WO2022207599A1

WO2022207599A1 - Inspection system and method for inspecting at least one test object

Info

Publication number: WO2022207599A1
Application number: PCT/EP2022/058201
Authority: WO
Inventors: Marco Erler; Martin Krenkel
Original assignee: Carl Zeiss Industrielle Messtechnik Gmbh
Priority date: 2021-03-29
Filing date: 2022-03-29
Publication date: 2022-10-06
Also published as: DE102021203119A1

Abstract

The invention relates to an inspection system (1) for inspecting at least one test object (10-x), comprising: at least one reflection X-ray tube (2-x) which is designed to emit X-ray radiation (4), at least one X-ray detector (6) which is designed to capture a radiography image (7), wherein the at least one reflection X-ray tube (2-x) and the at least one X-ray detector (6) are designed and configured such that only a high resolution section (4-x) of the X-ray radiation (4), which is emitted by the at least one reflection X-ray tube (2-x), is used for radiographing at least one section (18-x) of the at least one test object. The invention also relates to a method for inspecting at least one test object (10-x).

Description

Inspection system and method for inspecting at least one test object

The invention relates to an inspection system and a method for inspecting at least one test object.

In recent years, the demand for batteries such as lithium ion batteries has increased due to the development of mobile devices such as cellular phones and the practical use of electric vehicles. This increases the relevance of battery inspection for delivering safe and reliable batteries that will not cause short circuits or fires.

KR 2021 00092 71 A describes an X-ray inspection device. The X-ray inspection apparatus includes a main body, and an object transfer unit for transferring an object to be inspected to a non-inspection position and an inspection position disposed above the main body. Further, the X-ray inspection apparatus includes first and second X-ray inspection units for X-ray inspection, and a main shielding room surrounding the transmission unit and the first and second X-ray inspection units.

The invention is based on the technical problem of creating an improved inspection system and an improved inspection method for inspecting at least one test object, in particular at least one battery.

According to the invention, the technical problem is solved by an inspection system having the features of claim 1 and a method having the features of claim 6. Advantageous embodiments of the invention result from the dependent claims.

One of the key ideas of the invention is to use only a high-resolution portion of the X-rays emitted by at least one reflection X-ray tube. At least one section of at least one test object, in particular a battery, is radiographed (transmitted) in that this high-resolution section of the X-ray radiation is directed onto this at least one section and a Radiographic image (radiographic image) is detected by at least one X-ray detector.

In particular, an inspection system for inspecting at least one test object is proposed, comprising at least one reflection X-ray tube that is designed to emit X-ray radiation, at least one X-ray detector that is designed to capture a radiographic image, wherein the at least one reflection X-ray tube and the at least one X-ray detector are designed and arranged such that only a high-resolution portion of the X-ray radiation emitted by the at least one reflection X-ray tube is used for radiographing at least a portion of the at least one test object.

Furthermore, in particular a method for inspecting at least one test object is provided, comprising: radiographing at least a section of the at least one test object by using a design and arrangement of at least one reflection x-ray tube and at least one x-ray detector, in which only a high-resolution section of the x-ray radiation emitted by the at least one reflection x-ray tube is used, and acquiring a radiographic image of the at least one portion of the at least one test object with the at least one x-ray detector.

The inspection system and the method allow at least one test object, in particular at least one battery, to be radiographed with high-resolution X-ray radiation, which allows a high-resolution X-ray radiographic image to be obtained from the at least one section of the at least one test object.

A reflective X-ray tube, which may also be referred to as a reflective X-ray source, is specifically an X-ray tube in which the emitted X-rays are observed at an angle very different from the angle at which the electrons used to generate the X-rays hit the target meeting. With respect to a surface of the target, the viewing angle is usually very shallow compared to the angle at which the electrons hit the target. When an observation angle changes, the size of a focal spot to be observed may also change. In a particular direction, the spot size does not change because the change in viewing angle does not change the area of the projected electrons changes (for a planar target this corresponds to a change in the azimuth angle). In a direction perpendicular to that direction (for a planar target, ie the elevation angle), the spot size can be changed by changing the viewing angle. Normally, an arrangement between a reflectance x-ray tube and an x-ray detector is chosen that gives a uniform spot size over the entire detector area, so that the resulting resolution is isotropic in all directions. However, if the inspection task is clearly defined in terms of the spatial dimensions of the test object, the change in the focal spot size with the observation angle can be used. The invention uses the fact that the observed focal spot size and with it the resulting resolution can be changed with the observation angle. In particular, the invention uses only the high-resolution portion of the X-rays emitted by the reflective X-ray tube, ie the (elevation) angles from which a smaller focal spot size is observed, while the lower-resolution portion of the X-rays, ie the (elevation) Angles from which a larger focal spot size is observed is discarded. In particular, the inspection system and/or the at least one reflectance x-ray tube may include a collimator and/or a beam stop used to block the lower-resolution portion of the x-ray radiation of the at least one reflectance x-ray tube.

Reflectance x-ray tubes may be grouped into groups of reflective x-ray tubes, one group being associated with a single x-ray detector.

In particular, the high-resolution section can be selected according to predetermined parameters, such as a predetermined upper limit for the focal spot size observable from the respective angles (for a planar target in particular the elevation angles).

The at least one reflection X-ray tube is in particular a mini-focus (~mm) and/or a micro-focus (~10-100 μm) and/or a high-performance reflection X-ray tube. Examples of reflection x-ray tubes to be used are: Comet MXR160HP11, Comet MXR225HP11, Varex HPX-160-11 and/or Varex HPX-225-11. The at least one x-ray detector is in particular a flat panel detector. However, in principle, a line detector can also be used. Examples of X-ray detectors to be used are the following: Varex 4343 (size: 430 x 430 mm ² ,

3072 x 3072 px), Vieworks Vixix-4343 (size: 430 x 430 mm ² , 3072 x 3072 px), Varex 2530 (size: 250 x 300 mm ² , 1752 x 2176 px) and/or Varex XRD3025 (size:

250 x 300 mm ² , 3008 x 2512px).

The captured radiographic image can be analyzed by comparing it to a reference radiographic image and/or by taking measurements of features within the captured radiographic image. In particular, the acquired radiographic image can be analyzed using machine learning and/or artificial intelligence and/or computer vision methods. Based on the analysis results, an inspection result can be created and made available. The inspection result can be provided as an analogue or digital control signal.

The inspection system can comprise a control unit, which is used in particular to control the at least one reflection x-ray tube and the at least one x-ray detector and to provide and/or analyze the acquired radiographic image(s). In particular, the control unit can comprise at least one processing unit, for example a microprocessor or microcontroller, and at least one memory for storing instructions and/or data.

The inspection system is or can be part of an automatic inspection system, in particular during the in-line inspection during or after the production of the at least one test object, in particular the at least one battery.

In one embodiment, the inspection system comprises at least two reflection x-ray tubes, the at least two reflection x-ray tubes and the at least one x-ray detector being designed and arranged in such a way that the high-resolution sections of the x-ray radiation emitted by the at least two reflection x-ray tubes are imaged on separate sections of the at least one x-ray detector will. This allows the number of components used to be reduced because at least two reflection X-ray tubes can be used with one X-ray detector. This is made possible in particular by only the high-resolution portion of the X-ray radiation from the Reflection X-ray tubes is used, which occupies a smaller solid angle than when all X-ray radiation is used. In principle it is also possible to use more than two reflection X-ray tubes with a single X-ray detector, for example three or four reflection X-ray tubes. In particular, a radiographic image is captured as a single exposure for the X-ray radiation coming from each of the at least two reflectance X-ray tubes. In other words: the radiographic image of the at least one test object is not captured sequentially using the high-resolution sections of the X-ray radiation of the at least two X-ray tubes, but simultaneously.

The at least two reflection X-ray tubes can be of the same type or of different types (e.g. mini-focus, micro-focus, etc.) according to the inspection task.

In an equivalent embodiment of the method, radiography is carried out by using at least two reflection X-ray tubes and by using a design and arrangement of the at least two reflection X-ray tubes and the at least one X-ray detector in which the high-resolution portions of the X-rays emitted by the at least two reflection X-ray tubes are emitted , are imaged on separate sections of the at least one X-ray detector.

In particular, the at least two reflection x-ray tubes and the at least one x-ray detector can be provided as a compact module that is easy to assemble. An inspection system can easily be scaled by adding such modules of the same or different types.

In one embodiment, the inspection system comprises at least two reflection X-ray tubes, the at least two reflection X-ray tubes and the at least one X-ray detector being designed and arranged such that the high-resolution sections of the X-ray radiation emitted by at least some of the at least two reflection X-ray tubes are on different sides of the at least one X-ray detector are mapped. This makes it possible to use the at least one x-ray detector from both sides, in particular a front side and a back side, of a flat panel detector or a line detector. This Embodiment is particularly useful when the inspection system is used as an in-line inspection system. Because in-line inspection is usually associated with a time constraint for transporting test objects to and from the inspection system, this embodiment can be used to utilize the idle time of the detector during transport of a test object on one side of the detector by capturing a radiographic image of a another test object that is on the other side of the detector is detected and vice versa. In particular, a two-line inspection system with two transport feeds can be provided by using the X-ray detector on both sides. Examples of X-ray detectors that can be used by both sides are: Varex 2530HE and Varex 4343HE.

In an equivalent embodiment of the method, radiography is carried out by using at least two reflection x-ray tubes and by using a design and arrangement of the at least two reflection x-ray tubes and the at least one x-ray detector in which the high-resolution portions of the x-ray radiation emitted by at least some of the at least two reflection x-ray tubes is emitted, are imaged on different sides of the at least one X-ray detector.

In one embodiment, the inspection system includes at least one x-ray attenuating element to attenuate in a predetermined manner a portion of at least one of the high-resolution portions of x-ray radiation emitted from the at least one or at least two reflectance x-ray tubes. In this way, the intensity of the X-ray radiation can be adjusted. In particular, the X-ray attenuating member allows the X-ray intensity to be reduced within a portion of higher X-ray intensity and to be adjusted to an X-ray intensity in a portion of lower X-ray intensity. This is particularly useful to equalize x-ray intensity and/or to attenuate x-ray intensity locally (e.g. depending on position) to a predetermined level. An illustrative example is given below: The distance between the at least one reflectance x-ray tube and the at least one x-ray detector is normally adjusted to a lower intensity corresponding to a smaller focal spot size while the at least one test object is in the beam path. As the (elevation) angle changes, the focal spot size increases, such that portions of the at least one test object corresponding to the changed angle receive a greater x-ray intensity (due to the larger focal spot size that can be seen from the changed angle). If these sections were imaged onto the at least one x-ray detector, the detector would become saturated. To avoid this, the at least one beam attenuating element is used to reduce the intensity for that section. The at least one x-ray attenuator is arranged in particular between the at least one reflection x-ray tube and the at least one test object, more precisely, directly in front of the at least one reflection x-ray tube.

The at least one beam attenuating element can be, for example, a wedge of X-ray absorbing material (e.g. Al, Cu, ceramic, etc.). The wedge provides a position-dependent attenuation, which can be particularly useful for setting an (elevation) angle-dependent intensity of the X-ray radiation. Alternatively, the at least one beam attenuating element may consist of one or more layers of X-ray absorbing material, particularly of increasing thickness to allow easy adjustment of the attenuation magnitude.

In an equivalent embodiment of the method, a portion of at least one of the high-resolution portions of the X-ray radiation emitted from the at least one or at least two reflection X-ray tubes is attenuated in a predetermined manner by using at least one X-ray attenuating element.

In one embodiment, the inspection system comprises at least one beam catcher, wherein the at least one beam catcher is arranged between the at least one test object and the at least one X-ray detector, and wherein the at least one beam catcher comprises at least one opening which is aligned with the at least one section of the at least one radiographing test object is formed and arranged. This allows secondary radiation such as stray radiation to be reduced and a signal-to-noise ratio to be increased.

In an equivalent embodiment of the method, at least one beam catcher is used, the at least one beam catcher being arranged between the at least one test object and the at least one X-ray detector, and the at least one beam catcher comprising at least one opening which is in accordance is formed and arranged with the at least one portion of the at least one test object to be radiographed.

In one embodiment, the at least two reflection X-ray tubes and the at least one X-ray detector are designed and arranged in such a way that the high-resolution sections of the X-rays emitted by the at least two reflection X-ray tubes can run simultaneously from different directions through at least partially overlapping sections of the at least one test object. This embodiment allows additional depth information to be obtained from the at least one test object. In this way, in principle, a tomographic image/tomosynthesis of the at least one test object can be obtained by capturing a radiographic image as a single image.

In an equivalent embodiment of the method, at least one section of the at least one test object is radiographed simultaneously from different directions.

In one embodiment, the inspection system comprises at least one positioning means which is designed to transport and/or arrange the at least one test object to/in a predetermined position and/or alignment between the at least one or at least two reflection x-ray tubes and the at least one x-ray detector for radiographing . The positioning means may comprise a conveyor belt that transports the at least one test object to and from a predetermined measurement position between the at least one or at least two reflection x-ray tubes and the at least one x-ray detector. At the positions where the at least one test object is to be radiographed, this conveyor belt can have openings in order to avoid interference. Furthermore, the positioning means can comprise a carrier and/or a holder in order to hold the at least one test object in a predetermined position and/or orientation during the acquisition of the radiography. The positioning means can also include actuators and/or sensors for manipulation and control.

In one embodiment, the inspection system includes at least one actuator to position and/or align the at least one or at least two reflectance x-ray tubes and/or the at least one x-ray detector in a predetermined position and/or orientation. This allows the at least one or to position and/or align at least two reflection x-ray tubes and/or the at least one x-ray detector in accordance with special inspection tasks. In addition, this allows the inspection system to be reconfigured for different types of test objects, in particular different battery types (e.g. different sizes, shapes, etc.). A control unit of the inspection system may be provided to control the at least one actuator according to predetermined parameters corresponding to a specific configuration in which the at least one test object is to be inspected.

In a specific embodiment of the method, the at least one test object is a battery. In particular, the battery is a prismatic battery.

In a further developed embodiment of the method, at least one layer sequence of the at least one battery is radiographed. In particular, the layer sequence comprises alternating layers of an anode material, an insulating material and a cathode material. Using the radiographic image obtained by the method described in this disclosure, the delamination can be inspected and analyzed. The inspection and/or analysis may involve the use of artificial intelligence and/or machine learning and/or computer vision techniques.

In a special embodiment of the method, end sections of the at least one battery are radiographed. These end sections, for example corners of the at least one battery, are particularly suitable for inspecting the layer sequence and the layer separation.

In a further further developed embodiment of the method, at least some of the end sections of the at least one battery are arranged between the at least one reflection x-ray tube and the at least one x-ray detector in such a way that these end sections of the at least one battery are simultaneously exposed to the high-resolution section of the x-ray radiation emitted by the at least one reflection x-ray tube , to be radiographed.

In one embodiment of the method, the at least one test object or the battery is between the at least one during radiographing Reflection X-ray tube and the at least one X-ray detector arranged such that at least two sections of the at least one test object or the battery are radiographed from different sections of the high-resolution section of one of the at least one reflection X-ray tube and are imaged simultaneously on predetermined positions on the at least one X-ray detector. For example, the predetermined positions may be as closely spaced as possible so that the portions being radiographed are radiographed as close together as possible on the X-ray detector. In this way, multiple sections of the at least one test object or the at least one battery can be radiographed by a single reflectance x-ray tube.

In a further developed embodiment of the method, the at least one test object or the battery is arranged such that an imaginary axis connecting the at least two sections to be radiographed is inclined with respect to a plane of the at least one X-ray detector and/or a conveyor belt. In particular, inclined in this context means that a vector defining the imaginary axis has a component that cannot be expressed by the vectors defining the planes. This allows the at least two sections to be placed close together in a radiographic image. This is particularly advantageous because several sections can be radiographed at the same time with the high-resolution section of the X-ray radiation.

In one embodiment of the inspection system, the at least one reflection x-ray tube is inclined with respect to a plane of the at least one x-ray detector such that an angle between a plane of a surface of a target of the at least one reflection x-ray tube and a plane of the at least one x-ray detector has a predetermined angle.

In an equivalent embodiment of the method, during radiographing, the at least one reflection X-ray tube is inclined with respect to a plane of the at least one X-ray detector, such that an angle between a plane of a surface of a target of the at least one reflection X-ray tube and a plane of the at least one X-ray detector is a predetermined angle having. In this way, the higher-resolution parts of the higher-resolution section of the X-ray radiation can in particular (several) sections of the at least one test object or the battery to be radiographed. In other words: due to the tilting, a larger (predetermined) portion of the high-resolution portion of the radiation from the at least one reflection x-ray tube can be imaged onto the same portion of the at least one x-ray detector. In particular, the predetermined angle is set according to the sections to be radiographed, a resolution of the higher resolution section of the X-ray radiation to be used to perform the radiographing of those sections, and the positions to which the sections are imaged on the at least one X-ray detector should be.

In a special embodiment of the method, the at least one test object or the battery is arranged between the at least one reflection x-ray tube and the at least one x-ray detector during radiographing in such a way that a section of the at least one test object or the battery that is covered by a higher-resolution part of the high-resolution section of the X-ray radiation of the at least one reflection X-ray tube is closer to the at least one reflection X-ray tube than the portion of the at least one test object or the battery that is radiographed by a lower-resolution portion of the high-resolution portion of the X-ray radiation of the at least one reflection X-ray tube. In this way, the resolution of the sections of the acquired radiographic image can effectively be the same. Because the geometric magnification is the ratio of the distance between the X-ray source and the test object to the distance between the X-ray source and the X-ray detector, sections of the test object that are at a different distance from the detector are imaged with a different resolution (sampling). If the portion of the at least one test object or the battery that is radiographed by a higher-resolution part of the high-resolution portion of the x-ray radiation of the at least one reflection x-ray tube is closer to the at least one reflection x-ray tube than the portion of the at least one test object or the battery that is from a If the lower-resolution portion of the high-resolution portion of the x-rays from the at least one reflectance x-ray tube is radiographed, the two effects can cancel each other out so that the effective resolution is essentially the same.

Additionally or alternatively, the different resolutions of different sections of the at least one test object, which result from the arrangement of the at least of a test object can also be taken into account during the analysis of the acquired radiographic image. The analysis then takes into account the position and/or orientation of the at least one test object between the respective reflection x-ray tube and the x-ray detector and the angles of x-ray emission resulting therefrom (ie the elevation angles with respect to a target surface).

The invention will be explained below in more detail based on preferred exemplary embodiments with reference to the drawings. In the drawings:

FIG. 1 shows a schematic representation of an embodiment of the inspection system for inspecting at least one test object; Figure 2 is a schematic representation of a reflection type x-ray tube to illustrate the invention; FIG. 3a shows a schematic representation of an embodiment of the inspection system for inspecting at least one test object; FIG. 3b shows a schematic diagram of the angular dependence of the emission intensity of the X-ray radiation in order to illustrate an application of the embodiment of FIG. 3a; FIG. 4 shows a schematic representation of an embodiment of the inspection system for inspecting batteries; FIG. 5 shows a schematic perspective representation of the embodiment of FIG. 4; Figure 6 shows a schematic representation of the origin of a

to illustrate material contrast in a radiographic image of a prismatic battery; FIG. 7 shows a schematic representation of another embodiment of the inspection system for inspecting at least one test object; FIG. 8 shows a schematic representation of another embodiment of the inspection system for inspecting at least one test object; FIG. 9a shows a schematic representation of another embodiment of the inspection system for inspecting extended batteries as test objects; FIG. 9b shows a schematic representation of another embodiment of the inspection system for inspecting small compact batteries as test objects; FIG. 10 shows a schematic representation of another embodiment of the inspection system; FIG. 11 shows a schematic representation of another embodiment of the inspection system.

FIG. 1 shows a schematic representation of an embodiment of the inspection system 1 for inspecting at least one test object 10-1, 10-2. The inspection system 1 comprises two reflection X-ray tubes 2-1, 2-2 and an X-ray detector 6, which is in particular of the flat panel type. Furthermore, the inspection system 1 can comprise a control unit 8 which is used to control the inspection system 1 . The inspection system 1 is designed in particular to carry out the method described in this disclosure.

The reflection x-ray tubes 2 - 1 , 2 - 2 are designed to emit x-ray radiation 4 . The X-ray detector 6 is designed to capture a radiographic image 7 of the radiographed test objects 10-1, 10-2. The two reflection x-ray tubes 2-1, 2-2 and the x-ray detector 6 are designed and arranged in such a way that only a high-resolution section 4-1, 4-2 of the x-ray radiation 4 emitted by the reflection x-ray tubes 2-1, 2-2 is used for radiographing at least a section of the test objects 10-1, 10-2. For this purpose, the inspection system 1 comprises the collimators 3-1, 3-2 (or beamstops) in front of (or in the Inside the) reflection x-ray tubes 2-1, 2-2, which block the lower-resolution sections 5- 1, 5-2 of the emitted x-ray radiation 4.

The inspection system 1 can further comprise a shield (not shown) designed to shield the X-rays 4 emitted by the reflection X-ray tubes 2-1, 2-2, so that the inspection system 1 can be integrated in-line in a production line.

The control unit 8 comprises a processing unit 8-1 and a memory 8-2. The processing unit 8 - 1 can be a microprocessor or a microcontroller which is designed to execute program code stored in the memory 8 - 2 in order to analyze the radiographic image 7 captured by the x-ray detector 6 . The analysis may include using artificial intelligence and/or machine learning methods. After the analysis, the control unit 8 can provide a control signal 9 comprising information relating to parameters of the test objects 10-1, 10-2, for example whether the test objects 10-1, 10-2 meet predetermined parameters or meet predetermined quality criteria.

A specific embodiment of the inspection system 1 is designed to inspect one or more batteries by radiographing and analyzing a sequence of layers within the batteries.

The inspection system 1 can include at least one positioning means (not shown), which is designed to position the test objects 10-1, 10-2 in a predetermined position and/or orientation between the reflection X-ray tubes 2-1, 2-2 and the X-ray detector 6 to be transported and/or arranged for radiography. The positioning means may comprise a conveyor belt (not shown).

Figure 2 shows a schematic representation of a reflection x-ray tube 2 to illustrate the invention. In the reflection x-ray tube 2, an electron beam 11 is focused onto a (tungsten) target 12, thereby defining a focal spot on the target 12. FIG. By interaction of the electrons of the electron beam 11 with the target 12, x-rays are emitted in all directions defined by the hemisphere above the target 12. The resolution that can be achieved in a radiograph where X-rays are emitted in a specific direction depends on the size of the focal spot seen from that specific direction. In particular, the resolution depends on the angle of view in the plane of the paper of the schematic representation, ie a plane defined by the direction of movement of the electrons in the electron beam 11, and the direction in which the target 12 is tilted with respect to the direction of movement of the electrons. In other words, if the target 12 is planar, the resolution varies with elevation angle while remaining constant with azimuth angle. The angle dependent resolution is illustrated for two examples: At a steeper angle 13, the focal spot size is larger than for shallower angles 14. In an illustrative extreme example, the focal spot size would approach zero if a viewing angle parallel to the surface of the target 12 is chosen. Exemplary values for the angle dependent resolution vary from less than 100 pm for shallow angles to about 250 pm for steeper angles (see the virtual detector plane shown on the right side of Figure 2).

The invention uses this effect and only uses the high-resolution section of the X-ray radiation 4, which corresponds to the rather shallow angles. In contrast, the lower-resolution portion is blocked by a collimator and/or a beam stop (not shown).

FIG. 3a shows a schematic representation of an embodiment of the inspection system 1 for inspecting at least one test object 10. In principle, the embodiment is similar to the embodiment shown in FIG. Similar reference marks indicate similar features and terms.

The embodiment shown in FIG. 3a comprises an X-ray damping element 15. The X-ray damping element 15 is arranged in particular between the reflection X-ray tube 2 and the test object 10, more precisely, in front of the reflection X-ray tube 2. The beam damping element 15 can, for example, be a wedge made of X-ray absorbing material (e.g e.g. Al, Cu, ceramics, etc.). The wedge provides position or angle dependent attenuation, which can be particularly useful for setting an angle dependent x-ray intensity. Alternatively, the beam attenuating element 15 may consist of one or more stacked layers of X-ray absorbing material, particularly with increasing thickness in the direction of increasing intensity. FIG. 3b shows a schematic diagram of the angle dependency of the emission intensity of the X-ray radiation of a reflection X-ray tube (MXR-225HP/11) in order to illustrate an application of the embodiment of FIG. 3a. The x-axis 30 represents angle in degrees and the y-axis 31 represents dose rate in pGy/s as a measure of x-ray intensity. For all x-ray energies shown, x-ray intensity shows a strong angle dependence. Using the X-ray attenuating element 15 (FIG. 3a), this intensity can be adjusted in a predetermined manner, so that several sections of a test object can be radiographed with a predetermined, in particular a similar, X-ray intensity.

FIG. 4 shows a schematic representation of an embodiment of the inspection system 1 for inspecting batteries 16-1, 16-2 as the test objects 10-1, 10-2. In principle, the embodiment is similar to the embodiment shown in FIG. Similar reference marks indicate similar features and terms. A three-dimensional perspective view of the in-line inspection system integrated into a production line is shown in FIG.

The inspection system 1 includes two reflection X-ray tubes 2-1, 2-2 and an X-ray detector 6. The reflection X-ray tubes 2-1, 2-2 and the X-ray detector 6 can be combined to form a module. The two reflection X-ray tubes 2-1, 2-2 and the X-ray detector 6 are fixedly mounted around a positioning means 17 (FIG. 5). The positioning means 17 comprises a conveyor belt 27, which introduces the batteries 16-1, 16-2 into the inspection system 1 from one side and transports the batteries 16-1, 16-2 away from the inspection system 1 after the inspection. The X-ray detector 6 is arranged under a lower side of the conveyor belt 27; the reflection X-ray tubes 2-1, 2-2 are arranged above the conveyor belt 18. FIG. The batteries 16-1, 16-2 are inserted, two at a time, into the beam paths of the high-resolution sections 4-1, 4-2 of the X-rays emitted from the two reflection X-ray tubes 2-1, 2-2.

The end portions 18-1, 18-2, 18-3, 18-4 of the batteries 16-1, 16-2 are placed between the reflection X-ray tubes 2-1, 2-2 and the X-ray detector 6 so that the end portions 18-1 , 18-2, 18-3, 18-4 of the batteries 16-1, 16-2 simultaneously from the high-resolution section 4-1, 4-2 of the X-rays emitted by the Reflection X-ray tubes 2-1, 2-2 emitted can be radiographed. In order to reduce the transmission length (see black arrows inside the battery 16-2 in FIG. 4) of the X-ray radiation in the area of the end sections 18-1, 18-2, 18-3, 18-4, the end sections 18-1, 18-2, 18-3, 18-4 offset by an angle from a direction perpendicular to a plane of the X-ray detector 6. In order to further increase an offset angle, the reflection X-ray tubes 2-1, 2-2 (and with them the direction in which the respective X-rays are emitted) are additionally inclined by approximately another 10° with respect to the plane perpendicular to the X-ray detector 6 plane .

During radiographing, the batteries 16-1, 16-2 are arranged between the reflection X-ray tubes 2-1, 2-2 and the X-ray detector 6 so that a portion of the battery which is separated from a higher-resolution part of the high-resolution section 4-1, 4 -2 of the X-rays of the reflective X-ray tubes 2-1, 2-2 is radiographed closer to the respective reflective X-ray tube 2-1, 2-2 than the portion of the battery 16-1, 16-2 which is from a lower-resolution part of the high-resolution Section 4-1, 4-2 of the X-rays of the reflection X-ray tubes 2-1, 2-2 is radiographed. In the example shown, the resolution that can be achieved with the X-ray radiation 4-1, 4-2 decreases from the edges of the X-ray detector 6 to the middle of the detector. Therefore, also the end portions 18-2, 18-4, which are closer to the edges, are located closer to the detector 6, whereas the end portions 18-1, 18-3, which are closer to the center of the detector 6, are further away from it Detector 6 are arranged. Because the magnification varies in magnitude with the ratio of the distance between the reflective X-ray tube 2-1, 2-2 and the batteries 16-1, 16-2 and the distance between the reflective X-ray tube 2-1, 2-2 and the X-ray detector 6 the effective resolution that can be achieved for the end sections 18-1, 18-2, 18-3, 18-4 can be adjusted to be similar by using the end sections 18-1, 18-2, 18-3 , 18-4 of the batteries 16-1, 16-2 are so arranged.

The positioning means 17, in particular the conveyor belt 27, may comprise supports and/or holders (not shown) to hold the batteries 16-1, 16-2 in the appropriate position and/or orientation.

In order to avoid damage to the contact foils of the batteries 16-1, 16-2, the batteries 16-x can be arranged so that the batteries 16-3, 16-4 directly on the Batteries 16-1, 16-2 follow, offset in position in a direction parallel to the detector 6 plane. This offset can be repeated in pairs (as shown in Figure 5). Because the batteries 16-x can be placed very close to each other on the line in this way with respect to the direction of the X-rays 4-1, 4-2, it is possible with this embodiment of the inspection system 1 to take radiographs of end portions 18-x of to detect four batteries 16-x at the same time (see also the figure 7).

FIG. 6 shows a schematic illustration to illustrate the origin of a material contrast within a radiographic image of a (prismatic) battery 16. FIG. The battery 16 includes an arrangement of alternating layers of anode, insulating, and cathode material. A goal of battery inspection is to inspect a separation of these layers. When viewed from the direction shown in FIG. H. in cross-section of the layers, the layered arrangement of the (prismatic) battery 16 looks like a racetrack (only an end portion 18 is shown). When a single radiographic image of the end portion 18 is taken from a direction perpendicular to the viewing direction, only the portions of the layers that travel along the X-ray propagation directions 4-1 contribute to material contrast in a radiographic image taken with an X-ray detector 6 ( see the bold sections). The attenuation of the other sections balances out and does not add to the material contrast. The contribution to material contrast increases for the outer layers because the bend radius increases.

In this way, it is possible to inspect the layered arrangement of the (prismatic) battery 16 with a single radiograph. However, it is particularly important that the X-ray radiation 4-1 penetrates the layers in a direction which is substantially perpendicular to that axis 19 around which the layers of the end portion 18 are wrapped. In directions that are not essentially perpendicular to the axis 19, end sections of the slices are imaged onto different positions of the X-ray detector 6, resulting in a reduced material contrast. The resulting radiographic image would be less or not suitable for inspection.

FIG. 7 shows a schematic representation of another embodiment of the inspection system 1 for inspecting test objects 10-x. In principle, the embodiment is similar to the embodiment shown in FIG. Similar reference marks indicate similar features and terms. The test objects 10-x in In this example, the batteries 16-x are aligned so that the end portions 18-x (not all of which are marked with a reference sign) of two consecutive batteries 16-x on the line of one of the two reflection X-ray tubes 2-1, 2-2 are radiographed. The consecutive batteries 16-x are at different distances from the X-ray detector 6, so that the end sections 18-x of consecutive batteries 16-x can be radiographed together, but the sensitive contact foils of the consecutive batteries 16-x are not damaged.

In the embodiment shown, the inspection system 1 comprises a beam catcher 20, the beam catcher 20 being arranged between the test objects 10-x and the X-ray detector 6. The beam catcher 20 is arranged directly in front of the X-ray detector 6 . The beam stop 20 includes the openings 21-x formed and arranged in correspondence with portions of the inspection objects 10-x to be radiographed. In particular, the openings 21-x are in correspondence with positions of the end portions 18-x of the batteries 16-x. The beam catcher 20 can reduce the influence of scattered radiation in the signal from the X-ray detector 6 .

FIG. 8 shows a schematic representation of an embodiment of the inspection system 1 for inspecting at least one test object 10. In principle, the embodiment is similar to the embodiment shown in FIG. Similar reference marks indicate similar features and terms. The inspection system 1 comprises three reflection X-ray tubes 2-x and an X-ray detector 6. The three reflection X-ray tubes 2-x and the X-ray detector 6 are designed and arranged in such a way that the high-resolution portions 4-x of the X-rays emitted by the reflection X-ray tubes 2-x through at least partially overlapping sections 18 of the test object 10 (z. B. the battery 16) can run simultaneously from different directions. The radiographs from different directions are imaged on different sections of the X-ray detector 6 in a single radiograph image. Besides the high-resolution inspection of the inspection object 10, this embodiment can also provide additional information regarding the depth of features within the inspection object 10. Because the X-rays from different directions do not interact with each other and are imaged on different portions of the X-ray detector 6 capturing a single radiographic image, it is sufficient to obtain depth information within the radiographed portion 18 of the test object 10 to obtain. It is also possible to use fewer or more reflection X-ray tubes 2-x as long as the X-rays are detected from different directions by a different section of the X-ray detector 6, respectively.

Figures 9a and 9b show schematic representations of embodiments of the inspection system 1 for inspecting extended batteries 16-x (Figure 9a) and small compact batteries 16-x (Figure 9b) as the test objects 10-x.

In the embodiment shown in Figure 9a, the reflection X-ray tubes 2-1, 2-2 are arranged in a stacked arrangement with the sides on which the targets 12 are located facing each other. In this way, an upper portion of the X-ray detector 6 images the X-ray 4-1 coming out of the upper reflective X-ray tube 2-1, and a lower portion of the X-ray detector 6 images the X-ray 4-2 coming out of the lower reflective X-ray tube 2-2 comes. This arrangement is particularly suitable for inspecting extended 16-x batteries.

In the embodiment shown in Figure 9b, the reflection X-ray tubes 2-1, 2-2 are arranged in a side-by-side arrangement with the sides on which the targets 12 are located pointing in the same direction. In this way, a left portion of the X-ray detector 6 images the X-ray 4-1 coming out of the left reflective X-ray tube 2-1, and a right portion of the X-ray detector 6 images the X-ray 4-2 coming out of the right reflective X-ray tube 2-2 comes. This arrangement is particularly suitable for inspecting short 16-x compact batteries.

FIG. 10 shows a schematic representation of another embodiment of the inspection system 1. In principle, the embodiment is similar to the embodiment shown in FIG. 9a. Similar reference marks indicate similar features and terms. In the embodiment shown, the inspection system 1 comprises four reflection X-ray tubes 2-x and an X-ray detector 6, in particular an X-ray detector 6 of the flat panel type. The four reflection X-ray tubes 2-x and the X-ray detector 6 are constructed and arranged in such a way that the high-resolution sections 4-1, 4-2 of the X-ray radiation emitted by the two reflection X-ray tubes 2- 1, 2-2 is emitted, are imaged on a front side of the X-ray detector 6 and the high-resolution sections 4-3, 4-4 of the X-ray radiation emitted by the other two reflection X-ray tubes 2-3, 2-4 are imaged on a back side of the X-ray detector 6 are mapped. Similar to the embodiment shown in Figure 4, the reflection X-ray tubes 2-x are inclined with respect to the direction perpendicular to the X-ray detector 6 plane. The test objects 10-x, ie the batteries 16-x, are introduced into and removed from the inspection system 1 on both sides of the X-ray detector 6 by two positioning means 17, each of which comprises a conveyor belt 27. On each side of the detector 6, the batteries 16-x to be inspected are followed by a beam shield 22, the sequence being offset by one step on each side of the X-ray detector 6, so that the front of the X-ray detector 6 can receive X-ray radiation while X-rays are blocked on the back and vice versa. This embodiment allows the X-ray detector 6 to be used effectively because an idle time of the X-ray detector 6 can be minimized. In addition, the space required for the inspection system 1 can be reduced due to the use of an X-ray detector 6 from both sides.

FIG. 11 shows a schematic representation of another embodiment of the inspection system 1. The inspection system 1 is similar to the inspection system 1 shown in FIG. Similar reference marks indicate similar features and terms. The only difference is that the arrangement of the reflection X-ray tubes 2-x on each side of the X-ray detector 6 is similar to the embodiment shown in Figure 9a.

The embodiments shown in the figures are only exemplary embodiments. It is obvious to a person skilled in the art that the features of the embodiments can be combined in various ways. List of reference marks

1 inspection system

2, 2-x reflection X-ray tube

3, 3-x collimator 4 X-ray radiation

4-x high-resolution section

5-x lower resolution section 6 x-ray detector

7 radiographic image

8 control unit

8-1 processing unit

8-2 memory

10, 10-x test object

11 electron beam

12 targets

13 steeper angle

14 shallow angle

15 beam damping element

16, 16-x (prismatic) battery 17 positioning means

18, 18-x end section

19 axis

20 beam stop 21-x opening 22 beam shield 27 conveyor belt

30 x axis

31 y-axis

Claims

patent claims

1. Inspection system (1) for inspecting at least one test object (10-x), comprising the following: at least one reflection x-ray tube (2-x) which is designed to emit x-rays (4), at least one x-ray detector (6) which is designed to capture a radiographic image (7), the at least one reflection x-ray tube (2-x) and the at least one x-ray detector (6) being designed and arranged in such a way that only a high-resolution section (4-x) of the x-ray radiation (4th ) emitted by the at least one reflection x-ray tube (2-x) is used for radiographing at least a portion (18-x) of the at least one test object, the high-resolution portion (4-x) corresponding to the angles from which a smaller focal spot size is observed while rejecting a lower resolved portion of the x-ray radiation (4), the lower resolved portion corresponding to the angles from which a size re focal spot size can be observed.

2. Inspection system (1) according to Claim 1, characterized in that the inspection system (1) comprises at least two reflection X-ray tubes (2-x), the at least two reflection X-ray tubes (2-x) and the at least one X-ray detector (6) being designed and are arranged such that the high-resolution sections (4-x) of the X-rays (4) emitted by the at least two reflection X-ray tubes (2-x) are imaged on separate sections of the at least one X-ray detector (6).

3. Inspection system (1) according to one of the preceding claims, characterized in that the inspection system (1) comprises at least two reflection X-ray tubes (2-x), the at least two reflection X-ray tubes (2-x) and the at least one X-ray detector (6) being so are designed and arranged such that the high-resolution sections (4-x) of the X-rays (4) emitted by at least some of the at least two reflection X-ray tubes (2-x) are imaged on different sides of the at least one X-ray detector (6).

4. Inspection system (1) according to one of the preceding claims, characterized in that the inspection system (1) comprises at least one X-ray attenuation element (15) in order to block a section of at least one of the high-resolution sections (4-x) of the X-ray radiation (4) emitted by emitted by the at least one or at least two reflection X-ray tubes (2-x) in a predetermined manner.

5. Inspection system (1) according to one of Claims 2 to 4, characterized in that the at least two reflection X-ray tubes (2-x) and the at least one X-ray detector (6) are designed and arranged in such a way that the high-resolution sections (4-x) of the X-ray radiation (4), which is emitted by the at least two reflection X-ray tubes (2-x), can run simultaneously from different directions through at least partially overlapping sections of the at least one test object (10-x).

6. Method of inspecting at least one test object (10-x), comprising:

Radiographing at least one section (18-x) of the at least one test object (10-x) by using a design and arrangement of at least one reflection X-ray tube (2-x) and at least one X-ray detector (6) in which only a high-resolution section (4- x) the X-ray radiation (4) emitted by the at least one reflection X-ray tube (2-x) is used, the high-resolution section (4-x) corresponding to the angles from which a smaller focal spot size can be observed, while a lower resolved portion of the X-ray radiation (4) is discarded, the lower resolved portion corresponding to the angles from which a larger focal spot size can be observed, and capturing a radiographic image (7) of the at least one portion (18-x) of the at least one test object (10-x) with the at least one X-ray detector (6).

7. The method according to claim 6, characterized in that the radiographing is carried out by using at least two reflection X-ray tubes (2-x) and in that a design and arrangement of the at least two reflection X-ray tubes (2-x) and the at least one X-ray detector (6) are used in which the high-resolution sections (4-x) of the X-rays (4) emitted by the at least two reflection X-ray tubes (2-x) are imaged on separate sections of the at least one X-ray detector (6).

8. The method according to claim 6 or 7, characterized in that the radiographing is carried out by using at least two reflection X-ray tubes (2-x) and by a design and arrangement of the at least two reflection X-ray tubes (2-x) and the at least one X-ray detector ( 6) in which the high-resolution sections (4-x) of the X-rays (4) emitted by at least some of the at least two reflection X-ray tubes (2-x) are imaged on different sides of the at least one X-ray detector (6).

9. The method according to any one of claims 6 to 8, characterized in that at least one section of the at least one test object (10-x) is radiographed simultaneously from different directions.

10. The method according to any one of claims 6 to 9, characterized in that the at least one test object (10-x) is a battery (16-x).

11. The method according to claim 10, characterized in that at least one layer sequence of the at least one battery (16-x) is radiographed.

12. The method according to claim 10 or 11, characterized in that end sections (18-x) of the at least one battery (16-x) are radiographed.

13. The method according to claim 12, characterized in that at least some of the end portions (18-x) of the at least one battery (16-x) are arranged between the at least one reflection x-ray tube (2-x) and the at least one x-ray detector (6). that these end sections (18-x) of the at least one battery (16-x) are simultaneously radiographed by the high-resolution section (4-x) of the X-ray radiation (4) emitted by the at least one reflection X-ray tube (2-x).

14. The method according to any one of claims 6 to 13, characterized in that during radiographing the at least one test object (10-x) or the battery (16-x) between the at least one reflection X-ray tube (2-x) and the at least one X-ray detector (6) is arranged such that at least two sections (18-x) of the at least one test object (10-x) or the battery (16-x) differ from different sections of the high-resolution section (4-x) of one of the at least one reflection x-ray tube ( 2-x) are radiographed and simultaneously imaged on predetermined positions on the at least one X-ray detector (6).

15. The method according to claim 14, characterized in that the at least one test object (10-x) or the battery (16-x) is arranged such that an imaginary axis connecting the at least two sections (18-x) to be radiographed , is inclined with respect to a plane of the at least one X-ray detector (6) and/or a conveyor belt (27).

16. The method according to any one of claims 6 to 15, characterized in that during radiographing the at least one reflection X-ray tube (2-x) is inclined with respect to a plane of the at least one X-ray detector (6), so that an angle between a plane of a Surface of a target (12) of the at least one reflection X-ray tube (2-x) and a plane of the at least one X-ray detector (6) has a predetermined angle.

17. The method according to any one of claims 6 to 16, characterized in that during radiographing the at least one test object (10-x) or the battery (16-x) between the at least one reflection X-ray tube (2-x) and the at least one X-ray detector (6) is arranged in such a way that a section (18-x) of the at least one test object (10-x) or the battery (16-x) which is covered by a higher-resolution part of the high-resolution section (4-x) of the X-ray radiation ( 4) the at least one reflection X-ray tube (2-x) being radiographed is closer to the at least one reflection X-ray tube (2-x) than the portion (18-x) of the at least one test object (10-x) or the battery (16-x ), which is radiographed by a lower-resolution part of the high-resolution section (4-x) of the X-ray radiation (4) of the at least one reflection X-ray tube (2-x).