X-ray system

Abstract

An X-ray system for non-destructive material testing of an object to be irradiated (106), in particular a battery module (106b) of a vehicle or a battery module (106b) installed in a vehicle, comprising at least one radiation source (102) and at least one radiation detector (104), wherein the object to be irradiated (106) is arranged between the at least one radiation source (102) and the at least one radiation detector (104), the at least one radiation source (102) is arranged at a distance from the object to be irradiated (106) at least two, at least three, or at least five times the width (106b) of the scanning area (so that a fan-shaped radiation geometry is formed at least in the lateral direction), and the opening angle (100α) of the radiation geometry is less than 10°.

Description

[Technical Field]

[0001]

[0001] Embodiments of the present invention relate to an X-ray system for non-destructive material testing of irradiated objects, in particular battery modules (such as high-voltage batteries) of vehicles or battery modules installed in vehicles. Further embodiments relate to methods and computer programs for interpreting radiographs. Generally, embodiments of the present invention are in the field of high-speed battery inspection of entire vehicles by X-ray techniques. [Background technology]

[0002] It has not been possible to non-destructively view the interior of an electric vehicle's battery module. Here, the mechanical integrity of the battery module, for example after an accident, plays a key role in determining vehicle repair options. This method can also be used to assess the condition of vehicles with unknown vehicle histories in the used car market. Therefore, an improved approach is needed. Summary of the Invention [Problem to be solved by the invention]

[0003] The object of the present invention is to enable non-destructive material testing of vehicle batteries, in particular in electric vehicles. [Means for solving the problem]

[0004] This object is solved by the subject matter of the independent claims.

[0005] An embodiment of the present invention provides an X-ray system for non-destructive material testing of an irradiated object, such as a battery module of a vehicle or a battery module installed in a vehicle. The X-ray system includes at least one radiation source and at least one radiation detector. The irradiated object, such as a vehicle or a vehicle battery, is installed in the vehicle and is disposed between the at least one radiation source and the at least one radiation detector. The at least one radiation source is positioned at a distance from the irradiated object at least two, at least three, or at least five times the width of the scanning area so as to form a fan-shaped radiation geometry at least laterally. According to an embodiment, the scanning area can correspond to the width of the object or only a portion of the width of the object, i.e., only a portion of the object is imaged laterally. The opening angle of the radiation geometry is less than 10°.

[0006] According to embodiments, the distance between the radiation source and the object to be irradiated can be at least 5 m or even at least 10 m. It has been found that a distance of 11 m or at least 11 m allows for good scanning of a 2 m wide object. The 10° radiation geometry and distance are particularly intended to allow scanning of the object across its entire width or over at least a sufficiently wide scanning area across the object width (laterally).

[0007] According to embodiments, in order to obtain a good longitudinal scan of the object, the object can be moved or moved continuously in a forward direction, which can for example mean perpendicular to the lateral direction.

[0008] At least one radiation source can be formed by a plurality of individual radiation sources, so that a distance of, for example, less than 10 m, or, for example, less than 5 m, for example, 3 m, is sufficient. For example, at least one radiation source can be formed by a plurality of individual radiation sources arranged laterally relative to the object. For example, when two radiation sources are assumed, the distance can be reduced from 10 m to 5 m. When three individual radiation sources are assumed, the distance can be reduced from approximately 10 m to 3 m. This means that, according to embodiments, a plurality of radiation sources, referred to herein as individual radiation sources, are provided. Thus, according to embodiments, the distance to the irradiation object is at least 2 m or at least 3 m. In embodiments in which a high-voltage battery / battery module is irradiated, the high-voltage battery / battery module is the irradiation object. This irradiation object can be tested over its entire width, each resulting in a large scanning area, or only partially tested, resulting in only a small scanning area (per radiation source) and therefore a smaller emitter-object distance.

[0009] According to an embodiment, the distance from the radiation source is measured relative to the irradiated vehicle battery (battery module) or the surface of the irradiated vehicle battery facing the radiation source. The irradiated vehicle battery is typically a rectangular object with a main extension aligned along the vehicle's length or width. A square aspect ratio or a nearly square aspect ratio is also possible. In the depth direction, the vehicle battery module often has a height of a few centimeters, such as 10 cm, 15 cm, or 20 cm. The described arrangement of the radiation source emitting in the depth direction or parallel to the depth direction allows for good scanning of the object along a height of 10 cm, and as already explained, good resolution is possible across the length and width.

[0010] In the above embodiment, the battery extends in length and width directions essentially perpendicular to the radial direction. -by a radiation source far away, e.g. at least 10 m or by multiple radiation sources arranged transversely to the direction of advance, spaced, for example, by 3 or 5 m apart, It was to be irradiated.

[0011] In both illumination variations, the opening angle of the radiation geometry is limited to 10°.

[0012] The present invention is based on the finding that a combination of a large distance and a small beam cone width creates a radiation geometry that allows for clear imaging of gaps (between individual cells) extending along the length or width of a battery module. Advantageously, the X-ray energy can be selected to be only high enough to penetrate the vehicle's sheet metal structure, without necessarily penetrating the entire battery cell. This also makes it easier to find gaps between battery cells, since they absorb less light than the battery cells themselves. In this way, defects, such as contact points between battery cells, which indicate a battery defect, can be easily and efficiently detected.

[0013] The X-ray source is therefore configured to provide an energy of up to 450 KeV, or even up to 360 KeV, and the energy is therefore chosen to be very low so that irradiation of the intact object (intact battery cells) does not occur, but only the gaps between the battery cells.

[0014] In embodiments with several individual radiation sources, there are different variants. According to one embodiment, the radiation geometries of the individual radiation sources can form overlapping radiation fields and / or overlapping radiation fields in the focal plane. Here, it is possible to have a small overlap in the width of the radiation fields, for example up to 10%. According to further embodiments, the radiation geometries of the individual radiation fields can overlap in a large area (also in the focal plane). In this variant, according to an embodiment, an alternating operation of the individual radiation sources is selected.

[0015] According to an embodiment, the X-ray detector extends over the entire width of the object. According to a further embodiment, the X-ray detector is formed by a line detector or an area detector extending over the width of the object. According to an embodiment, the X-ray system comprises several radiation detectors or radiation sources arranged along the forward direction. The use of several X-ray detectors has the advantage that in this way several X-ray photographs are obtained from slightly different viewpoints, so that overlapping objects, such as parts of the car body that are in the out-of-focus plane during the irradiation of a vehicle with an irradiated high-voltage battery, can be detected and subsequently masked. Therefore, according to an embodiment, the X-ray system comprises an evaluation device configured to evaluate several photographs across several positions and / or several emitter-detector combinations. The evaluation device is configured to detect overlapping objects in individual photographs based on the several photographs and / or to compensate for overlapping object images in individual X-ray photographs, for example by subtraction. According to a further embodiment, the X-ray system comprises an evaluation device configured to detect overlapping objects based on reference photographs of the irradiated object and / or to compensate for overlapping object images in individual photographs. According to further embodiments, the evaluation device can also select photos with little or no overlap or prioritize them over other photos. According to further embodiments, the evaluation device includes an AI algorithm configured to detect such overlapping objects. Furthermore, the evaluation device is configured to detect morphological features. For example, the evaluation device can be configured to detect deviations from the normal morphology of an object or part of an object. When a cylindrical or prismatic cell is deformed, there is a deviation from the normal cylindrical or prismatic morphology. Also, deviations from the normal morphology of gap widths can be detected. Here, particular emphasis is placed on reducing deviations from the normal gap width. Thus, the evaluation device can be configured to determine the distance between lines of an object, such as cells of a battery module.

[0016] It is further noted that for X-ray systems, radiation geometries of less than 10° can be obtained by collimating the individual rays, e.g., each radiation source or individual radiation sources can include a collimator.

[0017] In order to adapt the focal spot or to adapt the X-ray system to several sources, according to embodiments the distance between at least one X-ray source and the object to be irradiated (and therefore also the distance to the radiation detector) can be adapted, which is particularly advantageous when different objects are irradiated, such as different vehicles (SUVs or cars).

[0018] Further embodiments relate to a method having the main steps of irradiating an object to be irradiated at a distance of the radiation source from the object to be irradiated that is at least twice, at least three times, or at least five times the width of the scanning area, and acquiring a first photograph.

[0019] Additionally, the method can include repeating the illuminating step for additional photographs. Additionally, the method can also include compensating for overlapping objects based on detecting overlapping objects in the photographs with the aid of the additional photographs.

[0020] According to a further embodiment, the method may be computer-implemented, which means that the further embodiment relates to a computer program.

[0021] Further developments are defined in the dependent claims. Preferred embodiments of the invention will now be described with reference to the accompanying drawings. [Brief explanation of the drawings]

[0022] [Figure 1a1] 1 is a schematic diagram illustrating the illumination of an object such as a vehicle with a vehicle battery when using the prior art to explain the problem addressed by the present invention; FIG. [Figure 1a2]1 is a schematic diagram illustrating the illumination of an object such as a vehicle with a vehicle battery when using the prior art to explain the problem addressed by the present invention; FIG. [Figure 1b1] 1 is a schematic diagram illustrating the illumination of an object such as a vehicle with a vehicle battery when using the prior art to explain the problem addressed by the present invention; FIG. [Figure 1b2] 1 is a schematic diagram illustrating the illumination of an object such as a vehicle with a vehicle battery when using the prior art to explain the problem addressed by the present invention; FIG. [Figure 2] 1 is a schematic block diagram for explaining an X-ray system according to a basic embodiment of the present invention. [Figure 3a1] Schematic diagram for illuminating an object, here a vehicle with a battery, according to an extended embodiment. [Figure 3a2] Schematic diagram for illuminating an object, here a vehicle with a battery, according to an extended embodiment. [Figure 3b1] Schematic diagram for illuminating an object, here a vehicle with a battery, according to an extended embodiment. [Figure 3b2] Schematic diagram for illuminating an object, here a vehicle with a battery, according to an extended embodiment. [Figure 4a1] FIG. 1 is a schematic diagram of an X-ray system according to an extended embodiment. [Figure 4a2] FIG. 1 is a schematic diagram of an X-ray system according to an extended embodiment. [Figure 4b1] FIG. 1 is a schematic diagram of an X-ray system according to an extended embodiment. [Figure 4b2] FIG. 1 is a schematic diagram of an X-ray system according to an extended embodiment. [Figure 5a] 10A-10C are schematic diagrams illustrating further aspects according to further embodiments. [Figure 5b] 10A-10C are schematic diagrams illustrating further aspects according to further embodiments. [Figure 5c] 10A-10C are schematic diagrams illustrating further aspects according to further embodiments. [Figure 6a] FIG. 10 is a schematic block diagram illustrating the processing of X-ray signals for absorption in an extended embodiment. [Figure 6b] FIG. 10 is a schematic block diagram illustrating the processing of X-ray signals for absorption in an extended embodiment. [Figure 6c] FIG. 10 is a schematic block diagram illustrating the processing of X-ray signals for absorption in an extended embodiment. [Figure 7a] 1 is an exemplary radiograph taken by an X-ray system according to an embodiment. [Figure 7b] 1 is an exemplary radiograph taken by an X-ray system according to an embodiment. [Figure 7c] 1 is an exemplary radiograph taken by an X-ray system according to an embodiment. [Figure 7d] 1 is an exemplary radiograph taken by an X-ray system according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0023] Before describing the embodiments of the present invention below based on the accompanying drawings, it should be noted that like elements and structures are given like reference numerals and their descriptions are mutually applicable or interchangeable.

[0024] FIG. 1 shows an X-ray system with an X-ray geometry 100 that is essentially defined by the arrangement of a radiation source 102 and a detector 104. The geometry is shown in FIG. 1a1 in a transverse direction and in FIG. 1b1 in a longitudinal direction. The irradiated object 106b is, for example, a high-voltage battery of a vehicle 106. The vehicle 106 is irradiated transversely in FIG. 1a1 and longitudinally in FIG. 1b2. The detector 104 can be, for example, a line detector 104 arranged transversely, i.e., laterally, of the vehicle 106. When irradiating the vehicle 106, particularly the battery module 106b, in the longitudinal direction, the object is moved in a forward direction 106v depending on the variation.

[0025] The object 106b to be irradiated is, for example, a high-voltage battery (lithium-ion battery) containing cells (individual cells of different shapes, cylindrical or prismatic) separated by gaps. The irradiation direction of the irradiation geometry 100 is selected so that the gaps between the cells are irradiated in the radial direction. This is clearly shown based on the parallelism of the central ray 100z of the radiation geometry. The irradiation of the battery module 106b with its battery cells and gaps results in maxima at the gaps and minima at the cells. This irradiation pattern is shown in FIG. 10d in the transverse direction (see FIG. 1a2) and in FIG. 11d in the longitudinal direction (see FIG. 1b2). As can be seen, FIG. 10d has good resolution around the central ray 100z, but moderate or significantly reduced resolution in the outer regions of the radiation geometry 100. In the longitudinal direction, scanning is primarily performed in the region of the central ray 100z, where the vehicle 100 with the battery module 100b is moving in the forward direction 106v. The situation shown here represents the starting situation for an embodiment of the invention, in which a vehicle 106 with a battery module 106b is X-rayed. Some of this description is already an aspect of the invention, such as the use of the option of advancement 106v along the longitudinal direction of the vehicle 106. As shown based on FIG. 1a2, there is a significant problem with the lateral resolution of the object 106b. The illustrated simplified absorption profile shows the contrast loss in the edge areas within the module resulting from the oblique view. Such known photographic geometries and techniques are indeed suitable for the purpose of battery cell testing. Now, in the following description of the embodiment, three different directions will be used: - Irradiation direction: This is the direction along the radiation propagation parallel to the central ray 100z of the radiation / X-ray source 102.

[0026] Forward direction: In some embodiments, the object 106 or 106b is assumed to move through the radiation geometry 100 in a forward direction 106v during illumination. This is the forward direction 106v. This forward direction 106v is orthogonal or essentially orthogonal to the illumination direction, and this applies not only to the embodiments shown herein in which the vehicle 106 is illuminated from a bird's-eye view, but also to other illuminations, such as from the side.

[0027] Width direction: this direction defines the illumination width in the radiation geometry 100, which is essentially determined by the aperture angle of the radiation geometry 100 and the width of the detector 104. The lateral direction therefore extends along the width of the detector 104, typically perpendicular to the advance direction. Furthermore, the lateral direction is essentially orthogonal to the illumination direction.

[0028] Longitudinal direction: In embodiments without advance, for example when an area detector is used instead of a line detector, the advance direction can also be called longitudinal direction.

[0029] In particular, in order to optimize the lateral resolution, the following configuration of the X-ray system or X-ray device is proposed:

[0030] FIG. 2 shows a radiation source 102 with opposing radiation detectors 104, spaced apart to form a radiation geometry 100′. This serves to irradiate an object 106 having a battery cell 106b. Exemplarily, three battery cells 106b1, 106b2, and 106b3 are shown. Between them, gaps 106s1 and 106s2 are formed. These gaps are essentially longitudinal with respect to the irradiation direction 100s. The detectors 104 are arranged transversely (see transverse direction 100q) with respect to the irradiation direction 106. The geometry 100′ is characterized by two specific features: an opening angle 100α′ of the geometry 100′, which is limited to 10° or less (≦10°), and a distance 100d′. Compared to conventional radiation detector structures, the spanned opening angle is essentially adjusted according to the minimum distance of the overall position, rather than specific requirements from an analysis such as battery cell analysis. This distance 100d' is at least two, three, or five times the width of the scanning area of ​​the object 106. In this embodiment, the scanning area corresponds to the width 106br of the object 106. The larger the distance 100d' compared to the scanning area, the more parallel the light beams become to the irradiation direction 100s. For example, if an object width of 2.2 m is assumed, the distance 100d' becomes 11 m by a factor of 5. This distance is preferably determined between the irradiation object 106b and the radiation source 102 or the focal point of the radiation source 102. Here, the surface of the object 106b facing the radiation source 102 is relevant. It is important to note that for the preferred application, the battery 106b of an electric vehicle 106 will be irradiated, which is typically located under the vehicle body, potentially resulting in a structural height of more than 1 m above the battery area 106b. As already mentioned, the light beams of the radiation geometry 100' are essentially parallel to the irradiation direction 100s. The gaps 106s1 and 106s2 also extend essentially parallel to the irradiation direction 100s, so that the X-rays can pass through the gaps 106s1 and 106s2 without crossing the battery cells 106b1, 106b2 and 106b3.This allows clear imaging of the gaps 106s1 and 106s2 and distinguishing them from the battery cells 106b1, 106b2, and 106b3. This allows for rapid X-ray inspection of the internal structure of the battery module 106b installed in the vehicle 106. Battery damage, such as a short circuit between battery cells, is indicated by a decrease in the gap width. In this way, the damage can be easily and efficiently determined. Due primarily to the fact that potential gaps are being inspected, in some embodiments, the energy level of the radiation source can be reduced, for example, to 450 KeV or even 360 KeV. This energy level is no longer sufficient to irradiate the battery cells themselves, but is sufficient to irradiate the gaps.

[0031] Therefore, an embodiment of the present invention provides an X-ray device or system including at least a radiation source 112 and an X-ray detector 104, which are arranged relative to one another so as to achieve an image of the characteristic cell shapes 106b1, 106b2, 106b3 with as little distortion as possible. According to an embodiment, the object 106, in particular 106b, can be scanned longitudinally by continuously moving the scanning unit (102+104) or the object 106+106b along the radiation axis 100s defined by the radiation source 102 and the detector 104. According to one embodiment, the X-ray energy is selected such that it can penetrate the metal seat structure of the vehicle chassis 106, but not necessarily the components of the battery cells 106b1, 106b2, and 106b3. The detection focuses on finding the gaps 106s1, 106s2 between the individual battery cells 106b1, 106b2 and 106b3, which are easily visible from a bird's-eye view and typically do not contain increased absorption (so that the X-rays of the radiation source 102 can be correspondingly detected by the detector 104).

[0032] In comparison with conventional X-ray systems, such as those used for X-raying large-volume objects such as containers, the radiation pattern 100s here is specifically adapted to the object 106 or 106b to be irradiated. The distance 100d', taking into account the geometry, particularly the aperture angle 100α', is selected depending on the inspected geometry of the object or the battery cells 106b1, 106b2, and 106b3 integrated in a battery module. A general rule for this is to determine the X-ray source-object distance 100d' to be greater than two, three, or even five times the scan width or object width 106b, depending on the embodiment. If only a portion of the object 106b is scanned in the width direction, the scan width can also be made smaller than the object width to capture a cross section. As a result, the distance 106b' is shorter, but the minimum ratio remains the same.

[0033] The aperture angle of the radiation geometry is limited to 10°, or for example, 8°, or 5°. This has the purpose of ensuring the parallelism of each of the light rays in the optical path. According to an embodiment, for optimal imaging of the internal structures 106b1, 106b2, 106b3, 106s1, 106s2, the aperture angle 100α′ of the light rays emitted by the X-ray source 102 can be made as small as possible, while at the same time selecting the largest possible radiation field (see the first general point). This makes it possible to avoid so-called parallax in the images. In contrast to point-by-point detection with a needle-like beam, this process is sufficiently time-efficient and therefore suitable for high-speed (serial) inspection. According to an embodiment, the limitation can be achieved by a collimator (not shown) coupled to the X-ray source 102.

[0034] The illumination direction 100s is aligned with the gaps 106s1 and 106s2, or generally with the illumination region with the lowest absorption length or absorption coefficient.

[0035] Combining one or several of these configuration maxima allows for a planar radiation geometry, which allows for a very large distance between the source 102 and the detector 104 to obtain an almost parallel image of the internal battery cell structure 106b across the vehicle 106, while according to a further embodiment the longitudinal axis of the vehicle 106 can be scanned layer by layer in a distortion-free manner, as shown based on FIG. 3 .

[0036] FIG. 3 shows a lateral scan in image 3a1 and a longitudinal scan in image 3b1.

[0037] The basic inspection system for analyzing battery modules is defined by a particularly large distance between the source and the detector in order to keep the aperture angle as small as possible. As shown in the absorption profile, the gap can be seen across the entire vehicle cross section.

[0038] The radiation source, radiation detector, radiation geometry, and irradiated object are again designated by the reference numerals 102, 104, 106, 106b, and 100′. As can be seen, the distance 100d′ is selected to be very large compared to the object width 106br. As shown in FIG. 3b1, the detector 104 is a line detector arranged in the width direction 106br. To enable longitudinal scanning of the vehicle 106, i.e., the battery module 106b, the vehicle 106 moves in a forward direction 106v relative to the X-ray system, which includes at least the elements 102 and 104. It should be noted that, according to the embodiment, the battery module includes a plurality of battery cells arranged in a plane (across the vehicle), for example, in the longitudinal and transverse directions (perpendicular to the irradiation direction). For example, the battery cells are arranged parallel to the irradiation direction, essentially parallel to the irradiation direction (-5° to +5° or -2° to +2°). For this purpose, the radiation source 102 is oriented according to the embodiment. This allows determining a good scan of the gap (see minimum and maximum values ​​in Fig. 3b2) in the longitudinal direction. The same applies to the scan in the width direction as shown in the diagram in Fig. 3a2. Here, a sufficiently good scan results even at the edges of the geometry 100', without a reduction in the radiant energy due to gap absorption.

[0039] 3a2 and 3b2 plot the illumination intensity versus the scanning direction (the width direction 106br in FIG. 3a2 and the longitudinal or forward direction 106v in FIG. 3b2). Comparing the diagram in FIG. 3a2 with FIG. 1a2, it becomes clear that good scanning is also possible in the width direction 106br. The reason for this is that sufficient parallelism of the radiation source 102's rays is ensured transversely to the vehicle 106, so that there is no overlap of adjacent battery cells in the resulting image, and therefore no masking of the gaps between the cells. Therefore, all of these regions of the ray cone can be used for evaluation.

[0040] When large objects, such as vehicles, are scanned, large X-ray holes are used to accommodate large dimensions, particularly large distances 106d' between the source 102 and the object 106b or between 102 and 104. Furthermore, powerful X-ray sources 102 with sufficient power can be used. To enable a more compact design in further embodiments, several X-ray tubes can be used along the vehicle transverse axis 106br. In this case, the radiation source 102 includes several individual radiation sources. In other words, the X-ray system can include several X-ray sources 102a-102c. The X-ray sources 102a-102c are arranged across the width direction 106br. These X-ray sources scan an angular area of ​​approximately 10° of the vehicle 106 in portions, as described in the context of Figures 4a1 and 4b1.

[0041] According to one embodiment, the radiation fields 100a', 100b', and 100c' can extend within a depth plane (focal plane) of the battery module 106b. The focal plane is designated by reference numeral 100f. As can be seen, there is minimal overlap or direct contact of the cones 100a', 100b', and 100c' at the focal plane 100f. This allows for continued detection of the battery module 106b.

[0042] To detect the battery modules segment by segment, each with a sufficiently small aperture angle, several X-ray sources 102a, 102b, and 102c are positioned along the vehicle's transverse axis 100b'. The individual image fields are stitched together into a continuous overall image through precise localization of the battery module's installation height within the vehicle. Each source-detector pair uses only the central region of the radiation cone, as seen in the absorption profile. The projected area of ​​the ray cone is collimated to minimize overlap between adjacent image regions. To optimize its effectiveness for different battery module installation heights, the detection system can be adjusted to accommodate different vehicle heights. Therefore, simple conversion between sedans and SUVs is possible.

[0043] The resulting X-ray signal is shown in the diagram of FIG. 4a2, again plotted against the width direction 106br.

[0044] According to a further embodiment, the radiation fields 100a"-100e" overlap over a large area. To this end, the radiation sources 102a"-102e" are arranged close to each other along the width direction 106br.

[0045] An arrangement of several X-ray sources 102a", 102b", 102c", 102d", and 102e" along the transverse axis of the vehicle for segment-by-segment detection of modules, where the X-ray sources 102a", 102b", 102c", 102d", and 102e" each comprise overlapping fields of view and are connected in sequence to obtain images with two angle settings in a single scan. Since the switch-on sequence is very short compared to the scanning progress, the image field remains almost constant and structures are detected from two field angles. This imaging mode allows masking of overlapping structures along the irradiation path, such as steering columns, seat linkages, or the center console. Here, the focal plane is also adapted to the vehicle type.

[0046] Here, according to an embodiment, X-ray tubes 102a"-102e" can be operated alternately, thereby allowing imaging of the same structure from different angular ranges. This approach minimizes spurious effects from overlapping structures, such as seat linkages or steering columns in vehicle 106.

[0047] According to the embodiment, in the embodiment of FIG. 4a1, the distance between the plane in which the X-ray sources 102a, 102b, and 102c are located and the object 106 is reduced by approximately a factor of three. In this way, 5x imaging can be reduced to 2x imaging. Further reduction is basically possible using several tubes, such as FIG. 4b1, by increasing the density of the X-ray tubes 102a"-102e" to further reduce the distance and use the above-mentioned effect of minimizing spurious effects due to overlapping structures. The resulting overlap signal is shown in FIG. 4b2, and processing is explained in the context of FIG. 6.

[0048] It should be noted that, according to an embodiment, the beam width of the geometries 100, 100a', 100b', 100c', 100a''-100e'' is limited by one collimator 103 for each of the X-ray sources 102a-102c and 102a''-102e'', respectively.

[0049] Note that in the embodiments of Figures 4a1 and 4b1, the focal point is always on the image of the object 106 or 106b in the lateral direction, i.e., along the width 106br. Overlap allows for a more compact design of the plant distance, while increasing the amount of data available for compensation. With reference to Figures 5a-5c, we explain how the information content can also be increased in the longitudinal or forward direction 106v. By using several consecutively arranged detectors / line detectors or by using a planar detector 104' (see Figure 5a), the conical beam of the radiation source 102 can be captured simultaneously at several positions along the forward direction 106 to obtain additional information, which allows, among other things, digital tomography to evaluate depth information. The information generated by tomography can be used, for example, to optimize the photographs generated by the X-ray system of Figures 2, 3, or 4. Here, tomography generates a measure of the overlapping structure sA, which can be subtracted from the desired but artifactual data set kU (see the diagram in Figure 5b). This allows the calculation of a compensated absorption process with reduced overlap, which is also shown in Figure 5c by reference kD.

[0050] This allows, for example, the use of several line or area detectors along the vehicle longitudinal axis to obtain data for compensating for overlapping structures or for depth-resolved displays.

[0051] Possible processes will now be described with reference to FIG.

[0052] FIG. 6a shows calculator 50, FIG. 6b shows calculator 50', and FIG. 6c shows calculator 50". Calculators 50, 50', and 50" are all configured to determine a compensated absorption process with reduced overlap, each with a different calculation method. In the following, three different calculation methods are discussed, and according to further embodiments, a combination of two or more calculation methods is possible.

[0053] 6a shows a calculator 50 configured to determine a compensated absorption process kA based on the orthogonal absorption process oA by taking into account an oblique absorption process sA inclined with respect to the gap of the battery cell detected by another detector area along the vehicle longitudinal axis. This means that, according to an embodiment, further pictures are taken during oblique illumination of the object, on the basis of which the pictures during orthogonal illumination are compensated.

[0054] Calculator 50' (FIG. 6b) also calculates a compensated, overlap-reduced absorption process KA, but based on the orthogonal absorption process OA as well as model data MD generated from a reference scan of an equivalent vehicle.

[0055] The calculator 50" (Figure 6c) calculates the compensated absorption process KA based on the orthogonal absorption process OA and the AI ​​model KM. The AI ​​model KM is a model and network generated by machine learning, deep learning, etc., based on a large amount of annotated data samples.

[0056] The embodiments of Figures 6a, 6b and 6c show that in addition to image acquisition, which is performed by advancing the vehicle across the detection unit or by advancing the detection unit (source and detector) layer by layer along the vehicle, image evaluation plays an important role.

[0057] The resulting X-ray absorption data is processed in a computing unit and automatically evaluated. Here, overlaps due to surrounding structures are subtracted from the image by an image processing operator (KA) to enable uniform imaging of the cell structure. Here, in case of application c), overlapping image areas are combined so that the areas least shadowed by external structures are added to the image.

[0058] According to an embodiment, the computer is adapted to the known structure of the battery module. By applying machine learning methods as well as classical image processing methods, the morphological features of the structure under inspection are automatically defined and evaluated. In particular, for prismatic cells, deviations from a rectangular cell shape are detected by measuring the longitudinal gaps within the cells. For cylindrical cells, the circularity of each cell and the distance to adjacent cells are determined, which can indicate deformation of the module. By using a sufficiently high irradiation energy, the degree of electrolyte filling in the cells can be determined. In the event of a leak, a significant decrease in absorption within each cell can be expected.

[0059] According to embodiments, the method can determine deviations in the overall shape of the module, for example, inspecting the shape deviations of the battery frame so that the effects of accident damage can be determined, and can also detect foreign particles in the cells and modules.

[0060] Therefore, the evaluation method can be generalized as follows.

[0061] for example by an X-ray device according to FIGS. 2, 3a1, 3b1 or 4a1 and 4b1, or possibly by carrying out the embodiment of FIGS. 5a to 5c of an orthogonal scan, - Compensating for overlaps based on the data of the scan obtained by taking into account reference data, data determined based on artificial intelligence, or photographs taken based on oblique illumination (oblique to the width of the object or oblique to the length of the object).

[0062] According to an embodiment, for example, overlapping objects can be detected based on orthogonal and oblique photographs, and the overlapping objects can be removed from the orthogonal photographs.

[0063] With reference to FIG. 7, overlapping objects will be described.

[0064] Figure 7a is an illuminated photograph showing multiple circular battery cells 72 and overlapping objects designated by reference numerals 70a, 70b, 70c, 70d, and 70e. Examples of overlapping objects are, for example, rear seat 70d, center console 70a, seat linkage 70b, or B-pillar 70c. The measurements shown in Figure 7a can also serve as comparative measurements from oblique illumination and can be considered with the actual photograph of the axial position in Figure 7b, which shows battery cells 72 with good resolution.

[0065] Figure 7c shows three potentially detectable errors at reference numerals 74a, 74b, and 74c. Error 74a indicates a shape shift resulting from cell expansion. Error 74b indicates density fluctuations due to electrolyte leakage. Error 74c indicates a contact error / disconnection.

[0066] Figure 7d shows further errors 74d, 74e, and 74f. Error 74d is a detection of cell compression / displacement, while error 74e is caused by density fluctuations due to electrolyte leakage. Error 74f is a contact error / disconnection.

[0067] It should be noted here that, according to a preferred embodiment, irradiation of a battery module is performed. A battery module typically includes cells. According to a preferred embodiment, these cells are arranged along the width direction and / or along the forward direction. This results in irradiation of the cells in such a way that the gaps between the cells are irradiated longitudinally, i.e., are arranged essentially along the direction or radiation direction of the X-ray radiation. According to an embodiment, the irradiation object is arranged so that the boundaries between the cells of the irradiation object extend along the irradiation direction.

[0068] A preferred application of the above concept is the analysis of batteries / high-voltage batteries of electric or hybrid vehicles, for example, after an accident, when selling a vehicle, to clarify the vehicle history, or for vehicle appraisal. These applications are particularly interesting for the used car market. However, the inspection can also be performed before the vehicle is transported on a cargo ship (e.g., at a port) or before it leaves the manufacturer in the factory (digital vehicle file for comparison during the lifecycle). An advantage is the fast inspection method with a detection period of about 5 minutes. The method can be used for all common battery module designs, for example, prismatic or annular. As explained above, analysis automation can be performed to assist the inspector by respective algorithms or AI.

[0069] According to an embodiment, the object to be irradiated can be arranged in a container or a flame-retardant container. It is also possible for a storage module or an entire vehicle to be arranged in a flame-retardant container. These flame-retardant containers can be, for example, part of the irradiation device. Alternatively, the flame-retardant container can form the object to be irradiated, and the object to be inspected can be arranged therein.

[0070] While some aspects have been described in the context of an apparatus, it is clear that these aspects also represent descriptions of corresponding methods, whereby blocks or devices of the apparatus also correspond to respective method steps or features of method steps. Similarly, aspects described in the context of a method step also represent descriptions of corresponding blocks or details or features of the corresponding apparatus. Some or all of the method steps may be performed by (or using) a hardware apparatus, such as a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, some or some of the most important method steps may be performed by such an apparatus.

[0071] Depending on specific implementation requirements, embodiments of the present invention can be implemented in hardware or software. Implementation can be performed using a digital storage medium, such as a floppy disk, DVD, Blu-ray disk, CD, ROM, PROM, EPROM, EEPROM or flash memory, hard drive or other magnetic or optical memory, on which electronically readable control signals are stored, which cooperates or can cooperate with a programmable computer system to perform the respective methods. Thus, the digital storage medium may be computer-readable.

[0072] Some embodiments according to the present invention include a data carrier having electronically readable control signals that can cooperate with a programmable computer system to perform one of the methods described herein.

[0073] In general, embodiments of the present invention may be implemented as a computer program product having program code that operates to perform one of the methods when the computer program product is run on a computer.

[0074] The program code may for example be stored on a machine readable carrier.

[0075] Other embodiments comprise the computer program for performing one of the methods described herein, stored on a machine readable carrier. In other words, an embodiment of the inventive method is, therefore, a computer program having a program code for performing one of the methods described herein, when the computer program runs on a computer.

[0076] A further embodiment of the inventive method is, therefore, a data carrier (or digital storage medium, or computer readable medium) comprising, recorded thereon, the computer program for performing one of the methods described herein.

[0077] A further embodiment of the inventive method is, therefore, a data stream or a sequence of signals representing the computer program for performing one of the methods described herein, The data stream or the sequence of signals can for example be adapted to be transferred via a data communication connection, for example via the Internet.

[0078] A further embodiment comprises a processing means, for example a computer, or a programmable logic device, configured to or adapted to perform one of the methods described herein.

[0079] A further embodiment comprises a computer having installed thereon the computer program for performing one of the methods described herein.

[0080] Further embodiments according to the present invention include an apparatus or system configured to transmit a computer program for performing at least one of the methods described herein to a receiver. The transmission may be, for example, electronic or optical. The receiver may be, for example, a computer, a mobile device, a memory device, or a similar device. The apparatus or system may, for example, include a file server for transmitting the computer program to the receiver.

[0081] In some embodiments, a programmable logic device (e.g., a field programmable gate array, FPGA) can be used to perform some or all of the functions of the methods described herein. In some embodiments, a field programmable gate array can cooperate with a microprocessor to perform one of the methods described herein. In general, the methods are preferably performed by any hardware apparatus. This can be universally applicable hardware, such as a computer processor (CPU), or method-specific hardware, such as an ASIC.

[0082] The above-described embodiments are merely illustrative of the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be apparent to those skilled in the art. It is therefore intended that the present invention be limited only by the scope of the appended claims, and not by the specific details presented by way of description and explanation of the embodiments herein. [Explanation of symbols]

[0083] 102 Radiation source 104 X-ray detectors (1D or 2D pixelated) 100 Ray cones with characteristic aperture angles 106 Vehicle with battery module in underbody area 106v Advancement of vehicle or scanner for layer-by-layer detection along vehicle longitudinal axis 100 Ray cones with characteristic aperture angles for segment-by-segment detection 103 Beam collimation for masking adjacent detectors 100f Focal plane of the ray cone that can incorporate battery modules continuously 100b”, 100c”, 100d” Additional ray cones for sequential detection from different viewing angles 10b Absorption process of a vehicle passing through the vehicle, where the intensity peak indicates that there is sufficient gap between the cells. 11d / OA Absorption process detected along the longitudinal axis of the vehicle, perpendicular to the gap of the battery cells sA absorption process inclined to the gap of the battery cell, detected by another detector area along the longitudinal axis of the vehicle kA Compensated absorption process with reduced overlap MD Model data generated from a reference scan of a comparable vehicle KM Models and networks generated by machine learning, deep learning, etc., based on large samples of annotated data

Claims

1. at least one radiation source (102); at least one radiation detector (104); 1. An X-ray system for non-destructive material testing of an object to be irradiated (106), in particular a battery module (106) of a vehicle or a battery module (106b) installed in a vehicle, comprising: the irradiation object (106) is disposed between the at least one radiation source (102) and the at least one radiation detector (104), the at least one radiation source (102) is disposed at a distance from the irradiation object (106) at least two times, or at least three times, or at least five times the width (106b) of the scanning area such that a fan-shaped radiation geometry is formed at least in the lateral direction, the scanning area being the width (106b) of the object (106), the scanning area corresponding to the width (106b) of the object (106) in the lateral direction, or the scanning area corresponding to a part of the width (106b) of the object (106); the opening angle (100α) of the radiation geometry is less than 10°; X-ray system.

2. the distance between the at least one radiation source (102) and the irradiation object (106) is at least 3 m, or at least 5 m, or at least 10 m, or at least 11 m (so that a 2 m wide object (106) can be scanned with a 10° radiation geometry); and / or the irradiated object includes a plurality of battery modules arranged along the lateral direction, The x-ray system of claim 1 .

3. the object (106) is moved in a forward direction for scanning, and / or is moved continuously in a forward direction perpendicular to the lateral direction, and / or The irradiation object includes a plurality of cells arranged along the forward direction.

3. An X-ray system according to claim 1 or 2.

4. 4. The X-ray system according to claim 1, wherein the at least one radiation source is formed by several individual radiation sources, or the at least one radiation source is formed by several individual radiation sources arranged laterally with respect to the object.

5. The X-ray system of claim 4 , wherein the radiation geometry of the individual radiation sources comprises overlapping radiation fields and / or overlapping radiation fields at the focal plane.

6. The x-ray system of claim 4 , wherein the radiation geometries of the individual radiation sources include large area overlapping radiation geometries.

7. 7. The x-ray system of claim 6, wherein the individual radiation sources operate in an alternating fashion.

8. the X-ray detector extends across the entire width (106b) of the object (106); and / or the X-ray detector is formed by a line detector or an area detector extending across the entire width (106b) of the object (106); An X-ray detector according to any one of claims 1 to 7.

9. 9. The X-ray system according to any one of claims 1 to 8, wherein the X-ray system comprises several radiation detectors (104) or radiation sources (102) arranged along a forward direction.

10. 10. The X-ray system of claim 1, wherein the radiation source (102) or the individual radiation sources are collimated or each comprise a collimator (103) that defines the radiation geometry of less than 10°.

11. 11. The X-ray system according to claim 1, wherein the distance between the at least one X-ray source and the object (106) and / or the at least one radiation detector (104) can be adjusted.

12. 12. The X-ray system of claim 1, wherein the at least one X-ray source provides an energy of up to 450 KeV or up to 360 KeV, and / or the energy is selected to be so low that irradiation of an intact object (106) or an intact battery cell does not occur.

13. 13. The X-ray system according to claim 1, further comprising an evaluation device configured to evaluate several pictures across several positions and / or several pictures across several emitter / detector combinations.

14. 14. The X-ray system of claim 13, wherein the evaluation device is configured to detect overlapping objects in the individual photographs based on the several photographs and / or to compensate for the images of the overlapping objects in the individual photographs.

15. 15. The X-ray system according to claim 1, further comprising an evaluation device configured to detect overlapping objects based on reference photographs of the irradiated object (106) and / or to compensate for the images of the overlapping objects in individual photographs.

16. 16. An X-ray system according to claim 14 or 15, wherein the evaluation device is configured to select only those photographs with little or no overlap.

17. 17. The X-ray system according to any one of claims 1 to 16, further comprising an evaluation device based on an AI algorithm and / or configured to detect morphological features.

18. 18. The X-ray system according to claim 17, wherein the evaluation device is configured to detect deviations of the object (106) or parts of the object (106) from a normal morphology (deformation of cylindrical cells, deformation of prismatic cells).

19. 19. The X-ray system according to claim 17 or 18, wherein the evaluation device is configured to determine a distance between two parts of the object (106), in particular between two battery cells.

20. the object is a battery module comprising several battery cells arranged in parallel, in particular cylindrical or prismatic battery cells, and the irradiation direction of the radiation source (102) is oriented parallel or essentially parallel to the battery cells; and / or The object is a battery module including a plurality of battery cells arranged in a planar and dispersed manner.

20. An X-ray system according to any one of claims 1 to 19.

21. the X-ray system comprises a container or a fire-resistant container in which the object to be irradiated is placed; and / or 21. An X-ray system according to any one of the preceding claims, wherein the irradiation object comprises a container or a fire-retardant container in which an inspection object, in particular a vehicle or a battery module of a vehicle, is placed.

22. 22. The X-ray system of claim 1, wherein the opening angle of the radiation geometry is less than 10[deg.] in both the lateral and forward directions.

23. irradiating an object (106) at a distance from the radiation source (102) that is at least two, at least three, or at least five times the width (106b) of the scanning area from the object (106) so as to form a fan-shaped radiation geometry in at least a lateral direction, thereby obtaining a first image; The scanning area corresponds to the lateral width (106b) of the object (106), or the scanning area corresponds to a portion of the lateral width (106b) of the object (106). A method for determining a radiograph by using an X-ray system according to any one of claims 1 to 22.

24. 24. The method of claim 23, wherein the method includes repeating the illuminating step for a further photograph, or the method includes repeating the illuminating step for a further photograph and compensating for overlapping objects based on detecting the overlapping objects in the photograph with the aid of the further photograph.

25. 25. The method of claim 23 or 24, wherein the further photograph is taken with oblique illumination of the object and the photograph is taken with orthogonal illumination.

26. 26. The method of any one of claims 23, 24 or 25, wherein the method comprises the step of arranging the radiation object such that cells of the radiation object are arranged along a lateral direction and / or along a forward direction.

27. A computer program for controlling an X-ray system according to any one of claims 1 to 21 in carrying out a method according to claim 23, 24 or 25.

Images