Apparatus and method for in-line quality control of components for solid-state batteries

Abstract

The invention relates to an apparatus and a method for in-line quality control for coatings of components for solid-state batteries, the apparatus (1a) comprising: a feed device (6) for a solid-state battery component (5) comprising a layer, in particular a layer produced by means of dry or wet coating, at least one first light source (2) for transmitted-light illumination of the layer, at least one second light source (3a) for bright-field illumination and / or dark-field illumination of a surface (7) of the layer, at least one camera (4a) for recording image data of the layer by means of the bright-field, dark-field and / or transmitted-light illumination, and an image processing device for processing the image data for the detection of defects of the layer.

Description

[0001] Device and method for in-line quality control of components for solid-state batteries

[0002] The invention relates to a device for in-line quality control or inspection of coatings or layers of components for solid-state batteries.

[0003] In the following, the term "solid-state battery" is used synonymously for all designations commonly used in the prior art for galvanic elements and cells that use at least one solid electrolyte as an ion-conducting connection between cathode and anode, such as metal solid-state battery, metal solid-state accumulator, all-solid-state battery (ASSB), cell, solid-state cell, polymer cell, and accumulator. In particular, rechargeable batteries (secondary batteries) are included. The terms "battery," "cell," and "electrochemical cell" are also used synonymously with the term "solid-state battery."

[0004] Solid-state batteries represent a further development of batteries with liquid electrolytes. The porous, liquid-soaked separator, which is responsible for ion transport and thus charge balance between the cathode and anode, is replaced with an ion-conducting solid. A preferred variant of the solid-state battery is the lithium-ion solid-state battery.

[0005] For reliable operation of a solid-state battery, ensuring the quality of layers or coatings on solid-state battery components, such as solid electrolyte layers, anode layers, cathode layers, and primer layers, is essential. Especially in the roll-to-roll process, which requires the highest level of automation, continuous quality monitoring and the detection of layer defects are essential for early detection of defective batches.

[0006] Schoo, A. et al., 'A. Coating Defects of Lithium-Ion Battery Electrodes and Their Inline Detection and Tracking', Batteries 2023, 9, 111 (https: / / doi.org / 10.3390 / batteries9020111) presents a device and a method for detecting coating defects on lithium-ion battery electrodes and their inline detection and tracking. Defects are detected optically using a camera. Two light sources are alternately activated for simultaneous defect detection. Defects are determined using scattered light (dark field) from a first LED light source and directly reflected light (bright field) from a second LED light source.

[0007] It is an object of the invention to provide an improved device and an improved method for in-line quality control of components for solid-state batteries.

[0008] This object is achieved according to the invention by the subject matter of claims 1, 7 and 10. Advantageous embodiments of the invention are the subject matter of the dependent claims and the description.

[0009] A device according to the invention for in-line quality control or inspection of layers or coatings of components for solid-state batteries has a feed device for a solid-state battery component. The solid-state battery component has at least one layer or is formed as a layer, which is produced, for example, by dry or wet coating. The layer can be single-layered or multi-layered. The component can be formed exclusively from the at least one layer (free-standing layer), or alternatively, a substrate (e.g., film) can be coated with the layer (coating). The component can also comprise multiple layers coated onto the same side of the carrier film. For example, with the structure: carrier film - layer A (e.g., high concentration of X) - layer B (e.g., low concentration of X). In addition, the component can have a coating on both sides, i.e.with the structure: layer A - carrier film - layer B, or alternatively without a carrier film with the structure: layer A - layer B. The device further comprises at least one first light source for transmitted light illumination of the layer, and additionally or alternatively at least one second light source for bright field illumination (directly reflected light) of a surface of the layer and additionally or alternatively for dark field illumination (scattered light) of the surface. At least one camera is arranged or aligned such that it can record image data of the layer using transmitted light, bright field and / or dark field illumination. In a bright field image, image data is generated using directly reflected light, and in a dark field image, scattered light is used.

[0010] The generated image data can then be processed using an image processing device to detect layer defects. Defects can be detected using a single image (transmitted light / bright field / dark field) or, in addition or alternatively, a combination of different images (transmitted light / bright field / dark field).

[0011] Using the described device, the following solid-state battery components or layers can be checked for defects: single- or multi-layer solid electrolyte layers, single- or multi-layer separator layers, single- or multi-layer anode layers, and / or single- or multi-layer cathode layers. These layers can be free-standing or alternatively applied to a transparent substrate. The solid-state battery components can be produced by dry coating or wet coating, both as a free-standing layer and as a coated transparent substrate. A solid electrolyte layer is essentially, or ideally, non-porous and conducts ions and can be formed, for example, from a polymer or ceramic material. The solid electrolyte is, for example, a polymeric, oxide, halide, and / or sulfide solid electrolyte, e.g.Argyrodite U6PS5CI (source: 'Janek et al., .Challenges in speeding up solid-state battery development', [https: / / doi.org / 10.1038 / s41560-023-01208- 9]). A transparent substrate can be a polymer film, e.g., PET.

[0012] Defects that can be detected using the device can be pinholes, contamination, dents, scratches, inhomogeneities, air pockets and / or surface particles. The various images (bright field / dark field / transmitted light) or a combination of these images or their image data are particularly suitable for detecting the various defects. For example, pinholes, i.e. holes in the layer, can be detected particularly well using transmitted light. The detection of pinholes is particularly relevant for solid electrolyte layers, since the solid electrolyte layer electrically separates the anode and cathode. In the presence of a pinhole, i.e. hole, this electrical insulation is no longer present, therefore the use of such a defective solid electrolyte can lead to an internal short circuit in a solid-state battery cell.

[0013] When using the device, the solid-state battery component can be continuously fed to the at least one camera and the light sources by means of the feed device for in-line quality monitoring or inspection of the solid-state battery component or layer. For example, in the case of a wet-coated solid-state battery component, the component can be inspected using the described device immediately after its completion or after the layer has dried, before the solid-state battery component is finally wound onto a roll. Analogously, an inspection of a layer produced by dry coating is possible using the device. For example, for quality control after the final rolling of a (free-standing) web-shaped layer, this can be fed to the device or camera and light sources by means of the feed device.

[0014] The at least one camera is arranged or aligned such that it receives transmitted light through the layer or solid-state battery component from the first light source, and / or receives scattered light from the second light source and / or receives directly reflected light from a surface of the layer or solid-state battery component. The at least one camera can be a line scan camera and / or a matrix camera. In one embodiment, the at least one camera can be arranged or aligned such that it receives exclusively transmitted light and scattered light (dark field), or alternatively exclusively transmitted light and directly reflected light (bright field). According to a further embodiment, the device can have two, three or more cameras that are arranged or aligned to take transmitted light, dark field and / or bright field images using the first and / or second light source.In particular, the device can be configured such that only transmitted-light images, bright-field images, or dark-field images can be generated using the first and / or second light source. For example, the device has only one light source for generating transmitted-light images. Alternatively, the device has only one light source arranged for generating bright-field images or dark-field images.

[0015] Particularly preferably, the at least one second light source is configured for both bright-field illumination and dark-field illumination of the solid-state battery component or layer. For example, the light source is switchable between coaxial illumination (bright-field observation) and ring illumination (dark-field observation).

[0016] Preferably, the described device or its components are arranged in a housing unit, so that the device can be easily integrated into a coating system as a module. An exemplary method for in-line quality control / inspection for coatings of components for solid-state batteries is described below, in particular using a device as described above, the method comprising:

[0017] - Producing a layer or coating of a solid-state battery component, wherein the layer can be formed in one or more layers, e.g. the component can comprise several layers which are coated on the same side of a carrier film,

[0018] - feeding the solid-state battery component by means of a feeding device to at least one camera, a first light source for transmitted light illumination of the layer, and a second light source for bright field and / or dark field illumination of a surface of the layer,

[0019] - capturing (optical) image data of at least a part of a surface of the layer by means of the at least one camera, and

[0020] - Evaluation of the generated image data using an image processing device to detect defects.

[0021] Using the device described above, one side or surface of a solid-state battery component or layer can be inspected or monitored. For the inspection of double- or two-sided coated (web-shaped) solid-state battery components, an arrangement for in-line quality control for coatings on solid-state battery components is provided as described below. Unless otherwise stated, the following components correspond to those described above. The arrangement has a feed device for a solid-state battery component with a two-sided / double-sided coating.By means of the feed device, the component is delivered to a first device for generating image data of a first surface or upper side of the solid-state battery component by means of transmitted light illumination, as well as bright field and / or dark field illumination, and to a second device for generating image data of an opposite second surface or underside of the solid-state battery component by means of transmitted light illumination, as well as bright field and / or dark field illumination. For this purpose, the first and second devices each have at least one camera and at least two light sources, which are preferably designed as described above for generating transmitted light, bright field and / or dark field images of the respective surface. Defects in the layers are detected by means of an image processing device for processing the image data of both surfaces of the solid-state battery component.With the described arrangement, simultaneous coating or two-sided coating can be effectively controlled in-line.

[0022] Further features of the invention emerge from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective specified combination, but also in other combinations or on their own.

[0023] The invention will now be explained in more detail using preferred embodiments and with reference to the drawings. They show:

[0024] Fig. 1 is a schematic, not to scale, side view of an apparatus for in-line quality control according to a first embodiment;

[0025] Fig. 2 is a schematic, not to scale, side view of an in-line quality control device according to a second embodiment;

[0026] Fig. 3 is a schematic, not to scale, side view of an in-line quality control device according to a third embodiment; and

[0027] Fig. 4 is a schematic, not to scale, side view of a wet coating system with an indication of the area where in-line quality control takes place.

[0028] Fig. 1 shows a schematic side view of a device 1a for in-line quality control of a solid-state battery component 5 according to a first embodiment.

[0029] A solid-state battery component 5 can be a free-standing single- or multi-layer film or a coated transparent substrate, which is preferably web-shaped. The device 1a has a camera 4a, as well as a first light source 2 for generating transmitted light and a second light source 3a for generating scattered light, wherein the camera 4a is aligned such that it can take transmitted-light images of the component 5 using the first light source and dark-field images of a surface 7 or side of the component 5 using the second light source 3a. Optionally, the light source 3a is designed to generate directly reflected light and scattered light, so that both dark-field and bright-field images can be generated with just one light source.

[0030] The web-shaped solid-state battery component 5 is continuously fed to the camera 4a and the light sources 2, 3a in the feed direction V by means of a feed device 6, so that a continuous or gapless inspection of the component 5 or the layer or coating can take place. The feed device 6 can have at least two rollers, e.g. for dry coating, as shown schematically in Fig. 1-3. Alternatively, as in the wet coating system 8 shown schematically in Fig. 4, a feed device 6' can have only one roller or deflection roller, over which a coated film or the solid-state battery component 5 is stretched for the transport of the component 5 in the feed direction V. The feed device 6, 6' or corresponding roller(s) is arranged in front of an area 9 (Fig. 4) in which the quality control takes place.

[0031] The image data generated by the camera is evaluated by an image processing device (not shown) to detect coating defects. Defects detectable with the device can include pinholes, contamination, dents, scratches, inhomogeneities, air pockets, and / or surface particles. Both individual images and combinations of transmitted-light and dark-field images can be used to detect individual defects. For example, pinholes can be optimally detected using transmitted-light images, and scratches can be detected using bright-field images.

[0032] Fig. 2 shows a second embodiment of a device 1b for in-line quality control of a solid-state battery component 5. Unless otherwise stated, the components of the device 1b described below correspond to those of the device 1a of the first embodiment.

[0033] In contrast to device 1a, device 1b, schematically illustrated in Fig. 2, has an additional light source 3b, which is arranged around a lens of camera 4a and has a recess or opening for the lens of camera 4a. By means of light source 3b, surface 7 of component 5 can be optimally illuminated from above for a bright-field image with directly reflected light. With this device 1b, transmitted-light, bright-field, and dark-field images can thus be generated, which are subsequently evaluated by the image processing device. Alternatively, device 1b can be used without light source 3a. For example, light source 3b can be switched between coaxial illumination (bright-field viewing) and ring illumination (dark-field viewing), so that transmitted-light, bright-field, and dark-field images can also be generated with light sources 2 and 3b.

[0034] Fig. 3 shows a third embodiment of a device 1c for in-line quality control of a solid-state battery component 5. Unless otherwise stated, the above-described components of the devices 1a, 1b of the first and second embodiments correspond to those of the device 1c of the third embodiment.

[0035] The device 1c has an additional camera 4b, which is aligned with the first light source 3a such that the angle of incidence / emission R of the directly reflected light is optimally aligned with the camera 4b. In this embodiment, optimal bright-field images can be generated using directly reflected light from the first light source 3a.

[0036] The devices 1a-c described above can be used to inspect a surface 7 or side of a solid-state battery component 5. For quality control of a solid-state battery component 5 coated on both sides, an arrangement with two of the described devices 1a-c can be provided, so that each side of the solid-state battery component 5 is monitored with one device. Such an arrangement has a feed device and an image processing device for processing image data of the two sides or surfaces 7 of the solid-state battery component. For this purpose, the arrangement has at least one camera and at least two light sources for each side of the solid-state battery component for recording transmitted-light, bright-field, and / or dark-field images, as described above.

[0037] The devices 1a-c described above or an arrangement for checking solid-state battery components coated on both sides preferably have a housing (not shown) so that they can be easily integrated or retrofitted as a module into a coating system. In Fig. 4, an area 9 is marked for the coating system 8 as an example, in which the quality control takes place, i.e. the area 9 in which one of the devices 1a-c described above for the in-line inspection of the layer(s) is arranged. As shown here as an example, a substrate or a film roll is unwound by means of an unwinder 10 and coated on one side. The coated substrate or the solid-state battery component 5 then passes through a number of ovens 12 to dry the coating and then, without interruption, through the quality control area 9 with a device 1a-c as described above.Finally, the web-shaped solid-state battery component 5 is wound into a roll by means of a winder 11.

[0038] The positions and angles of the light sources 2, 3a, 3b and cameras 4a, 4b to the solid-state battery component 5 shown in Figs. 1-3 serve only to illustrate the principle of the invention and are not intended to limit the scope of the invention to the positions and angles shown.

[0039] List of reference symbols

[0040] 1a-c Device

[0041] 2 Light source transmitted light

[0042] 3a, 3b Light source brightfield / darkfield

[0043] 4a, 4b Camera

[0044] 5 layer / component with coating

[0045] 6, 6' feeding device

[0046] 7 Surface / Top

[0047] 8 Coating system

[0048] 9 Area of ​​quality control

[0049] 10 processors

[0050] 11 winders

[0051] 12 oven

[0052] R angle of incidence / reflection

[0053] V feed direction

[0054] Z supply air

[0055] A exhaust air

Claims

Patent claims 1. Device for in-line quality control for coatings of components for solid-state batteries, characterized in that the device (1a-c) has: a feed device (6, 6') for a solid-state battery component (5) having a layer, in particular a layer produced by means of dry or wet coating, at least one first light source (2) for transmitted light illumination of the layer, and / or at least one second light source (3a, 3b) for bright field illumination and / or dark field illumination of a surface (7) of the layer, at least one camera (4a, 4b) for recording image data of the layer by means of the bright field, dark field and / or transmitted light illumination, and an image processing device for processing the image data for the detection of defects in the layer.

2. Device according to claim 1, characterized in that the layer is a solid electrolyte layer, anode layer, cathode layer, primer layer and / or separator layer.

3. Device according to claim 1 or 2, characterized in that defects detectable by means of the device (1a-c) are pinholes, impurities, dents, scratches, inhomogeneities, air inclusions and / or surface particles.

4. Device according to claim 1, 2 or 3, characterized in that the at least one second light source (3a, 3b) is designed for bright field illumination and dark field illumination of the layer.

5. Device according to claim 1, 2 or 3, characterized in that the second light source is arranged for bright field illumination or dark field illumination, and the device has a third light source which is arranged for dark field illumination or bright field illumination of the layer.

6. Device according to one of the preceding claims, with at least one further camera (4b) arranged to take a bright field image or a dark field image of the surface (7) of the layer.

7. A method for in-line quality control of coatings on components for solid-state batteries, in particular with a device according to one of the preceding claims, characterized in that the method comprises: Producing a layer of a solid-state battery component (5), in particular a solid electrolyte layer, anode layer, cathode layer, primer layer and / or separator layer, Feeding the solid-state battery component (5) by means of a feeding device (6, 6') to at least one camera (4a, 4b), a first light source (2) for transmitted light illumination of the layer, and / or a second light source (3a, 3b) for bright field and / or dark field illumination of a surface (7) of the layer, capturing image data of at least a portion of a surface (7) of the layer by means of the at least one camera (4a, 4b) and the first and / or second light source (2, 3a, 3b), and Evaluation of the generated image data using an image processing device to detect defects.

8. The method according to claim 7, characterized in that detectable defects are pinholes, impurities, dents, scratches, inhomogeneities, air inclusions and / or surface particles.

9. The method according to claim 7 or 8, characterized in that the solid-state battery component (5) is formed in a strip shape, in particular as a roll material, the layer is single- or multi-layered, the layer is produced by dry or wet coating, and / or the layer is formed as a free-standing layer or is formed on a transparent substrate.

0. Arrangement for in-line quality control for coatings of components for solid-state batteries, characterized in that the arrangement comprises: a feed device (6, 6') for a solid-state battery component having a two-sided coating, in particular by means of dry or wet coating, at least one camera (4a, 4b) and two light sources (2, 3a, 3b) for generating image data of a first surface (7) or upper side of the solid-state battery component by means of transmitted light illumination, bright field and / or dark field illumination, at least one further camera and two further light sources for generating image data of an opposite second surface or underside of the solid-state battery component by means of transmitted light illumination, bright field and / or dark field illumination,and an image processing device for processing the image data for detecting defects in the layers of the first and second surfaces of the solid-state battery component.

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