A method and device for detecting the coating quality of stacked core pole pieces

Abstract

The present invention relates to a method for detecting the coating quality of the electrode sheets of a core stack, which comprises the following steps: selecting at least two target right-angle positions according to the shape of the core stack to be tested and presetting a distance value; emitting X-rays at a predetermined angle to the central axis of the core stack to the at least two target right-angle positions of the core stack and receiving the X-rays transmitted through the core stack to obtain at least two images; obtaining the distance between the projections of the endpoints of the positive electrode sheet and the negative electrode sheet of any adjacent positive electrode sheet at the corresponding target right-angle position according to each of the images, and defining the distance as the positive and negative extreme difference; obtaining the maximum positive and negative extreme difference of each target right-angle position and comparing the maximum positive and negative extreme difference of each target right-angle position with the preset distance value respectively, and judging the coating quality between the positive and negative electrodes of the core stack to be tested according to the comparison result. The present invention calculates the distance (positive and negative extreme difference) between the projections of the endpoints of any adjacent positive electrode sheet and negative electrode sheet according to the imaging, and compares it with the given preset distance value, thereby judging the coating quality grade of the battery cell, thereby realizing battery cell coating quality control.

Description

Technical Field

[0001] The present invention relates to the technical field of detection of laminated core pole piece coating, and in particular to a method and device for detecting the coating quality of laminated core pole pieces. Background Art

[0002] Lithium-ion batteries have been widely used in portable devices such as mobile phones, laptops, and digital cameras, becoming the fastest-growing and largest-selling secondary battery system. Their high energy density and long cycle life make them the most widely used battery system in electric vehicles.

[0003] With the rapid expansion of electric vehicles, lithium-ion batteries will become increasingly important in the national economy and their strategic role in social development. However, safety incidents are frequent during the manufacturing and use of lithium batteries. The root cause of these safety issues lies in thermal runaway within the battery. This can lead to explosions and fires, directly endangering the lives and property of the public. Therefore, strict safety requirements cannot be overstated and must be given high priority.

[0004] During the production and manufacturing process of stacked lithium batteries, if the stacked cell electrode is poorly coated, it will at the very least affect the embedding and extraction of lithium ions in the positive electrode, resulting in a low overall cell capacity. At worst, it will cause lithium deposition on the surface of the negative electrode. In severe cases, it will cause a large number of lithium dendrites to be produced on the negative electrode surface, which will puncture the diaphragm during long-term use, causing a short circuit between the positive and negative electrodes, causing the battery to fail instantly and catch fire, affecting the personal safety of users. Therefore, it is very necessary to conduct a comprehensive inspection of lithium battery stacks during the manufacturing process to sort out products with unqualified electrode coating.

[0005] At present, the lithium battery manufacturing industry generally uses manual sampling to inspect the core package structure. The accuracy of the manual sampling method cannot be well guaranteed. Due to human factors, it is easy to make mistakes in judgment, which in turn causes defective coated products to flow to the subsequent process. At the same time, random sampling inspections cannot fully reflect the quality of the core package during the production of lithium batteries, and there are inspection loopholes. The patent with publication number CN108548491A discloses a method of using an imaging device to illuminate the battery cell and judge the coating condition of the battery cell pole piece by identifying the uniformity of the pole tab position. This method cannot accurately identify the coating quality of the large surface of the positive and negative pole pieces. It is easy to misjudge and miss the judgment when judging the coating condition only by the uniformity of the pole tab. Summary of the Invention

[0006] Based on this, the purpose of the present invention is to provide a method and device for detecting the coating quality of stacked core pole pieces, which determines the coating condition of the battery cell pole pieces by identifying the positive and negative pole differences at each corner of the stacked core. The principle is simple, the speed is fast, and the efficiency is high. It is non-contact and non-destructive to the test product, and can be used to monitor the coating condition of the stacked battery cells of enterprises.

[0007] The present invention provides a method for detecting the coating quality of stacked core pole pieces, which comprises the following steps:

[0008] S1. Select at least two target right-angle positions and preset distance values ​​according to the shape of the core stack to be measured;

[0009] S2. Emitting X-rays at a predetermined angle to the central axis of the core stack at right angles to at least two target positions of the core stack and receiving X-rays transmitted through the core stack to obtain at least two images;

[0010] S3. Obtain the distance between the projections of the endpoints of the positive and negative electrodes of any adjacent ones of the stacked core at the corresponding target right-angle positions based on each of the images, and define the distance as the positive and negative extremes; obtain the maximum positive and negative extremes of each target right-angle position and compare the maximum positive and negative extremes of each target right-angle position with the preset distance values, respectively, and judge the coating quality between the positive and negative electrodes of the stacked core to be tested based on the comparison results.

[0011] As a further improvement of the above solution of the present invention, the preset distance value includes a first preset value, a second preset value, and a third preset value, and the first preset value, the second preset value, and the third preset value decrease in sequence. In step S3, the method for judging the coating quality between the positive and negative electrodes of the stacked core to be tested is:

[0012] If the maximum positive-negative difference is greater than the first preset value, it is confirmed that the coating quality between the positive and negative electrodes of the stacked core to be tested is at an excellent level;

[0013] When the maximum positive and negative pole difference is less than the first preset value and greater than the second preset value, it is confirmed that the coating quality between the positive and negative poles of the stacked core to be tested is at a good level;

[0014] When the maximum positive and negative pole difference is less than the second preset value and greater than the third preset value, it is confirmed that the coating quality between the positive and negative electrodes of the stacked core to be tested is at a qualified level;

[0015] When the maximum positive-negative pole difference is less than the third preset value, it is confirmed that the coating quality between the positive and negative poles of the stacked core to be tested is at an unqualified level.

[0016] As a further improvement of the above solution of the present invention, it also includes the following steps:

[0017] S4. Obtain the distance between the projections of any two adjacent positive electrode end points of the stacked core at the corresponding target right-angle position based on each of the images, and define the distance as the positive electrode homogeneity range; obtain the maximum positive electrode homogeneity range of each target right-angle position and compare the maximum positive electrode homogeneity range of each target right-angle position with the preset distance value, and judge the coating quality between the positive electrodes of the stacked core to be tested based on the comparison results.

[0018] As a further improvement of the above solution of the present invention, the preset distance value further includes a fourth preset value, a fifth preset value, and a sixth preset value, and the fourth preset value, the fifth preset value, and the sixth preset value increase in sequence. In step S4, the method for judging the coating quality between the positive electrodes of the stacked core to be tested is:

[0019] When the maximum positive electrode same range is less than the fourth preset value, it is confirmed that the positive electrode coating quality of the stacked core to be tested is at an excellent level;

[0020] When the maximum positive electrode same range is greater than the fourth preset value and less than the fifth preset value, it is confirmed that the coating quality between the positive electrodes of the stacked core to be tested is at a good level;

[0021] When the maximum positive electrode same range is greater than the fifth preset value and less than the sixth preset value, it is confirmed that the coating quality between the positive electrodes of the stacked core to be tested is at a qualified level;

[0022] When the maximum positive electrode same range is greater than the sixth preset value, it is confirmed that the coating quality between the positive electrodes of the stacked core to be tested is at an unqualified level.

[0023] As a further improvement of the above solution of the present invention, it also includes the following steps:

[0024] S5. Obtain the distance between the projections of any two adjacent negative electrode end points of the stacked core at the corresponding target right-angle position based on each of the images, and define the distance as the negative electrode homogeneity range; obtain the maximum negative electrode homogeneity range of each target right-angle position and compare the maximum negative electrode homogeneity range of each target right-angle position with the preset distance value, and judge the coating quality between the negative electrodes of the stacked core to be tested based on the comparison results.

[0025] As a further improvement of the above solution of the present invention, the preset distance value further includes a seventh preset value, an eighth preset value, and a ninth preset value, and the seventh preset value, the eighth preset value, and the ninth preset value increase in sequence. In step S5, the method for judging the coating quality between the negative electrodes of the stacked core to be tested is:

[0026] When the maximum negative electrode same range is less than the seventh preset value, it is confirmed that the negative electrode coating quality of the stacked core to be tested is at an excellent level;

[0027] When the maximum negative electrode same range is greater than the seventh preset value and less than the eighth preset value, it is confirmed that the coating quality between the negative electrodes of the stacked core to be tested is at a good level;

[0028] When the maximum negative electrode same range is greater than the eighth preset value and less than the ninth preset value, it is confirmed that the coating quality between the negative electrodes of the stacked core to be tested is at a qualified level;

[0029] When the maximum negative electrode same range is greater than the ninth preset value, it is confirmed that the coating quality between the negative electrodes of the stacked core to be tested is at an unqualified level.

[0030] As a further improvement of the above solution of the present invention, it also includes the following steps:

[0031] S6. Determine the overall coating quality of the stacked core to be tested based on the coating quality between the positive and negative electrodes, the coating quality between the positive electrodes, and the coating quality between the negative electrodes.

[0032] As a further improvement of the above solution of the present invention, in step S6, the method for judging the overall coating quality of the stacked core to be tested is:

[0033] When the coating quality between positive electrodes, between negative electrodes, and between positive and negative electrodes are all at the excellent level, it is confirmed that the overall coating quality of the tested stacked core is at the excellent level;

[0034] When the coating quality between positive electrodes, between negative electrodes, and between positive and negative electrodes are all at good level or above, it is confirmed that the overall coating quality of the tested stacked core is at good level;

[0035] When the coating quality levels between the positive electrodes, between the negative electrodes, and between the positive and negative electrodes are all qualified or above, it is confirmed that the overall coating quality of the tested stacked core is qualified;

[0036] When at least one of the coating quality levels between positive electrodes, between negative electrodes, and between positive and negative electrodes is qualified, the overall coating quality of the tested stacked core is confirmed to be qualified;

[0037] Otherwise, the overall coating quality of the tested stacked core is confirmed to be unqualified.

[0038] As a further improvement of the above-mentioned scheme of the present invention, in step S1, when the stacked core to be tested is a square stacked core with the tabs on the same side, two right-angled positions of the stacked core to be tested away from the tabs are selected as target right-angled positions; when the stacked core to be tested is a square stacked core with the tabs on the opposite sides, one right-angled position on the non-tab side and one right-angled position on the tab side of the stacked core to be tested are selected as target right-angled positions; when the stacked core to be tested is an irregular-shaped stacked core, at least two right-angled positions on the non-tab side and one right-angled position on the tab side of the stacked core to be tested are selected as target right-angled positions.

[0039] The present invention proposes a device for detecting the coating quality of a core stack, which adopts the method for detecting the coating quality of a core stack pole piece as described above, and includes a rotating platform, two brackets, an X-ray emitter, an X-ray receiver and a detection mechanism; the rotating platform is used to drive the core stack to be tested to rotate; the two brackets are located on both sides of the rotating platform and arranged opposite to each other, the X-ray emitter and the X-ray receiver are respectively installed on the top of the two brackets, the X-ray emitter is used to emit X-rays at a right angle to the target position of the core stack to be tested, and the X-ray receiver is used to receive X-rays passing through the right angle to the target position of the core stack and form an image; the detection mechanism is connected to the X-ray receiver and performs coating quality detection on the core stack to be tested.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The present invention performs X-ray transmission imaging on appropriate positions at right angles on the tab side and non-tab side of the stacked core, calculates the distance between the projections of the endpoints of any adjacent positive and negative electrodes (positive and negative pole difference) based on the imaging, and compares it with a given preset distance value to judge the coating quality level of the battery cell, thereby achieving control of the battery cell coating quality with high accuracy and no misjudgment or missed judgment. The present invention has a simple principle, fast speed, high efficiency, is non-contact and non-destructive to the test product, and can be used to monitor the coating condition of stacked battery cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic structural diagram of a device for detecting the quality of core stacking, as proposed in an embodiment of the present invention;

[0043] Figure 2 Schematic diagram of the detection principle of a conventional square stacked core with tabs on the same side according to an embodiment of the present invention;

[0044] Figure 3 Schematic diagram of the detection principle of irregular-sized and shaped stacked cores in an embodiment of the present invention;

[0045] Figure 4 The imaging of the right-angle position of the stacked core target to be measured in the embodiment of the present invention;

[0046] Figure 5 Schematic diagram of the range difference between the positive and negative electrodes in an embodiment of the present invention.

[0047] Reference numerals: 1. rotating stage; 2. bracket; 3. X-ray transmitter; 4. X-ray receiver; 5. core stack to be tested. DETAILED DESCRIPTION

[0048] To facilitate understanding of the present invention, the present invention will be described more fully below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0050] This embodiment proposes a device for detecting the coating quality of a core stack, which includes a rotating platform 1, two brackets 2, an X-ray emitter 3, an X-ray receiver 4, and a detection mechanism. The rotating platform 1 is used to drive the core stack 5 to be tested to rotate. The two brackets 2 are located on both sides of the rotating platform and arranged opposite each other. The X-ray emitter 3 and the X-ray receiver 4 are respectively mounted on the top of the two brackets 2. The X-ray emitter 3 is used to emit X-rays at a target right angle to the core stack 5 to be tested, and the X-ray receiver 4 is used to receive X-rays that pass through the target right angle of the core stack 5 and form an image. In this embodiment, the X-ray receiver 4 adopts a flat-panel detector imaging mechanism. The detection mechanism is connected to the X-ray receiver 4 and performs coating quality detection on the core stack 5 to be tested. The detection mechanism includes a computer.

[0051] Based on the above-mentioned device for detecting the coating quality of stacked cores, this embodiment further provides a method for detecting the coating quality of stacked cores, which uses the above-mentioned device for detecting the coating quality of stacked cores and includes the following steps:

[0052] S1. The detection mechanism selects at least two target right-angle positions according to the shape of the stacked core to be tested and presets the distance value.

[0053] There are many types of stacked core structures, which currently mainly include conventional square stacked cores with tabs on the same side, conventional square stacked cores with tabs on the opposite sides, and special-shaped stacked cores. Figure 2 As shown, when the core to be tested is a square core with tabs on the same side, a two-angle detection method is adopted on the non-tab side, that is, the two right-angle positions A and B of the core to be tested away from the tab are selected as target right-angle positions; for conventional square cores with tabs on the same side with more special cases such as stack tilt, an aluminum tab angle detection is added, and the two right-angle positions A and B of the core to be tested away from the tab and the right-angle position C near the aluminum tab are selected. When the core to be tested is a square core with tabs on the opposite side, a diagonal detection method is adopted, and a right-angle position A on the non-tab side and a right-angle position C on the tab side of the core to be tested are selected as target right-angle positions. When the core to be tested is an irregular core, which is mainly a core with a non-square core body and multiple right-angle positions, at least two right-angle positions on the non-tab side and one right-angle position on the tab side of the core to be tested are selected as target right-angle positions, for example, Figure 3 As shown, for irregular-sized and special-shaped stacked cores, the copper tab angle detection is added, that is, four-corner detection, three right-angle positions A, B, and C away from the tab and the right-angle position D near the copper tab.

[0054] In this embodiment, the preset distance values ​​include three groups, the first group includes a first preset value, a second preset value, and a third preset value, and the first preset value, the second preset value, and the third preset value decrease in sequence; the second group includes a fourth preset value, a fifth preset value, and a sixth preset value, and the fourth preset value, the fifth preset value, and the sixth preset value increase in sequence; the third group includes a seventh preset value, an eighth preset value, and a ninth preset value, and the seventh preset value, the eighth preset value, and the ninth preset value increase in sequence.

[0055] Place the core stack to be tested on the rotating stage, start the X-ray transmitter and the X-ray receiver. In the initial state, the non-ear side of the core stack to be tested is parallel to the X-ray. When the operator inputs the model of the core stack to be tested into the detection mechanism, the detection mechanism will determine the target right-angle position of the core stack to be tested according to the shape of the core stack to be tested. At the same time, the detection mechanism also automatically generates a first preset value, a second preset value, a third preset value, a fourth preset value, a fifth preset value, a sixth preset value, a seventh preset value, an eighth preset value and a ninth preset value.

[0056] S2. Emit X-rays toward at least two target right-angle positions of the stacked core and receive X-rays that pass through the target right-angle positions of the stacked core to obtain at least two images.

[0057] The detection mechanism controls the rotating stage to drive the core stack to rotate a predetermined angle according to the target right angle position of the core stack to be tested, so that the target right angle position of the core stack to be tested reaches the X-ray path in turn, and the X-ray receiver generates the following Figure 4 Imaging at each right angle shown.

[0058] S3. Obtain the distance between the projections of any adjacent positive and negative electrode ends of the stacked core at the corresponding target right angles based on each image, such as Figure 5 As shown, this distance is defined as the positive and negative range. The maximum positive and negative range of each target right-angle position is obtained and compared with the first preset value, the second preset value, and the third preset value respectively. The coating quality between the positive and negative electrodes of the stacked core to be tested is determined based on the comparison results.

[0059] Specifically, when the maximum positive and negative pole difference is greater than the first preset value, it is confirmed that the coating quality between the positive and negative electrodes of the stacked core to be tested is at an excellent level; when the maximum positive and negative pole difference is less than the first preset value and greater than the second preset value, it is confirmed that the coating quality between the positive and negative electrodes of the stacked core to be tested is at a good level; when the maximum positive and negative pole difference is less than the second preset value and greater than the third preset value, it is confirmed that the coating quality between the positive and negative electrodes of the stacked core to be tested is at a qualified level; when the maximum positive and negative pole difference is less than the third preset value, it is confirmed that the coating quality between the positive and negative electrodes of the stacked core to be tested is at an unqualified level, and manual intervention is required for judgment.

[0060] S4. Obtain the distance between the projections of any two adjacent positive electrode end points of the stacked core at the corresponding target right angles according to each image, such as Figure 5 As shown, the distance is defined as the positive electrode range; the maximum positive electrode range of each target right-angle position is obtained and the maximum positive electrode range of each target right-angle position is compared with the fourth preset value, the fifth preset value, and the sixth preset value respectively, and the coating quality between the positive electrodes of the stacked core to be tested is judged according to the comparison results.

[0061] Specifically, when the maximum positive electrode same range is less than the fourth preset value, it is confirmed that the coating quality between the positive electrodes of the stacked core to be tested is at an excellent level; when the maximum positive electrode same range is greater than the fourth preset value and less than the fifth preset value, it is confirmed that the coating quality between the positive electrodes of the stacked core to be tested is at a good level; when the maximum positive electrode same range is greater than the fifth preset value and less than the sixth preset value, it is confirmed that the coating quality between the positive electrodes of the stacked core to be tested is at a qualified level; when the maximum positive electrode same range is greater than the sixth preset value, it is confirmed that the coating quality between the positive electrodes of the stacked core to be tested is at an unqualified level, and manual intervention is required for judgment.

[0062] S5. Obtain the distance between the projections of any two adjacent negative electrode end points of the stacked core at the corresponding target right angles according to each image, such as Figure 5 As shown, the distance is defined as the negative electrode range; the maximum negative electrode range of each target right-angle position is obtained and the maximum negative electrode range of each target right-angle position is compared with the seventh preset value, the eighth preset value, and the ninth preset value respectively, and the coating quality between the negative electrodes of the stacked core to be tested is judged according to the comparison results.

[0063] Specifically, when the maximum negative electrode same range is less than the seventh preset value, the negative electrode coating quality of the stacked core to be tested is confirmed to be at an excellent level; when the maximum negative electrode same range is greater than the seventh preset value and less than the eighth preset value, the negative electrode coating quality of the stacked core to be tested is confirmed to be at a good level; when the maximum negative electrode same range is greater than the eighth preset value and less than the ninth preset value, the negative electrode coating quality of the stacked core to be tested is confirmed to be at a qualified level; when the maximum negative electrode same range is greater than the ninth preset value, the negative electrode coating quality of the stacked core to be tested is confirmed to be at an unqualified level, and manual intervention is required for judgment.

[0064] S6. Determine the overall coating quality of the stacked core to be tested based on the coating quality between the positive and negative electrodes, the coating quality between the positive electrodes, and the coating quality between the negative electrodes.

[0065] Specifically, when the coating quality between the positive electrodes, between the negative electrodes, and between the positive and negative electrodes are all at the excellent level, the overall coating quality of the core stack to be tested is confirmed to be at the excellent level; when the coating quality between the positive electrodes, between the negative electrodes, and between the positive and negative electrodes are all at the good level or above, the overall coating quality of the core stack to be tested is confirmed to be at the good level; when the coating quality levels between the positive electrodes, between the negative electrodes, and between the positive and negative electrodes are all at the qualified level or above, the overall coating quality of the core stack to be tested is confirmed to be at the qualified level; when at least one of the coating quality levels between the positive electrodes, between the negative electrodes, and between the positive and negative electrodes is at the qualified level, the overall coating quality of the core stack to be tested is confirmed to be at the qualified level; otherwise, the overall coating quality of the core stack to be tested is confirmed to be at the unqualified level.

[0066] Next, the present invention is further described using a conventional square stacked core with tabs on the same side. The steps for testing the coating quality of the conventional square stacked core with tabs on the same side are as follows:

[0067] Step 1: Place the square stacked core with the conventional tabs on the same side on the rotating platform. The square stacked core includes 22 layers of positive electrode sheets and 23 layers of negative electrode sheets. The positive electrode sheets and the negative electrode sheets are arranged alternately. Figure 2 As shown, the two right-angled positions A and B on the non-ear side of the conventional square stacked core with the ear on the same side are selected as the target right-angled positions. According to experience, the first preset value is set to 1.5mm, the second preset value is 1mm, the third preset value is 0.5mm, the fourth preset value is 0.2mm, the fifth preset value is 0.35mm, the sixth preset value is 0.5mm, the seventh preset value is 0.2mm, the eighth preset value is 0.35mm, and the ninth preset value is 0.5mm.

[0068] Step 2: In the initial state, the AB angle of the square core is parallel to the X-ray. First, rotate the stage to drive the square core to rotate 45 degrees. At this time, the central axis of the square core is 45 degrees to the X-ray. The right angle position A is located on the X-ray path. The image of the right angle position A is obtained. According to the image of the right angle position A, the projection value C of the positive and negative pole pieces of any adjacent positive and negative pole pieces at the right angle position A is obtained. A-1 、C A-2 ...C A-44 , obtain the positive pole difference D of any two adjacent positive pole pieces at right angles to A A-1 、D A-2 ...D A-21 , obtain the negative pole difference E of any two adjacent negative pole pieces at right angles to A A-1 、E A-2 ...E A-22 ;

[0069] Step 3: The rotating stage drives the square core stack to rotate 90 degrees. At this time, the central axis of the square core stack is 45 degrees to the X-ray. The right angle position B is located on the X-ray path. The image of the right angle position B is obtained. According to the image of the right angle position B, the projection value C of the positive and negative pole pieces of any adjacent positive and negative pole pieces at the right angle position B is obtained. B-1 、C B-2 ...C B-44 , obtain the positive pole difference D of any two adjacent positive pole pieces at right angles to B B-1 、D B-2 ...D B-21 , obtain the negative pole difference E of any two adjacent negative pole pieces at right angles to B B-1 、E B-2 ...E B-22 ;

[0070] Step 4: Obtain the maximum positive pole range D at right angles A and B. A-max 、D B-max , the maximum negative electrode same range E A-max 、E B-max , maximum positive and negative difference CA-max , C B-max ;

[0071] Step 5: D A-max 、D B-max The values ​​are compared with the fourth preset value, the fifth preset value and the sixth preset value respectively to determine the coating quality level between the positive electrodes of the stacked core.

[0072] Step 6: E A-max 、E B-max Compare with the seventh preset value, the eighth preset value and the ninth preset value respectively to determine the coating quality level between the negative electrodes of the stacked core;

[0073] Step 7: C A-max 、C B-max Compare with the first preset value, the second preset value and the third preset value respectively to determine the coating quality level of the positive and negative electrodes of the stacked core;

[0074] Step 8: Comprehensively determine the coating quality level of the core stack based on the coating quality levels between the positive electrodes, between the negative electrodes, and between the positive and negative electrodes of the core stack.

[0075] Next, the present invention is further described using a special-shaped stacked core of unconventional size. The steps for testing the coating quality of the special-shaped stacked core of unconventional size are as follows:

[0076] Step 1: Place the irregular-sized stacked core on the rotating platform. The irregular-shaped stacked core includes 22 layers of positive electrode sheets and 23 layers of negative electrode sheets. The positive electrode sheets and the negative electrode sheets are arranged alternately. Figure 3 As shown, the three right-angle positions A, B, and C on the non-ear side of the special-shaped stacked core and the right-angle position D on the copper ear side are selected as the target right-angle positions. According to experience, the first preset value is set to 1.5mm, the second preset value is 1mm, the third preset value is 0.5mm, the fourth preset value is 0.2mm, the fifth preset value is 0.35mm, the sixth preset value is 0.5mm, the seventh preset value is 0.2mm, the eighth preset value is 0.35mm, and the ninth preset value is 0.5mm.

[0077] Step 2: In the initial state, the AB angle side of the special-shaped stacked core is parallel to the X-ray. First, the carrier is rotated to drive the special-shaped stacked core to rotate 45 degrees. The right angle position A is located on the X-ray path, and the image of the right angle position A is obtained. According to the image of the right angle position A, the projection value C of the positive and negative pole pieces of any adjacent positive and negative pole pieces at the right angle position A is obtained. A-1 、C A-2 ...C A-44 , obtain the positive pole difference D of any two adjacent positive pole pieces at right angles to A A-1 、D A-2 ...D A-21 , obtain the negative pole difference E of any two adjacent negative pole pieces at right angles to AA-1 、E A-2 ...E A-22 ;

[0078] Step 3: The rotating stage drives the shaped stacked core to rotate 90 degrees. At this time, the center axis of the shaped stacked core is 45 degrees to the X-ray. The right angle position B is located on the X-ray path. The image of the right angle position B is obtained. According to the image of the right angle position B, the projection value C of the positive and negative pole pieces of any adjacent positive and negative pole pieces at the right angle position B is obtained. B-1 、C B-2 ...C B-44 , obtain the positive pole difference D of any two adjacent positive pole pieces at right angles to B B-1 、D B-2 ...D B-21 , obtain the negative pole difference E of any two adjacent negative pole pieces at right angles to B B-1 、E B-2 ...E B-22 ;

[0079] Step 4: The rotating stage drives the special-shaped stacked core to rotate 90 degrees. The C right angle position is located on the X-ray path, and the image of the C right angle position is obtained. According to the image of the C right angle position, the projection value C of the positive and negative pole pieces of any adjacent positive and negative pole pieces at the C right angle position is obtained. C-1 、C C-2 ...C C-44 , obtain the positive pole difference D of any two adjacent positive pole pieces at right angles to C C-1 、D C- 2...D C-21 , obtain the negative pole difference E of any two adjacent negative pole pieces at right angles to C C-1 、E C-2 ...E C-22 ;

[0080] Step 5: The rotating stage drives the special-shaped stacked core to rotate 90 degrees. The right angle position D is located on the X-ray path, and the image of the right angle position D is obtained. According to the image of the right angle position D, the projection value C of the positive and negative pole pieces of any adjacent positive and negative pole pieces at the right angle position B is obtained. D-1 、C D-2 ...C D-44 , obtain the positive pole difference D of any two adjacent positive pole pieces at right angles to D D-1 、D D- 2...D D-21 , obtain the negative pole difference E of any two adjacent negative pole pieces at right angles to D D-1 、E D-2 ...E D-22 ;

[0081] Step 6: Get the maximum positive pole range D of right angle position A, right angle position B, right angle position C, and right angle position D A-max 、D B-max 、D C-max 、D D-max , the maximum negative electrode same range E A-max 、E B-max 、E C-max 、D D-max , maximum positive and negative difference C A-max , C B-max 、C C-max 、C D-max ;

[0082] Step 7: D A-max 、D B-max 、D C-max 、D D-max Compare with the fourth preset value, the fifth preset value and the sixth preset value respectively to determine the coating quality level between the positive electrodes of the stacked core;

[0083] Step 8: E A-max 、E B-max 、E C-max 、E D-max Compare with the seventh preset value, the eighth preset value and the ninth preset value respectively to determine the coating quality level between the negative electrodes of the stacked core;

[0084] Step 9: C A-max 、C B-max 、C C-max , C D-max Compare with the first preset value, the second preset value and the third preset value respectively to determine the coating quality level of the positive and negative electrodes of the stacked core;

[0085] Step 10: Comprehensively determine the coating quality level of the core stack based on the coating quality levels between the positive electrodes, between the negative electrodes, and between the positive and negative electrodes of the core stack.

[0086] It should be noted that when a component is referred to as being "mounted on" another component, it may be directly on the other component or there may be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a central component. When a component is considered to be "fixed to" another component, it may be directly fixed to the other component or there may be a central component.

[0087] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0088] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0089] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for detecting the coating quality of stacked core pole pieces, characterized in that: It includes the following steps: S1. Select at least two target right-angle positions and preset distance values ​​according to the shape of the core stack to be measured; S2. Emitting X-rays at a predetermined angle to the central axis of the core stack at right angles to at least two target positions of the core stack and receiving X-rays transmitted through the core stack to obtain at least two images; S3. Obtain the distance between the projections of the endpoints of the positive and negative electrodes of any adjacent ones of the stacked core at the corresponding target right-angle positions based on each of the images, and define the distance as the positive and negative extremes; obtain the maximum positive and negative extremes of each target right-angle position and compare the maximum positive and negative extremes of each target right-angle position with the preset distance values, respectively, and judge the coating quality between the positive and negative electrodes of the stacked core to be tested based on the comparison results.

2. The method for detecting the coating quality of stacked core pole pieces according to claim 1, characterized in that: The preset distance values ​​include a first preset value, a second preset value, and a third preset value, and the first preset value, the second preset value, and the third preset value decrease in sequence. In step S3, the method for determining the coating quality between the positive and negative electrodes of the stacked core to be tested is: When the maximum positive-negative difference is greater than the first preset value, it is confirmed that the coating quality between the positive and negative electrodes of the stacked core to be tested is at an excellent level; When the maximum positive and negative pole difference is less than the first preset value and greater than the second preset value, it is confirmed that the coating quality between the positive and negative poles of the stacked core to be tested is at a good level; When the maximum positive and negative pole difference is less than the second preset value and greater than the third preset value, it is confirmed that the coating quality between the positive and negative electrodes of the stacked core to be tested is at a qualified level; When the maximum positive-negative pole difference is less than the third preset value, it is confirmed that the coating quality between the positive and negative poles of the stacked core to be tested is at an unqualified level.

3. The method for detecting the coating quality of stacked core pole pieces according to claim 1, characterized in that: It also includes the following steps: S4. Obtain the distance between the projections of any two adjacent positive electrode end points of the stacked core at the corresponding target right-angle position based on each of the images, and define the distance as the positive electrode range; obtain the maximum positive electrode range of each target right-angle position and compare the maximum positive electrode range of each target right-angle position with the preset distance value, and judge the coating quality between the positive electrodes of the stacked core to be tested based on the comparison results.

4. The method for detecting the coating quality of stacked core pole pieces according to claim 3, characterized in that: The preset distance value further includes a fourth preset value, a fifth preset value, and a sixth preset value, and the fourth preset value, the fifth preset value, and the sixth preset value increase in sequence. In step S4, the method for judging the coating quality between the positive electrodes of the stacked core to be tested is: When the maximum positive electrode same range is less than the fourth preset value, it is confirmed that the positive electrode coating quality of the stacked core to be tested is at an excellent level; When the maximum positive electrode same range is greater than the fourth preset value and less than the fifth preset value, it is confirmed that the coating quality between the positive electrodes of the stacked core to be tested is at a good level; When the maximum positive electrode same range is greater than the fifth preset value and less than the sixth preset value, it is confirmed that the coating quality between the positive electrodes of the stacked core to be tested is at a qualified level; When the maximum positive electrode same range is greater than the sixth preset value, it is confirmed that the coating quality between the positive electrodes of the stacked core to be tested is at an unqualified level.

5. The method for detecting the coating quality of stacked core pole pieces according to claim 3, characterized in that: It also includes the following steps: S5. Obtain the distance between the projections of any two adjacent negative electrode end points of the stacked core at the corresponding target right-angle position based on each of the images, and define the distance as the negative electrode homogeneity range; obtain the maximum negative electrode homogeneity range of each target right-angle position and compare the maximum negative electrode homogeneity range of each target right-angle position with the preset distance value, and judge the coating quality between the negative electrodes of the stacked core to be tested based on the comparison results.

6. The method for detecting the coating quality of stacked core pole pieces according to claim 5, characterized in that: The preset distance values ​​further include a seventh preset value, an eighth preset value, and a ninth preset value, and the seventh preset value, the eighth preset value, and the ninth preset value increase in sequence. In step S5, the method for determining the coating quality between the negative electrodes of the stacked core to be tested is: When the maximum negative electrode same range is less than the seventh preset value, it is confirmed that the negative electrode coating quality of the stacked core to be tested is at an excellent level; When the maximum negative electrode same range is greater than the seventh preset value and less than the eighth preset value, it is confirmed that the coating quality between the negative electrodes of the stacked core to be tested is at a good level; When the maximum negative electrode same range is greater than the eighth preset value and less than the ninth preset value, it is confirmed that the coating quality between the negative electrodes of the stacked core to be tested is at a qualified level; When the maximum negative electrode same range is greater than the ninth preset value, it is confirmed that the coating quality between the negative electrodes of the stacked core to be tested is at an unqualified level.

7. The method for detecting the coating quality of stacked core pole pieces according to claim 5, characterized in that: It also includes the following steps: S6. Determine the overall coating quality of the stacked core to be tested based on the coating quality between the positive and negative electrodes, the coating quality between the positive electrodes, and the coating quality between the negative electrodes.

8. The method for detecting the coating quality of stacked core pole pieces according to claim 7, characterized in that: In step S6, the method for judging the overall coating quality of the stacked core to be tested is: When the coating quality between positive electrodes, between negative electrodes, and between positive and negative electrodes are all at the excellent level, it is confirmed that the overall coating quality of the tested stacked core is at the excellent level; When the coating quality between positive electrodes, between negative electrodes, and between positive and negative electrodes are all at good level or above, it is confirmed that the overall coating quality of the tested stacked core is at good level; When the coating quality levels between the positive electrodes, between the negative electrodes, and between the positive and negative electrodes are all qualified or above, it is confirmed that the overall coating quality of the tested stacked core is qualified; When at least one of the coating quality levels between the positive electrodes, between the negative electrodes, and between the positive and negative electrodes is at a qualified level, it is confirmed that the overall coating quality of the tested stacked core is at a qualified level; Otherwise, the overall coating quality of the tested stacked core is confirmed to be unqualified.

9. The method for detecting the coating quality of stacked core pole pieces according to claim 1, characterized in that: In step S1, when the stacked core to be tested is a square stacked core with the tabs on the same side, two right-angled positions of the stacked core to be tested away from the tabs are selected as target right-angled positions; when the stacked core to be tested is a square stacked core with the tabs on the opposite sides, one right-angled position on the non-tab side and one right-angled position on the tab side of the stacked core to be tested are selected as target right-angled positions; when the stacked core to be tested is an irregular-shaped stacked core, at least two right-angled positions on the non-tab side and one right-angled position on the tab side of the stacked core to be tested are selected as target right-angled positions.

10. A device for detecting the quality of core stacking, characterized in that: It adopts the method for detecting the coating quality of the stacked core pole piece according to any one of claims 1 to 9, which comprises a rotating stage, two brackets, an X-ray transmitter, an X-ray receiver and a detection mechanism; The rotating stage is used to drive the stacked core to be tested to rotate; The two brackets are located on both sides of the rotating platform and arranged opposite to each other. The X-ray emitter and the X-ray receiver are respectively installed on the top of the two brackets. The X-ray emitter is used to emit X-rays at the target right angle of the core stack to be tested, and the X-ray receiver is used to receive the X-rays passing through the target right angle of the core stack and form an image; the detection mechanism is connected to the X-ray receiver and performs coating quality inspection on the core stack to be tested.

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