Battery pole piece winding tension control method and device and winding equipment

Abstract

The invention relates to a battery pole piece winding tension control method and device and winding equipment. The method comprises the following steps: acquiring the diameter of a roller and the winding thickness of a pole piece wound on the roller; according to the rolling thickness, the initial rolling tension and the tension taper coefficient are determined; wherein the size relation between the winding thickness and the initial tension is a reverse relation, and the size relation between the winding thickness and the tension taper coefficient is a forward relation; according to the roller diameter, the winding thickness, the initial tension, the tension taper coefficient and a preset algorithm, the winding tension for winding the pole piece on the roller is determined; and controlling the winding of the pole piece according to the winding tension. According to the scheme, according to the universal control method suitable for pole piece winding, the good winding effect of different types of material rolls is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of pole piece production, and particularly relates to a method and system for controlling the winding tension of battery pole pieces and a winding device. Background Art

[0002] In the process of lithium battery cell production and manufacturing in the lithium battery industry, the winding process of pole pieces is involved in coating machines, roller presses, slitting machines, and winding machines. The control of winding tension in the winding process plays an important role in the winding effect of pole pieces.

[0003] In the related art, generally, the magnitude of the winding tension is set as a linear function or a piecewise function related to the diameter of the coil. However, due to the different materials, thicknesses, and winding diameters of different types of pole pieces, the winding tension calculated by simple piecewise or linear functions is prone to problems such as pole piece slack, wrinkles, and bulging ribs during winding due to sudden tension changes or unreasonable changes. There will also be phenomena such as deviation and sliding of the pole piece in the horizontal position, affecting the winding effect of the pole piece. Therefore, the winding tension control method in the related art cannot achieve good winding effects for different types of coils.

[0004] Therefore, there is an urgent need to study a general control method applicable to pole piece winding to achieve good winding effects for different types of coils. Summary of the Invention

[0005] To solve or partially solve the problems existing in the related art, the present application provides a method and system for controlling the winding tension of battery pole pieces and a winding device, which can achieve good winding effects for different types of coils according to a general control method applicable to pole piece winding.

[0006] The first aspect of the present application provides a method for controlling the winding tension of battery pole pieces, including: Obtaining the diameter of the roller and the winding thickness of the pole piece on the roller; Determining the initial tension and the tension taper coefficient of the winding according to the winding thickness; wherein, the magnitude relationship between the winding thickness and the initial tension is an inverse relationship, and the magnitude relationship between the winding thickness and the tension taper coefficient is a direct relationship; Determining the winding tension of the pole piece wound on the roller according to the roller diameter, the winding thickness, the initial tension, the tension taper coefficient, and according to a preset algorithm; Controlling the winding of the pole piece according to the winding tension.

[0007] As an optional embodiment, the preset algorithm is as follows: F j = F0×[1 - K×r j / (r j + 1 - rj / R)] In the formula, F j is the winding tension corresponding to the j-th layer of the pole piece wound on the roller, R is the roller diameter, and r j is the winding thickness of the pole piece wound on the roller to the j-th layer, F0 is the initial tension corresponding to the winding thickness r j and K is the tension taper coefficient corresponding to the winding thickness r j .

[0008] As an optional embodiment, the preset algorithm satisfies: The residual friction force and the normal pressure of each layer of the pole piece calculated by using the winding thickness r j and the winding tension F j satisfy the following relationship: when the pole piece is wound to the j-th layer, the residual friction force of the i-th layer of the pole piece is greater than the first set value, and the normal pressure is less than the second set value.

[0009] As an optional embodiment, the formula for calculating the normal pressure is as follows:

[0010] In the formula, N(i, j) is the normal pressure of the i-th layer of the pole piece when the pole piece on the roller is wound to the j-th layer, h is the pole piece thickness, ν is the Poisson's ratio of the pole piece, and r i is the winding thickness of the pole piece wound on the roller to the i-th layer, r t is the winding thickness of the pole piece wound on the roller to the t-th layer, and F t is the winding tension corresponding to the t-th layer of the pole piece wound on the roller.

[0011] As an optional embodiment, the formula for calculating the residual friction force is as follows:

[0012] In the formula, E(i, j) is the residual friction force of the i-th layer of the pole piece when the pole piece on the roller is wound to the j-th layer, fmax(i) is the maximum static friction force of the pole piece wound on the roller to the i-th layer, and F j is the winding tension corresponding to the j-th layer of the pole piece wound on the roller, and r j is the winding thickness of the pole piece wound on the roller to the j-th layer, r i is the winding thickness of the pole piece wound on the roller to the i-th layer, and T(i, j) is the circumferential force of the i-th layer of the pole piece when the pole piece on the roller is wound to the j-th layer.

[0013] As an optional embodiment, the obtaining of the roller diameter and the winding thickness of the pole piece wound on the roller includes: Obtaining the number of winding layers of the pole piece on the roller, the pole piece thickness, and the roller diameter; Calculate the winding thickness of the electrode tab based on the number of winding layers of the electrode tab on the roller, the thickness of the electrode tab, and the diameter of the roller.

[0014] As an optional embodiment, determining the initial tension and the tension taper coefficient for winding according to the winding thickness includes: Determine the initial tension range and the tension taper coefficient range according to the winding thickness threshold range of the electrode tab; Divide the initial tension range and the tension taper coefficient range into segments according to multiple set winding thickness range segments, obtaining multiple initial tension range segments and multiple tension taper coefficient range segments, where each set winding thickness range segment corresponds to one initial tension range segment and one tension taper coefficient range segment; Determine the corresponding set winding thickness range segment according to the winding thickness, and determine the initial tension range segment and the tension taper coefficient range segment corresponding to this set winding thickness range segment.

[0015] As an optional embodiment, when the winding thickness threshold range of the electrode tab is 0.8 m to 1.2 m, the initial tension range is 80 N to 200 N, and the tension taper coefficient range is 0.6 to 1.

[0016] The first aspect of the present application provides a battery electrode tab winding tension control device, including: An acquisition module for acquiring the roller diameter and the winding thickness of the electrode tab wound on the roller; A parameter determination module for determining the initial tension and the tension taper coefficient for winding according to the winding thickness; wherein, the relationship between the winding thickness and the initial tension is an inverse relationship, and the relationship between the winding thickness and the tension taper coefficient is a positive relationship; A calculation module for determining the winding tension of the electrode tab wound on the roller according to the roller diameter, the winding thickness, the initial tension, the tension taper coefficient, and a preset algorithm; A control module for controlling the winding of the electrode tab according to the winding tension.

[0017] The third aspect of the present application provides a pole piece winding device, including: A processor; and A memory storing executable code thereon, which, when executed by the processor, causes the processor to execute the method as described above.

[0018] The fourth aspect of the present application provides a computer-readable storage medium storing executable code thereon, which, when executed by a processor of an electronic device, causes the processor to execute the method as described above.

[0019] The fifth aspect of the present application provides a computer program product, which includes computer instructions that, when executed by a processor, implement the method described above.

[0020] The technical solution provided by the present application may include the following beneficial effects: In the present application, the initial tension and the tension taper coefficient of winding are determined according to the winding thickness. The relationship between the winding thickness and the initial tension is an inverse relationship, and the relationship between the winding thickness and the tension taper coefficient is a positive relationship. For example, when the winding thickness is small, the initial tension can be large and the tension taper coefficient can be small; when the winding thickness is large, the initial tension can be small and the tension taper coefficient can be large. Then, a relationship between the winding tension, the roller diameter, the winding thickness, the initial tension, and the tension taper coefficient is established using a preset algorithm. The preset algorithm can be derived based on the pole piece attributes and the winding pressure mathematical model. After simulation and experimental verification, the corresponding relationship that satisfies the preset algorithm can prevent the inner layer of the pole piece from collapsing during winding and can also prevent the pole piece from slipping sideways. Therefore, the winding tension calculated using the preset algorithm can adapt to pole pieces of different materials, and can avoid the inner layer of the pole piece being crushed due to excessive normal pressure as the winding thickness increases, and can also prevent the pole piece from slipping sideways, ensuring the flatness at both ends of the wound pole piece and improving the winding quality.

[0021] The technical solution of the present application can also: According to the preset algorithm F j =F0×[1 - K×r j / (r j +1 - r j / R)], calculate the winding tension F j corresponding to different winding thicknesses r j during the winding process. And this preset algorithm belongs to a function in which the winding tension decreases dynamically as the winding thickness increases, and it is a general-purpose algorithm applicable to the winding of pole pieces, which can dynamically adjust the winding tension during the winding process to adapt to pole pieces of different materials and different winding thicknesses, and improve the accuracy of winding tension control.

[0022] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] By describing the exemplary embodiments of the present application in more detail in conjunction with the drawings, the above and other objects, features, and advantages of the present application will become more obvious. Among them, in the exemplary embodiments of the present application, the same reference numerals generally represent the same components.

[0024] Figure 1 is a schematic flow chart of a method for controlling the winding tension of a battery pole piece shown in an embodiment of the present application; Figure 2 It is a schematic diagram showing the change of the winding tension with the winding thickness as shown in the embodiments of the present application; Figure 3 It is a curve graph showing the change of the normal pressure of different layers of electrode sheets during the winding process with the increase of the number of electrode sheet layers as shown in the embodiments of the present application; Figure 4 It is a comparison graph of the friction residual amount of each layer of electrode sheet when winding to different numbers of layers as shown in the embodiments of the present application; Figure 5 It is a comparison graph of the friction residual amounts of different numbers of layers during the winding process as shown in the embodiments of the present application; Figure 6 It is a schematic structural diagram of a battery electrode sheet winding tension control device as shown in the embodiments of the present application; Figure 7 It is a schematic structural diagram of a pole piece winding device as shown in the embodiments of the present application. Detailed implementation manners

[0025] The embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0026] The terms used in the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "the" and "said" used in the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0027] It should be understood that although the terms "first", "second", "third", etc. may be used in the present application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality" means two or more unless otherwise specifically defined.

[0028] In the related art, the winding tension is generally set as a linear function or a piecewise function related to the diameter of the coil. However, due to the different materials, thicknesses, and winding diameters of different types of electrode sheets, the winding tension calculated by a simple piecewise or linear function is prone to problems such as the electrode sheet becoming loose, wrinkled, or bulging during winding due to sudden changes or unreasonable changes in tension. There will also be problems such as deviation and sliding of the electrode sheet in the lateral position, which will affect the winding effect of the electrode sheet. Therefore, the winding tension control method in the related art cannot achieve good winding effects for different types of coils.

[0029] In view of the above problems, the embodiments of the present application provide a method and system for controlling the winding tension of battery electrode sheets and a winding device, which can achieve good winding effects for different types of coils according to the general control method applicable to the winding of electrode sheets.

[0030] The technical solutions of the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0031] Figure 1 It is a schematic flow chart of the method for controlling the winding tension of battery electrode sheets shown in the embodiments of the present application.

[0032] See Figure 1 , the embodiments of the present application provide a method for controlling the winding tension of battery electrode sheets, including: S1. Obtain the roller diameter and the winding thickness of the electrode sheet wound on the roller.

[0033] In the embodiments of the present application, the electrode sheet is wound on the roller of the winding device, and the winding of the electrode sheet can be controlled by controlling the rotation of the roller. Among them, the roller diameter can be a fixed value; the winding thickness of the electrode sheet wound on the roller can refer to the winding radius in the winding of the electrode sheet, and the winding thickness is a non-fixed value, which increases with the increase of the winding layers; and when the electrode sheet is wound from the i-th layer to the (i + 1)-th layer, as long as the winding length of the electrode sheet on the (i + 1)-th layer increases, the winding thickness of the electrode sheet will increase. That is to say, the winding thickness of the electrode sheet winding can be obtained when initially winding the (i + 1)-th layer, and based on this winding thickness, the winding tension of the (i + 1)-th layer can be calculated. The embodiments of the present application can obtain the winding thickness of the electrode sheet wound on the roller in real time in the following ways: (1) Calculate the winding thickness through the angular velocity and linear velocity of traction, winding, and unwinding; (2) Calculate the area through the thickness of the electrode sheet material, so as to obtain the winding thickness; (3) Directly measure the winding thickness through a sensor; (4) Calculate the winding thickness through the length and thickness of the electrode sheet.

[0034] S2. Determine the initial tension and tension taper coefficient of winding according to the winding thickness. Among them, the relationship between the winding thickness and the initial tension is an inverse relationship, and the relationship between the winding thickness and the tension taper coefficient is a positive relationship.

[0035] In the embodiments of the present application, for different winding thicknesses, the corresponding initial tensions and tension taper coefficients are different. And there is a first correspondence between the winding thickness and the initial tension and tension taper coefficient of winding. The relationship between the winding thickness and the initial tension is an inverse relationship, and the relationship between the winding thickness and the tension taper coefficient is a positive relationship. Exemplarily, when the winding thickness is small, the initial tension can be relatively large and the tension taper coefficient can be relatively small; when the winding thickness is large, the initial tension can be relatively small and the tension taper coefficient can be relatively large.

[0036] The first correspondence can be obtained through derivation simulation calculation and experiments of no wrinkling of the pole piece winding. According to the first correspondence, the initial tension and tension taper coefficient can be dynamically adjusted according to the winding thickness of the pole piece, improving the matching degree between the initial tension and tension taper coefficient and the winding thickness, so that the pole piece does not wrinkle during winding.

[0037] S3. Determine the winding tension of the pole piece wound on the roller according to the roller diameter, winding thickness, initial tension and tension taper coefficient, and according to a preset algorithm.

[0038] In the embodiments of the present application, a second correspondence between the winding tension and the roller diameter, winding thickness, initial tension and tension taper coefficient is established through a preset algorithm. In the second correspondence, as the winding thickness increases, the winding tension decreases smoothly. The preset algorithm can be derived from the pole piece attributes and the winding pressure mathematical model. After simulation and experimental verification, the corresponding relationship that satisfies the preset algorithm can make the inner layer of the pole piece not collapse during winding, and the pole piece will not collapse. Therefore, the winding tension calculated using the preset algorithm can adapt to pole pieces of different materials, and can avoid the inner layer of the pole piece being crushed due to excessive positive pressure as the winding thickness increases, and can also avoid the pole piece from slipping sideways, ensuring the flatness of both ends of the wound pole piece and improving the winding quality.

[0039] S4. Control the winding of the pole piece according to the winding tension.

[0040] In the embodiments of the present application, the winding tension of the winding device can be adjusted by adjusting the output torque of the winding device, so that the winding tension of the winding device is adjusted to the calculated winding tension, and the winding of the pole piece is controlled based on this winding tension.

[0041] In the embodiment of the present application, the initial tension and the tension taper coefficient of winding are determined according to the winding thickness. The relationship between the winding thickness and the initial tension is an inverse relationship, and the relationship between the winding thickness and the tension taper coefficient is a positive relationship. For example, when the winding thickness is small, the initial tension can be large and the tension taper coefficient can be small; when the winding thickness is large, the initial tension can be small and the tension taper coefficient can be large. Then, a relationship between the winding tension, the roller diameter, the winding thickness, the initial tension, and the tension taper coefficient is established using a preset algorithm. The preset algorithm can be derived based on the pole piece attributes and the winding pressure mathematical model. After simulation and experimental verification, the corresponding relationship that satisfies the preset algorithm can prevent the inner layer of the pole piece from collapsing during winding and prevent the pole piece from slipping sideways. Therefore, the winding tension calculated using the preset algorithm can adapt to pole pieces of different materials, avoid the excessive positive pressure on the inner layer of the pole piece and its collapse as the winding thickness increases, and also prevent the pole piece from slipping sideways, ensuring the flatness at both ends of the wound pole piece and improving the winding quality.

[0042] As an optional embodiment, the preset algorithm is as follows: F j = F0 × [1 - K × r j / (r j + 1 - r j / R)] In the formula, F j is the winding tension corresponding to the pole piece wound to the j-th layer on the roller, with the unit of N; R is the roller diameter, with the unit of m; r j is the winding thickness of the pole piece wound to the j-th layer on the roller, with the unit of m; F0 is the initial tension corresponding to the winding thickness r j , with the unit of N; K is the tension taper coefficient corresponding to the winding thickness r j ; where j = 1, 2, 3......n, and n is the number of winding layers corresponding to the winding thickness threshold r n .

[0043] See Figure 2 , the preset algorithm of the embodiment of the present application belongs to a function in which the winding tension decreases dynamically as the winding thickness increases. When initially winding, that is, when the winding thickness is 0, the initial value of the winding tension can be set as F0; when the winding length on the roller increases, that is, when winding the first layer, F1 = F0 × [1 - K × r1 / (r1 + 1 - r1 / R)], and the pole piece of the first layer is wound according to F1; when winding the second layer, F2 = F0 × [1 - K × r2 / (r2 + 1 - r2 / R)], and the pole piece of the second layer is wound according to F2;......; when winding the j-th layer, F j = F0 × [1 - K × r j / (r j + 1 - r j / R)], and the winding is carried out according to Fj The pole piece of the j-th layer during winding;......; When winding the n-th layer, F n =F0×[1-K×r n / (r n +1-r n / R)], according to F n wind the pole piece of the n-th layer.

[0044] In the embodiment of the present application, the winding thickness threshold r n can be set according to actual application requirements or the properties of the wound pole piece. The properties of the wound pole piece include pole piece material, pole piece thickness, pole piece length, etc. The present application does not limit the value of the winding thickness threshold r n , for example, it can take values in the range of 0.8 m to 1.2 m. The roller diameter R can be 0.15 m to 0.4 m.

[0045] As a preferred embodiment, the preset algorithm satisfies: Using the winding thickness r j and the winding tension F j The friction residual and the normal pressure of each layer of pole piece calculated satisfy the following relationship: the friction residual of the i-th layer of pole piece when the pole piece is wound to the j-th layer is greater than the first set value, and the normal pressure of the i-th layer of pole piece when the pole piece is wound to the j-th layer is less than the second set value, i = 1, 2, 3......j.

[0046] During the process of winding the pole piece, the critical conditions for no winding defects include: as the winding thickness increases, there is no side slip between each layer of pole pieces, and the inner layer of pole pieces will not be crushed.

[0047] Based on this critical adjustment, the inventors of the present application studied the reasons for the defects in pole piece winding, including: as the winding thickness increases, the friction residual between each layer of pole pieces is less than 0, resulting in side slip of the pole pieces; and the normal pressure of the inner layer of pole pieces is too large, resulting in crushing of the inner layer of pole pieces. Based on the above defect reasons, it is set that the preset algorithm needs to satisfy: as the winding thickness increases, the friction residual between each layer of pole pieces is greater than the first set value, indicating that there is residual friction between each layer of pole pieces and there is no side slip between the pole pieces; and the normal pressure of the inner layer of pole pieces is less than the second set value, indicating that the normal pressure of the inner layer of pole pieces is small and will not cause the inner layer of pole pieces to be crushed. Among them, the inner layer of pole pieces can refer to the pole pieces other than the outermost layer. Among them, the first set value can be 0 or other empirical values greater than 0, and the present application does not limit this. Moreover, generally, as long as the friction residual between each layer of pole pieces is greater than 0, it means that there is residual friction and there is no side slip. The second set value can be the limit value of the pressure that the pole piece can withstand or a set percentage of the limit value of the pressure that the pole piece can withstand, such as 90%, 80%, and the present application does not limit this.

[0048] Based on the conditions that the preset algorithm of the present application needs to meet, starting from the physical model of the battery pole piece winding, the inventors of the present application determined a general preset algorithm applicable to the pole piece winding through model training. Therefore, the winding tension calculated using this preset algorithm can avoid the excessive positive pressure on the inner-layer pole piece causing it to collapse as the winding thickness increases, and can also avoid the side-slip of the pole piece, ensuring the flatness of both ends of the wound pole piece and improving the winding quality.

[0049] As a preferred embodiment, in the embodiment of the present application, the formula for calculating the positive pressure is as follows:

[0050] In the formula, N(i, j) is the positive pressure of the i-th layer of the pole piece when the pole piece on the roller is wound to the j-th layer, with the unit of N; h is the thickness of the pole piece, with the unit of m; ν is the Poisson's ratio of the pole piece; r i is the winding thickness of the pole piece on the roller when it is wound to the i-th layer, with the unit of m; r t is the winding thickness of the pole piece on the roller when it is wound to the t-th layer, with the unit of m; F t is the winding tension corresponding to the pole piece on the roller when it is wound to the t-th layer, with the unit of N.

[0051] Among them, the thickness of the pole piece can be 0.8 m to 1.2 m or set according to the actual application scenario, and the present application does not limit this. The Poisson's ratio of the pole piece can refer to the ratio of the transverse normal strain to the axial normal strain when the pole piece is unidirectionally tensioned or compressed, also called the transverse deformation coefficient. It is an elastic constant reflecting the transverse deformation of the pole piece material. It is related to the specific material and manufacturing process of the pole piece and will vary due to different materials. The value of the Poisson's ratio of the pole piece can be obtained by detecting the pole piece, and the present application does not limit the value of the Poisson's ratio of the pole piece.

[0052] See Figure 3 , Figure 3 is the curve graph showing the change of the positive pressure of different layers of pole pieces during the winding process shown in the embodiment of the present application as the number of pole piece layers increases.

[0053] Figure 3 In, the changes in the positive pressure of the 1st layer, 1000th layer, 3000th layer, and 5000th layer during the winding process are selected for analysis.

[0054] The positive pressure of the first layer during the winding process represents the change in the positive pressure of the first-layer electrode sheet during the winding process with the increase in the number of electrode sheet layers (the number of electrode sheet winding layers). It first increases and then slowly increases until it levels off as the number of electrode sheet layers increases, indicating that as the winding thickness increases, the growth rate of the positive pressure of the first-layer electrode sheet (the innermost electrode sheet) slows down and will not cause the inner-layer electrode sheet to be crushed. And when reaching the maximum number of layers, the positive pressure of the first-layer electrode sheet does not exceed the limit value of the pressure that the electrode sheet can withstand. In the embodiments of the present application, the limit value of the pressure that the electrode sheet can withstand is related to the winding thickness threshold r n of the electrode sheet. Different electrode sheets have different winding thickness thresholds r n corresponding to different limit values of the pressure that the electrode sheet can withstand, and the present application does not limit this. Exemplarily, Figure 3 the limit value in

[0055] is 120 N. The positive pressure of the 1000th layer during the winding process represents the change in the positive pressure of the 1000th-layer electrode sheet during the winding process with the increase in the number of electrode sheet layers. It first increases and then slowly increases until it levels off as the number of electrode sheet layers increases, indicating that as the winding thickness increases, the growth rate of the positive pressure of the 1000th-layer electrode sheet slows down and will not cause the inner-layer electrode sheet to be crushed.

[0056] The positive pressure of the 3000th layer during the winding process represents the change in the positive pressure of the 3000th-layer electrode sheet during the winding process with the increase in the number of electrode sheet layers. It first increases and then slowly increases until it levels off as the number of electrode sheet layers increases, indicating that as the winding thickness increases, the growth rate of the positive pressure of the 3000th-layer electrode sheet slows down and will not cause the inner-layer electrode sheet to be crushed.

[0057] The positive pressure of the 5000th layer during the winding process represents the change in the positive pressure of the 5000th-layer electrode sheet during the winding process with the increase in the number of electrode sheet layers. It first increases and then slowly increases until it levels off as the number of electrode sheet layers increases, indicating that as the winding thickness increases, the growth rate of the positive pressure of the 5000th-layer electrode sheet slows down and will not cause the inner-layer electrode sheet to be crushed.

[0058] Therefore, from Figure 3 the above analysis, it can be seen that by calculating the positive pressure of each layer of electrode sheet using the winding tension calculated by the preset algorithm, the positive pressure of the electrode sheet is less than the second set value, and when reaching the maximum number of layers, the positive pressure of the innermost electrode sheet does not exceed the limit value of the pressure that the electrode sheet can withstand.

[0059] As a preferred embodiment, in the embodiments of the present application, the calculation formula for the residual friction force is as follows:

[0060] In the formula, E(i, j) is the residual friction force of the i-th layer of electrode sheet when the electrode sheet on the roller is wound to the j-th layer, and the unit is N; f max(i) is the maximum static friction when the pole piece on the roller is wound to the i-th layer, with the unit of N; F j is the winding tension corresponding to the pole piece on the roller wound to the j-th layer, with the unit of N; r j is the winding thickness of the pole piece on the roller wound to the j-th layer, with the unit of m; r i is the winding thickness of the pole piece on the roller wound to the i-th layer, with the unit of m; T(i, j) is the circumferential force of the i-th layer of the pole piece when the pole piece on the roller is wound to the j-th layer, with the unit of N.

[0061] Among them, the calculation formula of the circumferential force is as follows:

[0062] In the formula, T(i, j) is the circumferential force of the i-th layer of the pole piece when the pole piece on the roller is wound to the j-th layer, with the unit of N; T i is the circumferential force of the pole piece when the pole piece on the roller is wound to the i-th layer, with the unit of N; h is the pole piece thickness, with the unit of m; ν is the Poisson's ratio of the pole piece; r i is the winding thickness of the pole piece on the roller wound to the i-th layer, with the unit of m; r t is the winding thickness of the pole piece on the roller wound to the t-th layer, with the unit of m; F t is the winding tension corresponding to the pole piece on the roller wound to the t-th layer, with the unit of N.

[0063] Regarding the circumferential force T i , when the pole piece on the roller is wound to the first layer, the circumferential force T1 = the winding tension F1; according to the circumferential force calculation formula, T2 can be calculated based on T1, and T3 can be calculated based on T2, and so on, the circumferential force T of each layer of the pole piece can be calculated. i .

[0064] Among them, the calculation formula of the maximum static friction is as follows:

[0065] In the formula, f max (i) is the maximum static friction when the pole piece on the roller is wound to the i-th layer, with the unit of N; μ is the friction coefficient; h is the pole piece thickness, with the unit of m; ν is the Poisson's ratio of the pole piece; r i is the winding thickness of the pole piece on the roller wound to the i-th layer, with the unit of m; r t is the winding thickness of the pole piece on the roller wound to the t-th layer, with the unit of m; F t is the winding tension corresponding to the pole piece on the roller wound to the t-th layer, with the unit of N. In the embodiments of the present application, the value range of μ can be 0.1~0.5, or other empirical values, and the present application does not limit this.

[0066] In the embodiments of the present application, the pole piece thickness can be 80μm~300μm.

[0067] See Figure 4 and Figure 5 , Figure 4 which is a comparison chart of the residual friction force of each layer of the pole piece when wound to different numbers of layers shown in the embodiments of the present application. Figure 5 which is a comparison chart of the residual friction force at different numbers of layers during the winding process shown in the embodiments of the present application.

[0068] Figure 4 In [], the residual friction forces of the 1st to 1000th layers when wound to 1000 layers, the residual friction forces of the 1st to 3000th layers when wound to 3000 layers, the residual friction forces of the 1st to 6000th layers when wound to 6000 layers, and the residual friction forces of the 1st to 8000th layers when wound to 8000 layers are selected for the analysis of the residual friction force.

[0069] The residual friction forces of the 1st to 1000th layers when wound to 1000 layers, the residual friction forces of the 1st to 3000th layers when wound to 3000 layers, the residual friction forces of the 1st to 6000th layers when wound to 6000 layers, and the residual friction forces of the 1st to 8000th layers when wound to 8000 layers all gradually decrease with the increase in the number of pole piece layers, but the residual friction forces are basically greater than 0, indicating that there is residual friction force for each layer during winding and no side slip will occur. And it is allowed that the residual friction force of some layers during the winding process is less than 0. For example, among the residual friction forces of the 1st to 1000th layers when wound to 1000 layers, the values of some layers are less than 0, but this does not affect the overall winding effect.

[0070] Figure 5 In [], the changes in the residual friction forces of the 1st, 1000th, 3000th, and 5000th layers during the winding process are selected for analysis.

[0071] The residual friction forces of the 1st, 1000th, 3000th, and 5000th layers during the winding process all gradually increase with the increase in the number of pole piece layers, and the residual friction forces are basically greater than 0, indicating that there is residual friction force for each layer during winding and no side slip will occur. Among them, the residual friction force of the 1000th layer during the winding process is less than 0 in the initial stage of winding (for example, before the number of pole piece layers reaches 3000). Although the residual friction force is less than 0 during this period, with the increase in the number of pole piece layers, the residual friction force of the 1000th layer increases accordingly. This part of the residual friction force less than 0 can be ignored and has no impact on the overall winding efficiency.

[0072] Therefore, from Figure 4 and Figure 5From the analysis, it can be seen that the residual friction value of each layer of the pole piece is calculated by using a preset algorithm to calculate the winding tension, and the residual friction value of each layer of the pole piece is basically greater than 0, indicating that there is residual friction for each layer of the pole piece and no side slip will occur.

[0073] As an optional embodiment, obtaining the roller diameter and the winding thickness of the pole piece on the roller includes: S10. Obtain the winding layers of the pole piece on the roller, the pole piece thickness, and the roller diameter.

[0074] In the embodiment of the present application, the winding layers of the pole piece are the winding layers of the pole piece on the roller. For example, when the pole piece is wound to the first layer on the roller, the winding layers of the pole piece are 1. S11. Calculate the winding thickness of the pole piece according to the winding layers of the pole piece on the roller, the pole piece thickness, and the roller diameter.

[0075] In the embodiment of the present application, the winding thickness of the pole piece is related to the winding layers and the pole piece thickness, and the initial tension and the tension taper coefficient are also related to the winding layers and the pole piece thickness. Therefore, the initial tension and the tension taper coefficient can be set according to the winding thickness of the pole piece. And the winding thickness calculated according to the winding layers and the pole piece thickness of the pole piece, as well as the initial tension and the tension taper coefficient determined according to the winding thickness, can make the winding tension calculated based on the winding thickness, the initial tension, and the tension taper coefficient also related to the winding layers and the pole piece thickness of the pole piece, that is, related to the attributes of the pole piece. Thus, the preset algorithm provided by the embodiment of the present application can be applied to the winding control of different types of pole pieces (different materials, thicknesses, etc.).

[0076] Exemplarily, both the winding layers L and the pole piece thickness h are positively correlated with the winding thickness r of the pole piece. For example, the winding thickness r = winding layers L × pole piece thickness h, and the winding thickness of the pole piece can be calculated through this relationship.

[0077] As an optional embodiment, determining the initial tension and the tension taper coefficient of the winding according to the winding thickness includes: S20. Determine the initial tension range and the tension taper coefficient range according to the winding thickness threshold range of the pole piece.

[0078] In the embodiment of the present application, the winding thickness threshold range of the pole piece can be set according to actual application requirements or the attributes of the wound pole piece. The attributes of the wound pole piece include pole piece material, pole piece thickness, winding layers, etc. The present application does not limit the value of the winding thickness threshold. For example, it can be 0.8 m to 1.2 m. Exemplarily, the initial tension range can be 80 N to 200 N, and the tension taper coefficient range can be 0.6 to 1.

[0079] S21. According to multiple set winding thickness range segments, segment the initial tension range and the tension taper coefficient range according to the set winding thickness range segments, obtaining multiple initial tension range segments and multiple tension taper coefficient range segments. Each set winding thickness range segment corresponds to an initial tension range segment and a tension taper coefficient range segment.

[0080] In the embodiment of the present application, the set winding thickness range segments can be set according to the winding thickness threshold range. Taking the winding thickness threshold range as 0.8m to 1.2m, the initial tension range as 80N to 200N, and the tension taper coefficient range as 0.6 to 1 as an example for illustration.

[0081] Set the winding thickness range segments to be 3 segments, including (0m, 0.3m), [0.3m, 0.6), [0.6m, 1m]. Each segment corresponds to an initial tension range segment and a tension taper coefficient range segment.

[0082] S22. According to the winding thickness, determine the corresponding set winding thickness range segment, and determine the initial tension range segment and the tension taper coefficient range segment corresponding to this set winding thickness range segment.

[0083] Exemplarily, the winding thickness of the pole piece is 0.3m, corresponding to the second winding thickness range segment [0.3m, 0.6). According to this winding thickness range segment, determine the corresponding initial tension range segment and tension taper coefficient range segment.

[0084] Further preferably, when the winding thickness of the pole piece is (0m, 0.3m), the initial tension is 150N and the tension taper coefficient is 0.8; when the winding thickness of the pole piece is [0.3m, 0.6), the initial tension is 135N and the tension taper coefficient is 0.85; when the winding thickness of the pole piece is [0.6m, 1m], the initial tension is 120N and the tension taper coefficient is preferably 0.9.

[0085] As a preferred embodiment, when the winding thickness threshold range of the pole piece is 0.8m to 1.2m, the initial tension range is 80N to 200N, and the tension taper coefficient range is 0.6 to 1.

[0086] Corresponding to the foregoing application function implementation method embodiments, the present application also provides a battery pole piece winding tension control device, a pole piece winding device, and corresponding embodiments.

[0087] Figure 6 It is a schematic structural diagram of the battery pole piece winding tension control device shown in the embodiment of the present application.

[0088] See Figure 6 , the embodiment of the present application provides a battery pole piece winding tension control device 600, including: An acquisition module 601, configured to acquire the roller diameter and the winding thickness of the electrode sheet wound on the roller.

[0089] A parameter determination module 602, configured to determine the initial tension and the tension taper coefficient of winding according to the winding thickness; wherein, the relationship between the winding thickness and the initial tension is an inverse relationship, and the relationship between the winding thickness and the tension taper coefficient is a direct relationship.

[0090] A calculation module 603, configured to determine the winding tension of the electrode sheet wound on the roller according to the roller diameter, the winding thickness, the initial tension, the tension taper coefficient, and a preset algorithm.

[0091] A control module 604, configured to control the winding of the electrode sheet according to the winding tension.

[0092] The parameter determination module 602 in the embodiment of the present application can determine the initial tension and the tension taper coefficient of winding according to the winding thickness; wherein, the relationship between the winding thickness and the initial tension is an inverse relationship, and the relationship between the winding thickness and the tension taper coefficient is a direct relationship. For example, when the winding thickness is small, the initial tension can be large, and the tension taper coefficient can be small; when the winding thickness is large, the initial tension can be small, and the tension taper coefficient can be large; then the calculation module 603 is used to establish the relationship between the winding tension and the roller diameter, the winding thickness, the initial tension, and the tension taper coefficient according to the preset algorithm. The preset algorithm can be derived from the electrode sheet attributes and the winding pressure mathematical model, and through simulation and experimental verification, the corresponding relationship that meets the preset algorithm can make the inner layer of the electrode sheet not collapse during winding, and the electrode sheet will not slip laterally. Therefore, the winding tension calculated by using the preset algorithm can adapt to electrode sheets of different materials, and can avoid the inner layer of the electrode sheet being crushed due to excessive positive pressure as the winding thickness increases, and can also avoid the lateral slip of the electrode sheet, ensuring the flatness at both ends of the wound electrode sheet and improving the winding quality.

[0093] As an optional embodiment, the preset algorithm is as follows: F j =F0×[1-K×r j / (r j +1-r j / R)] In the formula, F j is the winding tension corresponding to the jth layer of the electrode sheet wound on the roller, R is the roller diameter, r j is the winding thickness of the electrode sheet wound on the roller to the jth layer, F0 is the initial tension corresponding to the winding thickness r j , and K is the tension taper coefficient corresponding to the winding thickness r j ; wherein, j = 1, 2, 3......n, and n is the number of winding layers corresponding to the winding thickness threshold r n .

[0094] As an alternative embodiment, the preset algorithm satisfies: Using the winding thickness r j and the winding tension F j The residual friction force and the normal pressure of each layer of the pole piece calculated satisfy the following relationship: when the pole piece is wound to the j-th layer, the residual friction force of the i-th layer of the pole piece is greater than the first set value, and the normal pressure is less than the second set value, where i = 1, 2, 3......j.

[0095] As an alternative embodiment, the obtaining module 601 is configured to obtain the winding length, the pole piece thickness, and the roller diameter when the pole piece on the roller is wound to the j-th layer; calculate the winding thickness r of the pole piece when it is wound to the j-th layer according to the winding length, the pole piece thickness, and the roller diameter of the pole piece on the roller when it is wound to the j-th layer j .

[0096] As an alternative embodiment, the parameter determination module 602 is configured to determine the initial tension range and the tension taper coefficient range according to the winding thickness threshold range of the pole piece; divide the initial tension range and the tension taper coefficient range into segments according to a plurality of set winding thickness range segments to obtain a plurality of initial tension range segments and a plurality of tension taper coefficient range segments, and each of the set winding thickness range segments corresponds to an initial tension range segment and a tension taper coefficient range segment; determine the corresponding set winding thickness range segment according to the winding thickness, and determine the initial tension range segment and the tension taper coefficient range segment corresponding to the set winding thickness range segment.

[0097] Regarding the device in the above embodiments, the specific manners in which each module performs operations have been described in detail in the embodiments related to the method, and will not be elaborated herein.

[0098] Figure 7 is a schematic structural diagram of a pole piece winding device shown in the embodiments of the present application.

[0099] See Figure 7 , the pole piece winding device 700 includes a memory 710 and a processor 720.

[0100] The processor 720 may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The memory 710 may include various types of storage units, such as system memory, read-only memory (ROM), and permanent storage devices. Among them, the ROM may store static data or instructions required by the processor 720 or other modules of the computer. The permanent storage device may be a readable and writable storage device. The permanent storage device may be a non-volatile storage device that does not lose the stored instructions and data even when the computer is powered off. In some embodiments, the permanent storage device uses a mass storage device (such as a magnetic or optical disk, flash memory) as the permanent storage device. In some other embodiments, the permanent storage device may be a removable storage device (such as a floppy disk, optical drive). The system memory may be a readable and writable storage device or a volatile readable and writable storage device, such as dynamic random access memory. The system memory may store some or all of the instructions and data required by the processor during operation. In addition, the memory 710 may include any combination of computer-readable storage media, including various types of semiconductor storage chips (such as DRAM, SRAM, SDRAM, flash memory, programmable read-only memory), and magnetic disks and / or optical disks may also be used. In some embodiments, the memory 710 may include a removable storage device that is readable and / or writable, such as a compact disc (CD), read-only digital versatile disc (such as DVD-ROM, dual-layer DVD-ROM), read-only Blu-ray disc, super density disc, flash memory card (such as SD card, min SD card, Micro-SD card, etc.), magnetic floppy disk, etc. Computer-readable storage media do not include carrier waves and instantaneous electronic signals transmitted wirelessly or by wire.

[0101] Executable code is stored on the memory 710, and when the executable code is processed by the processor 720, it may cause the processor 720 to execute some or all of the methods described above.

[0102] In addition, the method according to the present application can also be implemented as a computer program or a computer program product, which includes computer program code instructions for performing some or all of the steps in the above method of the present application.

[0103] Alternatively, the present application can also be implemented as a computer-readable storage medium (or a non-transitory machine-readable storage medium or a machine-readable storage medium), on which executable code (or a computer program or computer instruction code) is stored. When executed by a processor of an electronic device (or a server, etc.), the processor is caused to execute some or all of the steps of the above method according to the present application.

[0104] The present application also provides a computer program product, which includes computer instructions that, when executed by a processor, implement the method as described above.

[0105] The embodiments of the present application have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles of the embodiments, the practical application, or the improvement of the technology in the market, or to enable other ordinary skill in the art in the technical field to understand the embodiments disclosed herein.

Claims

1. A method for controlling the winding tension of a battery electrode sheet, characterized in that, Including: Obtain the roller diameter and the winding thickness of the electrode sheet wound on the roller; Determine the initial tension and the tension taper coefficient for winding according to the winding thickness; wherein, the relationship between the winding thickness and the initial tension is an inverse relationship, and the relationship between the winding thickness and the tension taper coefficient is a direct relationship; Determine the winding tension of the electrode sheet wound on the roller according to the roller diameter, the winding thickness, the initial tension, the tension taper coefficient, and a preset algorithm; Control the winding of the electrode sheet according to the winding tension.

2. The method according to claim 1, wherein The preset algorithm is as follows: F j = F0 × [1 - K × r j / (r j + 1 - r j / R)] Where, F j is the winding tension corresponding to the j-th layer of the pole piece wound on the roller, R is the diameter of the roller, r j is the winding thickness of the pole piece wound on the roller to the j-th layer, F0 is the initial tension corresponding to the winding thickness r j and K is the tension taper coefficient corresponding to the winding thickness r j .

3. The method according to claim 2, characterized in that The preset algorithm satisfies: Using the winding thickness r j and the winding tension F j The residual friction force and the normal pressure of each layer of the pole piece calculated satisfy the following relationship: when the pole piece is wound to the jth layer, the residual friction force of the ith layer of the pole piece is greater than the first set value, and the normal pressure is less than the second set value.

4. The method according to claim 3, wherein The formula for the normal pressure is as follows: In the formula, N(i, j) is the normal pressure of the i-th layer of the electrode sheet when the electrode sheet on the roller is wound to the j-th layer, h is the thickness of the electrode sheet, ν is the Poisson's ratio of the electrode sheet, ri is the winding thickness of the electrode sheet on the roller when wound to the i-th layer, rt is the winding thickness of the electrode sheet on the roller when wound to the t-th layer, and Ft is the winding tension corresponding to the electrode sheet on the roller when wound to the t-th layer.

5. The method according to claim 3, wherein The formula for the residual friction force is as follows: Wherein, E(i, j) is the residual friction force of the i-th layer of the pole piece when the pole piece on the roller is wound to the j-th layer, fmax(i) is the maximum static friction force of the pole piece on the roller when it is wound to the i-th layer, F j is the winding tension corresponding to the pole piece on the roller when it is wound to the j-th layer, r j is the winding thickness of the pole piece on the roller when it is wound to the j-th layer, r i is the winding thickness of the pole piece on the roller when it is wound to the i-th layer, and T(i, j) is the circumferential force of the i-th layer of the pole piece when the pole piece on the roller is wound to the j-th layer.

6. The method according to claim 1, wherein The obtaining the roller diameter and the winding thickness of the electrode sheet wound on the roller includes: Obtain the number of winding layers of the electrode sheet on the roller, the thickness of the electrode sheet, and the roller diameter; Calculate the winding thickness of the electrode sheet according to the number of winding layers of the electrode sheet on the roller, the thickness of the electrode sheet, and the roller diameter.

7. The method according to claim 1, characterized in that, The determining the initial tension and the tension taper coefficient for winding according to the winding thickness includes: Determine the initial tension range and the tension taper coefficient range according to the threshold range of the winding thickness of the electrode sheet; According to multiple set winding thickness range segments, segment the initial tension range and the tension taper coefficient range according to the set winding thickness range segments, to obtain multiple initial tension range segments and multiple tension taper coefficient range segments, and each of the set winding thickness range segments corresponds to one initial tension range segment and one tension taper coefficient range segment; Determine the corresponding set winding thickness range segment according to the winding thickness, and determine the initial tension range segment and the tension taper coefficient range segment corresponding to this set winding thickness range segment.

8. The method according to claim 7, wherein When the threshold range of the winding thickness of the electrode sheet is 0.8 m to 1.2 m, the initial tension range is 80 N to 200 N, and the tension taper coefficient range is 0.6 to 1.

9. A winding tension control device for a battery electrode sheet, characterized in that, Including: An obtaining module, configured to obtain the roller diameter and the winding thickness of the electrode sheet wound on the roller; A parameter determining module, configured to determine the initial tension and the tension taper coefficient for winding according to the winding thickness; wherein, the relationship between the winding thickness and the initial tension is an inverse relationship, and the relationship between the winding thickness and the tension taper coefficient is a direct relationship; A calculating module, configured to determine the winding tension of the electrode sheet wound on the roller according to the roller diameter, the winding thickness, the initial tension, the tension taper coefficient, and a preset algorithm; A control module, configured to control the winding of the electrode sheet according to the winding tension.

10. A pole piece winding device, characterized in that, Including: A processor; And A memory, on which executable code is stored, and when the executable code is executed by the processor, the processor executes the method according to any one of claims 1-8.

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