Winding electrode assembly measurement method and apparatus

Abstract

A kind of winding electrode assembly (102) measurement method and device, wherein the measurement method includes: obtaining the pixel equivalent parameter corresponding to the i th winding reference electrode assembly (1 ') circle, including: the first pixel equivalent of the first anode pole piece (11 ') of reference electrode assembly (1 ') and the second pixel equivalent of the first cathode pole piece (12 '); In the process of winding the i th circle of the electrode assembly (1) to be measured, the image of the second anode pole piece (11) of the electrode assembly (1) to be measured is shot, the first pixel coordinates of the width edge of the second anode pole piece (11) are obtained from the image, and the image of the second cathode pole piece (12) of the electrode assembly (1) to be measured is shot, and the second pixel coordinates of the width edge of the second cathode pole piece (12) are obtained from the image;According to the first pixel equivalent and the second pixel equivalent corresponding to the i th circle of the reference electrode assembly (1 '), and the first pixel coordinates and the second pixel coordinates of the i th circle of the electrode assembly (1) to be measured, the second anode pole piece (11) in the i th circle of the electrode assembly (1) to be measured is calculated relative to the second cathode pole piece (12) along the winding axis (K) The excess width Wi.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a winding electrode assembly measurement method and device. BACKGROUND

[0002] With the advantages of high energy density, high power density, multiple cycle times, long storage time and the like, lithium ion batteries and the like have been widely used in electric vehicles.

[0003] In the production process of lithium batteries, anode sheets, cathode sheets and separators are wound into battery cells. The winding process has various standard requirements for the sheets, one of which is that the width dimension of the anode sheet exceeding the cathode sheet remains consistent during winding, i.e., the alignment of the anode sheet and the cathode sheet in the width direction. The detection accuracy of this parameter directly affects the performance of the battery, but improving the detection accuracy of this parameter has always been a problem in the industry. SUMMARY

[0004] The purpose of the present application is to improve the performance of the battery.

[0005] According to a first aspect of the present application, a winding electrode assembly measurement method is provided, comprising:

[0006] The pixel equivalent acquisition step: acquiring the pixel equivalent parameters corresponding to the i th circle of the winding reference electrode assembly, the pixel equivalent parameters including the first pixel equivalent of the first anode sheet of the reference electrode assembly and the second pixel equivalent of the first cathode sheet, 1≤i≤n, and i is a natural number, n is the total number of circles;

[0007] The pixel coordinate acquisition step: in the process of winding the i th circle of the to-be-measured electrode assembly, an image of the second anode sheet of the to-be-measured electrode assembly is taken, and the first pixel coordinates of the second anode sheet width edge are obtained from the image, and an image of the second cathode sheet of the to-be-measured electrode assembly is taken, and the second pixel coordinates of the second cathode sheet width edge are obtained from the image;

[0008] The excess width calculation step: according to the first pixel equivalent and the second pixel equivalent corresponding to the i th circle of the reference electrode assembly, and the first pixel coordinates and the second pixel coordinates of the i th circle of the to-be-measured electrode assembly, the excess width Wi of the second anode sheet relative to the second cathode sheet along the winding axis in the i th circle of the to-be-measured electrode assembly is calculated.

[0009] The embodiment of the present application can improve the calculation accuracy of the excess width Wi by obtaining the first pixel equivalent for each circle of the first anode pole piece in the reference electrode assembly and obtaining the second pixel equivalent for each circle of the first cathode pole piece, and using the corresponding first pixel equivalent and second pixel equivalent to calculate the excess width Wi of the circle during winding of the electrode assembly to be measured, and automatically compensating for the change in pixel equivalent during winding of the electrode assembly to be measured by an algorithm, thereby improving the calculation accuracy of the excess width Wi.

[0010] By improving the calculation accuracy of the excess width Wi, the alignment of the second anode pole piece and the second cathode pole piece along the winding axis in the electrode assembly to be measured can be improved, so that lithium ions are more easily embedded in the anode active material region of the second anode pole piece, preventing the phenomenon of lithium ion precipitation, and allowing the cathode active material on the second cathode pole piece to fully function, thereby improving the performance of the battery monomer, and improving the cycle life and fast charging capacity of the battery monomer, and reducing safety problems such as burning and explosion.

[0011] In addition, the winding electrode assembly measurement method of the present application can reduce the requirement for the shooting accuracy of the first shooting component and the second shooting component, and does not need to select a higher-precision shooting component, nor does it need to set up a driving mechanism to move the first shooting component and the second shooting component, thereby saving space and facilitating installation in the narrow space in the winding machine, thereby reducing costs.

[0012] In some embodiments, the winding electrode assembly measurement method further comprises:

[0013] The step of calibrating the pixel equivalent comprises: during winding of the i th circle of the reference electrode assembly, calibrating the first pixel equivalent of the i th circle of the reference electrode assembly according to the image of the first anode pole piece and the actual size of the first anode pole piece; and calibrating the second pixel equivalent of the i th circle of the reference electrode assembly according to the image of the first cathode pole piece and the actual size of the first cathode pole piece.

[0014] The embodiment of the present application can pre-calibrate the first pixel equivalent and the second pixel equivalent of each circle during winding of the reference electrode assembly, and then use the pre-calibrated pixel equivalent parameters when winding the electrode assembly to be measured, thereby automatically compensating for the change in pixel equivalent during winding of the electrode assembly to be measured, thereby improving the calculation accuracy of the excess width Wi, and further improving the performance, life and safety of the battery monomer.

[0015] In some embodiments, calibrating the first pixel equivalent of the i th circle of the reference electrode assembly according to the image of the first anode pole piece and the actual size of the first anode pole piece comprises:

[0016] The image of the i th circle of the first anode pole piece is obtained, and the first calibration pixel coordinates of the first anode pole piece width edge are obtained from the image;

[0017] measuring a first actual width of the first anode tab;

[0018] calculating the first pixel equivalent according to the first calibration pixel coordinate and the first actual width.

[0019] The embodiment of the present application can obtain the pixel width size of the first anode tab through the image during the winding of the i th circle of the reference electrode assembly, measure the physical width size of the first anode tab, and thus calculate the first pixel equivalent. Since the overall width of the first anode tab is relatively large, the measurement of the physical width size and the obtaining of the pixel width size are more accurate, and the accuracy of the calibration of the first pixel equivalent can be improved. Alternatively, the first pixel equivalent can also be calibrated based on the exceeding width Wi.

[0020] In some embodiments, calibrating the second pixel equivalent of the i th circle of the reference electrode assembly according to the image of the first cathode tab and the actual size of the first cathode tab comprises:

[0021] obtaining the image of the i th circle of the first cathode tab, and obtaining a second calibration pixel coordinate of the width edge of the first cathode tab from the image;

[0022] measuring a second actual width of the first cathode tab;

[0023] calculating the second pixel equivalent according to the second calibration pixel coordinate and the second actual width.

[0024] The embodiment of the present application can obtain the pixel width size of the first cathode tab through the image during the winding of the i th circle of the reference electrode assembly, measure the physical width size of the first cathode tab, and thus calculate the second pixel equivalent. Since the overall width of the first cathode tab is relatively large, the measurement of the physical width size and the obtaining of the pixel width size are more accurate, and the accuracy of the calibration of the second pixel equivalent can be improved.

[0025] In some embodiments, the winding electrode assembly measurement method further comprises:

[0026] After the step of calibrating the pixel equivalent, the number of circles during the winding of the reference electrode assembly is stored in correspondence with the first pixel equivalent and the second pixel equivalent.

[0027] The embodiment stores the pixel equivalent parameters of each circle of the reference electrode assembly in correspondence with the number of circles after calibrating the pixel equivalent parameters of each circle of the reference electrode assembly, so as to facilitate the retrieval when calculating the exceeding width Wi, so as to efficiently calculate the corresponding exceeding width Wi of each circle of the electrode assembly to be measured.

[0028] In some embodiments, the step of calculating the exceeding width comprises:

[0029] According to the first pixel coordinates of the first pixel equivalent of the i th circle of the reference electrode assembly and the second pixel coordinates of the width edge of the second anode tab of the i th circle of the electrode assembly to be measured, a first distance L1i between the width edge of the second anode tab and the reference line is obtained;

[0030] According to the first pixel coordinates of the first pixel equivalent of the i th circle of the reference electrode assembly and the second pixel coordinates of the width edge of the second anode tab of the i th circle of the electrode assembly to be measured, a first distance L1i between the width edge of the second anode tab and the reference line is obtained;

[0031] According to the difference between the first distance L1i and the second distance Li, the overwidth Wi of the i th circle of the second anode tab relative to the second cathode tab is calculated.

[0032] The embodiment of the present application can obtain the overwidth Wi of the i th circle of the second anode tab relative to the second cathode tab based on the corresponding pixel equivalent parameters of each i th circle of the reference electrode assembly, and can accurately and conveniently calculate the overwidth Wi to improve the performance, service life and safety of the battery cell.

[0033] In some embodiments, calculating the overwidth Wi of the second anode tab relative to the second cathode tab according to the difference between the first distance L1i and the second distance Li includes:

[0034] obtaining a deviation adjustment value in advance;

[0035] summing the difference and the deviation adjustment value to calculate the overwidth Wi of the second anode tab relative to the second cathode tab.

[0036] The embodiment of the present application takes into account the actual physical position deviation of the first and second shooting components arranged in the winding axis direction, and by introducing a deviation adjustment value, the midlines of the respective shooting images of the first and second shooting components can be made to coincide, so as to unify the reference for obtaining the first and second pixel coordinates and improve the accuracy of the calculation result.

[0037] In some embodiments, during the winding of the electrode assembly to be measured, the pixel coordinate obtaining steps are sequentially performed from the 1st circle to the n th circle, and after all the pixel coordinate obtaining steps are performed, the overwidth calculation step is performed for each circle of the electrode assembly to be measured to obtain W1, W, …, Wi, Wn.

[0038] The winding electrode assembly measurement method further includes:

[0039] In the case where the difference between the maximum overwidth and the minimum overwidth in W1, W, …, Wi, Wn of the electrode assembly to be measured does not exceed the preset deviation, it is determined that the winding of the electrode assembly to be measured is qualified.

[0040] The embodiment of the present application calculates the excess width Wi of each circle after the electrode assembly to be measured is completely wound, so as to determine whether the winding of the electrode assembly to be measured is qualified. This method can compare the excess widths Wi of all circles to obtain the maximum deviation. As long as the maximum deviation does not exceed the preset deviation, the winding is determined to be qualified. Moreover, this method can make the overall winding process of the electrode assembly to be measured more continuous, keep the tension of the electrode sheet uniform during the winding process, and improve the winding efficiency.

[0041] According to a second aspect of the present application, a winding electrode assembly measurement device is provided, comprising:

[0042] a first shooting component configured to shoot an image of a first anode electrode sheet of a reference electrode assembly or an image of a second anode electrode sheet of an electrode assembly to be measured;

[0043] a second shooting component configured to shoot an image of a first cathode electrode sheet of the reference electrode assembly or an image of a second cathode electrode sheet of the electrode assembly to be measured; and

[0044] a control component configured to obtain a pixel equivalent parameter corresponding to the i th circle of the winding reference electrode assembly, the pixel equivalent parameter comprising a first pixel equivalent of the first anode electrode sheet of the reference electrode assembly and a second pixel equivalent of the first cathode electrode sheet; and during the winding of the i th circle of the electrode assembly to be measured, obtaining an image of the second anode electrode sheet of the electrode assembly to be measured, obtaining a first pixel coordinate of the width edge of the second anode electrode sheet from the image, and obtaining an image of the second cathode electrode sheet of the electrode assembly to be measured, obtaining a second pixel coordinate of the width edge of the second cathode electrode sheet from the image; and then calculating the excess width Wi of the second anode electrode sheet relative to the second cathode electrode sheet along the winding axis in the i th circle of the electrode assembly to be measured according to the first pixel equivalent and the second pixel equivalent of the i th circle of the reference electrode assembly and the first pixel coordinate and the second pixel coordinate of the i th circle of the electrode assembly to be measured.

[0045] The embodiment of the present application obtains the first pixel equivalent of each circle of the first anode electrode sheet of the reference electrode assembly and the second pixel equivalent of each circle of the first cathode electrode sheet, so as to calculate the excess width Wi of the circle by using the corresponding first pixel equivalent and second pixel equivalent during the winding of different circles of the electrode assembly to be measured. The algorithm can automatically compensate the change of the pixel equivalent during the winding of the electrode assembly to be measured, so as to improve the calculation accuracy of the excess width Wi and the performance, life and safety of the battery cell.

[0046] In addition, the winding electrode assembly measurement method of the present application can reduce the requirement for the shooting accuracy of the first and second shooting components, and does not need to select a shooting component with high accuracy or shoot in macro mode, and does not need to set a driving mechanism to move the first and second shooting components, thereby saving space, facilitating installation in a narrow space in the winding machine, and thus reducing the cost.

[0047] In some embodiments, the first and second shooting components are fixedly arranged on the same side of the winding shaft of the reference electrode assembly or the electrode assembly to be measured.

[0048] The embodiment of the present application arranges the first and second shooting components on the same side of the winding shaft, which can save the space occupied in the winding machine, facilitate installation, and facilitate selection of the reference line based on the installation position of the shooting components. In addition, the first and second shooting components are fixedly arranged, and do not need to be moved by a driving mechanism, which can further save space, facilitate installation in a narrow space in the winding machine, and thus reduce the cost.

[0049] In some embodiments, the control component comprises:

[0050] The calibration unit is configured to calibrate the first pixel equivalent of the i th winding of the reference electrode assembly according to the image of the first anode tab and the actual size of the first anode tab, and calibrate the second pixel equivalent of the i th winding of the reference electrode assembly according to the image of the first cathode tab and the actual size of the first cathode tab.

[0051] The embodiment of the present application can pre-calibrate the first and second pixel equivalents of each winding during the winding of the reference electrode assembly, and then use the pre-calibrated pixel equivalent parameters during the winding of the electrode assembly to be measured, which can automatically compensate for the change of the pixel equivalent during the winding of the electrode assembly to be measured, thereby improving the calculation accuracy of the excess width Wi, and further improving the performance, life and safety of the battery cell.

[0052] In some embodiments, the winding electrode assembly measurement device further comprises:

[0053] The measurement component is configured to measure the first actual width of the first anode tab and the second actual width of the first cathode tab in the reference electrode assembly.

[0054] The calibration unit is configured to obtain an image of the i th winding of the first anode tab, and obtain first calibration pixel coordinates of a width edge of the first anode tab from the image, and calculate a first pixel equivalent according to the first calibration pixel coordinates and a first actual width; and obtain an image of the i th winding of the first cathode tab, and obtain second calibration pixel coordinates of a width edge of the first cathode tab from the image, and calculate a second pixel equivalent according to the second calibration pixel coordinates and a second actual width.

[0055] The embodiment of the present application can obtain the pixel width size of the first anode tab and the first cathode tab from the image, and measure the physical width size of the first anode tab and the first cathode tab during the winding of the i th winding of the reference electrode assembly, so as to calculate the first pixel equivalent and the second pixel equivalent. Since the overall width of the first anode tab and the first cathode tab is relatively large, the measurement of the physical width size and the obtaining of the pixel width size are more accurate, and the accuracy of the calibration of the first pixel equivalent and the second pixel equivalent can be improved.

[0056] In some embodiments, the winding electrode assembly measurement device further comprises:

[0057] The storage component is configured to store the number of windings during the winding of the reference electrode assembly after calibration, and the first pixel equivalent and the second pixel equivalent.

[0058] The embodiment stores the pixel equivalent parameters of each winding of the reference electrode assembly and the number of windings in a corresponding relationship after calibrating the pixel equivalent parameters of each winding, so as to facilitate the calling when the excess width Wi is calculated, so as to efficiently calculate the excess width Wi corresponding to each winding of the electrode assembly to be measured.

[0059] In some embodiments, the control component comprises:

[0060] The alignment degree calculation unit is configured to, during the winding of the i th winding of the electrode assembly, obtain a first distance L1i between the width edge of the second anode tab and the reference line according to the first pixel equivalent of the i th winding of the reference electrode assembly and the first pixel coordinates of the width edge of the second anode tab of the i th winding of the electrode assembly to be measured; and obtain a second distance Li between the width edge of the second cathode tab and the reference line according to the second pixel equivalent of the i th winding of the reference electrode assembly and the second pixel coordinates of the width edge of the second cathode tab of the i th winding of the electrode assembly to be measured; and calculate the excess width Wi of the second anode tab relative to the second cathode tab according to the difference between the first distance L1i and the second distance Li.

[0061] The embodiment of the present application can obtain the exceeding width Wi of the i th anode tab relative to the cathode tab based on the corresponding pixel equivalent parameter of each i th circle in the reference electrode assembly, and can accurately and conveniently calculate the exceeding width Wi to improve the performance, life and safety of the battery cell.

[0062] In some embodiments, the alignment calculation unit is configured to sum the difference value and a pre-acquired deviation adjustment value to calculate the exceeding width Wi of the anode tab relative to the cathode tab.

[0063] The embodiment of the present application considers that there is a deviation in the actual physical position of the first and second shooting components arranged in the winding axis direction, and by introducing the deviation adjustment value, the midlines of the images shot by the first and second shooting components can be coincided to unify the reference of the obtained first and second pixel coordinates, and improve the accuracy of the calculation result. BRIEF DESCRIPTION OF DRAWINGS

[0064] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the drawings.

[0065] Figure 1 It is an exploded view of some embodiments of the battery cell in the present application.

[0066] Figure 2 It is a state schematic diagram of some embodiments before winding the electrode assembly. Figure 1

[0067] It is an enlarged view of A in Figure 3 Figure 2

[0068] Figure 4 It is a structural schematic diagram of some embodiments of the electrode assembly after winding. Figure 1

[0069] Figure 5 It is a structural schematic diagram of some embodiments of the winding electrode assembly measurement device of the present application.

[0070] Figure 6 It is a schematic diagram of the size of the second anode tab exceeding the second cathode tab along the winding axis in the electrode assembly to be measured.

[0071] Figure 7 It is a flowchart of some embodiments of the winding electrode assembly measurement method of the present application.

[0072] Figure 8 ​​​Flowchart for some embodiments of the method of measuring a wound electrode assembly.

[0073] Figure 9 Flowchart for calibrating a first pixel equivalent in the step of calibrating pixel equivalents.

[0074] Figure 10 Flowchart for calibrating a second pixel equivalent in the step of calibrating pixel equivalents.

[0075] Figure 11 Flowchart for some embodiments of the method of measuring a wound electrode assembly.

[0076] Figure 12 Flowchart for some embodiments of the step of calculating an excess width.

[0077] Figure 13 Block diagram of some embodiments of the apparatus for measuring a wound electrode assembly.

[0078] Figure 14 Block diagram of some embodiments of the apparatus for measuring a wound electrode assembly.

[0079] In the drawings, the drawings are not drawn according to the actual proportions.

[0080] Reference signs in the detailed description of the embodiments are as follows:

[0081] 10, battery cell; 101, housing; 102, electrode assembly; 103, adapter; 104, end cap assembly; 104A, end cap body; 104B, positive terminal; 104C, negative terminal; 104D, pressure relief component;

[0082] 1', reference electrode assembly; 11', first anode tab; 12', first cathode tab; 13', first separator; K, winding axis; BL, base line;

[0083] 1, electrode assembly to be measured; 11, second anode tab; 12, second cathode tab; 13, second separator;

[0084] 2, first shooting component; 3, second shooting component; 4, control component; 41, calibration unit; 42, alignment calculation unit; 5, measurement component; 6, storage component. DETAILED DESCRIPTION

[0085] The embodiments of the present application will be further described in conjunction with the drawings and examples. The detailed description of the following examples and drawings are used to illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0086] In the description of the application, it is necessary to point out that, unless otherwise specified, the meaning of "a plurality of" is more than two; the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicate the orientation or positional relationship only for the purpose of facilitating the description of the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the application.

[0087] In addition, the terms "first", "second", "third" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable range of error. "Parallel" is not strictly parallel, but within the allowable range of error. The orientation words appearing in the following description are the directions shown in the drawings, and are not a limitation on the specific structure of the application.

[0088] In the description of the application, it is also necessary to point out that, unless otherwise specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0089] In this paper, "embodiment" means that the specific features, structures or characteristics described in conjunction with the embodiment can be included in at least one embodiment of the application. The phrase appears at various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment independent of or alternative to other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0090] In the description of the embodiments of the application, the term "a plurality of" refers to more than two (including two), and similarly, "a plurality of groups" refers to more than two groups (including two groups), and "a plurality of pieces" refers to more than two pieces (including two pieces).

[0091] In the description of the embodiments of the application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, only for the purpose of facilitating the description of the embodiments of the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the embodiments of the application.

[0092] At present, from the development of market situation, the application of power battery is more and more extensive. Power battery is not only applied to energy storage power supply system of water power, fire power, wind power and solar power station, but also widely applied to electric bicycle, electric motorcycle, electric vehicle and other electric vehicles, military equipment, aerospace and other fields. With the continuous expansion of the application field of power battery, the demand of its market is also increasing.

[0093] During the use of the battery, the performance is prone to decline and the cycle life is prone to shorten, and even in some cases, there is a safety problem. For many years, the skilled person in the art has tried to solve the problem from many different angles, but the expected effect has not been achieved.

[0094] As part of the application process, the inventor found that one of the reasons for the existence of the above problems in the battery is that the width of the anode tab exceeding the cathode tab in the electrode assembly cannot be kept consistent during winding, that is, the alignment accuracy of the anode tab and the cathode tab in the width direction is low. The existence of this problem may make it difficult for lithium ions to be embedded in the anode active material area of the anode tab, causing lithium precipitation phenomenon, and the cathode active material of the cathode tab is also difficult to fully play a role, thereby affecting the performance of the battery, also greatly shortening the cycle life of the battery, limiting the fast charging capacity of the battery, and possibly causing safety problems such as burning and explosion.

[0095] In order to solve this problem, during the winding of the electrode assembly, the images of the anode tab and the cathode tab are respectively taken by two shooting components at a preset distance, so as to calculate the excess width of the anode tab relative to the cathode tab according to the images.

[0096] However, the inventor found that the calculated value of the width size depends on the pixel equivalent of the shooting component, which is the actual physical size represented by one pixel point in the image. However, as the tab is continuously wound, the electrode assembly becomes thicker and thicker, and the distance between the two shooting components and the corresponding tab is dynamically changing. Since the shooting component has the phenomenon of "big near and small far", the pixel equivalent is also dynamically changing. If a fixed pixel equivalent is used to calculate the excess width, errors will occur in the calculation of the excess width.

[0097] In order to compensate for the change of the pixel equivalent caused by the change of the distance between the shooting component and the tab, if the shooting component is moved by a driving mechanism during winding to keep the distance between the shooting component and the tab at the best shooting focal length value at all times, this way also faces many problems in actual application, such as the small internal space of the winding machine is difficult to leave additional space, the control accuracy of the driving mechanism is required to be high, and the maintenance of the driving mechanism is difficult and the cost is high.

[0098] Based on the above considerations, the inventors have proposed a layered calibration of the electrode assembly, and designed a winding electrode assembly measurement method based on the idea, comprising: a pixel equivalent acquisition step, a pixel coordinate acquisition step and a calculation of the excess width step.

[0099] The pixel equivalent acquisition step: acquiring the pixel equivalent parameters corresponding to the i th winding reference electrode assembly, the pixel equivalent parameters including the first pixel equivalent of the first anode tab of the reference electrode assembly and the second pixel equivalent of the first cathode tab, 1≤i≤n, and i is a natural number, n is the total number of turns.

[0100] The pixel coordinate acquisition step: in the process of winding the i th turn of the measured electrode assembly, the image of the second anode tab of the measured electrode assembly is taken, and the first pixel coordinates of the width edge of the second anode tab are obtained from the image, and the image of the second cathode tab of the measured electrode assembly is taken, and the second pixel coordinates of the width edge of the second cathode tab are obtained from the image.

[0101] The calculation of the excess width step: according to the first pixel equivalent and the second pixel equivalent corresponding to the i th turn of the reference electrode assembly, and the first pixel coordinates and the second pixel coordinates of the i th turn of the measured electrode assembly, the excess width Wi of the second anode tab relative to the second cathode tab along the winding axis in the i th turn of the measured electrode assembly is calculated.

[0102] The winding electrode assembly measurement method, which respectively acquires the first pixel equivalent of each turn of the first anode tab in the reference electrode assembly and the second pixel equivalent of each turn of the first cathode tab, can calculate the excess width Wi using the corresponding first pixel equivalent and second pixel equivalent in the process of winding different turns of the measured electrode assembly, automatically compensate the change of the pixel equivalent in the winding process of the electrode assembly through algorithm, improve the calculation accuracy of the excess width Wi, and thus improve the performance, service life and safety of the battery. Moreover, it can reduce the requirement for the shooting accuracy of the shooting component, and does not need to set a driving mechanism to move the shooting component, which is convenient to install in the winding machine and can also reduce the cost.

[0103] In order to more clearly illustrate the winding electrode assembly measurement method of the present application, as shown in Figure 1 The structure of the smallest unit battery monomer 10 in the battery is first described.

[0104] The battery monomer 10 includes a shell 101, an electrode assembly 102 and an end cover assembly 104, the end cover assembly 104 is connected with the shell 101 to form the outer shell of the battery monomer 10, the electrode assembly 102 is arranged in the shell 101, and the shell 101 is filled with electrolyte. The battery monomer 10 can be square, cylindrical or other shapes.

[0105] The end cap assembly 104 is provided on top of the electrode assembly 102, and includes an end cap body 104A, a positive electrode terminal 104B, a negative electrode terminal 104C, and a pressure relief component 104D. The positive electrode terminal 104B and the negative electrode terminal 104C are respectively provided with an adapter 103, which is located between the end cap body 104A and the electrode assembly 102. For example, Figure 1 The tab 102A of the electrode assembly 102 is located on the top, and the cathode tab is connected to the positive electrode terminal 104B through an adapter 103, and the anode tab is connected to the negative electrode terminal 104C through another adapter 103. The pressure relief component 104D is provided on the end cap body 104A and is configured to be actuated when the internal pressure of the battery cell 10 reaches a threshold value to release the internal pressure of the battery cell 10.

[0106] According to actual use requirements, the electrode assembly 102 can be provided as a single or multiple. As shown in Figure 1 At least two independently wound electrode assemblies 102 can also be provided in the battery cell 10. The electrode assembly 102 needs to measure the excess width Wi of the anode tab with respect to the cathode tab during winding, so it is called the electrode assembly 1 to be measured, and the standard electrode assembly used to obtain the pixel equivalent parameter is called the reference electrode assembly 1'. In fact, the electrode assembly 1 to be measured and the reference electrode assembly 1' have the same structure, and only different names and reference numerals are assigned for convenience of description.

[0107] As shown in Figure 2 and Figure 3 The reference electrode assembly 1' can be formed by winding the first anode tab 11', the first cathode tab 12', and the first separator 13' for isolating the first anode tab 11' and the first cathode tab 12', as shown in Figure 4 For example, before winding, the first separator 13', the first anode tab 11', the first separator 13', and the first cathode tab 12' can be stacked in order from bottom to top, and the first separator 13' is an insulator between the first anode tab 11' and the first cathode tab 12'. The first anode tab 11' can be coated with an anode active material, such as graphite or silicon; and the first cathode tab 12' can be coated with a cathode active material, such as a ternary material, lithium manganese oxide, or lithium iron phosphate. After winding, the reference electrode assembly 1' can have a flat structure as shown in Figure 4 or a circular structure as shown in Figure 5 .

[0108] Similarly, the electrode assembly under test 1 can be formed by winding the second anode tab 11, the second cathode tab 12 and the second separator 13 for isolating the second anode tab 11 and the second cathode tab 12 together.

[0109] As shown in Figure 5 , taking the electrode assembly under test 1 as an example, the second anode tab 11, the second cathode tab 12 and the second separator 13 arranged in layers are inserted into the winding machine and wound in the winding station with the winding shaft K as the center. The winding station can be used to wind the electrode assembly under test 1. The first shooting component 2 and the second shooting component 3 are arranged on the same side of the winding shaft K, for example, the shooting components can be various cameras. In order to obtain clear images, the first shooting component 2 and the second shooting component 3 can adopt different shooting angles. Alternatively, a reference electrode assembly 1' can also be arranged on the winding station to obtain the pixel equivalent parameters in the process of winding the reference electrode assembly 1'.

[0110] The first shooting component 2 is configured to shoot the image of the second anode tab 11 of the electrode assembly under test 1. Specifically, an infrared camera can be used to shoot the second anode tab 11 wound on the winding shaft K through the second separator 13. The distance between the first shooting component 2 and the second anode tab 11 is S1.

[0111] The second shooting component 3 is configured to shoot the image of the second cathode tab 12 of the electrode assembly under test 1. Specifically, the second cathode tab 12 to be wound on the winding shaft K can be shot. The distance between the second shooting component 3 and the second cathode tab 12 is S2.

[0112] As shown in Figure 6 , in the process of winding the i th turn of the electrode assembly under test 1, the second anode tab 11 needs to have an excess width Wi relative to the second cathode tab 12 on both sides along the winding shaft K. The method and device for measuring the excess width Wi are described in detail below. Figure 7 to Figure 14

[0113] In some embodiments, as shown in Figure 7 , the winding electrode assembly measurement method of the present disclosure includes:

[0114] S110, a pixel equivalent acquisition step: acquiring the pixel equivalent parameters corresponding to the i th turn of the winding reference electrode assembly 1', the pixel equivalent parameters including: the first pixel equivalent of the first anode tab 11' and the second pixel equivalent of the first cathode tab 12' of the reference electrode assembly 1', wherein 1≤i≤n, and i is a natural number, and n is the total number of turns.

[0115] ​S120, a pixel coordinate acquisition step: during winding of the i-th winding of the electrode assembly 1 under test, an image of the second anode tab 11 of the electrode assembly 1 under test is captured, and a first pixel coordinate of the width edge of the second anode tab 11 is obtained from the image; and an image of the second cathode tab 12 of the electrode assembly 1 under test is captured, and a second pixel coordinate of the width edge of the second cathode tab 12 is obtained from the image.

[0116] S130, a width excess calculation step: based on the first pixel equivalent and the second pixel equivalent corresponding to the i-th winding of the reference electrode assembly 1', and the first pixel coordinate and the second pixel coordinate of the i-th winding of the electrode assembly 1 under test, the width excess Wi of the second anode tab 11 relative to the second cathode tab 12 along the winding axis K in the i-th winding of the electrode assembly 1 under test is calculated.

[0117] In S101, it is assumed that the pixel equivalent parameters corresponding to the i-th winding of the reference electrode assembly 1' have been obtained by calibration or other methods and stored in the storage component 6, and the pixel equivalent parameters are obtained from the storage component 6 by the control component 4 before the width excess Wi is calculated.

[0118] For example, if the width excess Wi of each winding is calculated after the winding of the electrode assembly 1 under test is completed, the pixel equivalent parameters of the 1st to nth windings can be obtained once before, during or after the winding of the electrode assembly 1 under test; if the width excess Wi of the i-th winding is calculated after the winding of the i-th winding is completed, the pixel equivalent parameters of the i-th winding can be obtained before, before the winding of the i-th winding starts, or during the winding of the i-th winding.

[0119] The reference electrode assembly 1' is a standard electrode assembly made for obtaining pixel equivalent parameters, and the pixel equivalent is the actual physical size represented by one pixel point in the image. The pixel equivalent parameters include the first pixel equivalent of the first anode tab 11' and the second pixel equivalent of the first cathode tab 12' of the reference electrode assembly 1'. The first pixel equivalent corresponding to the first anode tab 11' of the 1st to nth windings of the reference electrode assembly 1' are all different, and the second pixel equivalent corresponding to the first cathode tab 12' of the 1st to nth windings are all different. Thus, when calculating the width excess Wi of the i-th winding, the change in the shooting distance during winding can be compensated by adjusting the pixel equivalent parameters of each winding.

[0120] In step S120, during the i-th turn of winding the electrode assembly 1 under test, images of the second anode electrode 11 and the second cathode electrode 12 are captured by the first imaging component 2 and the second imaging component 3, respectively. These images can be numbered and named according to the number of turns. Next, the first pixel coordinates of the width edge of the second anode electrode 11 and the second pixel coordinates of the width edge of the second cathode electrode 12 are obtained from the images. The first pixel coordinates represent the position of the width edge of the second anode electrode 11 in the image, and the second pixel coordinates represent the position of the width edge of the second cathode electrode 12 in the image.

[0121] In S130, refer to Figure 6 The length segment between the two dashed lines represents one turn of the electrode. When calculating the excess width Wi of the i-th turn of the electrode assembly 1 under test, the basic principle used is that the pixel equivalent multiplied by the pixel coordinates equals the actual physical size. Figure 6 As shown, the second anode electrode 11 can extend beyond the second cathode electrode 12 on both sides along the winding axis K. For the i-th turn, the extension width Wi on both sides can be the same or different.

[0122] Specifically, by multiplying the first pixel equivalent corresponding to the i-th turn of the reference electrode assembly 1' by the first pixel coordinate of the width edge of the second anode electrode 11 in the i-th turn of the electrode assembly 1 under test, the actual physical position of the width edge of the second anode electrode 11 can be obtained; by multiplying the second pixel equivalent corresponding to the i-th turn of the reference electrode assembly 1' by the second pixel coordinate of the width edge of the second cathode electrode 12 in the i-th turn of the electrode assembly 1 under test, the actual physical position of the width edge of the second cathode electrode 12 can be obtained. Therefore, the over-width Wi of the second anode electrode 11 relative to the second cathode electrode 12 along the winding axis K in the i-th turn of the electrode assembly 1 under test can be calculated. The winding axis K is aligned with the width direction of either the second anode electrode 11 or the second cathode electrode 12.

[0123] Regarding the execution order of each step in this embodiment: If the excess width Wi of each turn is calculated after the electrode assembly 1 under test is wound, S120 is executed once for each turn to obtain an image of each turn during the winding process. After the electrode assembly 1 under test is wound, S130 is executed uniformly for each turn. S110 for each turn can be executed uniformly before winding the electrode assembly 1 under test, or during the winding process, or before executing S130 after winding. If the excess width Wi of the i-th turn is calculated after the i-th turn is wound, then S110, S120, and S130 for the i-th turn can be executed sequentially.

[0124] The embodiment of the present application can improve the calculation accuracy of the excess width Wi by obtaining the first pixel equivalent for each circle of the first anode tab 11 and the second pixel equivalent for each circle of the first cathode tab 12 in the reference electrode assembly 1, and can automatically compensate the change of the pixel equivalent during the winding of the electrode assembly 1 by algorithm, thereby improving the calculation accuracy of the excess width Wi.

[0125] By improving the calculation accuracy of the excess width Wi, the alignment of the second anode tab 11 and the second cathode tab 12 along the winding axis K in the electrode assembly 1 can be improved, so that lithium ions are more easily embedded in the anode active material area of the second anode tab 11, preventing the phenomenon of lithium ion precipitation, and the cathode active material on the second cathode tab 12 can fully play a role, thereby improving the performance of the battery monomer 10, and improving the cycle life and fast charging capacity of the battery monomer 10, and reducing safety problems such as burning and explosion.

[0126] In addition, the winding electrode assembly measurement method of the present application can reduce the requirement for the shooting accuracy of the first shooting component 2 and the second shooting component 3, and does not need to select a shooting component with high accuracy, nor does it need to set a driving mechanism to move the first shooting component 2 and the second shooting component 3, thereby saving space and facilitating installation in the narrow space of the winding machine, thereby reducing costs.

[0127] In some embodiments, the first pixel equivalent of the i+1th circle is less than the first pixel equivalent of the ith circle, and the second pixel equivalent of the i+1th circle is greater than the second pixel equivalent of the ith circle.

[0128] As shown in Figure 5 The distance between the first shooting component 2 and the second anode tab 11 is S1, and the distance between the second shooting component 3 and the second cathode tab 12 is S2.

[0129] As the tab winding thickness increases, S1 gradually decreases, and if the first pixel equivalent remains unchanged, the actual physical size corresponding to a single pixel point in the shooting image will increase, so the first pixel equivalent needs to be gradually reduced to accurately calculate the actual physical position of the width edge of the second anode tab 11. Therefore, the first pixel equivalent of the i+1th circle is less than the first pixel equivalent of the ith circle.

[0130] As the tab winding thickness increases, S2 gradually increases, and if the second pixel equivalent remains unchanged, the actual physical size corresponding to a single pixel point in the shooting image will decrease, so the second pixel equivalent needs to be gradually increased to accurately calculate the actual physical position of the width edge of the second cathode tab 12. Therefore, the second pixel equivalent of the i+1th circle is greater than the second pixel equivalent of the ith circle.

[0131] The embodiment of the present application can automatically compensate for the change of the pixel equivalent in the winding process of the to-be-measured electrode assembly 1 by gradually reducing the first pixel equivalent of the first to nth turns in the reference electrode assembly 1' and gradually increasing the second pixel equivalent, thereby improving the calculation accuracy of the excess width Wi and further improving the performance, life and safety of the battery monomer 10.

[0132] In some embodiments, as shown in Figure 8 The winding electrode assembly measurement method further includes:

[0133] S100, a pixel equivalent calibration step: in the process of winding the i th turn of the reference electrode assembly 1', according to the image of the first anode tab 11' and the actual size of the first anode tab 11', the first pixel equivalent of the i th turn of the reference electrode assembly 1' is calibrated; and according to the image of the first cathode tab 12' and the actual size of the first cathode tab 12', the second pixel equivalent of the i th turn of the reference electrode assembly 1' is calibrated.

[0134] Wherein, S100 is executed before S110, before winding a single, multiple or a batch of same to-be-measured electrode assemblies 1, in order to obtain the pixel equivalent parameters corresponding to each turn, the reference electrode assembly 1' can be calibrated. In the calibration process, the reference electrode assembly 1' can be wound at the winding station as shown in Figure 5 The image of the first anode tab 11' is captured by the first shooting component 2, and the actual size of the first anode tab 11' is measured to calibrate the first pixel equivalent of the i th turn; or the image of the first cathode tab 12' is captured by the second shooting component 3, and the actual size of the first cathode tab 12' is measured to calibrate the second pixel equivalent of the i th turn, so as to be used in the calculation of the excess width Wi of the i th turn in S130.

[0135] The embodiment of the present application can pre-calibrate the first pixel equivalent and the second pixel equivalent of each turn in the process of winding the reference electrode assembly 1', and then use the pre-calibrated pixel equivalent parameters when winding the to-be-measured electrode assembly 1, which can automatically compensate for the change of the pixel equivalent in the winding process of the to-be-measured electrode assembly 1, thereby improving the calculation accuracy of the excess width Wi and further improving the performance, life and safety of the battery monomer 10.

[0136] In some embodiments, as shown in Figure 9 The first pixel equivalent of the i th turn of the reference electrode assembly 1' is calibrated according to the image of the first anode tab 11' and the actual size of the first anode tab 11' in S100, which includes:

[0137] S101, acquire an image of the i th winding first anode pole piece 11', and obtain first calibration pixel coordinates of the width edges of the first anode pole piece 11' from the image;

[0138] S102, measure a first actual width of the first anode pole piece 11';

[0139] S103, calculate a first pixel equivalent according to the first calibration pixel coordinates and the first actual width.

[0140] Wherein, S103 is executed after S101 and S102, and the execution order of S101 and S102 is not limited.

[0141] In S101, an image of the first anode pole piece 11' photographed by the first photographing component 2 is acquired, and first calibration pixel coordinates of the width edges of the first anode pole piece 11' are obtained from the image, so as to obtain a pixel width size of the first anode pole piece 11' from the image.

[0142] In S102, the first actual width of the first anode pole piece 11' can be measured by the measuring component 5, which can be a precise image type surveying instrument, so as to measure a physical width size of the first anode pole piece 11'.

[0143] In S103, specifically, the first calibration pixel coordinates of the width edges of the first anode pole piece 11' can be subtracted to obtain a pixel width size of the first anode pole piece 11', and the physical width size of the first anode pole piece 11' is divided by the pixel width size of the first anode pole piece 11', so as to calculate the first pixel equivalent.

[0144] The embodiment of the application can obtain a pixel width size of the first anode pole piece 11' from an image and measure a physical width size of the first anode pole piece 11' in the process of winding the i th winding of the reference electrode assembly 1', so as to calculate the first pixel equivalent. Since the overall width of the first anode pole piece 11' is relatively large, the measurement of the physical width size and the obtaining of the pixel width size are more accurate, and the accuracy of the calibration of the first pixel equivalent can be improved. Alternatively, the first pixel equivalent can also be calibrated based on the part exceeding the width Wi.

[0145] In some embodiments, as shown in Figure 10 Calibrating the second pixel equivalent of the i th winding of the reference electrode assembly 1' according to the image of the first cathode pole piece 12' and the actual size of the first cathode pole piece 12' in S100 includes:

[0146] S104, acquire an image of the i th winding first cathode pole piece 12', and obtain second calibration pixel coordinates of the width edges of the first cathode pole piece 12' from the image;

[0147] S105, measure a second actual width of the first cathode pole piece 12';

[0148] S106, calculate a second pixel equivalent according to the second calibration pixel coordinates and the second actual width.

[0149] Wherein, S106 is executed after S104 and S105, and the execution order of S104 and S105 is not limited.

[0150] In S104, the image of the first cathode pole piece 12' shot by the second shooting component 3 is obtained, and the second calibration pixel coordinates of the width edges on both sides of the first cathode pole piece 12' are obtained from the image, so as to obtain the pixel width size of the first cathode pole piece 12' from the image.

[0151] In S105, the second actual width of the first cathode pole piece 12' can be measured by the measuring component 5, which can be a precise image type surveying instrument, so as to measure the physical width size of the first cathode pole piece 12'.

[0152] In S106, specifically, the second calibration pixel coordinates of the width edges on both sides of the first cathode pole piece 12' can be subtracted to obtain the pixel width size of the first cathode pole piece 12', and the physical width size of the first cathode pole piece 12' is divided by the pixel width size of the first cathode pole piece 12', so as to calculate the second pixel equivalent.

[0153] The embodiment of the present application can obtain the pixel width size of the first cathode pole piece 12' from the image and measure the physical width size of the first cathode pole piece 12' during the winding of the i th coil of the reference electrode assembly 1', so as to calculate the second pixel equivalent. Since the overall width of the first cathode pole piece 12' is large, the measurement of the physical width size and the obtaining of the pixel width size are more accurate, and the accuracy of the calibration of the second pixel equivalent can be improved.

[0154] In some embodiments, as shown in Figure 11 The winding electrode assembly measurement method further comprises:

[0155] S100', after the calibration pixel equivalent step, the number of coils in the winding process of the reference electrode assembly 1' is stored corresponding to the first pixel equivalent and the second pixel equivalent.

[0156] Wherein, S100' is performed between S100 and S110. The "corresponding storage" here refers to storage according to the mapping relationship between the number of turns and the first pixel equivalent and the second pixel equivalent, that is, each turn corresponds to a first pixel equivalent and a second pixel equivalent. The corresponding relationship can be stored in the storage component 6, and when subsequent acquisition is required, the control component 4 only needs to send a turn number instruction to the storage component 6, and the first pixel equivalent and the second pixel equivalent corresponding to the turn number can be obtained through table lookup.

[0157] After calibrating the pixel equivalent parameters of each turn of the reference electrode assembly 1', the pixel equivalent parameters of each turn and the number of turns are stored according to the corresponding relationship, which facilitates retrieval when calculating the excess width Wi, so as to efficiently calculate the corresponding excess width Wi of each turn of the electrode assembly 1 to be measured.

[0158] In some embodiments, as shown in Figure 12 The step of S130 of calculating the excess width includes:

[0159] S131, according to the first pixel equivalent of the i th turn of the reference electrode assembly 1' and the first pixel coordinates of the width edge of the second anode pole piece 11 of the i th turn of the electrode assembly 1 to be measured, the first distance L1i between the width edge of the second anode pole piece 11 and the reference line BL is obtained;

[0160] S132, according to the second pixel equivalent of the i th turn of the reference electrode assembly 1' and the second pixel coordinates of the width edge of the second cathode pole piece 12 of the i th turn of the electrode assembly 1 to be measured, the second distance L2i between the width edge of the second cathode pole piece 12 and the reference line BL is obtained;

[0161] S133, according to the difference between the first distance L1i and the second distance L2i, the excess width Wi of the i th turn of the second anode pole piece 11 relative to the second cathode pole piece 12 is calculated.

[0162] Wherein, S133 is performed after S131 and S132, and the execution order of S131 and S132 is not limited.

[0163] In S131, the reference line BL can be selected first, and according to the first pixel coordinates of the width edge of the second anode pole piece 11 and the position of the reference line BL, the pixel distance between the width edge of the second anode pole piece 11 and the reference line BL in the image is obtained; then, the pixel distance of the i th turn is multiplied by the first pixel coordinates to obtain the first distance L1i between the width edge of the second anode pole piece 11 and the reference line BL, which is the actual physical size.

[0164] In S132, a pixel distance between the second cathode tab 12 width edge and the reference line BL in the image is obtained according to the second pixel coordinates of the second cathode tab 12 width edge and the position of the reference line BL with the same reference line BL, and then the pixel distance of the i th turn is multiplied by the second pixel coordinates to obtain a second distance L2i between the width edge of the second cathode tab 12 and the reference line BL, which is an actual physical size.

[0165] In S133, the overwidth Wi of the i th turn of the second anode tab 11 relative to the second cathode tab 12 is calculated according to the difference between the first distance L1i and the second distance L2i. When calculating the overwidth Wi on one side, the pixel coordinates of the corresponding width edges of the second anode tab 11 and the second cathode tab 12 on the side can be used for calculation.

[0166] The embodiment of the present application can obtain the overwidth Wi of the i th turn of the second anode tab 11 relative to the second cathode tab 12 based on the corresponding pixel equivalent parameters of each i th turn in the reference electrode assembly 1', and can accurately and conveniently calculate the overwidth Wi to improve the performance, life and safety of the battery monomer 10.

[0167] In some embodiments, S133 calculates the overwidth Wi of the second anode tab 11 relative to the second cathode tab 12 according to the difference between the first distance L1i and the second distance L2i, which includes:

[0168] The deviation adjustment value is obtained in advance;

[0169] The difference and the deviation adjustment value are summed to calculate the overwidth Wi of the second anode tab 11 relative to the second cathode tab 12.

[0170] The deviation adjustment value can be set according to the deviation of the actual physical positions of the first shooting component 2 and the second shooting component 3 in the winding axis K direction to compensate for the inherent error of the detection device, and the purpose is to make the center lines of the respective shooting images of the first shooting component 2 and the second shooting component 3 coincide to unify the reference when calculating the first pixel coordinates and the second pixel coordinates.

[0171] The embodiment of the present application considers that the actual physical positions of the first shooting component 2 and the second shooting component 3 set in the winding axis K direction are deviated, and by introducing the deviation adjustment value, the center lines of the respective shooting images of the first shooting component 2 and the second shooting component 3 can be made to coincide, so as to unify the reference for obtaining the first pixel coordinates and the second pixel coordinates, and improve the accuracy of the calculation result.

[0172] In some embodiments, the reference line BL is a center line between the two width edges of the second anode tab 11 of the electrode assembly 1 to be measured, or a center line between the two width edges of the second cathode tab 12. Since the distance between the center line of the tab and the two width edges of the tab is uniform, it prevents a large error in the calculation of the width Wi of the two sides of the electrode assembly 1 to be measured due to the reference line BL being too close or too far, and makes the calculation of the width Wi of the two sides of the electrode assembly 1 to be measured more accurate. Alternatively, the reference line BL can also be selected at other positions.

[0173] In some embodiments, during the winding of the electrode assembly 1 to be measured, the pixel coordinate acquisition step is sequentially performed from the first to the nth circle, and after all the pixel coordinate acquisition steps are performed, the calculation of the excess width step is performed on each circle of the electrode assembly 1 to be measured to obtain W1, W2, …, Wi, Wn. The winding electrode assembly measurement method further comprises:

[0174] determining whether the difference between the maximum excess width and the minimum excess width in W1, W2, …, Wi, Wn of the electrode assembly 1 to be measured exceeds a preset deviation, and if not, determining that the winding of the electrode assembly 1 to be measured is qualified, and if so, determining that the winding of the electrode assembly 1 to be measured is unqualified.

[0175] In some embodiments, during the winding of each circle of the electrode assembly 1 to be measured, the pixel coordinate acquisition step is sequentially performed to obtain the first pixel coordinates of the width edge of the second anode tab 11 and the second pixel coordinates of the width edge of the second cathode tab 12 from the images captured by the first and second shooting components 2 and 3. After the winding of the electrode assembly 1 to be measured is completed, the excess width Wi of each circle is calculated respectively, and S140 is used to determine whether the winding of the electrode assembly 1 to be measured is qualified. The preset deviation is set according to the process requirements of the electrode assembly 1 to be measured, for example, by testing the performance of the battery monomer 10 under different preset deviations to obtain an acceptable preset deviation.

[0176] In some embodiments, after the winding of the electrode assembly 1 to be measured is completed, the excess width Wi of each circle is calculated respectively, so as to determine whether the winding of the electrode assembly 1 to be measured is qualified. This method can compare all the excess widths Wi corresponding to the circles to obtain the maximum deviation, and as long as the maximum deviation does not exceed the preset deviation, the winding is determined to be qualified. Moreover, this method can also make the overall winding process of the electrode assembly 1 to be measured more continuous, keep the tab tension uniform during the winding process, and improve the winding efficiency.

[0177] Optionally, the step of obtaining pixel coordinates is performed during the winding of the i-th turn of the electrode assembly to be measured, and the step of calculating the excess width is performed before the winding of the i+1-th turn, which is advantageous in that the excess width Wi of each turn can be determined after the winding of each turn, so that the size requirement can be met more strictly, and adjustment measures can be taken if the requirement is not met.

[0178] Some specific embodiments will be given below with reference to the accompanying drawings, in which Figure 7 to Figure 11 The winding electrode assembly measurement method of the present application is as follows:

[0179] 1. Start winding a reference electrode assembly 1' in a winding machine, and perform S100, the step of calibrating pixel equivalent, by the control component 4 during the winding of each turn, which includes the following steps (1) to (3).

[0180] (1) Take images of the first anode tab 11' and the first cathode tab 12' by the first shooting component 2 and the second shooting component 3 respectively during the winding of the i-th turn, and obtain the first calibration pixel coordinates of the first anode tab 11' width edge and the second calibration pixel coordinates of the first cathode tab 12' from the two images respectively.

[0181] (2) Measure the first actual width of the first anode tab 11' and the second actual width of the first cathode tab 12' respectively.

[0182] (3) Calculate the first pixel equivalent according to the first calibration pixel coordinates and the first actual width, and calculate the second pixel equivalent according to the second calibration pixel coordinates and the second actual width.

[0183] 2. Perform S100', store the number of turns during the winding of the reference electrode assembly 1' after the step of calibrating pixel equivalent, and correspond to the first pixel equivalent and the second pixel equivalent.

[0184] 3. Start winding a to-be-measured electrode assembly 1 in a winding machine, and perform S120, the step of obtaining pixel coordinates, during the winding of each turn, which includes:

[0185] During the winding of the i-th turn of the to-be-measured electrode assembly 1, take an image of the second anode tab 11 of the to-be-measured electrode assembly 1, obtain the first pixel coordinates of the width edge of the second anode tab 11 from the image, and take an image of the second cathode tab 12 of the to-be-measured electrode assembly 1, obtain the second pixel coordinates of the width edge of the second cathode tab 12 from the image.

[0186] 4. After the winding of the to-be-measured electrode assembly 1 is completed, calculate the excess width Wi of each turn respectively, and the specific calculation method is as follows:

[0187] For each turn, the control component 4 sequentially executes the pixel equivalent obtaining step S110 and the overwidth calculating step S130 to read the pixel equivalent parameters of the layer from the storage component 6 and to calculate the overwidth Wi.

[0188] 5. Determine whether the difference between the maximum overwidth and the minimum overwidth in W1, W2, …, Wi, Wn of the to-be-tested electrode assembly 1 exceeds the preset deviation. If not, determine that the to-be-tested electrode assembly 1 is wound qualified; if yes, determine that the to-be-tested electrode assembly 1 is wound unqualified.

[0189] Secondly, the present disclosure provides a wound electrode assembly measurement device. In the following embodiments, some terms have been explained in detail in the subject of the wound electrode assembly measurement method, and thus will not be repeated here.

[0190] In some embodiments, as shown in FIGS. 1 and 2, the wound electrode assembly measurement device comprises: Figure 5 and 12 as shown in FIGS. 1 and 2, the wound electrode assembly measurement device comprises:

[0191] The first shooting component 2 is configured to shoot an image of the first anode tab 11’ of the reference electrode assembly 1’ or an image of the second anode tab 11 of the to-be-tested electrode assembly 1;

[0192] The second shooting component 3 is configured to shoot an image of the first cathode tab 12’ of the reference electrode assembly 1’ or an image of the second cathode tab 12 of the to-be-tested electrode assembly 1; and

[0193] The control component 4 is configured to obtain the pixel equivalent parameters corresponding to the i-th turn of the wound reference electrode assembly 1’, the pixel equivalent parameters comprising the first pixel equivalent of the first anode tab 11’ and the second pixel equivalent of the first cathode tab 12’ of the reference electrode assembly 1’, and in the process of winding the i-th turn of the to-be-tested electrode assembly 1, to obtain the image of the second anode tab 11 of the to-be-tested electrode assembly 1, to obtain the first pixel coordinates of the width edge of the second anode tab 11 from the image, and to obtain the image of the second cathode tab 12 of the to-be-tested electrode assembly 1, to obtain the second pixel coordinates of the width edge of the second cathode tab 12 from the image; and to calculate the overwidth Wi of the second anode tab 11 relative to the second cathode tab 12 along the winding axis K in the i-th turn of the to-be-tested electrode assembly 1 according to the first pixel equivalent and the second pixel equivalent of the i-th turn of the reference electrode assembly 1’ and the first pixel coordinates and the second pixel coordinates of the i-th turn of the to-be-tested electrode assembly 1.

[0194] The first shooting component 2 and the second shooting component 3 can be various cameras. Taking the electrode assembly 1 to be measured as an example, the first shooting component 2 can be an infrared camera to shoot the second anode tab 11 wound on the winding shaft K through the second diaphragm 13, and the distance between the first shooting component 2 and the second anode tab 11 is S1; the second shooting component 3 can shoot the second cathode tab 12 to be wound on the winding shaft K, and the distance between the second shooting component 3 and the second cathode tab 12 is S2. S1 and S2 can be selected according to actual needs.

[0195] In this embodiment of the present application, the first pixel equivalent of each circle of the first anode tab 11' in the reference electrode assembly 1' is obtained respectively, and the second pixel equivalent of each circle of the first cathode tab 12' is obtained respectively. In the process of winding different circles of the electrode assembly 1 to be measured, the corresponding first pixel equivalent and second pixel equivalent are used to calculate the excess width Wi of the circle, the change of the pixel equivalent in the winding process of the electrode assembly 1 to be measured is automatically compensated by the algorithm, the calculation accuracy of the excess width Wi is improved, and thus the performance, service life and safety of the battery monomer 10 are improved.

[0196] In addition, the winding electrode assembly measurement method of the present application can reduce the requirement for the shooting accuracy of the first shooting component 2 and the second shooting component 3, without the need to select a shooting component with higher accuracy or to shoot with a macro shooting mode, and without the need to set a driving mechanism to move the first shooting component 2 and the second shooting component 3, thereby saving space and facilitating installation in a narrow space in the winding machine, thereby reducing costs.

[0197] In some embodiments, as shown in FIG. 1, the first shooting component 2 and the second shooting component 3 are fixed on the same side of the winding shaft K of the reference electrode assembly 1' or the electrode assembly 1 to be measured. Figure 5

[0198] In the plane perpendicular to the winding shaft K, the first shooting component 2 and the second shooting component 3 can be arranged at different positions along the circumference of the winding shaft K, so that the first shooting component 2 and the second shooting component 3 have different angles of shooting to obtain the best shooting angle. In the extension direction of the winding shaft K, the first shooting component 2 and the second shooting component 3 can be located at the same position or staggered. In order to ensure the shooting effect, a fill light can also be arranged.

[0199] In this embodiment of the present application, the first shooting component 2 and the second shooting component 3 are arranged on the same side of the winding shaft K, which can save the space occupied in the winding machine, facilitate installation, and facilitate selection of the reference line BL based on the installation position of the shooting components. In addition, the first shooting component 2 and the second shooting component 3 are fixedly arranged, without the need to set a driving mechanism to move the first shooting component 2 and the second shooting component 3, which can further save space and facilitate installation in a narrow space in the winding machine, thereby reducing costs. ​

[0200] In some embodiments, as shown in Figure 14 The control component 4 includes a calibration unit 41 configured to calibrate the first pixel equivalent of the i th winding of the reference electrode assembly 1 ’ according to the image of the first anode tab 11 ’ and the actual size of the first anode tab 11 ’, and to calibrate the second pixel equivalent of the i th winding of the reference electrode assembly 1 ’ according to the image of the first cathode tab 12’ and the actual size of the first cathode tab 12’.

[0201] This embodiment of the present application can pre-calibrate the first pixel equivalent and the second pixel equivalent of each winding during the winding of the reference electrode assembly 1 ’, and subsequently, when winding the to-be-tested electrode assembly 1, the pre-calibrated pixel equivalent parameters can be used to automatically compensate for the changes in the pixel equivalent during the winding of the to-be-tested electrode assembly 1, thereby improving the calculation accuracy of the width Wi exceeding part, and further improving the performance, life and safety of the battery monomer 10.

[0202] In some embodiments, as shown in Figure 14 The winding electrode assembly measurement device further includes a measurement component 5 configured to measure the first actual width of the first anode tab 11 ’ and the second actual width of the first cathode tab 12’ in the reference electrode assembly 1 ’.

[0203] The calibration unit 41 is configured to obtain the image of the i th winding of the first anode tab 11 ’, and obtain the first calibration pixel coordinates of the width edge of the first anode tab 11 ’ from the image, and calculate the first pixel equivalent according to the first calibration pixel coordinates and the first actual width; and obtain the image of the i th winding of the first cathode tab 12’, and obtain the second calibration pixel coordinates of the width edge of the first cathode tab 12’ from the image, and calculate the second pixel equivalent according to the second calibration pixel coordinates and the second actual width.

[0204] The measurement component 5 can be a precise image surveying instrument, and the first actual width and the second actual width are both physical width sizes.

[0205] This embodiment of the present application can obtain the pixel width size of the first anode tab 11 ’ and the first cathode tab 12’ from the image during the winding of the i th winding of the reference electrode assembly 1 ’, and measure the physical width size of the first anode tab 11 ’ and the first cathode tab 12’, thereby calculating the first pixel equivalent and the second pixel equivalent. Since the overall width of the first anode tab 11 ’ and the first cathode tab 12’ is relatively large, the measurement of the physical width size and the obtaining of the pixel width size are both more accurate, which can improve the accuracy of the calibration of the first pixel equivalent and the second pixel equivalent.

[0206] In some embodiments, as shown in Figure 14As shown, the winding electrode assembly measurement device further comprises a storage component 6 configured to store the number of turns in the winding process of the calibrated reference electrode assembly 1' corresponding to the first pixel equivalent and the second pixel equivalent.

[0207] The "corresponding storage" here refers to storage according to the mapping relationship between the number of turns and the first pixel equivalent and the second pixel equivalent, i.e. each turn corresponds to a first pixel equivalent and a second pixel equivalent. The corresponding relationship can be stored in the storage component 6, and when subsequently acquired, the control component 4 only needs to send a turn number instruction to the storage component 6, and the first pixel equivalent and the second pixel equivalent corresponding to the turn number can be obtained by table lookup. For example, the storage component 6 can be a disk, a flash memory or any other non-volatile storage medium.

[0208] After calibrating the pixel equivalent parameters of each turn of the reference electrode assembly 1', the pixel equivalent parameters of each turn and the number of turns are stored according to the corresponding relationship, which facilitates retrieval when calculating the width Wi exceeding the width Wi, so as to efficiently calculate the corresponding width Wi exceeding the width Wi of each turn of the electrode assembly 1 to be measured.

[0209] In some embodiments, as shown, Figure 14 The control component 4 comprises an alignment calculation unit 42 configured to, in the process of winding the i-th turn of the electrode assembly 1, obtain the first distance L1i between the width edge of the second anode tab 11 and the reference line BL according to the first pixel equivalent of the i-th turn of the reference electrode assembly 1' and the first pixel coordinates of the width edge of the i-th turn of the electrode assembly 1; and obtain the second distance L2i between the width edge of the second cathode tab 12 and the reference line BL according to the second pixel equivalent of the i-th turn of the reference electrode assembly 1' and the second pixel coordinates of the i-th turn of the electrode assembly 1; and calculate the width Wi exceeding the width Wi of the second anode tab 11 relative to the second cathode tab 12 according to the difference between the first distance L1i and the second distance L2i.

[0210] The embodiment of the present application can obtain the width Wi exceeding the width Wi of the second anode tab 11 relative to the second cathode tab 12 based on the corresponding pixel equivalent parameters of each i-th turn of the reference electrode assembly 1', and can accurately and conveniently calculate the width Wi exceeding the width Wi to improve the performance, life and safety of the battery monomer 10.

[0211] In some embodiments, the alignment calculation unit 42 is configured to sum the difference and a pre-acquired deviation adjustment value to calculate the width Wi exceeding the width Wi of the second anode tab 11 relative to the second cathode tab 12.

[0212] The deviation adjustment value can be set according to the deviation of the actual physical positions of the first and second shooting components 2 and 3 in the winding axis K direction, to compensate for the inherent error of the detection device, and the purpose is to make the center lines of the respective first and second shooting images coincide, to unify the reference for calculating the first and second pixel coordinates.

[0213] The embodiment of the present application takes into account the deviation of the actual physical positions of the first and second shooting components 2 and 3 in the winding axis K direction, and by introducing the deviation adjustment value, the center lines of the respective first and second shooting images can be made to coincide, to unify the reference for obtaining the first and second pixel coordinates, and improve the accuracy of the calculation results.

[0214] In some embodiments, the reference line BL is the center line between the two width edges of the second anode tab 11 of the electrode assembly 1 to be measured, or the center line between the two width edges of the second cathode tab 12. Since the distance between the tab center line and the two width edges of the tab is consistent, it prevents large errors in the calculation results of the two width Wi sides due to the reference line BL being too close or too far, and can make the calculation results of the two width Wi sides of the electrode assembly 1 to be measured more accurate. Alternatively, the reference line BL can also be selected at other positions.

[0215] The control component 4, the calibration unit 41 and the alignment calculation unit 42 in the above embodiments can be a general-purpose processor, a programmable logic controller (PLC), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or any appropriate combination thereof, for executing the functions described in the present disclosure.

[0216] Although the present application has been described with reference to the preferred embodiments, various modifications can be made to it without departing from the scope of the present application, and equivalent components can be substituted therefor. In particular, the technical features mentioned in each embodiment can be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for measuring a wound electrode assembly, comprising: Steps for obtaining pixel equivalents: Obtain the pixel equivalent parameters corresponding to the i-th turn of the winding reference electrode assembly (1'). The pixel equivalent parameters include the first pixel equivalent of the first anode electrode (11') and the second pixel equivalent of the first cathode electrode (12') of the reference electrode assembly (1'), where 1≤i≤n, and i is a natural number and n is the total number of turns. Steps for obtaining pixel coordinates: During the i-th turn of winding the electrode assembly under test (1), an image of the second anode plate (11) of the electrode assembly under test (1) is captured, and the first pixel coordinates of the width edge of the second anode plate (11) are obtained from the image. An image of the second cathode plate (12) of the electrode assembly under test (1) is captured, and the second pixel coordinates of the width edge of the second cathode plate (12) are obtained from the image. Step to calculate the overwidth: Based on the first pixel equivalent and the second pixel equivalent corresponding to the i-th turn of the reference electrode assembly (1'), and the first pixel coordinate and the second pixel coordinate of the i-th turn of the electrode assembly under test (1), calculate the overwidth Wi of the second anode plate (11) relative to the second cathode plate (12) along the winding axis (K) in the i-th turn of the electrode assembly under test (1).

2. The measurement method for the wound electrode assembly according to claim 1 further includes: Pixel equivalent calibration steps: During the i-th turn of the reference electrode assembly (1'), the first pixel equivalent of the i-th turn of the reference electrode assembly (1') is calibrated based on the image of the first anode electrode (11') and the actual size of the first anode electrode (11'); and the second pixel equivalent of the i-th turn of the reference electrode assembly (1') is calibrated based on the image of the first cathode electrode (12') and the actual size of the first cathode electrode (12').

3. The measurement method for the wound electrode assembly according to claim 2, wherein, Based on the image of the first anode electrode (11') and the actual size of the first anode electrode (11'), the first pixel equivalent of the i-th ring of the reference electrode assembly (1') is calibrated as follows: Obtain an image of the first anode electrode (11') in the i-th ring, and obtain the first calibrated pixel coordinates of the width edge of the first anode electrode (11') from the image; Measure the first actual width of the first anode electrode (11'); The first pixel equivalent is calculated based on the first calibrated pixel coordinates and the first actual width.

4. The measurement method for the wound electrode assembly according to claim 2, wherein, Based on the image of the first cathode electrode (12') and the actual size of the first cathode electrode (12'), the second pixel equivalent of the i-th ring of the reference electrode assembly (1') is calibrated as follows: Obtain an image of the first cathode electrode (12') in the i-th ring, and obtain the second calibration pixel coordinates of the width edge of the first cathode electrode (12') from the image; Measure the second actual width of the first cathode electrode (12'); The second pixel equivalent is calculated based on the second calibrated pixel coordinates and the second actual width.

5. The method for measuring a wound electrode assembly according to claim 2, further comprising: After the pixel equivalent calibration step, the number of turns of the reference electrode assembly (1') during the winding process is stored in correspondence with the first pixel equivalent and the second pixel equivalent.

6. The method for measuring a wound electrode assembly according to any one of claims 1 to 5, wherein, The step of calculating the width excess includes: Based on the first pixel equivalent of the i-th ring of the reference electrode assembly (1') and the first pixel coordinate of the width edge of the second anode electrode (11) of the i-th ring of the electrode assembly under test (1), the first distance L1i between the width edge of the second anode electrode (11) and the baseline (BL) is obtained. Based on the second pixel equivalent of the i-th ring of the reference electrode assembly (1') and the second pixel coordinate of the width edge of the second cathode electrode (12) of the i-th ring of the electrode assembly under test (1), the second distance L2i between the width edge of the second cathode electrode (12) and the baseline (BL) is obtained. Based on the difference between the first distance L1i and the second distance L2i, the over-width Wi of the second anode plate (11) relative to the second cathode plate (12) in the i-th ring is calculated.

7. The method for measuring a wound electrode assembly according to claim 6, wherein, Based on the difference between the first distance L1i and the second distance L2i, the over-width Wi of the second anode electrode (11) relative to the second cathode electrode (12) is calculated, including: Pre-obtain the deviation adjustment value; The difference is summed with the deviation adjustment value to calculate the overwidth Wi of the second anode electrode (11) relative to the second cathode electrode (12).

8. The method for measuring a wound electrode assembly according to any one of claims 1 to 5, wherein, During the winding of the electrode assembly under test (1), the pixel coordinate acquisition step is executed sequentially from the first turn to the nth turn, and after all the pixel coordinate acquisition steps are completed, the overwidth calculation step is executed for each turn of the electrode assembly under test (1) to obtain W1, W2, ..., Wi, Wn; The measurement method for the wound electrode assembly further includes: If the difference between the maximum and minimum over-widths of W1, W2, ..., Wi, Wn in the electrode assembly under test (1) does not exceed a preset deviation, the electrode assembly under test (1) is deemed to be wound to be qualified.

9. A measuring device for a wound electrode assembly, comprising: The first imaging component (2) is configured to capture an image of the first anode plate (11') of the reference electrode assembly (1') or an image of the second anode plate (11) of the electrode assembly to be tested (1); The second imaging component (3) is configured to capture an image of the first cathode electrode (12') of the reference electrode assembly (1') or an image of the second cathode electrode (12) of the electrode assembly to be tested (1); and The control unit (4) is configured to acquire the pixel equivalent parameters corresponding to the i-th turn of the reference electrode assembly (1'), the pixel equivalent parameters including: the first pixel equivalent of the first anode electrode (11') and the second pixel equivalent of the first cathode electrode (12') of the reference electrode assembly (1'); and during the i-th turn of the winding of the electrode assembly to be tested (1), acquire an image of the second anode electrode (11) of the electrode assembly to be tested (1), obtain the first pixel coordinates of the width edge of the second anode electrode (11) from the image, and acquire the... The image of the second cathode electrode (12) of the electrode assembly under test (1) is used to obtain the second pixel coordinates of the width edge of the second cathode electrode (12) from the image; then, based on the first pixel equivalent and the second pixel equivalent of the i-th turn of the reference electrode assembly (1'), and the first pixel coordinates and the second pixel coordinates of the i-th turn of the electrode assembly under test (1), the over-width Wi of the second anode electrode (11) relative to the second cathode electrode (12) along the winding axis (K) in the i-th turn of the electrode assembly under test (1) is calculated.

10. The measuring device for the wound electrode assembly according to claim 9, wherein, The first imaging component (2) and the second imaging component (3) are fixed on the same side of the winding shaft (K) of the reference electrode assembly (1') or the electrode assembly under test (1).

11. The measuring device for the wound electrode assembly according to claim 9, wherein, The control component (4) includes: The calibration unit (41) is configured to, during the i-th turn of winding the reference electrode assembly (1'), calibrate the first pixel equivalent of the i-th turn of the reference electrode assembly (1') based on the image of the first anode electrode (11') and the actual size of the first anode electrode (11'); and calibrate the second pixel equivalent of the i-th turn of the reference electrode assembly (1') based on the image of the first cathode electrode (12') and the actual size of the first cathode electrode (12').

12. The winding electrode assembly measuring device according to claim 11, further comprising: The measuring component (5) is configured to measure the first actual width of the first anode electrode (11') and the second actual width of the first cathode electrode (12') in the reference electrode assembly (1'); The calibration unit (41) is configured to acquire an image of the first anode electrode (11') in the i-th ring, obtain the first calibration pixel coordinates of the width edge of the first anode electrode (11') from the image, and calculate the first pixel equivalent based on the first calibration pixel coordinates and the first actual width; and acquire an image of the first cathode electrode (12') in the i-th ring, obtain the second calibration pixel coordinates of the width edge of the first cathode electrode (12') from the image, and calculate the second pixel equivalent based on the second calibration pixel coordinates and the second actual width.

13. The measuring device for the wound electrode assembly according to claim 11, wherein, Also includes: The storage unit (6) is configured to store the number of turns of the calibrated reference electrode assembly (1') during the winding process in correspondence with the first pixel equivalent and the second pixel equivalent.

14. The measuring apparatus for the wound electrode assembly according to any one of claims 9 to 13, wherein, The control component (4) includes: The alignment calculation unit (42) is configured to, during the i-th turn of winding the electrode assembly (1), calculate the first distance L1i between the width edge of the second anode electrode (11) and the baseline (BL) based on the first pixel equivalent of the i-th turn of the reference electrode assembly (1') and the first pixel coordinate of the width edge of the second anode electrode (11) of the i-th turn of the electrode assembly (1) under test; and calculate the second distance L2i between the width edge of the second cathode electrode (12) and the baseline (BL) based on the second pixel equivalent of the i-th turn of the reference electrode assembly (1') and the second pixel coordinate of the width edge of the second cathode electrode (12) of the i-th turn of the electrode assembly (1) under test; and calculate the over-width Wi of the second anode electrode (11) relative to the second cathode electrode (12) based on the difference between the first distance L1i and the second distance L2i.

15. The measuring device for the wound electrode assembly according to claim 14, wherein, The alignment calculation unit (42) is configured to sum the difference with a pre-acquired deviation adjustment value to calculate the overwidth Wi of the second anode electrode (11) relative to the second cathode electrode (12).

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