image sensors. These dimensions have proven particularly useful, at least with regard to the detection of carbon particles and other particles during electrode inspection during or after their manufacture, in order to be able to clearly detect defects that could potentially endanger the quality and / or safety of the electrodes.

[0035] In some embodiments, the image sensor system has an optic in its beam path with a magnification factor in the range of -0.675x to -0.875x, in particular a lens optic with at least one optical lens. These magnification values ​​have proven particularly useful for achieving large fields of view (FoV) despite the compact design of the device. In particular, the optics can have at least one spacer ring to determine the magnification factor. In this way, the magnification factor can be kept particularly stable due to the distances between the image sensors (in particular line scan cameras) and the optics, which are (co-)determined by the spacer ring(s). The distance of the optics from the object is also clearly defined, at least in terms of a minimum distance.The desired field of view and resolution can thus be achieved by using special distance rings, particularly to set a defined ratio between the distances from the optics to the object and from the optics to the image sensor. The diameter of the distance rings should preferably be sufficiently large so that the intensity of the radiation (especially light) incident on the sensor can be maintained at least approximately uniformly.

[0036] In some embodiments, the shielding device comprises one or more darkrooms in which the N line scan cameras are housed in order to protect them from radiation not originating from the illumination device. This can particularly effectively prevent potential impairments to the image quality provided by the image sensor system and thus to the resulting quality of the inspection.

[0037] In some embodiments, the device is configured to control or regulate a recording frame rate of the image sensor system as a function of the transport speed of the object during its continuous transport through the transport device. Thus, depending on the defined dependency (which can in particular be defined via a mathematical function), it is possible in particular to (i) achieve a variable setting of the extent of the field of view of the image sensor system along the transport direction as a function of the transport speed, or (ii) also keep this extent invariant with respect to different transport speeds. For this purpose, in particular a measuring device (e.g. encoder) can be provided, which can be connected to the drive of the transport device and the image sensor system.

[0038] In some embodiments, the illumination device comprises one or more light-emitting diodes as radiation sources for illuminating the respective surface of the object to be inspected. This allows for the realization of particularly compact designs with low energy consumption and / or, at least essentially, monochromatic illumination (and thus particularly high image sharpness).

[0039] In some embodiments, the illumination device has a main radiation direction and is configured to illuminate the surface of the object to be inspected such that the main radiation direction runs at a fixed or time-varying acute angle a, with a < 90°, to a support surface present on the transport device for receiving the object during image sensor detection. Due to the acute angle a, any shadows cast by the object can be created and used for subsequent image analysis to more easily identify defects on the inspected object surface indicated by the shadow.

[0040] In some embodiments, the illumination device is configured to diffusely illuminate the respective surface of the object to be inspected. This makes it particularly easy to visualize defects that would be impossible or difficult to detect with directed illumination from only one irradiation direction. In particular, using diffuse illumination allows shadows cast by particles or many other types of defects in different directions to be generated, and also allows differences in the direction-dependent reflection of the incident radiation on the object to be detected. Overall, this increases the probability of detecting defects, especially very small defects.

[0041] In some embodiments, the transport device is configured such that its position can be adjusted along a direction extending transversely, in particular orthogonally, to the transport path. This allows the transport path to be adjusted relative to the image sensor system, which can be used, in particular, to optimally position the object to be inspected within the field of view of the image sensor system.

[0042] In some embodiments, the device further comprises an image evaluation device for evaluating image material captured by the image sensor system in order to detect any deviations of the object depicted in the image material from a reference state, in particular from a predefined target state, of the object by means of image processing.

[0043] A second aspect of the present solution relates to a method for sensor-based inspection of a physical object, in particular a plate-shaped or strip-shaped one, wherein the method is carried out using a device according to one of the preceding claims. The object can in particular be an electrode for a galvanic element, in particular for a lithium-ion cell or battery, or a precursor of such an electrode, such as an electrode substrate (e.g., copper foil) not yet coated with anode or cathode material or an electrode substrate already coated in this way before or after calendering (rolling the anode or cathode material) and / or singulating.

[0044] A third aspect of the present solution relates to the use of a device according to the first aspect or the method according to the second aspect, in each case for inspecting an electrode substrate, in particular a plate-shaped or strip-shaped one, of an electrode for a galvanic element or a coating of such an electrode substrate with an anode or cathode material. Such use can occur in particular within the framework of a process for producing such an electrode, in particular in order to be able to detect defects on the electrode surface, such as unwanted particle deposits, at an early stage and to be able to remove such defective products or precursors from the process as scrap or for reprocessing before their completion. The features and advantages explained with reference to the first aspect of the invention also apply accordingly to the further aspects of the invention.

[0045] Further advantages, features, and possible applications of the present invention will become apparent from the following detailed description in conjunction with the figures. Herein:

[0046] Fig. 1 shows a first embodiment of a device for sensor-based inspection of one or more physical objects, in particular electrodes;

[0047] Fig. 2 shows a second embodiment of the device;

[0048] Fig. 3 shows a third embodiment of the device;

[0049] Fig. 4 shows a fourth embodiment of the device;

[0050] Fig. 5 shows a first variant for the arrangement of the image sensors;

[0051] Fig. 6 shows a second variant for the arrangement of the image sensors;

[0052] Fig. 7 shows a third variant for the arrangement of the image sensors;

[0053] Fig. 8 shows a fourth variant for the arrangement of the image sensors;

[0054] Fig. 9 is a side view of an arrangement of a plurality of line cameras of the image sensor system;

[0055] Fig. 10 is a plan view of several electrodes to be inspected lying on the transport device and the position of the fields of view of the cameras of the image sensor system relative to them; and

[0056] Fig. 11 is a flow chart illustrating an embodiment of a method for inspecting objects using the device, in particular the device from Fig. 1.

[0057] In the figures, like reference numerals designate like, similar, or corresponding elements. Elements shown in the figures are not necessarily drawn to scale. Rather, the various elements shown in the figures are depicted in such a way that their function and general purpose will be understood by those skilled in the art. Connections and couplings between functional units and elements shown in the figures can also be implemented as indirect connections or couplings, unless expressly stated otherwise. Functional units can, in particular, be implemented as hardware, software, or a combination of hardware and software.

[0058] Fig. 1 illustrates a first embodiment 100 of a device for sensor-based inspection of one or more physical objects O. In principle, this enables the inspection of a wide variety of objects O with opposing, essentially flat surfaces. Accordingly, the objects O can be, in particular, strip-shaped, foil-shaped, sheet-shaped, or plate-shaped. In the following, without this being understood as a limitation, examples of objects O will be discussed which are foil-shaped or plate-shaped electrodes E for galvanic elements, in particular for lithium-ion cells.

[0059] The device 100 comprises a transport device comprising a first vacuum conveyor belt 105a and a second vacuum conveyor belt 105b, each configured to transport the objects O along a transport path along a transport direction x at a speed v that can be constant or variable over time. The two vacuum conveyor belts 105a and 105b are arranged relative to one another in such a way that an object O can initially be transported lying down on the first vacuum conveyor belt 105a and then transported further in a suspended position by the second vacuum conveyor belt 105b (or vice versa, not shown).For this purpose, the two vacuum conveyor belts overlap in a transfer area and are spaced apart from each other there so that the objects O can be moved into the resulting gap in the transfer area and can be sucked up there by the second vacuum conveyor belt in order to be able to transport the other one hanging on it.

[0060] Accordingly, in the region of the first vacuum conveyor belt 105a, a first (upper) main surface of the respective object O is accessible, while its second main surface, opposite the first main surface, rests on the first vacuum conveyor belt 105a. In the region of the second vacuum conveyor belt 105b, the object rests with its first main surface suspended from the second vacuum conveyor belt 105b, while its second (lower) main surface is accessible.

[0061] To enable image sensor detection of the two main surfaces, the device 100 has an image sensor system comprising two separate image acquisition units 110a and 110b, each of which has N digital line scan cameras 160, with N > 1, in particular a group of several line scan cameras 160 arranged coaxially (along the Z direction) and thus transversely, in particular orthogonally, to the transport direction x, adjacent to one another (see Figures 9 and 10). In the following, it is assumed by way of example that each image acquisition unit 110a or 110b has several line scan cameras 160, i.e., that N > 1 then applies.

[0062] These line scan cameras 160 are configured to image-sensor-scan the object O transported along the image acquisition units 110a and 110b during its transport in order to generate corresponding image material (image data) that represents at least a portion of the scanned surface and can serve as the basis for subsequent image analysis by an image analysis device 150 for detecting disturbances, in particular any particles present, on or in the respective surface. The image analysis device 150 can, in particular, simultaneously be configured as a control device for the device 100, in particular for controlling its individual functional components and their interaction.

[0063] Each of the image capture units 110a and 110b is equipped with a respective shielding device 115a or 115b in the form of a darkroom, which is configured to provide extensive shading of the field of view of the line-scan cameras 160 against radiation originating from outside the respective shielding device 115a or 115b, in particular stray light. For the purpose of illuminating the surfaces of the objects O to be scanned by the line-scan cameras 160, an illumination device 120a or 120b is provided in each of the darkrooms, which can in particular have one or more light-emitting diodes as radiation sources. Further details of the illumination device of the image capture units 110a and 110b will be referred to below with reference to Figures 5 to 10.

[0064] A respective cleaning device 125a or 125b (relative to the transport direction x) is arranged upstream of each of the two image capture units 110a and 110b. Each cleaning device 125a or 125b is configured to clean, in particular to vacuum, the surface of the objects O to be scanned by the subsequent image capture unit 110a or 110b, respectively. This allows, in particular, deposited particles to be removed, thereby increasing the yield of defect-free objects according to the subsequently generated inspection result. Now that the inspection section of the device 100 has been explained, the following will discuss a preparation section of the device 100 arranged upstream of the inspection section, which serves to feed and separate the objects O to be inspected.In the preparation section, the device 100 has a supply roll 140 for providing a strip- or foil-shaped starting substrate B, in particular an electrode substrate (such as a metal foil that may already be coated with an anode or cathode material). Furthermore, the device 100 has a separating device 130 in the preparation section, which can be designed in particular as a punch, for example as a roller punch, which serves to separate, in particular cut or punch out, individual objects O, in particular electrodes E (optionally with their conductor lugs A), from the starting substrate B.

[0065] In particular, it is possible for the separating device 130 to comprise a lower tool and an upper tool. The upper tool can comprise an eccentric drive shaft for cyclically moving a cutting blade or a punching die toward the starting substrate B. It is also possible for the separating device 130 to have a clamping device that allows individual objects O to be cut or punched out of the starting substrate B to be clamped before and / or during the cutting or punching process. This makes it possible to cut or punch out the objects O with particularly precise positioning. The clamping device can be mechanically connected to the upper tool.

[0066] The starting substrate B is fed from the supply roll 140 to the singulating device 130, in particular by means of a plurality of guide rollers 135, one or more of which, in particular a pair of rollers, can be driven. Furthermore, a transport table 145 with two associated fixing devices 145a and 145b can be arranged in the preparation section, each of which is mounted on the transport table 145 so as to be translationally displaceable at least along the transport direction x. The transport table 145 with its fixing devices 145a and 145b is configured to feed the starting substrate B step by step to the singulating device 130.

[0067] In particular, this configuration can be designed such that during operation of the transport table 145, the fixing device 145a first grips the starting substrate B and pulls or pushes it in the direction of the separating device 130, while the fixing device 145b is released, i.e., does not fix the starting substrate B. The feed is designed such that the starting substrate B is brought into a predetermined cutting or punching position relative to the separating device 130, so that when, in a next step, the fixing device 145b now fixes the starting substrate B while the fixing device 145a returns to its starting position, the starting substrate B can be separated into individual objects O or electrodes by the separating device 130 while it is held in position by the fixing device 145b.The continuous transport by the transport device here therefore only affects the objects O that have already been separated. The starting substrate B, on the other hand, is transported step by step as described, with pauses between the steps during which the separation takes place. Alternatively, the starting substrate B can be secured to a support of the transport table 145 with negative pressure. In some embodiments, a storage section, i.e., belt buffer (not shown), can be arranged upstream of the transport table 145 (relative to the transport direction x) in order to at least temporarily store the starting substrate B. This enables a continuous advance of the starting substrate B upstream of the transport table 145. x.

[0068] Fig. 2 shows a second embodiment 200 of the device, which is a modification of embodiment 100. It results from the latter in that the second vacuum conveyor belt 105b is pivoted about the z-direction relative to the first vacuum conveyor belt 105a by a fixed angle. Accordingly, the units assigned to the second vacuum conveyor belt 105b, in particular the cleaning device 120b, the shielding device or darkroom 115b, and the image capture unit 110b with the illumination device 120b located therein, are also pivoted accordingly. In this way, a particularly compact design of the device can be achieved. The device 200 can, in particular, have a preparation section (only partially shown in Fig. 2) that corresponds to that of the device 100.

[0069] Fig. 3 shows a third embodiment 300 of the device, which is also a modification of embodiment 100. In contrast to the latter, here the two vacuum conveyor belts 105a and 105b are arranged such that a gap exists between them along the transport direction x, through which gap the objects O can be image-sensored on both sides by the image capture units 110a and 110b, which here face each other. A further difference is that the objects O each rest with the same side on the two vacuum conveyor belts 105a and 105b, in particular—as illustrated—lying down. A variant of this embodiment with the objects being transported suspended instead is also conceivable.

[0070] The device 300 can, in particular, have a preparation section (only partially shown in Fig. 3) corresponding to that of the device 100. The design of 300 enables, in particular, simultaneous image sensor detection of both sides of the objects O and, due to the opposing arrangement of the two image acquisition units 110a and 110b, also a particularly compact design.

[0071] Fig. 4 shows a fourth embodiment 400 of the device, which is also a modification of embodiment 100. In contrast to the latter, only a single vacuum conveyor belt 105 and a single image capture unit 110 with associated shielding device 115 and illumination device 120 are provided here. In order to also enable double-sided image sensor detection of the objects here, the device 400 has a turning device 155 which is configured such that it turns an object O lying with a first side on the vacuum conveyor belt 105 such that it comes to rest on the same vacuum conveyor belt 105 with a second side opposite the first side. In this way, it is possible to image-sensor-capture the first side before turning and the second side after turning, each of the same image capture unit 110.A wide variety of configurations are conceivable for the design of the turning device 155, in particular in addition to that shown in Fig. 4 also those where the objects, after turning, are fed to the image capture unit 110 again from the front, ie from the end of the vacuum conveyor belt 105 facing the separating device 130.

[0072] The device 400 can, in particular, have a preparation section (only partially shown in Fig. 4) corresponding to that of the device 100. The design of 400 enables, in particular, simultaneous image sensor detection of both sides of the objects O by means of a single image capture unit 110 and thus also a particularly compact design.

[0073] Fig. 5 shows a first variant 500 for the arrangement of the image sensor system or of its assembly assigned to a respective image acquisition unit 110 (or 110 a, b). The shielding device 115 is not shown here. The image acquisition unit 110 has at least one line scan camera 160, in particular—as already described above—a group of several coaxially arranged line scan cameras 160. Each line scan camera 160 is combined with an optical system 180 having at least one first lens 170 spaced from the line scan camera 160 by a first spacer ring 165. This distance is particularly important for determining a magnification factor of the optical system 180. In particular, the magnification factor can be in the range from -0.675x to -0.875x. Furthermore, the optics 180 can have a second spacer ring 175, in which in particular a second lens (or several lenses) can be provided.Overall, the optics 180 thus defines an optical image of a surface section of the object O currently located in the field of view along an optical axis 185 of the image acquisition unit 110 onto the line camera 160 assigned to the optics 180.

[0074] The illumination device 120 here has at least one light source, in particular—as shown—two light sources, which illuminate the surface section of the object to be captured by the image sensor from above from different sides at a respective angle a, which can in particular be an acute angle (a < 90°). With multiple light sources, these respective angles a can differ with respect to the light sources or, as illustrated, can be the same in order to achieve the most homogeneous illumination possible. The use of such oblique irradiation is particularly advantageous with regard to avoiding reflections of the radiation from the illumination device 120 on the surface of the object O along the optical axis 185.Due to the acute angle a, any shadows cast by the object O can also be created and used for the subsequent image analysis in order to more easily identify defects on the inspected object surface indicated by the shadow.

[0075] The image capture unit 110 is translationally displaceable along the y-direction and / or the z-direction. This allows adjustment of the size of the field of view and, on the other hand, its relative position to the vacuum conveyor belt 105 or the objects O transported thereby along the z-direction, which is orthogonal to the transport direction x. Adjustment along the x-direction is also conceivable, which can be used in particular to adapt the position of the image capture unit 110 to different product sizes. The image capture unit 110a or 110b or the shielding device 115a or 115b can, in particular, be arranged on a rail that is translationally displaceable along the z-direction and can be moved out of the shielding device 115, e.g., for maintenance purposes. Fig. 6 shows a second variant 600 for the arrangement of the image sensors or of their assembly assigned to a respective image capture unit 110 (or 110 a, b).The variant 600 is a modification of the first variant 500, in which the image acquisition unit 110 is tilted relative to a vertical on the transport direction x or on the surface of the vacuum conveyor belt 105 (or 105a, b) and thus forms an (acute) angle <p mit <p < 90°einschließt.

[0076] Fig. 7 shows a third variant 700 for the arrangement of the image sensors, which is particularly applicable within the framework of the third embodiment from Fig. 3. A special feature of this third variant 700 is that the two image acquisition units 110a and 110b are each arranged such that their respective optical axes run parallel to the transport direction x and are directed towards a respective mirror 190a or 190b, which deflects a surface section of a respective side of the object O that is to be scanned at a particular time in the direction of the respective optical axis, in order to thus enable image sensor acquisition by the respective line scan cameras 160. In this way, particularly flat designs (relative to the y-direction) are possible.

[0077] Fig. 8 shows a fourth variant 800 for the arrangement of the image sensors, which has emerged as a modification of variant 700 and how this is particularly applicable within the framework of the third embodiment from Fig. 3. Compared to variant 700, variant 800 has at least one further image acquisition unit 110c or 110d on each side (top and bottom in Fig. 8), which are each arranged such that their respective optical axes run parallel to the transport direction x and are directed towards a respective mirror 190a or 190b, which deflects a surface section of a respective side of the object O that is to be scanned at a time in the direction of the respective optical axis in order to thus enable image sensor acquisition by the respective line scan cameras 160. In this way, particularly flat designs of the device (with respect to the y-direction) are possible.

[0078] Fig. 9 shows a detailed view 900 of an image acquisition unit 110 in a side view in the viewing direction antiparallel to the transport direction (x-direction). The image acquisition unit 110 has a plurality of line scan cameras 160, which in turn each have at least one row of K, with K > 1, camera pixels, which together, in interaction with the optics 180 (not shown here), (co-)define a field of view 195a to 195f of the respective line scan camera 160. The value for K can differ for the various line scan cameras 160. The line scan cameras 160 are arranged coaxially along the z-direction such that their respective fields of view 195a to 195f each overlap with the adjacent fields of view, resulting in an overall uninterrupted scanning area aligned along the z-direction. In addition, a further camera 111 with its own field of view 196 can be provided, which can also be a line scan camera or a 2D or 3D camera.In the present example, it is particularly intended to extend the cumulative field of view of the image acquisition unit 110 laterally along the z-direction in order to be able to also capture lateral projections of the objects O that extend beyond the cumulative field of view of the line scan cameras 160, x.

[0079] This is illustrated by way of example in Fig. 10, which shows an application example 1000 in a plan view of objects lying on a vacuum conveyor belt 105, in which electrodes E for galvanic elements serve as objects O to be inspected, wherein each of the electrodes E has a lateral projection A which serves to divert an electrical current from the electrode during its later use in a galvanic element and is usually referred to as a collector tab. The further camera 111 was used to specifically inspect the collector tab, while the line scan cameras 160 are used to inspect the main surfaces of the electrodes E that are chemically active during later operation. In particular, the size of the collector tab and, for example, the coating transition between the active main surface and the collector tab can also be inspected.

[0080] In one embodiment, the one- or two-sided inspection of the arrester lug using the camera 111 can be carried out upstream of the singulation device 130, i.e., it can be carried out before or after the inspection using the image sensor system 110. For example, the surface quality of the arrester lug can be determined using dark field illumination (illumination at approximately 45 degrees). It is then also possible to generate one or more different illumination patterns on the surface of the arrester lug during the inspection and use them to illuminate the surface. Since the arrester lug generally does not have a coating of active material, it is usually highly light-reflecting, which may require different illumination. It is therefore also conceivable for the line scan cameras 160 and the further camera 111 to have spatially separate fields of view (FoV).

[0081] An inspection of the plume upstream of the separation point might have the advantage that a lower transport speed can prevail there

[0082] The inspection of the conductor lug can be carried out, in particular, at a speed of the starting substrate B that is lower than the speed of the individual objects O during their inspection by means of the image sensor system 110. Fig. 11 shows, using a flowchart, an exemplary embodiment 1100 of a method for sensor-based inspection of a physical object, wherein the method can be carried out, in particular, with a device according to the solution, for example, according to the embodiments of such a device described herein. In the following, reference is made specifically to the embodiment 100 of Fig. 1 by way of example.

[0083] The method comprises a process 1105 for feeding a starting substrate B, in particular an electrode substrate, to a singulation device 130 of the device. In a further process 1110, a single electrode E (or precursor thereof) is singulated from the starting substrate B using the singulation device 130, in particular by cutting or punching.

[0084] Then, in a further process 1115, the separated electrode E is picked up by a first conveyor device, in particular a first vacuum conveyor belt 105a, and then continuously transported during the further course of the method 1100. During transport, the electrode is guided by the first conveyor device past a cleaning device 125a, where a first main surface of the electrode E is cleaned, in particular by means of suction and / or blown air (optionally ionized blown air), before being image-captured by a first image capture unit 110a in a further process 1125.

[0085] The electrode E is then transferred to a second conveyor, in particular a second vacuum conveyor belt 105b, in such a way that the second main surface of the electrode E, opposite the first main surface, becomes accessible for inspection. As already explained above with reference to Fig. 1, this can be achieved in particular by the electrode E being transported further while suspended from the second vacuum conveyor belt 105b.

[0086] This is followed by another cleaning process 1140, this time for the second main surface, and a subsequent image sensor acquisition 1145 of the second main surface by means of a second image acquisition unit 110b. The digital image material, in particular video material, acquired by the two image acquisition units 110a and 110b is fed to an image evaluation unit 150 of the device, in which the image material is evaluated. This evaluation can be carried out in particular by comparing the image material with a reference image material, which can in particular correspond to an undisturbed surface of the electrodes, so that any deviations between the surface depicted in the image material and a corresponding surface from the reference image material can be detected and evaluated, in particular classified, by means of, in particular, automated image comparison methods.The use of machine learning-based evaluation methods is also conceivable for this purpose. The evaluation provides an inspection result that at least indicates whether a fault was detected or not. In the context of a more complex classification, it is also conceivable that the inspection result could additionally or instead indicate the frequency and / or type of the detected fault(s).

[0087] The inspection result can finally be used to either further process the inspected electrode in a further process 1155 depending on the inspection result, for example to assemble it into a galvanic cell by means of at least one separator and a further electrode of opposite polarity, or to reject it as defective in order to save further time and material expenditure for further processing that is then no longer effective.

[0088] While at least one exemplary embodiment has been described above, it should be appreciated that a wide variety of variations exist. It should also be understood that the described exemplary embodiments are merely non-limiting examples and are not intended to limit the scope, applicability, or configuration of the devices and methods described herein. Rather, the foregoing description will provide one skilled in the art with guidance for implementing at least one exemplary embodiment, it being understood that various changes in the operation and arrangement of the elements described in an exemplary embodiment may be made without departing from the subject matter as defined in the appended claims, as well as their legal equivalents.

[0089] LIST OF REFERENCE SYMBOLS

[0090] 100 first embodiment of a device for sensor-based

[0091] Inspecting one or more physical objects, especially electrodes

[0092] 105, 105a, b Vacuum conveyor belt, each part of the transport device

[0093] 110, 110a-d image acquisition unit

[0094] 111 additional cameras, especially for the inspection of conductor flags A

[0095] 115, 115a,b Shielding device, especially darkroom

[0096] 120, 120a, b Lighting device with light-emitting diodes

[0097] 125a, b cleaning device

[0098] 130 Separation device, in particular punching device

[0099] 135 Guide rollers for strip-shaped electrode substrate B

[0100] 140 Supply roll for strip-shaped electrode substrate B

[0101] 145 Transport table

[0102] 145a, b Fixing devices

[0103] 150 Image evaluation device, optionally also control of the device

[0104] 155 Turning device

[0105] 160 single line scan cameras

[0106] 165 first spacer ring

[0107] 170 first lens

[0108] 175 second spacer ring with second lens

[0109] 180 Optics

[0110] 185 optical axis of the line scan camera 160

[0111] 190a,b mirror

[0112] 195a-f Field of view of the respective line scan camera 160

[0113] 196 Field of view of the additional camera 111

[0114] 200 second embodiment of the device

[0115] 300 third embodiment of the device

[0116] 400 fourth embodiment of the device

[0117] 500 first variant for the arrangement of the image sensors

[0118] 600 second variant for the arrangement of the image sensors

[0119] 700 third variant for the arrangement of the image sensors

[0120] 800 fourth variant for the arrangement of the image sensors

[0121] 900 Detailed view 900 of an image acquisition unit 110

[0122] 1000 Application example electrode inspection

[0123] A arrester lug

[0124] B Starting object, in particular flat starting substrate E (isolated) electrode

[0125] O Object to be inspected, especially electrode E with / without

[0126] Conductor flag A v Transport velocity x, y, z Coordinate axes of a Cartesian coordinate system

Claims

CLAIMS Device (100; 200; 300; 400) for sensor-based inspection of a physical object (O), wherein the device (100; 200; 300; 400) comprises: a transport device (105; 105a, 105b) for transporting a physical object (O) to be inspected along a transport path; an image sensor (110; 110a, 110b) with at least one image sensor (160) for at least sectionally image-sensory detection of the object (O) while it is continuously moved along the transport path relative to the image sensor (110; 110a, 110b) by the transport device (105; 105a, 105b); a lighting device (120; 120a, 120b) for illuminating a surface of the object (O) to be inspected in a wavelength range detectable by the image sensor (110; 110a, 110b), so that the image sensor (110; 110a, 110b) can detect the surface in such an illuminated surface area at least section by section;and a shielding device (115; 115a, 115b) for shielding the image sensor (110; 110a, 110b) from radiation not originating from the illumination device (120; 120a, 120b); wherein the image sensor (110; 110a, 110b) comprises a number N, with N > 1, of digital line cameras (160) each having a plurality of camera pixels arranged in a line, wherein the lines of the line cameras (160) each run perpendicular to the transport path. Device (100; 200; 300; 400) according to claim 1, wherein the transport device (105; 105a, 105b) is configured to move the object (O) relative to the image sensor (110; 110a, 110b) such that at least two opposite sides of the object (O) can be image-sensored simultaneously or sequentially by the image sensor (110; 110a, 110b). Device (100; 200) according to claim 2, wherein the transport device (105;105a, 105b) comprises: a first conveying device configured to transport the object (O) lying down, while a first side of the object (O) is at least partially detected by the image sensor (110; 110a, 110b); and a second conveying device configured to transport the object (O) hanging down, while a second side opposite the first side is detected; The object (O) is at least partially detected by the image sensors (110; 110a, 110b). Device (400) according to claim 2, wherein the transport device (105; 105a, 105b) has a turning device (155) for turning the object (O), which is configured to turn the object (O) between at least partial image sensor detection of a first side of the object (O) and at least partial image sensor detection of a second side of the object (O) opposite the first side.Device (300) according to claim 2, wherein the transport device (105; 105a, 105b) comprises two conveying devices separated from each other by a gap, each configured to transport the object (O) lying down or hanging upside down, and the image sensors (110; 110a, 110b) are configured to image-sensor the two opposite sides of the object (O) while a section of the object (O) to be image-sensor detected on both sides passes through the gap during operation of the transport device (105; 105a, 105b). Device (100; 200; 300; 400) according to any one of the preceding claims, further comprising a singulation device (130) upstream of the image sensors (110; 110a, 110b) on the transport path for singulating the object (O) from an output object (B).Device (100; 200; 300; 400) according to one of the preceding claims, wherein: the transport device (105; 105a, 105b) has a transport table (145) which is positioned upstream of the singulation device (130) with respect to the transport path and has at least two asynchronously operating fixing devices (145a, 145b) which are movable along the direction of the transport path for temporarily fixing the object (O) on the transport table (145); wherein the device (100; 200; 300; 400) is configured to control the movements of the fixing devices (145a, 145b) in such a coordinated manner that they interact to feed the output object (B) step by step to the singulation device (130) in order to enable the singulation of the object (O) from the output object (B) in each step, while the output object (B) is at rest relative to the transport device (105; 105a, 105b).

8. Device (100; 200; 300; 400) according to one of the preceding claims, further comprising a cleaning device (125a; 125b) upstream of at least one of the line cameras (160) of the image sensor system (110; 110a, 110b) in relation to the transport path for cleaning the object (O).

9. Device (100; 200; 300; 400) according to one of the preceding claims, wherein the image sensor (110; 110a, 110b) is configured such that at least one of its line cameras (160) has an optical axis (185) whose direction relative to a support surface on the transport device (105; 105a, 105b) for receiving the object (O) during image sensor detection defines a fixed or variably adjustable acute angle < > with < > < 90°.

10. Device (100; 200; 300; 400) according to one of the preceding claims, wherein the image sensor (110; 110a, 110b) has at least one mirror (190a; 190b) and is configured such that at least one of the line cameras (160) has an optical axis (185) directed towards the mirror (190a; 190b), so that the line camera (160) can image-sensor a mirror image of at least one section of the object (O) generated by the mirror (190a; 190b).

11. Device (100; 200; 300; 400) according to one of the preceding claims, wherein the image sensor system (110; 110a, 110b) has, in addition to the N line cameras (160), at least one further camera (111) whose field of view (196) extends along a direction perpendicular to the transport direction (x) beyond the cumulative field of view (195a,... ,195f) of the N line cameras (160).

12. Device (100; 200; 300; 400) according to one of the preceding claims, wherein the image resolution of at least one of the line cameras (160) is at least 6.8 zm per pixel, preferably at least 2.0 zm per pixel.

13. Device (100; 200; 300; 400) according to one of the preceding claims, wherein the image sensor (110; 110a, 110b) has in its beam path an optic (180) with a magnification factor from the range of -0.675x to -0.875x.

14. Device (100; 200; 300; 400) according to claim 13, wherein the optics (180) have at least one spacer ring (165; 175) for determining the magnification factor.

15. Device (100; 200; 300; 400) according to one of the preceding claims, wherein the shielding device (115; 115a, 115b) has one or more dark chambers in which the N line cameras (160) are housed in total to protect them from radiation not originating from the illumination device (120; 120a, 120b).

16. Device (100; 200; 300; 400) according to one of the preceding claims, wherein the device (100; 200; 300; 400) is configured to have a recording frame rate of the image sensor (110; 110a, 110b) depending on the to control or regulate the transport speed of the object (O) during its continuous transport through the transport device (105; 105a, 105b).

17. Device (100; 200; 300; 400) according to one of the preceding claims, wherein the lighting device (120; 120a, 120b) comprises one or more light-emitting diodes as radiation sources for illuminating the surface of the object (O) to be inspected.

18. Device (100; 200; 300; 400) according to one of the preceding claims, wherein the lighting device (120; 120a, 120b) has a main emission direction and is configured to illuminate the surface of the object (O) to be inspected such that the main emission direction is at a fixed or time-varying acute angle α with α < 90° to a support surface on the transport device (105; 105a, 105b) for receiving the object (O) during image sensor acquisition.

19. Device (100; 200; 300; 400) according to one of the preceding claims, wherein the lighting device (120; 120a, 120b) is configured to provide diffuse illumination of the surface of the object (O) to be inspected.

20. Device (100; 200; 300; 400) according to one of the preceding claims, wherein the transport device (105; 105a, 105b) is configurable such that The device (100; 200; 300; 400) according to one of the preceding claims further comprises an image evaluation device (150) for evaluating image material captured by the image sensors (110; 110a, 110b) in order to detect any To detect deviations of the object (O) depicted in the image material from a reference state of the object (O) by means of image processing. A method for sensor-based inspection of a physical object (O), wherein the method is carried out using a device (100; 200; 300; 400) according to one of the preceding claims. Using a device (100; 200; 300; 400) according to one of claims 1 to 21 or the method according to claim 22, in each case for inspecting an electrode substrate of an electrode (E, A) for a galvanic cell or a coating of such an electrode substrate with an anode or cathode material.

Images