Detection system and detection method for electrode sheet

Abstract

A detection system and detection method for an electrode sheet (10). The detection system comprises: a transport medium (21) used for transporting an electrode sheet (10); a position sensor (22) used for sending a position trigger signal when detecting that the electrode sheet (10) has been transported to a predetermined position by the transport medium (21); a controller (23) used for sending a photographing instruction signal when receiving the position trigger signal; and a camera (24) used for photographing the edge of the electrode sheet (10) when receiving the photographing instruction signal, so as to obtain image information of the edge of the electrode sheet (10).

Description

Detection system and detection method for pole piece

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202410252548.9, filed on March 6, 2024, entitled “Detection system and detection method for pole pieces,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to the technical field of battery pole piece detection, and in particular to a pole piece detection system and detection method. Background Art

[0004] With the rapid development of the new energy vehicle market, the demand for lithium-ion power batteries is growing, and power battery shipments are climbing steadily. During the manufacturing process of lithium-ion batteries, burrs may be generated on the battery electrodes, which have a significant impact on battery safety and performance.

[0005] In the related art, burr defects on the edge of the pole piece can be detected by manual measurement.

[0006] Summary of the Invention

[0007] According to one aspect of the present disclosure, a detection system for an electrode is provided, comprising: a transmission medium for transporting the electrode; a position sensor for issuing a position trigger signal upon detecting that the electrode is transported to a predetermined position by the transmission medium; a controller for issuing a photographing instruction signal after receiving the position trigger signal; and a camera for photographing the edge of the electrode after receiving the photographing instruction signal to obtain image information of the edge of the electrode.

[0008] In the technical solution of the embodiment of the present disclosure, the pole piece is transported by a transmission medium, and the position sensor sends a position trigger signal when detecting that the pole piece is transported to a predetermined position. After receiving the position trigger signal, the controller sends a photo command signal. After receiving the photo command signal, the camera takes a photo of the edge of the pole piece to obtain image information of the edge of the pole piece, thereby realizing automatic detection of the pole piece and saving labor costs.

[0009] In some embodiments, the inspection system further includes a roller in contact with the transport medium; wherein the transport direction of the transport medium changes from a first transport direction to a second transport direction at the location of the roller; the predetermined position includes the location where the transport medium begins to deviate from the first transport direction; and the camera's photographic direction forms an angle with the second transport direction. Thus, when the electrode piece passes through the roller, the edge of the electrode piece will slightly tilt, facilitating the camera's ability to detect defects on the electrode piece's edge end face, thereby improving the accuracy of electrode piece edge defect detection.

[0010] In some embodiments, the angle is greater than 15°. Such an angle setting facilitates detection of the edge of the pole piece.

[0011] In some embodiments, the angle is an acute angle, which facilitates the transport of the pole piece by the transmission medium.

[0012] In some embodiments, the camera's photographing direction is parallel to the first transport direction, which facilitates the camera's photographing of the pole piece and improves the accuracy of pole piece edge detection.

[0013] In some embodiments, the camera is further configured to transmit the image information to the controller; the controller is further configured to identify, based on the image information, whether there are burrs on the edge of the electrode, and thereby determine whether the electrode is defective. This enables automatic detection of electrode defects.

[0014] In some embodiments, the image information includes multiple images; the controller is configured to issue the photographing instruction signal at a first predetermined interval; and the camera is configured to photograph and obtain an image at the current photographing position each time the photographing instruction signal is received, so that the multiple images are continuously photographed at the current photographing position. This enables the camera to continuously photograph and obtain multiple images at the current photographing position, facilitates obtaining the clearest image from the multiple images, and improves the accuracy of electrode edge defect detection.

[0015] In some embodiments, the camera satisfies the following conditions for photographing: S1≤vt≤S2, where v is the speed of the pole piece, t is the time it takes for the camera to continuously photograph and obtain at least a portion of the multiple images, S1 is the distance between the edge of the pole piece and the front end of the camera's depth of field when the camera starts photographing, and S2 is the distance between the edge of the pole piece and the back end of the camera's depth of field when the camera starts photographing. This allows the camera to photograph while the pole piece is within the camera's depth of field, thereby obtaining relatively clear images.

[0016] In some embodiments, the controller is configured to select the clearest image from the multiple images and perform defect detection on the edge of the pole piece based on the clearest image, thereby improving the accuracy of defect detection on the edge of the pole piece.

[0017] In some embodiments, the controller is further configured to send a motion instruction signal to the camera at a second preset time interval, wherein the second preset time interval is greater than the first preset time interval; the camera is further configured to, upon receiving the motion instruction signal, move a predetermined distance in a direction parallel to the edge of the electrode piece to move from a current photographing position to a next photographing position, and photograph the next electrode piece at the next photographing position according to the photographing instruction signal sent again by the controller. In this embodiment, since the electrode pieces of the same inspection batch can be considered to be approximately the same, the above-described photographing method is equivalent to achieving the detection of different portions of the electrode piece edge.

[0018] In some embodiments, the predetermined distance is less than or equal to the size of the camera's field of view in the longitudinal direction, wherein the size of the camera's field of view in the longitudinal direction is the size of the camera's field of view in a direction parallel to the edge of the pole piece. This maximizes overlap between images of adjacent portions of the pole piece edge, thereby minimizing the presence of unphotographed portions between adjacent portions of the pole piece edge and minimizing the likelihood of missed edge portions being detected during pole piece edge detection.

[0019] In some embodiments, the pole piece moves a first distance while the camera continuously captures the multiple images at its current position; and a second distance while the camera moves from its current capturing position to a next capturing position. The sum of the first and second distances is less than the sum of the width of the pole piece in the transport direction and the spacing between adjacent pole pieces. This allows the camera to continuously capture the edge of the current pole piece at its current position, and reduces the risk of the next pole piece having already moved beyond the captured position by the time the camera captures the next pole piece, thereby improving the accuracy of pole piece edge detection.

[0020] In some embodiments, the camera is further configured to, after moving from a first restricted position to a second restricted position, start moving from the second restricted position in a direction from the second restricted position to the first restricted position, wherein the first restricted position is a photographing position of the camera and corresponds to one end of the edge of the pole piece, and the second restricted position is another photographing position of the camera and corresponds to the other end of the edge of the pole piece. This allows the camera to move from one end of the pole piece edge to the other during the photographing process and then move in the reverse direction to continue photographing, thereby improving the efficiency of detecting defects on the pole piece edge.

[0021] In some embodiments, the detection system further comprises a light source, wherein the light source and the camera are located on the same side of the transmission medium. Providing a light source can improve the clarity of the image, thereby improving the accuracy of detecting edge defects of the electrode piece.

[0022] According to another aspect of the present disclosure, a method for detecting an electrode is provided, comprising: a transmission medium transporting the electrode; a position sensor issuing a position trigger signal upon detecting that the electrode is transported to a predetermined position by the transmission medium; a controller issuing a photographing instruction signal after receiving the position trigger signal; and a camera photographing the edge of the electrode to obtain image information of the edge of the electrode after receiving the photographing instruction signal.

[0023] In the technical solution of the embodiment of the present disclosure, the pole piece is transported by a transmission medium, and the position sensor sends a position trigger signal when detecting that the pole piece is transported to a predetermined position. After receiving the position trigger signal, the controller sends a photo command signal. After receiving the photo command signal, the camera takes a photo of the edge of the pole piece to obtain image information of the edge of the pole piece, thereby realizing automatic detection of the pole piece and saving labor costs.

[0024] In some embodiments, the transport direction of the transport medium changes from a first transport direction to a second transport direction at the location of the roller; the predetermined location includes the location where the transport medium begins to deviate from the first transport direction; and the camera's photographic direction forms an angle with the second transport direction. This allows the edge of the pole piece to slightly tilt as it passes over the roller, facilitating camera imaging for detecting defects on the pole piece's edge end face, thereby improving the accuracy of pole piece edge defect detection.

[0025] In some embodiments, the detection method further includes: the camera transmitting the image information to the controller; and the controller identifying, based on the image information, whether there are burrs on the edge of the electrode piece, thereby determining whether the electrode piece has a defect. This achieves automatic detection of electrode piece defects.

[0026] In some embodiments, the image information includes multiple images; the controller sending a photographing instruction signal includes: the controller sending the photographing instruction signal every first preset time interval; and the camera photographing the edge of the pole piece after receiving the photographing instruction signal includes: the camera photographing an image at a current photographing position each time the camera receives the photographing instruction signal, thereby continuously photographing multiple images at the current photographing position. This enables the camera to continuously photograph multiple images at the current photographing position, facilitates obtaining the clearest image from the multiple images, and improves the accuracy of pole piece edge defect detection.

[0027] In some embodiments, the controller performing defect detection on the edge of the pole piece based on the image information includes: the controller selecting the clearest image from the multiple images, and performing defect detection on the edge of the pole piece based on the clearest image. This can improve the accuracy of detecting defects on the edge of the pole piece.

[0028] In some embodiments, the detection method further includes: the controller sending a motion instruction signal to the camera every second preset time, wherein the second preset time is greater than the first preset time; and after receiving the motion instruction signal, the camera moves a predetermined distance in a direction parallel to the edge of the pole piece to move from the current photographing position to the next photographing position, and photographs the next pole piece at the next photographing position according to the photographing instruction signal sent again by the controller. In this embodiment, since the pole pieces of the same inspection batch can be considered to be approximately the same, the above-mentioned photographing method is equivalent to realizing the detection of different parts of the pole piece edge.

[0029] In some embodiments, the detection method further includes: after the camera moves from the first restricted position to the second restricted position, it moves from the second restricted position in the direction from the second restricted position to the first restricted position, wherein the first restricted position is a photographing position of the camera and corresponds to one end of the edge of the pole piece, and the second restricted position is another photographing position of the camera and corresponds to the other end of the edge of the pole piece. In this way, after the camera moves from one end of the pole piece edge to the other end during the photographing process, it moves in the reverse direction to continue photographing, thereby improving the efficiency of detecting defects on the edge of the pole piece.

[0030] Other features and advantages of the present disclosure will become apparent from the following detailed description of exemplary embodiments of the present disclosure with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0032] The present disclosure can be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

[0033] FIG1 is a schematic diagram illustrating a pole piece according to some embodiments of the present disclosure;

[0034] FIG2 is a schematic diagram showing the structure of a detection system for a pole piece according to some embodiments of the present disclosure;

[0035] FIG3 is an enlarged schematic diagram showing a partial structure of a detection system for a pole piece according to some embodiments of the present disclosure;

[0036] FIG4 is a schematic diagram showing a camera used in a detection system for a pole piece according to some embodiments of the present disclosure;

[0037] FIG5 is a schematic diagram showing a camera used in a detection system for a pole piece according to other embodiments of the present disclosure;

[0038] FIG6 is a schematic diagram showing a camera used in a detection system for a pole piece according to other embodiments of the present disclosure;

[0039] FIG7 is a flow chart illustrating a method for detecting a pole piece according to some embodiments of the present disclosure;

[0040] FIG8 is a flow chart illustrating a method for detecting a pole piece according to other embodiments of the present disclosure.

[0041] It should be understood that the size of each part shown in the drawings is not drawn according to the actual proportional relationship.In addition, the same or similar reference numerals represent the same or similar components. DETAILED DESCRIPTION

[0042] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the present disclosure, its application, or use. The present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present disclosure thorough and complete and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of parts and steps, the composition of materials, numerical expressions, and numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary and not as limiting.

[0043] The terms "first", "second" and similar terms used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. The terms "include" or "comprises" and similar terms mean that the elements before the term include the elements listed after the term, and do not exclude the possibility of also including other elements. The terms "upper", "lower", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0044] In the present disclosure, when a specific device is described as being located between a first device and a second device, an intervening device may or may not be present between the specific device and the first device or the second device. When a specific device is described as being connected to another device, the specific device may be directly connected to the other device without an intervening device, or may be not directly connected to the other device but with an intervening device.

[0045] All terms (including technical or scientific terms) used in this disclosure have the same meaning as those understood by one of ordinary skill in the art to which this disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in, for example, general dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an idealized or highly formal sense, unless explicitly defined herein.

[0046] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0047] In related technologies, lithium-ion batteries are primarily divided into laminated and wound types. In both types of lithium-ion batteries, burrs can form on the electrode sheets, with laminated batteries being more prone to burrs during the cutting and stacking process. This can have a significant impact on battery safety and performance.

[0048] In the related art, the method for detecting burr defects on the edge of the pole piece is mainly implemented through first-piece inspection, process sampling, and regular cleaning and replacement of new tools. For example, before cutting and stacking, a trial cut is made to obtain a small sample. The employee detects burrs on the small sample under a microscope, and debugs the equipment and cleans the tool according to the test results. After the small sample is qualified, the continuous cutting and stacking process is carried out, and a small number of pole pieces are sampled during the process. In the related art, the burr defects on the edge of the pole piece are detected by manual measurement. Manual detection is labor-intensive and time-consuming, and it is easy to miss or misdetect the burrs. Once a problem occurs, it will affect the quality of the lithium-ion battery.

[0049] In view of this, embodiments of the present disclosure provide a detection system or method for electrode sheets to achieve automatic detection of electrode sheets and save labor costs. The detection system or method is suitable for detecting battery electrode sheets and, in turn, for detecting batteries.

[0050] FIG1 is a schematic diagram illustrating a pole piece according to some embodiments of the present disclosure.

[0051] As shown in FIG1 , pole piece 10 may include a first edge 11, a second edge 12, a third edge 13, and a fourth edge 14. First edge 11 is opposite second edge 12, first edge 11 is adjacent to third edge 13, and third edge 13 is opposite fourth edge 14. For example, either third edge 13 or fourth edge 14 may be inspected.

[0052] FIG2 is a schematic structural diagram illustrating a detection system for a pole piece according to some embodiments of the present disclosure.

[0053] As shown in FIG. 2 , the detection system includes a transmission medium 21 , a position sensor 22 , a controller 23 , and a camera 24 .

[0054] The transmission medium 21 is used to transport the electrode 10. For example, the transmission medium includes a conveyor belt, on which the electrode is adsorbed and moves along with the conveyor belt. The transmission medium can also be a diaphragm, on which the electrode is coated and moves along with the diaphragm.

[0055] The position sensor 22 is used to send a position trigger signal when it detects that the pole piece 10 is transported to a predetermined position by the transmission medium 21. The position sensor 22 can detect the edge of the pole piece 10. For example, the position sensor includes a color sensor or a photoelectric sensor.

[0056] The controller 23 is used to send a photo command signal after receiving the position trigger signal. Here, after receiving the position trigger signal sent by the position sensor, the controller 23 knows that the pole piece has been transported to the predetermined position, and therefore sends a photo command signal to the camera, thereby causing the camera to take a photo.

[0057] The camera 24 is used to take a picture of the edge of the pole piece 10 after receiving a picture taking instruction signal to obtain image information of the edge of the pole piece 10. For example, the camera 24 includes a CCD (Charge Coupled Device) camera.

[0058] Thus, a detection system for a pole piece according to some embodiments of the present disclosure is provided. The detection system includes: a transmission medium for transporting the pole piece; a position sensor for issuing a position trigger signal upon detecting that the pole piece has been transported to a predetermined position by the transmission medium; a controller for issuing a photographing instruction signal upon receiving the position trigger signal; and a camera for photographing the edge of the pole piece to obtain image information of the edge of the pole piece upon receiving the photographing instruction signal. This detection system enables automatic detection of the pole piece, saving labor costs.

[0059] In some embodiments, as shown in FIG2 , the detection system further includes a roller 27 . The roller 27 is in contact with the transport medium 21 . For example, the roller 27 is a circular arc roller. As shown in FIG2 , the transport direction of the transport medium 21 changes from a first transport direction 310 to a second transport direction 320 at the location of the roller 27 .

[0060] In some embodiments, the predetermined position includes a position where the transport medium begins to deviate from the first transport direction. For example, the predetermined position is a position above the roller 27. For example, when the pole piece moves above the roller, causing the position sensor to detect an edge of the pole piece, the position sensor 22 sends a position trigger signal to the controller 23.

[0061] The camera 24's photographing direction forms an angle α with the second transport direction 320. In this embodiment, the transport direction of the transport medium changes at the roller, and the camera's photographing direction forms an angle with the second transport direction. As a result, when the electrode passes through the roller, the edge of the electrode is slightly raised, making it easier for the camera to take photos and detect defects on the electrode edge end face, thereby improving the accuracy of electrode edge defect detection.

[0062] In some embodiments, the angle α is greater than 15°. Such an angle setting facilitates detection of the edge of the pole piece.

[0063] In some embodiments, the angle α is an acute angle, which facilitates the transport of the pole piece by the transport medium.

[0064] In some embodiments, the angle α is an acute angle greater than 15°, which is convenient for detecting the edge of the electrode and for transporting the electrode by the transmission medium.

[0065] In some embodiments, the camera 24 is directed in a direction parallel to the first transport direction 310. This allows the camera to be directed directly toward the edge of the pole piece when photographing the edge of the pole piece, thereby facilitating photographing the pole piece and improving the accuracy of pole piece edge detection.

[0066] In some embodiments, the camera 24 is further configured to transmit image information to the controller 23. The controller is further configured to identify whether there are burrs on the edge of the electrode in the image information, and further determine whether there are defects in the electrode.

[0067] In some embodiments, as shown in FIG2 , the detection system further includes a light source 25. The light source 25 and the camera 24 are located on the same side of the transmission medium 21. For example, the light source 25 can be located above or below the camera 24, or can be aligned with the camera in the same linear direction (the camera's image capturing direction). The scope of this disclosure is not limited to a specific camera location.

[0068] It should be noted that the detection system may not include a light source. For example, the detection system can perform detection under natural light (such as daylight) without the need for an additional light source.

[0069] In some embodiments, the image information includes a plurality of images.

[0070] In some embodiments, the controller 23 is configured to send a photographing instruction signal every first preset time. For example, the first preset time ranges from 0.5 ms (milliseconds) to 5 ms. Of course, those skilled in the art will appreciate that the scope of the present disclosure is not limited to the specific value of the first preset time.

[0071] In some embodiments, the camera 24 is configured to capture an image at the current photographing position each time it receives a photographing instruction signal, so that the multiple images are captured continuously at the current photographing position. Specifically, the controller issues a photographing instruction signal at first predetermined intervals, and the camera captures an image at the current photographing position each time it receives a photographing instruction signal. Thus, if the controller issues multiple photographing instruction signals, the camera can capture multiple images continuously under the control of the multiple photographing instruction signals.

[0072] In the above embodiment, the camera can continuously take pictures at the current picture taking position to obtain multiple images, thereby facilitating subsequent acquisition of the clearest image from the multiple images and improving the accuracy of detecting edge defects of the electrode piece.

[0073] FIG3 is an enlarged schematic diagram showing a partial structure of a detection system for a pole piece according to some embodiments of the present disclosure. FIG3 shows the photographic focus 242 of the camera and the distance E between the detection position of the position sensor and the photographic focus 242. Furthermore, FIG3 also shows the depth of field H of the camera 24, the distance S0 of the pole piece moved from the edge of the pole piece sensed by the position sensor to the time when the camera starts taking pictures, the distance S1 between the position 311 of the pole piece edge when the camera starts taking pictures and the front end 241 of the depth of field of the camera, and the distance S2 between the position 311 of the pole piece edge when the camera starts taking pictures and the rear end 243 of the depth of field of the camera. Here, the distance E, the depth of field H, and the distances S0, S1, and S2 can be measured or set according to actual needs.

[0074] It should be noted that the above distance S0 can be set according to the speed of the pole piece movement and the time from the position sensor sensing the edge of the pole piece to the camera starting to take pictures (for example, 40ms (milliseconds)), so that when the pole piece moves the above distance S0, the camera starts taking pictures.

[0075] In some embodiments, the camera 24 satisfies the following conditions for taking photos: S1≤vt≤S2, (1)

[0076] Wherein, v is the speed of the pole piece movement, t is the time taken by the camera to continuously take pictures to obtain at least a part of the multiple images, S1 is the distance between the position of the edge of the pole piece when the camera starts taking pictures and the front end of the depth of field of the camera, and S2 is the distance between the position of the edge of the pole piece when the camera starts taking pictures and the back end of the depth of field of the camera.

[0077] That is to say, in the above embodiment, while the camera is continuously taking pictures at the current position, the pole piece is always in motion. If the camera satisfies the above-mentioned photographing condition (1), the pole piece can be moved to within the depth of field of the camera after a period of time t, so that the camera can take pictures as clearly as possible.

[0078] In some cases, the camera may continue to take pictures after the pole piece moves beyond the distance S2. That is, the camera can take pictures continuously before the pole piece enters the depth of field of the camera, in the depth of field, and in the process of moving out of the depth of field, thereby obtaining multiple images. In this way, the clearest image can be obtained from the multiple images (that is, the image obtained by the camera when the pole piece is in the depth of field).

[0079] Therefore, the above-mentioned photographing conditions enable the camera to take pictures when the pole piece is within the depth of field of the camera, thereby obtaining a relatively clear image.

[0080] In some embodiments, the controller 23 is configured to select the clearest image from the plurality of images and perform defect detection on the edge of the pole piece based on the clearest image, thereby improving the accuracy of defect detection on the edge of the pole piece.

[0081] As mentioned above, the controller may utilize a defect detection algorithm known to those skilled in the art to implement defect detection when performing defect detection on the edge of the pole piece. The scope of this disclosure is not limited to the specific content of the defect detection algorithm.

[0082] Figure 4 is a schematic diagram showing a camera in a detection system for a pole piece according to some embodiments of the present disclosure. Figure 5 is a schematic diagram showing a camera in a detection system for a pole piece according to other embodiments of the present disclosure.

[0083] In some embodiments, the controller 23 is further configured to send a motion instruction signal to the camera every second preset time. The second preset time is greater than the first preset time. As shown in Figures 4 and 5, the camera 24 is further configured to, after receiving the motion instruction signal, move a predetermined distance D in a direction parallel to the fourth edge 14 or the third edge 13 of the pole piece 10 (for example, the first camera movement direction 430 shown in Figure 6) to move from the current photographing position (for example, the photographing position of the camera shown in Figure 4) to the next photographing position (for example, the photographing position of the camera shown in Figure 5), and take a photograph of the next pole piece at the next photographing position according to the photographing instruction signal sent again by the controller.

[0084] In the above embodiment, since the electrode piece is constantly in motion as it is transported by the transport medium, the camera can capture the edge of the current electrode piece at the photographing position shown in FIG4 . However, since the electrode piece is constantly in motion, during the process of the camera capturing and moving, the current electrode piece (e.g., electrode piece 10 shown in FIG4 ) may have already moved along the second transport direction of the transport medium. The next electrode piece (e.g., electrode piece 10 shown in FIG5 ) may have already been transported to the detection position of the position sensor. Upon detecting the next electrode piece, the position sensor sends a position trigger signal to the controller. Upon receiving the position trigger signal, the controller sends a photographing instruction signal to the camera. At this point, the camera has already moved to the next photographing position under the control of the motion instruction signal, as shown in FIG5 . Therefore, the camera can capture the next electrode piece at the next photographing position in response to the photographing instruction signal sent again by the controller. Since these electrode pieces are from the same inspection batch, it can be assumed that the electrode pieces from the same inspection batch are approximately identical. Therefore, the above photographing method is equivalent to detecting different portions of the electrode piece edge.

[0085] In some embodiments, the predetermined distance D ranges from 3 mm (millimeter) to 10 mm. For example, the predetermined distance is 4 mm. Of course, the predetermined distance can be set according to actual conditions or actual needs, and the scope of this disclosure is not limited to the specific value of the predetermined distance.

[0086] In some embodiments, as shown in FIG5 , the predetermined distance D is less than or equal to the dimension L2 of the camera's longitudinal field of view. Here, the dimension L2 of the camera's longitudinal field of view is the dimension of the camera's field of view in a direction parallel to the fourth edge 14 or the third edge 13 of the pole piece 10. This maximizes overlap between images of adjacent portions of the pole piece edge (e.g., as shown in FIG5 ), thereby minimizing the presence of unimaged portions between adjacent portions of the pole piece edge and minimizing the likelihood of missed edge portions being detected during pole piece edge detection.

[0087] In some embodiments, the pole piece moves a first distance while the camera continuously takes pictures at the current position to obtain the multiple images; the pole piece moves a second distance while the camera moves from the current picture taking position to the next picture taking position; wherein the sum of the first distance and the second distance is less than the sum of the width of the pole piece in the transport direction and the spacing between adjacent pole pieces.

[0088] Here, as mentioned above, in the process of the camera taking pictures continuously at the current position to obtain the multiple images, the pole piece has been following the movement of the transmission medium. Here, the movement distance of the pole piece in this process is recorded as the first distance; then, in the process of the camera moving from the current shooting position to the next shooting position, the pole piece is also moving. The distance the pole piece moves in this process is recorded as the second distance. In this way, from the beginning of the camera taking pictures to the movement of the camera to the next shooting position, the distance the pole piece moves is the sum of the first distance and the second distance. Figure 2 shows the width L1 of the pole piece in the transport direction and the spacing F between adjacent pole pieces. The sum of the first distance and the second distance is less than L1+F. This enables the camera to continuously take pictures of the edge of the current pole piece at the current position, and it is not easy to have the problem that the next pole piece has moved beyond the position being photographed when the camera takes pictures of the next pole piece, thereby improving the accuracy of pole piece edge detection.

[0089] FIG6 is a schematic diagram showing a camera in a system for detecting a pole piece according to other embodiments of the present disclosure.

[0090] In some embodiments, the camera 24 is further configured to, after moving from the first restricted position to the second restricted position, move from the second restricted position in a direction from the second restricted position to the first restricted position (e.g., second camera movement direction 440 shown in FIG6 ). The first restricted position is a photographic position of the camera and corresponds to one end of the edge of the pole piece. For example, the first restricted position is the photographic position of the camera shown in FIG4 . The second restricted position is another photographic position of the camera and corresponds to the other end of the edge of the pole piece. For example, the second restricted position is the photographic position of the camera shown in FIG6 .

[0091] That is, after the camera moves from the first restricted position shown in FIG. 4 to the second restricted position shown in FIG. 6 , it then moves in the reverse direction from the second restricted position, i.e., toward the first restricted position. Furthermore, during this movement from the second restricted position to the first restricted position, the camera continues to perform photo detection in the same or similar manner as during the movement from the first restricted position to the second restricted position. This allows the camera to move from one end of the electrode edge to the other during the photo detection process and then reverse direction to continue taking photos, thereby improving the efficiency of detecting electrode edge defects.

[0092] FIG7 is a flow chart illustrating a method for detecting a pole piece according to some embodiments of the present disclosure. As shown in FIG7 , the detection method includes steps S702 to S708 .

[0093] In step S702, the pole piece is transported by a conveying medium.

[0094] In step S704, the position sensor sends a position trigger signal when detecting that the pole piece is transported to a predetermined position by the transport medium.

[0095] In step S706, after receiving the position trigger signal, the controller sends a photo-taking instruction signal.

[0096] In step S708, after receiving the photographing instruction signal, the camera photographs the edge of the pole piece to obtain image information of the edge of the pole piece.

[0097] Thus, a method for detecting a pole piece according to some embodiments of the present disclosure is provided. In this detection method, a transmission medium transports the pole piece, and a position sensor sends a position trigger signal when detecting that the pole piece has been transported to a predetermined position. After receiving the position trigger signal, a controller sends a photo command signal. After receiving the photo command signal, a camera takes a photo of the edge of the pole piece to obtain image information of the edge of the pole piece. This achieves automatic detection of the pole piece and saves labor costs.

[0098] In some embodiments, the transport direction of the transport medium changes from a first transport direction to a second transport direction at the location of the roller; the predetermined location includes the location where the transport medium begins to deviate from the first transport direction; and the camera's photographic direction forms an angle with the second transport direction. This allows the edge of the pole piece to slightly tilt as it passes over the roller, facilitating camera imaging for detecting defects on the pole piece's edge end face, thereby improving the accuracy of pole piece edge defect detection.

[0099] In some embodiments, the detection method further includes: the camera transmitting image information to a controller; and the controller identifying, based on the image information, whether there are burrs on the edge of the electrode piece, thereby determining whether the electrode piece is defective. This achieves automatic detection of electrode piece defects.

[0100] In some embodiments, the image information includes multiple images; the controller sending a photographing instruction signal includes: the controller sending a photographing instruction signal every first preset time interval; and the camera photographing the edge of the pole piece after receiving the photographing instruction signal includes: the camera photographing an image at a current photographing position each time the photographing instruction signal is received, so that multiple images are continuously photographed at the current photographing position. This enables the camera to continuously photograph multiple images at the current photographing position, facilitates obtaining the clearest image from the multiple images, and improves the accuracy of detecting pole piece edge defects.

[0101] In some embodiments, the controller performing defect detection on the edge of the pole piece based on the image information includes: the controller selecting the clearest image from the multiple images, and performing defect detection on the edge of the pole piece based on the clearest image. This can improve the accuracy of defect detection on the edge of the pole piece.

[0102] In some embodiments, the detection method further includes: the controller sending a motion command signal to the camera at a second preset time interval, wherein the second preset time interval is greater than the first preset time interval; and after receiving the motion command signal, the camera moves a predetermined distance in a direction parallel to the edge of the electrode piece to move from the current photographing position to the next photographing position, and photographs the next electrode piece at the next photographing position according to the photographing command signal sent again by the controller. In this embodiment, since the electrode pieces of the same inspection batch can be considered to be approximately the same, the above-mentioned photographing method is equivalent to realizing the detection of different portions of the electrode piece edge.

[0103] In some embodiments, the detection method further includes: after the camera moves from the first restricted position to the second restricted position, it moves from the second restricted position in a direction from the second restricted position to the first restricted position, wherein the first restricted position is a photographing position of the camera and corresponds to one end of the edge of the pole piece, and the second restricted position is another photographing position of the camera and corresponds to the other end of the edge of the pole piece. In this way, after the camera moves from one end of the pole piece edge to the other during the photographing process, it moves in the reverse direction to continue photographing, thereby improving the efficiency of detecting pole piece edge defects.

[0104] FIG8 is a flow chart illustrating a method for detecting a pole piece according to some other embodiments of the present disclosure. As shown in FIG8 , the detection method includes steps S802 to S818 .

[0105] In step S802, the pole piece moves along the transport direction, and the position sensor senses the edge of the pole piece and triggers the camera to take a photo.

[0106] For example, the transmission medium transports the pole piece so that the pole piece moves along the transport direction. When the position sensor detects that the edge of the pole piece reaches the position above the roller, it sends a position trigger signal to the controller. After receiving the position trigger signal, the controller sends a photo command signal to the camera. After receiving the photo command signal, the camera takes a photo of the edge of the pole piece to obtain image information of the edge of the pole piece.

[0107] For example, after the electrode pieces are cut and stacked, burrs on the third edge 13 or the fourth edge 14 of the electrode pieces can be detected. The electrode pieces move along with the conveying medium, and are generally laminated on a diaphragm or adsorbed on a conveyor belt.

[0108] For example, at the camera's shooting point, the camera's shooting direction has a certain angle α with the pole piece's movement direction. For example, α>15°. This allows the pole piece edge to be clearly detected without being obstructed when using the light source and camera to take pictures. Since the pole piece is laminated or adsorbed on the transmission medium, when the pole piece passes through the roller (i.e., the arc roller), the pole piece edge will be slightly raised, which also facilitates the camera to take pictures and measure the end face burrs of the pole piece.

[0109] For example, the speed of the transmission medium (i.e., the speed of the pole piece) is 30 m / min (meters / minute) = 500 mm / s (millimeter / second) = 0.5 mm / ms (millimeter / millisecond), the camera's depth of field is 0.8 mm, the frame rate is 1000 frames / s, the camera's field of view is 4.2 mm × 2 mm (i.e., the camera's field of view is 4.2 mm long and 2 mm wide), and the length of the pole piece's fourth edge 14 is 100 mm. Since the camera's frame rate is 1000 frames / s, the camera takes a picture every 1 ms.

[0110] For example, the time from when the position sensor senses the edge of the pole piece to when the camera starts taking a picture is 40 ms, and the aforementioned distance S0 can be set to 20 mm.

[0111] In step S804, the camera continuously takes multiple images corresponding to one end of the pole piece.

[0112] For example, as previously described, the camera 24 satisfies the following conditions for capturing images: S1 ≤ vt ≤ S2, where v is the speed of the pole piece, t is the time it takes for the camera to continuously capture at least a portion of the multiple images, S1 is the distance between the edge of the pole piece and the front end of the camera's depth of field when the camera begins capturing images, and S2 is the distance between the edge of the pole piece and the back end of the camera's depth of field when the camera begins capturing images. Since the camera's frame rate is 1000 frames per second, meaning the camera captures one image every 1 millisecond, if the unit of time t is milliseconds, then if t images are captured continuously over time t, the camera satisfies the following conditions for capturing images: S1 ≤ 0.5 × t images ≤ S2.

[0113] Since distances S1 and S2 are known quantities that can be measured, the number of images that the camera needs to capture continuously can be determined based on the above equation. For example, the number of images that the camera needs to capture continuously can be 5, 10, etc. The number of images that the camera needs to capture continuously can be set based on actual circumstances or needs, and the scope of this disclosure is not limited to a specific value for the number of images that the camera needs to capture continuously.

[0114] In step S806 , the clearest image is selected from the multiple images for defect detection.

[0115] In step S808, after taking a photo, the camera moves a predetermined distance to reach the next photo taking position.

[0116] For example, after the camera captures multiple images continuously, it moves a predetermined distance, such as 4 mm, along the first camera motion direction 430 in Figures 4 and 5 before continuing to trigger the capture cycle. Here, the camera's longitudinal field of view is 4.2 mm. Therefore, the predetermined distance is smaller than the longitudinal field of view of the camera. This ensures that the two images corresponding to adjacent portions of the pole piece edge have an overlap as much as possible.

[0117] For example, as mentioned above, the pole piece movement speed is 0.5mm / ms. For example, the camera continuous shooting time is 10ms. During the camera continuous shooting time, the pole piece has moved a first distance W, W is 5mm; the camera moves 4mm along the first camera movement direction 430. If the camera movement speed is 1m / s (i.e., 1mm / ms), then when the camera moves from the current shooting position to the next shooting position (i.e., the next workstation), the pole piece has moved a second distance U along the transport direction, U is 2mm. At this time, it is necessary to satisfy U+W<L1+F. L1 is the width of the pole piece in the transport direction, and F is the spacing between adjacent pole pieces.

[0118] In step S810 , the position sensor senses the edge of the next pole piece and triggers the camera to take a photo.

[0119] For example, when the position sensor detects that the edge of the next pole piece reaches the position above the roller, it sends a position trigger signal to the controller. After receiving the position trigger signal, the controller sends a photo command signal to the camera. After receiving the photo command signal, the camera takes a photo of the edge of the next pole piece to obtain image information of the edge of the next pole piece.

[0120] In step S812, the camera continuously takes multiple images.

[0121] In step S814, the above operations are looped, for example, steps S806 to S812 are looped.

[0122] In step S816, the camera moves to the other end of the pole piece and completes taking pictures.

[0123] For example, the camera moves 4 mm in a cycle to reach the next photographing position and takes pictures until the fourth edge 14 of the entire pole piece (for example, the length of the fourth edge 14 is 100 mm) is completely photographed, and a total of 25 or more pictures are required.

[0124] In step S818, the camera moves in the reverse direction and continues to take pictures in a loop. For example, as shown in FIG6 , the camera continues to take pictures along the second camera movement direction 440 (ie, the reverse direction).

[0125] Here, the process of the camera moving from the first limit position to the second limit position can be considered as one cycle, and the process of the camera returning from the second limit position to the first limit position can be considered as another cycle. The camera can take pictures of the entire edge of the pole piece in one cycle to detect defects.

[0126] Thus, a method for detecting electrode sheets according to other embodiments of the present disclosure is provided. This method can automatically detect edge burr defects in cut and stacked electrode sheets, saving labor costs and improving the accuracy of electrode sheet edge defect detection, thereby enhancing battery quality and safety.

[0127] Thus far, various embodiments of the present disclosure have been described in detail. To avoid obscuring the concept of the present disclosure, some details well known in the art have not been described. Based on the above description, those skilled in the art can fully understand how to implement the technical solutions disclosed herein.

[0128] Although some specific embodiments of the present disclosure have been described in detail through examples, those skilled in the art will understand that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. Those skilled in the art will understand that the above embodiments may be modified or some technical features may be replaced with equivalents without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A detection system for a pole piece, comprising: Transmission medium, used to transport the pole piece; a position sensor, configured to send a position trigger signal when detecting that the pole piece is transported to a predetermined position by the transmission medium; A controller, configured to send a photo-taking instruction signal after receiving the position trigger signal; and The camera is used to take a picture of the edge of the pole piece after receiving the picture taking instruction signal to obtain image information of the edge of the pole piece.

2. The detection system according to claim 1, further comprising: a roller in contact with the transmission medium; Wherein, the transport direction of the transmission medium changes from the first transport direction to the second transport direction at the position where the roller is located; The predetermined position includes a position where the transport medium begins to deviate from the first transport direction; The photographing direction of the camera forms an angle with the second transport direction.

3. The detection system according to claim 2, wherein: The angle is greater than 15°.

4. The detection system according to claim 2 or 3, wherein: The included angle is an acute angle.

5. The detection system according to any one of claims 2 to 4, wherein: The photographing direction of the camera is parallel to the first transport direction.

6. The detection system according to any one of claims 1 to 5, wherein: The camera is further configured to transmit the image information to the controller; The controller is further configured to identify, based on the image information, whether there are burrs on the edge of the pole piece, and further determine whether there are defects on the pole piece.

7. The detection system according to claim 6, wherein: The image information includes a plurality of images; The controller is used to send the photo-taking instruction signal every first preset time; The camera is used to take a photo at the current photo location and obtain an image each time after receiving the photo instruction signal, so as to continuously take photos at the current photo location to obtain the multiple images.

8. The detection system according to claim 6 or 7, wherein: The camera's photographing conditions are: S1≤vt≤S2, Wherein, v is the speed of the pole piece movement, t is the time taken by the camera to continuously take pictures to obtain at least a portion of the multiple images, S1 is the distance between the position of the edge of the pole piece when the camera starts taking pictures and the front end of the depth of field of the camera, and S2 is the distance between the position of the edge of the pole piece when the camera starts taking pictures and the back end of the depth of field of the camera.

9. The detection system according to claim 7, wherein: The controller is used to select the clearest image from the multiple images and perform defect detection on the edge of the pole piece based on the clearest image.

10. The detection system according to any one of claims 7 to 9, wherein: The controller is further configured to send a motion instruction signal to the camera every second preset time, wherein the second preset time is greater than the first preset time; The camera is also used to move a predetermined distance in a direction parallel to the edge of the pole piece after receiving the motion instruction signal to move from the current photographing position to the next photographing position, and to take a photograph of the next pole piece at the next photographing position according to the photographing instruction signal sent again by the controller.

11. The detection system according to claim 10, wherein: The predetermined distance is less than or equal to the size of the camera's field of view in the longitudinal direction, wherein the size of the camera's field of view in the longitudinal direction is the size of the camera's field of view in a direction parallel to the edge of the pole piece.

12. The detection system according to claim 10 or 11, wherein: During the process of the camera continuously taking pictures at the current position to obtain the multiple images, the pole piece moves a first distance; When the camera moves from a current photographing position to a next photographing position, the pole piece moves a second distance; The sum of the first distance and the second distance is smaller than the sum of the width of the pole piece in the transport direction and the spacing between adjacent pole pieces.

13. The detection system according to any one of claims 10 to 12, wherein: The camera is also used to move from the first limit position to the second limit position, and then move from the second limit position in the direction from the second limit position to the first limit position, wherein the first limit position is a photographing position of the camera and corresponds to one end of the edge of the pole piece, and the second limit position is another photographing position of the camera and corresponds to the other end of the edge of the pole piece.

14. The detection system according to any one of claims 1 to 13, further comprising: A light source is located on the same side of the transmission medium as the camera.

15. A method for detecting a pole piece, comprising: The transmission medium transports the pole piece; The position sensor sends a position trigger signal when detecting that the pole piece is transported to a predetermined position by the transmission medium; After receiving the position trigger signal, the controller sends a photo-taking instruction signal; and After receiving the photographing instruction signal, the camera photographs the edge of the pole piece to obtain image information of the edge of the pole piece.

16. The detection method according to claim 15, wherein: The transport direction of the transmission medium changes from the first transport direction to the second transport direction at the position where the roller is located; The predetermined position includes a position where the transport medium begins to deviate from the first transport direction; The photographing direction of the camera forms an angle with the second transport direction.

17. The detection method according to claim 15 or 16, further comprising: The camera transmits the image information to the controller; and The controller identifies whether there are burrs on the edge of the pole piece in the image information based on the image information, and further determines whether there are defects on the pole piece.

18. The detection method according to claim 17, wherein: The image information includes a plurality of images; The controller sending the photographing instruction signal includes: the controller sending the photographing instruction signal every first preset time; The camera takes a picture of the edge of the pole piece after receiving the picture-taking instruction signal, comprising: the camera takes a picture at the current picture-taking position and obtains an image each time after receiving the picture-taking instruction signal, so as to obtain multiple images by continuously taking pictures at the current picture-taking position.

19. The detection method according to claim 18, wherein The controller detecting defects on the edge of the pole piece according to the image information includes: The controller selects the clearest image from the multiple images and performs defect detection on the edge of the pole piece based on the clearest image.

20. The detection method according to claim 18 or 19, further comprising: The controller sends a motion instruction signal to the camera every second preset time, wherein the second preset time is greater than the first preset time; and After receiving the motion instruction signal, the camera moves a predetermined distance in a direction parallel to the edge of the pole piece to move from the current photographing position to the next photographing position, and photographs the next pole piece at the next photographing position according to the photographing instruction signal sent again by the controller.

21. The detection method according to claim 20, further comprising: After the camera moves from the first limit position to the second limit position, it starts to move from the second limit position along the direction from the second limit position to the first limit position, wherein the first limit position is a photographing position of the camera and corresponds to one end of the edge of the pole piece, and the second limit position is another photographing position of the camera and corresponds to the other end of the edge of the pole piece.

Images