Production process of diaphragm ending one-way roller based on winding procedure

Abstract

The invention relates to the technical field of battery manufacturing, in particular to a production process of a diaphragm ending one-way roller based on a winding procedure, which comprises the following steps: acquiring an end face image and a side face image of a naked battery cell wound on a winding machine; based on the interlayer gap uniformity index, determining whether the interlayer gap uniformity of the naked battery cell reaches the standard or not, and according to the difference value, determining the preset pressure and the rotating speed applied to the winding machine by the one-way roller; determining whether the flatness of the side surface of the naked battery cell is qualified or not based on the microscopic fluctuation characterization parameters, and determining the preset number of rerotation turns of the winding machine and increasing the preset pressure according to the relative difference; determining whether the winding stability of the naked battery cell reaches the standard or not based on the batch gap fluctuation rate, determining to increase the tension applied to the battery cell material belt in the winding process of the next batch according to the ratio, and increasing the number of turns of rotation; and after the winding is completed, the gluing machine attaches a termination adhesive tape to the qualified naked battery cell. The winding efficiency of the naked battery cell in the winding process is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery manufacturing, and in particular to a production process of a diaphragm tailing one-way roller based on a winding process. Background Art

[0002] In the lithium battery production process, the winding process winds the positive electrode sheet, negative electrode sheet and separator in a specific order to shape the basic shape of the battery cell. The winding machine winds the slit electrode sheet and separator into a core. In the winding process, a series of technical problems are very likely to occur in the separator finishing stage. If the interlayer spacing of the separator winding is uneven, it will cause an imbalance in the electric field distribution inside the battery, and then the battery capacity cannot be fully released, and the charging and discharging efficiency is greatly reduced. In addition, once wrinkles are generated during the separator winding process, it will not only cause the local thickness of the separator to change, affecting the transmission of lithium ions, but may also cause the separator to be damaged during subsequent battery use due to stress concentration, resulting in a short circuit between the positive and negative electrodes, posing a serious safety hazard.

[0003] Chinese patent application publication number: CN119725346A discloses a pole piece composite device, a bare cell winding device and a bare cell winding method, including: a first composite roller assembly, including a first composite roller and a second composite roller, the first composite roller and the second composite roller are arranged opposite to each other, and the first composite roller and the second composite roller are used to laminate the first diaphragm, the first pole piece and the second diaphragm together in sequence; a side diaphragm composite assembly, used to composite the part of the first diaphragm extending beyond the side of the first pole piece with the part of the second diaphragm extending beyond the side of the first pole piece.

[0004] However, the following problems exist in the existing technology: after the positive and negative electrode sheets and the diaphragm are compounded, a winding process is carried out, and the uneven interlayer spacing and surface unevenness existing in the final stage of the diaphragm in the winding process are not deeply processed, resulting in a low quality pass rate of the bare battery cells in the winding process, and thus resulting in a low winding efficiency of the bare battery cells in the winding process. Summary of the Invention

[0005] To this end, the present invention provides a production process for a one-way roller for finishing the diaphragm based on a winding process, which is used to overcome the problem in the prior art that the positive and negative electrode sheets and the diaphragm are compounded before the winding process, and the uneven interlayer spacing and surface unevenness existing in the diaphragm finishing stage of the winding process are not deeply processed, resulting in a low quality pass rate of the bare battery cells in the winding process, thereby resulting in a low winding efficiency of the bare battery cells in the winding process.

[0006] To achieve the above-mentioned object, the present invention provides a production process for a diaphragm tailing one-way roller based on a winding process, comprising: Acquire end-face and side-face images of the bare battery cell wound on the winding machine; Extracting the bare cell interlayer spacing feature of the end face image to determine whether the bare cell interlayer spacing uniformity meets the standard based on the obtained interlayer gap uniformity index, and determining the preset pressure applied by the one-way roller to the winder and the re-rotation speed of the winder according to the difference between the interlayer gap uniformity index and the preset interlayer gap uniformity index; Extracting microscopic relief features from the side image to determine whether the flatness of the side of the bare cell is qualified based on the obtained microscopic relief characterization parameter, and determining a preset number of rotations of the winding machine and an increase in the preset pressure based on a relative difference between the microscopic relief characterization parameter and a preset microscopic relief characterization parameter; Obtaining layer gap data of several different batches of qualified bare battery cells to determine whether the bare battery cell winding stability meets the standard based on the obtained batch gap fluctuation rate, and determining to increase the tension applied to the battery cell strip during the next batch of winding according to the ratio of the preset batch gap fluctuation rate to the batch gap fluctuation rate, and increasing the preset number of rotations when the increased tension reaches the rated maximum tension; After winding is completed, the gluing machine attaches the termination tape to the qualified bare battery cells.

[0007] Furthermore, the non-compliance of the uniformity of the interlayer spacing of the bare cell is determined based on a comparison result that the interlayer gap uniformity index is greater than a preset interlayer gap uniformity index.

[0008] Furthermore, the process of determining the interlayer gap uniformity index includes: Extracting the inter-layer boundary of the end face image by graying and binarization to obtain the gap value of each layer; The average value of the gap between each layer of several bare cells that have passed the winding test in the past is recorded as the reference gap value, and the deviation between the gap between each layer and the reference gap value is calculated; The interlayer gap uniformity index is determined according to the deviation value, the reference layer gap value, the number of layer gaps, and the maximum deviation value.

[0009] Furthermore, under the condition that it is determined that the uniformity of the interlayer spacing of the bare battery core does not meet the standard, the process of determining the preset pressure of the one-way roller and the speed of the winding machine based on the difference between the interlayer gap uniformity index and the preset interlayer gap uniformity index includes: Determining, based on the comparison result that the difference is less than or equal to the preset difference, that the one-way roller applies pressure to the winder at a first preset pressure, and reducing the speed of the winder at a first preset speed adjustment coefficient; Based on the comparison result that the difference is greater than the preset difference, it is determined that the one-way roller applies pressure to the winder at a second preset pressure, and the speed of the winder is reduced by a second preset speed adjustment coefficient.

[0010] Furthermore, the unqualified flatness of the side of the bare cell is determined based on the comparison result that the micro-undulation characterization parameter is greater than the preset micro-undulation characterization parameter.

[0011] Furthermore, the process of determining the micro-relief characterization parameter includes: Reconstruct the three-dimensional shape of the side image through stereo vision algorithm; Selecting several areas on the three-dimensional topography, extracting the height data of the areas, and calculating the average height deviation of the areas; The average height deviation of the side of the bare battery cells that pass the winding process is recorded as the reference deviation; The micro-relief characterization parameter is determined based on the average height deviation and the reference deviation.

[0012] Furthermore, under the condition that the flatness of the side of the bare battery cell is determined to be unqualified, the process of determining the preset number of rotations of the winding machine and adjusting the preset pressure of the one-way roller based on the relative difference between the micro-undulation characterization parameter and the preset micro-undulation characterization parameter includes: Determining, based on the comparison result that the relative difference is less than or equal to the preset relative difference, that the winding machine rotates at a first preset number of revolutions, and increasing the preset pressure of the one-way roller by a first preset pressure adjustment coefficient; Based on the comparison result that the relative difference is greater than the preset relative difference, it is determined that the winder rotates at a second preset number of rotations, and the preset pressure of the one-way roller is increased by a second preset pressure adjustment coefficient.

[0013] Furthermore, the fact that the winding stability of the bare battery cell does not meet the standard is determined based on the comparison result that the batch gap fluctuation rate is greater than the preset batch gap fluctuation rate.

[0014] Furthermore, under the condition that it is determined that the winding stability of the bare battery cell does not meet the standard, based on the comparison result that the ratio of the preset batch gap fluctuation rate and the batch gap fluctuation rate is less than or equal to the preset ratio, it is determined that the tension applied to the battery cell strip during the next batch winding process is increased by the first preset tension adjustment coefficient, and when the increased tension reaches the rated maximum tension, the preset number of rotations is increased by the first preset number of turns adjustment coefficient.

[0015] Furthermore, under the condition that it is determined that the winding stability of the bare battery cell does not meet the standard, based on the comparison result that the ratio of the preset batch gap fluctuation rate and the batch gap fluctuation rate is greater than the preset ratio, it is determined that the tension applied to the battery cell strip during the next batch winding process is increased by a second preset tension adjustment coefficient, and when the increased tension reaches the rated maximum tension, the preset number of rotations is increased by the second preset number of turns adjustment coefficient.

[0016] Compared with the prior art, the beneficial effect of the present invention is that the present invention obtains end and side images, and judges whether the uniformity of the interlayer spacing of the bare battery core meets the standard according to the interlayer gap uniformity index of the end image, determines the preset pressure applied by the one-way roller on the winder and the speed of the winder to rotate again according to the difference between the interlayer gap uniformity index and the preset interlayer gap uniformity index, dynamically adjusts the pressure of the one-way roller and the speed of the winder to optimize the winding process and make the interlayer spacing more uniform, judges whether the flatness of the side of the bare battery core meets the standard according to the micro-undulation characterization parameters of the side image, and determines the time for the winder to rotate again according to the relative difference between the micro-undulation characterization parameters and the preset micro-undulation characterization parameters. The preset number of rotations and the increase of preset pressure improve the flatness of the side of the bare battery cell. The winding stability of the bare battery cell is judged according to the batch gap fluctuation rate. If it does not meet the standard, the tension applied to the battery cell material strip during the winding process of the next batch is increased. When the increased tension reaches the rated maximum tension, the preset number of rotations is increased, which improves the quality consistency of the product and the stability of the winding process, accurately controls the uniformity of the interlayer gap, reduces the fluctuation of the battery internal resistance, and improves the consistency of energy density. The optimization of the side flatness reduces the risk of wrinkles on the battery cell surface, reduces the quality fluctuation caused by material differences, reduces the risk of electrode breakage, and improves the winding efficiency of the bare battery cell in the winding process.

[0017] Furthermore, the present invention analyzes the uniformity of interlayer spacing through the end face image of the bare battery cell, dynamically adjusts the unidirectional roller pressure and the winding machine speed, optimizes the tension of the battery cell strip, improves the winding stability, reduces quality fluctuations, and enhances the flexibility of the production line, thereby improving the winding efficiency of the bare battery cell in the winding process.

[0018] Furthermore, the present invention determines whether the flatness is qualified through the micro-undulation characterization parameters obtained through the side image. If it is unqualified, the number of rotations of the winding machine and the preset pressure of the one-way roller are adjusted to avoid problems such as poor connection of the tab welding and reduced sealing of the package due to excessive micro-undulations. The pressure and the number of rotations work together to improve the side undulations through mechanical compaction, and simultaneously optimize the uniformity of the interlayer gap, thereby reducing the risk of internal short circuit in the battery cell.

[0019] Furthermore, the present invention calculates the batch gap fluctuation rate by obtaining the layer gap data of different batches of bare battery cells, and compares it with the preset batch gap fluctuation rate to determine whether the winding stability meets the standard. If it does not meet the standard, the tension of the battery cell strip and the number of rotations of the winding machine during the next batch of winding are adjusted according to the ratio of the preset batch gap fluctuation rate to the batch gap fluctuation rate, thereby improving the winding stability and consistency of the bare battery cells, reducing rework and scrapping caused by winding stability problems, and improving production efficiency. The winding stability improves the uniformity and stability of the internal structure of the battery cells, thereby improving the safety of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a flow chart of a production process of a diaphragm finishing one-way roller based on a winding process according to an embodiment of the present invention; Figure 2 A flow chart for determining whether the uniformity of the spacing between bare cell layers meets the standards according to an embodiment of the present invention; Figure 3 This is a flow chart for determining whether the flatness of the side of a bare cell is qualified according to an embodiment of the present invention; Figure 4 This is a flow chart for determining whether the winding stability of a bare battery cell meets the standards according to an embodiment of the present invention; Figure 5 Schematic diagram of a production process of a diaphragm finishing one-way roller based on a winding process according to an embodiment of the present invention; In the figure, 1. Battery core strip; 2. Winding machine; 3. One-way roller; 4. Gluing machine. DETAILED DESCRIPTION

[0021] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention.

[0022] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0023] It should be pointed out that the data in this embodiment are obtained by comprehensive analysis and evaluation of the historical test data and the corresponding historical test results of the three months before this test. It can be understood by those skilled in the art that the present invention can determine the above parameters for a single item by selecting the value with the highest proportion as the preset standard parameter based on the data distribution, using weighted summation to use the obtained value as the preset standard parameter, substituting each historical data into a specific formula and using the value obtained by the formula as the preset standard parameter or other selection methods, as long as the present invention can clearly define the different specific situations in the single determination process through the obtained values.

[0024] See also Figure 1 As shown, it is a flow chart of the production process of the diaphragm tailing one-way roller based on the winding process according to an embodiment of the present invention.

[0025] The production process of the diaphragm finishing one-way roller based on the winding process in the embodiment of the present invention includes: Step S1, obtaining an end face image and a side face image of a bare battery cell wound on a winding machine; Step S2: extracting the bare cell interlayer spacing feature of the end face image to determine whether the bare cell interlayer spacing uniformity meets the standard based on the obtained interlayer gap uniformity index, and determining the preset pressure applied by the one-way roller on the winder and the speed of the winder's re-rotation according to the difference between the interlayer gap uniformity index and the preset interlayer gap uniformity index; Step S3, extracting micro-undulation features of the side image to determine whether the flatness of the side of the bare cell is qualified based on the obtained micro-undulation characterization parameter, and determining the preset number of rotations of the winder and the increase of the preset pressure according to the relative difference between the micro-undulation characterization parameter and the preset micro-undulation characterization parameter; Step S4, obtaining the layer gap data of several different batches of qualified bare battery cells to determine whether the bare battery cell winding stability meets the standard based on the obtained batch gap fluctuation rate, and determining to increase the tension applied to the battery cell strip during the next batch of winding according to the ratio of the preset batch gap fluctuation rate to the batch gap fluctuation rate, and increasing the preset number of rotations when the increased tension reaches the rated maximum tension; Step S5: After the winding is completed, the gluing machine affixes the termination tape to the bare battery cell that has passed the winding.

[0026] Specifically, the present invention obtains end and side images, and judges whether the uniformity of the interlayer spacing of the bare battery core meets the standard based on the interlayer gap uniformity index of the end image; determines the preset pressure applied by the one-way roller on the winder and the speed of the winder's re-rotation based on the difference between the interlayer gap uniformity index and the preset interlayer gap uniformity index; dynamically adjusts the pressure of the one-way roller and the speed of the winder to optimize the winding process and make the interlayer spacing more uniform; judges whether the flatness of the side of the bare battery core is qualified based on the micro-undulation characterization parameters of the side image; and determines the preset number of rotations of the winder's re-rotation based on the relative difference between the micro-undulation characterization parameters and the preset micro-undulation characterization parameters. and increase the preset pressure, improve the flatness of the side of the bare battery cell, judge whether the winding stability of the bare battery cell meets the standard according to the batch gap fluctuation rate, and increase the tension applied to the battery cell material strip during the winding process of the next batch if it does not meet the standard. When the increased tension reaches the rated maximum tension, increase the preset number of rotations, improve the quality consistency of the product, improve the stability of the winding process, accurately control the uniformity of the interlayer gap, reduce the fluctuation of the battery internal resistance, and improve the consistency of energy density. The optimization of the side flatness reduces the risk of wrinkles on the battery cell surface, reduces the quality fluctuation caused by material differences, reduces the risk of electrode breakage, and improves the winding efficiency of the bare battery cell in the winding process.

[0027] Specifically, in an embodiment of the present invention, the positive electrode sheet, the negative electrode sheet and the separator are compounded through a process to form a battery material strip for winding a bare battery cell. The battery material strip is wound on a winding machine through a winding process to form a bare battery cell. The tension of the battery material strip is 0.1 to 0.3 N / mm², preferably 0.2 N / mm². The above process is a conventional process and will not be repeated here.

[0028] Specifically, in the embodiment of the present invention, the bare cell winding is determined to be qualified under the conditions that the uniformity of the bare cell layer spacing meets the standard and the side flatness is qualified.

[0029] Specifically, after the winding is completed, the embodiment of the present invention uses a hot cutter or laser to cut the diaphragm to retain the end length of the diaphragm, and the gluing machine attaches the termination tape after the bare battery cell is wound to the standard.

[0030] Specifically, in an embodiment of the present invention, industrial cameras are provided in front of and on the side of the winding machine, and the industrial cameras are used to obtain end face images and side face images of the bare battery cells wound on the winding machine.

[0031] See also Figure 2 As shown, it is a flow chart of determining whether the uniformity of the bare cell layer spacing meets the standard according to an embodiment of the present invention.

[0032] Specifically, under the condition of determining to obtain the end face image of the bare cell, the embodiment of the present invention extracts the bare cell interlayer spacing feature of the end face image to obtain the interlayer gap uniformity index and compares it with the preset interlayer gap uniformity index to determine whether the interlayer spacing uniformity of the bare cell meets the standard; When the interlayer gap uniformity index is less than or equal to the preset interlayer gap uniformity index, it is determined that the interlayer gap uniformity of the bare cell meets the standard; When the interlayer gap uniformity index is greater than the preset interlayer gap uniformity index, it is determined that the interlayer gap uniformity of the bare cell does not meet the standard.

[0033] In the embodiment of the present invention, the preset interlayer gap uniformity index value range is [0.08, 0.15], preferably 0.12, but the above value is not limited thereto, and those skilled in the art can also adjust the value according to actual needs.

[0034] In an embodiment of the present invention, the process of obtaining the interlayer gap uniformity index is as follows: the interlayer boundaries of the end face image are extracted by grayscale and binarization to obtain the gap values ​​of each layer; the average value of the gap values ​​of each layer of several bare battery cells that have passed the historical winding test is recorded as the reference layer gap value, and the deviation value of each layer gap from the reference layer gap value is calculated; the interlayer gap uniformity index is the product of the absolute value of the sum of several deviation values ​​divided by the reference layer gap value and divided by the number of layer gaps plus the product of the maximum deviation value divided by the absolute value of the reference layer gap value and the weight coefficient, and the weight coefficient is 0.3.

[0035] Specifically, in an embodiment of the present invention, when it is determined that the uniformity of the spacing between the bare battery core layers does not meet the standard, the one-way roller is pressed against the side of the winder with a preset pressure, and then the winder rotates again.

[0036] Specifically, the embodiment of the present invention determines the preset pressure of the one-way roller and the speed of the winder according to the comparison result of the difference between the interlayer gap uniformity index and the preset interlayer gap uniformity index and the preset difference; When the difference is less than or equal to the preset difference, it is determined that the one-way roller applies pressure to the winder at a first preset pressure, and the speed of the winder is reduced to a corresponding value at a first preset speed adjustment coefficient of 0.97; When the difference is greater than the preset difference, it is determined that the one-way roller applies pressure to the winder at a second preset pressure, and the speed of the winder is reduced to a corresponding value at a second preset speed adjustment coefficient of 0.93; The difference is the difference between the interlayer gap uniformity index and the preset interlayer gap uniformity index.

[0037] In the embodiment of the present invention, the preset difference value range is [0.11, 0.23], preferably 0.18, but the above value is not limited thereto, and those skilled in the art can also adjust the value according to actual needs.

[0038] In the embodiment of the present invention, the first preset pressure range is 0.1N / mm² to 0.2N / mm², preferably 0.15N / mm², and the second preset pressure range is 0.25N / mm² to 0.35N / mm², preferably 0.3N / mm².

[0039] In an embodiment of the present invention, the reduced speed is the product of the speed and the preset speed adjustment coefficient. The preset speed adjustment coefficient includes a first preset speed adjustment coefficient, which has a value of 0.97 and a second preset speed adjustment coefficient, which has a value of 0.93. In order to ensure that the adjusted speed meets actual needs, the adjustment range should not be too large, so the corresponding adjustment coefficient is set to control the adjustment range.

[0040] Specifically, the present invention uses the end face image of the bare battery cell to analyze the uniformity of the interlayer spacing, dynamically adjusts the unidirectional roller pressure and the winding machine speed, optimizes the tension of the battery cell strip, improves the winding stability, reduces quality fluctuations, and enhances the flexibility of the production line, thereby improving the winding efficiency of the bare battery cell in the winding process.

[0041] See also Figure 3 As shown, it is a flow chart of determining whether the flatness of the side of a bare cell is qualified according to an embodiment of the present invention.

[0042] Specifically, the embodiment of the present invention obtains a side image of the bare cell, extracts microscopic relief features of the side image, and compares the obtained microscopic relief characterization parameter with a preset microscopic relief characterization parameter to determine whether the flatness of the side of the bare cell is qualified; When the micro-undulation characterization parameter is less than or equal to the preset micro-undulation characterization parameter, it is determined that the flatness of the side surface of the bare cell is qualified; When the micro-undulation characterization parameter is greater than the preset micro-undulation characterization parameter, it is determined that the flatness of the side surface of the bare cell is unqualified.

[0043] In the embodiment of the present invention, the preset micro-roughness characterization parameter value range is [1.0, 1.2], preferably 1.1, but the above value is not limited thereto, and those skilled in the art can also adjust the value according to actual needs.

[0044] In an embodiment of the present invention, the process of obtaining the micro-undulation characterization parameter is as follows: reconstructing the three-dimensional morphology of the side image through a stereo vision algorithm; selecting several areas on the three-dimensional morphology and extracting the height data of the areas; calculating the average height deviation of the several areas; recording the average height deviation of the side of the qualified bare battery cell as the reference deviation; the micro-undulation characterization parameter is the ratio of the average height deviation to the reference deviation, and the average height deviation is the sum of the differences between the heights of several areas and the average heights of several areas divided by the number of areas.

[0045] Specifically, in an embodiment of the present invention, under the condition that the flatness of the side surface of the bare cell is determined to be unqualified, a preset number of rotations of the winding machine is determined and a preset pressure of the one-way roller is adjusted according to a comparison result of a relative difference between the micro-undulation characterization parameter and the preset micro-undulation characterization parameter and a preset relative difference; When the relative difference is less than or equal to the preset relative difference, it is determined that the winder rotates at a first preset number of rotations, and the preset pressure of the one-way roller is increased to a corresponding value with a first preset pressure adjustment coefficient of 1.06; When the relative difference is greater than the preset relative difference, it is determined that the winder rotates at a second preset number of rotations, and the preset pressure of the one-way roller is increased to a corresponding value with a second preset pressure adjustment coefficient of 1.12; The relative difference is the relative difference between the micro-relief characterization parameter and the preset micro-relief characterization parameter.

[0046] In the embodiment of the present invention, the preset relative difference value range is [0.35, 0.45], preferably 0.4, but the above value is not limited thereto, and those skilled in the art can also adjust the value according to actual needs.

[0047] In the embodiment of the present invention, the first preset number of rotations is 2 to 4, preferably 3, and the second preset number of rotations is 6 to 8, preferably 7.

[0048] In an embodiment of the present invention, the increased preset pressure is the product of the preset pressure and the preset pressure adjustment coefficient. The preset pressure adjustment coefficient includes a first preset pressure adjustment coefficient, which has a value of 1.06 and a second preset pressure adjustment coefficient, which has a value of 1.12. The preset pressure includes the first preset pressure and the second preset pressure. In order to ensure that the adjusted preset pressure meets actual needs, the adjustment range should not be too large, so the adjustment coefficient is set accordingly to control the adjustment range.

[0049] Specifically, the present invention determines whether the flatness is qualified through the micro-undulation characterization parameters obtained through the side image. If it is unqualified, the number of rotations of the winding machine and the preset pressure of the one-way roller are adjusted to avoid problems such as poor connection of the tab welding and reduced sealing of the package due to excessive micro-undulations. The pressure and the number of rotations work together to improve the side undulations through mechanical compaction, and simultaneously optimize the uniformity of the interlayer gap, thereby reducing the risk of internal short circuit in the battery cell.

[0050] See also Figure 4 As shown, it is a flow chart of determining whether the winding stability of the bare battery cell meets the standards according to an embodiment of the present invention.

[0051] Specifically, the embodiment of the present invention obtains the layer gap data of several different batches of qualified bare battery cells to obtain the batch gap fluctuation rate, and determines whether the bare battery cell winding stability meets the standard based on the comparison result of the batch gap fluctuation rate and the preset batch gap fluctuation rate; When the batch gap fluctuation rate is less than or equal to the preset batch gap fluctuation rate, it is determined that the winding stability of the bare cell meets the standard; When the batch gap fluctuation rate is greater than the preset batch gap fluctuation rate, it is determined that the winding stability of the bare cell does not meet the standard.

[0052] In the embodiment of the present invention, the preset batch interval fluctuation rate range is [5%, 15%], preferably 10%, but the above value is not limited thereto, and those skilled in the art can also adjust the value according to actual needs.

[0053] In an embodiment of the present invention, the batch gap volatility is obtained by calculating the standard deviation of the layer gap data for each batch; calculating the average of all batch standard deviations, which is recorded as the average batch standard deviation; and calculating the standard deviation of all batch standard deviations, which is recorded as the fluctuation standard deviation. The batch gap volatility is the ratio of the fluctuation standard deviation to the average batch standard deviation multiplied by 100%.

[0054] Specifically, in an embodiment of the present invention, when it is determined that the winding stability of the bare battery cell does not meet the standard, the tension applied to the battery cell strip during the next batch of winding is adjusted according to a comparison result of the preset batch gap fluctuation rate and the ratio of the batch gap fluctuation rate and the preset ratio, and the number of rotations of the winding machine is adjusted when the adjusted tension reaches the rated maximum tension; When the ratio is less than or equal to the preset ratio, it is determined that the tension applied to the battery core strip during the next batch of winding is increased to a corresponding value by a first preset tension adjustment coefficient of 1.15, and when the increased tension reaches the rated maximum tension, the preset number of rotations is increased to a corresponding value by a first preset number of turns adjustment coefficient of 2; When the ratio is greater than the preset ratio, it is determined that the tension applied to the battery core strip during the next batch of winding is increased to a corresponding value by a second preset tension adjustment coefficient of 1.25, and when the increased tension reaches the rated maximum tension, the preset number of rotations is increased to a corresponding value by a second preset number of turns adjustment coefficient of 4; The ratio is the ratio of the preset batch-to-batch fluctuation rate to the batch-to-batch fluctuation rate.

[0055] In the embodiment of the present invention, the preset ratio range is [0.16, 0.24], preferably 0.19, but the above value is not limited thereto, and those skilled in the art can also adjust the value according to actual needs.

[0056] In an embodiment of the present invention, the increased tension is the product of the tension and a preset tension adjustment coefficient, where the preset tension adjustment coefficient includes a first preset tension adjustment coefficient, whose value is 1.15, and a second preset tension adjustment coefficient, whose value is 1.25.

[0057] In an embodiment of the present invention, the increased preset number of rotations is the preset number of rotations and the preset number adjustment coefficient. The preset number adjustment coefficient includes a first preset number adjustment coefficient, which has a value of 2 and a second preset number adjustment coefficient, which has a value of 4. The preset number of rotations includes the first preset number of rotations and the second preset number of rotations. In order to ensure that the adjusted preset number of rotations meets actual needs, the adjustment range should not be too large, so the adjustment coefficient is set accordingly to control the adjustment range.

[0058] Specifically, the present invention calculates the batch gap fluctuation rate by obtaining the layer gap data of different batches of bare battery cells, and compares it with the preset batch gap fluctuation rate to determine whether the winding stability meets the standard. If it does not meet the standard, the tension of the battery cell strip and the number of rotations of the winding machine during the next batch of winding are adjusted according to the ratio of the preset batch gap fluctuation rate to the batch gap fluctuation rate, thereby improving the winding stability and consistency of the bare battery cells, reducing rework and scrapping caused by winding stability problems, and improving production efficiency. The winding stability improves the uniformity and stability of the internal structure of the battery cells, thereby improving the safety of the battery.

[0059] See also Figure 5 As shown, it is a schematic diagram of the production process of the diaphragm tailing one-way roller based on the winding process according to an embodiment of the present invention; Battery core strip 1, which is used to composite the positive electrode sheet, negative electrode sheet and separator; A winding machine 2, which is used to wind the battery core strip 1 into a bare battery core; One-way roller 3, which is used to apply a preset pressure on the side of the winder during the winding process of the bare battery cell to improve the uniformity of the interlayer gap and the flatness of the side; The gluing machine 4 is used to attach the end tape to the end of the diaphragm after the bare battery cell is wound and qualified.

[0060] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A production process for a diaphragm tailing one-way roller based on a winding process, characterized in that: include: Acquire end-face and side-face images of the bare battery cell wound on the winding machine; Extracting the bare cell interlayer spacing feature of the end face image to determine whether the bare cell interlayer spacing uniformity meets the standard based on the obtained interlayer gap uniformity index, and determining the preset pressure applied by the one-way roller to the winder and the re-rotation speed of the winder according to the difference between the interlayer gap uniformity index and the preset interlayer gap uniformity index; Extracting microscopic relief features from the side image to determine whether the flatness of the side of the bare cell is qualified based on the obtained microscopic relief characterization parameter, and determining a preset number of rotations of the winding machine and an increase in the preset pressure based on a relative difference between the microscopic relief characterization parameter and a preset microscopic relief characterization parameter; Obtaining layer gap data of several different batches of qualified bare battery cells to determine whether the bare battery cell winding stability meets the standard based on the obtained batch gap fluctuation rate, and determining to increase the tension applied to the battery cell strip during the next batch of winding according to the ratio of the preset batch gap fluctuation rate to the batch gap fluctuation rate, and increasing the preset number of rotations when the increased tension reaches the rated maximum tension; After winding is completed, the gluing machine attaches the termination tape to the qualified bare battery cells.

2. The production process of the diaphragm finishing one-way roller based on the winding process according to claim 1 is characterized in that: The non-compliance of the uniformity of the interlayer spacing of the bare cell is determined based on the comparison result that the interlayer gap uniformity index is greater than the preset interlayer gap uniformity index.

3. The production process of the diaphragm finishing one-way roller based on the winding process according to claim 2 is characterized in that: The process of determining the interlayer gap uniformity index includes: Extracting the inter-layer boundary of the end face image by graying and binarization to obtain the gap value of each layer; The average value of the gap between each layer of several bare cells that have passed the winding test in the past is recorded as the reference gap value, and the deviation between the gap between each layer and the reference gap value is calculated; The interlayer gap uniformity index is determined according to the deviation value, the reference layer gap value, the number of layer gaps, and the maximum deviation value.

4. The production process of the diaphragm finishing one-way roller based on the winding process according to claim 3 is characterized in that: Under the condition that it is determined that the uniformity of the interlayer spacing of the bare battery core does not meet the standard, the process of determining the preset pressure of the one-way roller and the speed of the winding machine based on the difference between the interlayer gap uniformity index and the preset interlayer gap uniformity index includes: Determining, based on the comparison result that the difference is less than or equal to the preset difference, that the one-way roller applies pressure to the winder at a first preset pressure, and reducing the speed of the winder at a first preset speed adjustment coefficient; Based on the comparison result that the difference is greater than the preset difference, it is determined that the one-way roller applies pressure to the winder at a second preset pressure, and the speed of the winder is reduced by a second preset speed adjustment coefficient.

5. The production process of the diaphragm finishing one-way roller based on the winding process according to claim 4 is characterized in that: The unqualified flatness of the side of the bare cell is determined based on the comparison result that the micro-undulation characterization parameter is greater than the preset micro-undulation characterization parameter.

6. The production process of the diaphragm finishing one-way roller based on the winding process according to claim 5 is characterized in that: The process of determining the micro-relief characterization parameter includes: Reconstruct the three-dimensional shape of the side image through stereo vision algorithm; Selecting several areas on the three-dimensional topography, extracting the height data of the areas, and calculating the average height deviation of the areas; The average height deviation of the side of the bare battery cells that pass the winding process is recorded as the reference deviation; The micro-relief characterization parameter is determined based on the average height deviation and the reference deviation.

7. The production process of the diaphragm finishing one-way roller based on the winding process according to claim 6 is characterized in that: Under the condition that the flatness of the side of the bare battery cell is determined to be unqualified, the process of determining the preset number of rotations of the winding machine and adjusting the preset pressure of the one-way roller based on the relative difference between the micro-undulation characterization parameter and the preset micro-undulation characterization parameter includes: Determining, based on the comparison result that the relative difference is less than or equal to the preset relative difference, that the winding machine rotates at a first preset number of revolutions, and increasing the preset pressure of the one-way roller by a first preset pressure adjustment coefficient; Based on the comparison result that the relative difference is greater than the preset relative difference, it is determined that the winder rotates at a second preset number of rotations, and the preset pressure of the one-way roller is increased by a second preset pressure adjustment coefficient.

8. The production process of the diaphragm finishing one-way roller based on the winding process according to claim 7 is characterized in that: The bare cell winding stability does not meet the standard based on the comparison result that the batch gap fluctuation rate is greater than the preset batch gap fluctuation rate.

9. The production process of the diaphragm finishing one-way roller based on the winding process according to claim 8, characterized in that: Under the condition that it is determined that the winding stability of the bare battery cell does not meet the standard, based on the comparison result that the ratio of the preset batch gap fluctuation rate and the batch gap fluctuation rate is less than or equal to the preset ratio, it is determined that the tension applied to the battery cell strip during the next batch winding process is increased by the first preset tension adjustment coefficient, and when the increased tension reaches the rated maximum tension, the preset number of rotations is increased by the first preset number of turns adjustment coefficient.

10. The production process of the diaphragm finishing one-way roller based on the winding process according to claim 9, characterized in that: Under the condition that it is determined that the winding stability of the bare battery cell does not meet the standard, based on the comparison result that the ratio of the preset batch gap fluctuation rate and the batch gap fluctuation rate is greater than the preset ratio, it is determined that the tension applied to the battery cell strip during the next batch winding process is increased by a second preset tension adjustment coefficient, and when the increased tension reaches the rated maximum tension, the preset number of rotations is increased by the second preset number of turns adjustment coefficient.

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