A method for high-speed laser drilling of composite current collector PP film

Abstract

The present invention relates to the field of laser drilling technology, and in particular to a method for high-speed laser drilling of a composite current collector PP film, comprising: using a 25W ultraviolet nanosecond laser with a wavelength of 355nm, a pulse energy of more than 500uj, a repetition frequency of 40-300KHZ, a pulse width of less than 20ns, and a beam quality of M 2 <1.2; the vertical point spacing is controlled by the movement speed of the assembly line and the speed of the rotating mirror, which specifically includes the following steps: collecting the movement speed of the coil line, performing state recognition analysis based on the movement speed time series, and judging the stability of the movement speed of the coil line; adjusting the rotating mirror speed according to the judged stability of the movement speed of the coil line; the present invention judges the stability of the movement speed of the coil line by real-time monitoring and analysis of the movement speed of the assembly line, and makes corresponding matching schemes when the movement speed of the assembly line is unstable, so as to ensure the uniformity of laser drilling of the composite current collector PP film.

Description

Technical Field

[0001] The invention relates to the technical field of laser drilling of current collector PP films, and in particular to a method for high-speed laser drilling of composite current collector PP films. Background Art

[0002] The current collector is one of the indispensable electrode materials for lithium-ion batteries. It has the important functions of carrying active substances (carrying capacity) and collecting microcurrents (conductivity). Thinning and functionalization are the main development directions of current collectors. The 8-9um Al foil current collector and the 4-5um Cu foil current collector have almost reached the ultimate level of manufacturability of lithium-ion batteries. Further thinning of the current collector leads to reduced strength and difficulty in mass application. Although functionalized current collectors such as carbon coating, LFP, and ceramics can improve adhesion, internal resistance, safety performance, etc., there are still some negative effects, such as higher process control requirements, increased costs, or reduced energy density. Composite current collectors integrate the characteristics of thin and light, high-safety current collectors and have been widely studied in recent years.

[0003] The composite current collector is a "sandwich" structure, with a polymer layer (such as PET, PP or PI) as the inner layer and metal conductive layers (such as Al or Cu) on both sides. The composite copper foil in the current industrial mass production of composite current collectors uses 4.5um OPP (polypropylene) as the substrate. First, a 50nm copper layer is magnetron sputtered on both sides of the substrate, and then water electroplating is performed on the surface of the copper layer to thicken the copper layer to about 1um. Composite aluminum foil usually uses 6um PET (polyethylene terephthalate) as the substrate, and then 1um aluminum layers are evaporated on both sides of the substrate.

[0004] In the prior art, during the high-speed laser drilling process of the composite current collector PP membrane, the movement speed of the assembly line will fluctuate and become unstable. In the prior art, it is impossible to effectively monitor and analyze the movement speed of the assembly line, and to make corresponding matching plans when the movement speed of the assembly line is unstable, so as to ensure the uniformity of laser drilling of the composite current collector PP membrane. Summary of the invention

[0005] The object of the present invention is to provide a method for high-speed laser drilling of a composite current collector PP film to solve at least one of the above-mentioned problems of the prior art.

[0006] A method for high-speed laser drilling of composite current collector PP film, comprising the following steps: using a 25W ultraviolet nanosecond laser with a wavelength of 355nm, a pulse energy of more than 500uJ, a repetition frequency of 40-300KHZ, a pulse width of less than 20ns, and a beam quality of M 2 <1.2; The vertical point spacing is controlled by the movement speed of the assembly line and the mirror rotation speed, which specifically includes the following steps:

[0007] S1, collecting the moving speed of the coil line;

[0008] S2. Perform state recognition analysis based on the speed sequence to determine the stability of the moving speed of the coil line;

[0009] S3. According to the stability of the moving speed of the coil line, the speed of the rotating mirror is adjusted.

[0010] As a further solution of the present invention: in S2, adjacent elements of the speed time series are subjected to difference calculation to obtain a speed difference sequence, and it is determined whether there is a non-zero element in the speed difference sequence;

[0011] If there is a non-zero element in the speed difference sequence, a signal of unqualified speed of the coil line is generated;

[0012] When a signal of unqualified moving speed of the coil line is obtained, the time points corresponding to the non-zero elements in the moving speed difference sequence are extracted, and the time interval in which the moving speed of the coil line is unstable is determined according to the time continuity;

[0013] Based on the time interval during which the moving speed of the coil line is unstable, the unstable time period value and the unstable moving speed period value are analyzed and obtained;

[0014] Obtain the time intervals during the drilling process when the moving speed of all coil wire bodies is unstable, record them as unstable moving speed time intervals, analyze the lengths of all unstable moving speed time intervals and the time intervals between adjacent unstable moving speed time intervals, and generate a time period signal if they meet the requirements;

[0015] When the time period signal is obtained, the similarity in each time interval of unstable speed is calculated through the correlation coefficient; the similarity in each time interval of unstable speed is averaged, if it meets the requirements, a drilling uniform fluctuation signal is generated, if not, a drilling uneven fluctuation signal is generated.

[0016] As a further solution of the present invention: the process of obtaining the speed difference sequence is as follows:

[0017] Get any two adjacent elements of the speed sequence, calculate the difference between the speed sequence at the later time and the speed sequence at the earlier time to obtain the speed difference, arrange all the speed differences in chronological order to obtain a speed difference sequence.

[0018] As a further solution of the present invention: the generation process of the time period signal is:

[0019] Get the length of all unstable time intervals, and calculate the variance to get the length variance of the unstable time intervals;

[0020] Obtain the time intervals of all the adjacent unstable time intervals, and obtain the interval variance of the unstable time intervals through variance calculation;

[0021] The length variance of the unstable time interval and the interval variance of the unstable time interval are averaged to obtain the unstable time period value;

[0022] If the unstable time period value is less than the unstable time period threshold, a time period signal is generated.

[0023] As a further solution of the present invention: the generation process of the drilling uneven fluctuation signal is:

[0024] Extract any two time intervals of unstable speed, calculate the difference of the elements in any two time intervals of unstable speed in order, obtain the difference of each equal sequence, average the difference of all equal sequences, and obtain the similarity of any two time intervals of unstable speed; calculate the average of the similarities in each time interval of unstable speed, and obtain the unstable speed period value;

[0025] If the unstable speed cycle value is less than the unstable speed cycle threshold, an uneven drilling fluctuation signal is generated.

[0026] As a further solution of the present invention: in S3, when the drilling uneven fluctuation signal is obtained, the matching difficulty coefficient is analyzed through the concurrent fluctuation coefficient, the simultaneous fluctuation coefficient and the cycle proportion; and the control scheme is determined according to the size of the matching difficulty coefficient;

[0027] Among them, the analysis process of the matching difficulty coefficient is:

[0028] Obtain the same period volatility coefficient, simultaneous volatility coefficient and cycle proportion, and mark them as XT, XS and BT respectively. , calculate the matching difficulty coefficient XP.

[0029] As a further solution of the present invention: when the matching difficulty coefficient is small, extract the speed differences in all unstable speed time intervals, calculate the average of the speeds of all the same numbers in all unstable speed time intervals, obtain the average of the speeds of all the same numbers, and construct a sequence {V1, V2, ..., V m}, according to the preset proportional coefficient K between the movement speed of the assembly line and the mirror speed, the mirror speed corresponding to the unstable speed time interval is controlled by a sequence {K*V1, K*V2, ..., K*V m}.

[0030] As a further solution of the present invention: the process of obtaining the volatility coefficient during the same period is:

[0031] Extract each speed difference in the unstable speed time interval, calculate the difference between each speed difference in the unstable speed time interval and its adjacent speed difference, and obtain the change value of the adjacent element; calculate the fluctuation coefficient of the same period of each unstable speed time interval through the formula, the formula is as follows:

[0032] ,

[0033] Among them, i=1,2,...,n, n represents the number of changes in the values ​​of adjacent elements in the time interval of unstable speed, Z i Indicates the change value of the i-th adjacent element, represents the mean of all the adjacent element change values ​​in the unstable speed time interval, and w represents the allowable error value of the adjacent element change values ​​in the set unstable speed time interval;

[0034] The mean of the concurrent fluctuation coefficients of all unstable speed time intervals is calculated to obtain the concurrent fluctuation coefficient.

[0035] As a further solution of the present invention: the process of obtaining the fluctuation coefficient is:

[0036] Extract all speed differences in all unstable speed time intervals, and calculate the speed differences of each same serial number in all unstable speed time intervals through the formula to obtain the simultaneous fluctuation coefficient of each same serial number. The formula is as follows:

[0037]

[0038] Where j = 1, 2, ..., m, where m represents the number of time intervals with unstable speed, and X j Indicates the speed difference of the jth same sequence number, represents the mean of the speed differences of the jth items with the same sequence number;

[0039] Calculate the mean of all simultaneous fluctuation coefficients with the same serial number to obtain the simultaneous fluctuation coefficient.

[0040] As a further solution of the present invention: the process of obtaining the cycle proportion is:

[0041] Get the number of time intervals with unstable speed and the number of change values ​​of adjacent elements in the time intervals with unstable speed, and calculate the cycle ratio through the formula. The formula is as follows:

[0042]

[0043] Among them, m represents the number of time intervals with unstable speed, n represents the number of change values ​​of adjacent elements in the time interval with unstable speed, and N represents the number of all elements in the speed time series.

[0044] Beneficial effects of the present invention:

[0045] The present invention collects the moving speed of the coil line; performs state recognition analysis based on the moving speed time sequence to determine the stability of the moving speed of the coil line; regulates the rotating mirror speed according to the determined stability of the moving speed of the coil line; during the high-speed laser drilling of the composite current collector PP film, the moving speed of the assembly line is monitored and analyzed in real time to determine the stability of the moving speed of the coil line, and makes a corresponding matching plan when the moving speed of the assembly line is unstable to ensure the uniformity of laser drilling of the composite current collector PP film. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0047] Figure 1 The present invention is a flow chart of a method for high-speed laser drilling of a composite current collector PP film. DETAILED DESCRIPTION

[0048] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0049] like Figure 1 As shown, a method for high-speed laser drilling of a composite current collector PP film provided by an embodiment of the present invention specifically comprises the following steps:

[0050] The material to be laser processed is PP film (polypropylene), the material thickness is 4um, the material width is 1200mm, to achieve high-speed flying drilling on such a wide coil, the hole diameter is required to be 6-10um, the hole spacing is 0.5-2mm adjustable, the present invention adopts a 25W ultraviolet nanosecond laser, the wavelength is 355nm, the pulse energy is greater than 500uj, the repetition frequency is 40-300KHZ, the pulse width is less than 20ns, and the beam quality is M 2 <1.2, we use a single laser pulse to process the film material, and control the horizontal point spacing by mirror offset and matching the laser processing frequency, and control the vertical point spacing by the movement speed of the assembly line and the mirror speed;

[0051] Since the present invention has very high requirements for dotting speed, only a rotating mirror can meet the requirements. A high-power quartz field mirror is used to focus the light spot, with a focal length of F160mm and a focused spot size of 5.8um. ​​Under the requirement of 1000mm / s for the coil line, when the point spacing is 0.5mm, the rotating mirror speed is 25000mm / s, the power used is 11.5W, the frequency is 50KHZ, and the single pulse energy of 530uj can penetrate the material with an aperture of 10um. When the point spacing is 2mm, the rotating mirror speed is 100000mm / s, the power used is 11.5W, the frequency is 50KHZ, and the single pulse energy of 530uj can penetrate the material with an aperture of 10um. The present invention can achieve 800,000 dots / m on the PP film. 3 , which belongs to high-speed flying drilling;

[0052] The vertical point spacing is controlled by the movement speed of the assembly line and the speed of the rotating mirror. However, during the high-speed laser drilling of the composite current collector PP film, the movement speed of the assembly line will fluctuate and become unstable. In the prior art, the movement speed of the assembly line cannot be effectively monitored and analyzed, and a corresponding matching scheme cannot be made when the movement speed of the assembly line is unstable to ensure the uniformity of the laser drilling of the composite current collector PP film. The specific solution includes the following steps:

[0053] S1, collecting the moving speed of the coil line;

[0054] In some embodiments, the moving speed of the coil line is collected in real time by a speed sensor, and a sequence of the moving speed of the coil line during processing time is constructed, which is recorded as a moving speed time sequence;

[0055] S2. Perform state recognition analysis based on the speed sequence to determine the stability of the moving speed of the coil line;

[0056] In some embodiments, a speed time sequence is obtained, adjacent elements of the speed time sequence are difference-calculated to obtain a speed difference sequence, and it is determined whether there is a non-zero element in the speed difference sequence;

[0057] If there is no non-zero element in the speed difference sequence, it means that the moving speed of the coil wire is uniform during the drilling process, and a qualified signal of the moving speed of the coil wire is generated;

[0058] If there is a non-zero element in the speed difference sequence, it means that the moving speed of the coil body is uneven during the drilling process, and a signal indicating that the moving speed of the coil body is unqualified is generated;

[0059] When a signal of unqualified moving speed of the coil line is obtained, the time points corresponding to the non-zero elements in the moving speed difference sequence are extracted, and the time interval in which the moving speed of the coil line is unstable is determined according to the time continuity;

[0060] Based on the time interval during which the moving speed of the coil line is unstable, the unstable time period value and the unstable moving speed period value are analyzed and obtained;

[0061] Obtain all time intervals during the drilling process when the moving speed of the coil wire is unstable, recorded as unstable moving speed time intervals, and analyze the lengths of all unstable moving speed time intervals and the time intervals between two adjacent unstable moving speed time intervals. If they meet the requirements, it means that the moving speed of the coil wire presents periodic changes in time, and a time period signal is generated. If they do not meet the requirements, it means that the moving speed of the coil wire does not present periodic changes in time, and a non-time period signal is generated.

[0062] When the time period signal is obtained, the similarity in each time interval of unstable speed is calculated through the correlation coefficient; the similarity in each time interval of unstable speed is averaged. If it is consistent, it means that during the drilling process, the moving speed of the coil wire body not only shows periodic changes in time, but also shows periodic changes in the moving speed, generating a uniform drilling fluctuation signal; if it is not consistent, it means that during the drilling process, the moving speed of the coil wire body shows periodic changes in time, but the moving speed does not show periodic changes, generating an uneven drilling fluctuation signal;

[0063] In a first exemplary embodiment, the process of acquiring the speed difference sequence is as follows:

[0064] Get any two adjacent elements of the speed sequence, calculate the difference between the speed sequence at the later time and the speed sequence at the earlier time to get the speed difference, arrange all the speed differences in chronological order to get the speed difference sequence;

[0065] Second, illustratively, the specific process of analyzing the lengths of all unstable speed time intervals and the time intervals between two adjacent unstable speed time intervals is as follows:

[0066] Get the length of all unstable time intervals, and calculate the variance to get the length variance of the unstable time intervals;

[0067] Obtain the time intervals of all the adjacent unstable time intervals, and obtain the interval variance of the unstable time intervals through variance calculation;

[0068] The length variance of the unstable time interval and the interval variance of the unstable time interval are averaged to obtain the unstable time period value;

[0069] If the unstable time period value is compared with the unstable time period threshold;

[0070] If the unstable time period value is greater than or equal to the unstable time period threshold, a no time period signal is generated;

[0071] If the unstable time period value is less than the unstable time period threshold, a time period signal is generated;

[0072] Thirdly, by way of example, the specific process of calculating the similarity in each unstable speed time interval by means of the correlation coefficient is as follows:

[0073] Extract any two time intervals of unstable speed, calculate the difference of the elements in any two time intervals of unstable speed in order, obtain the difference of each equal sequence, average the difference of all equal sequences, and obtain the similarity of any two time intervals of unstable speed; calculate the average of the similarities in each time interval of unstable speed, and obtain the unstable speed period value;

[0074] Compare the unstable speed period value with the unstable speed period threshold;

[0075] If the unstable speed cycle value is greater than or equal to the unstable speed cycle threshold, it means that during the drilling process, the moving speed of the coil wire body not only shows periodic changes in time, but also in the moving speed, generating a drilling uniform fluctuation signal;

[0076] If the unstable speed cycle value is less than the unstable speed cycle threshold, it means that during the drilling process, the moving speed of the coil body shows periodic changes in time, but the moving speed does not show periodic changes, and an uneven drilling fluctuation signal is generated;

[0077] S3, adjusting the speed of the rotating mirror according to the stability of the moving speed of the coil line;

[0078] In some embodiments, when a drilling uniform fluctuation signal is obtained, each unstable speed time interval is obtained, and the elements in each unstable speed time interval are obtained, and the average value is calculated to obtain the speed difference, that is, the periodic speed control value of the moving speed of the coil wire body during the drilling process is obtained;

[0079] For example, if the preset moving speed of the coil wire is A, the length of the unstable speed time interval is B, the time interval between two adjacent unstable speed time intervals is C, and the speed difference is D, that is, during the drilling process, the time to obtain the uniform drilling fluctuation signal is used for timing. When the time interval is C, the preset moving speed of the coil wire is adjusted to (A+D);

[0080] When the uneven fluctuation signal of drilling is obtained, the matching difficulty coefficient is analyzed by the synchronous fluctuation coefficient, the simultaneous fluctuation coefficient and the cycle proportion; the control scheme is determined according to the size of the matching difficulty coefficient, that is, when the matching difficulty coefficient is small, the speed differences in all unstable speed time intervals are extracted, and the moving speeds of the same sequence number in all unstable speed time intervals are averaged to obtain the average moving speed of each same sequence number, and the sequence of the moving speed averages in the unstable speed time intervals {V1, V2, ..., V m}, according to the preset proportional coefficient K between the movement speed of the assembly line and the mirror speed, the mirror speed corresponding to the unstable speed time interval is controlled by a sequence {K*V1, K*V2, ..., K*V m}, when the matching difficulty coefficient is high, perform a fault check on the reel of the coiling line;

[0081] Specifically, the analysis process of the matching difficulty coefficient is as follows:

[0082] Obtain the same period volatility coefficient, simultaneous volatility coefficient and cycle proportion, and mark them as XT, XS and BT respectively. , calculate the matching difficulty coefficient XP;

[0083] First, illustratively, the process of obtaining the volatility coefficient during the same period is as follows:

[0084] Extract each speed difference in the unstable speed time interval, calculate the difference between each speed difference in the unstable speed time interval and its adjacent speed difference, and obtain the change value of the adjacent element; calculate the fluctuation coefficient of the same period of each unstable speed time interval through the formula, the formula is as follows:

[0085]

[0086] Among them, i=1,2,...,n, n represents the number of changes in the values ​​of adjacent elements in the time interval of unstable speed, Z i Indicates the change value of the i-th adjacent element, represents the mean of all the adjacent element change values ​​in the unstable speed time interval, and w represents the allowable error value of the adjacent element change values ​​in the set unstable speed time interval;

[0087] The mean of the fluctuation coefficients of all the time intervals with unstable speed is calculated to obtain the fluctuation coefficients of the same period;

[0088] In a second exemplary embodiment, the process of obtaining the simultaneous fluctuation coefficient is:

[0089] Extract all speed differences in all unstable speed time intervals, and calculate the speed differences of each same serial number in all unstable speed time intervals through the formula to obtain the simultaneous fluctuation coefficient of each same serial number. The formula is as follows:

[0090]

[0091] Where j = 1, 2, ..., m, where m represents the number of time intervals with unstable speed, and X j Indicates the speed difference of the jth same sequence number, represents the mean of the speed differences of the jth items with the same sequence number;

[0092] Calculate the mean of all simultaneous fluctuation coefficients with the same serial number to obtain the simultaneous fluctuation coefficient;

[0093] In a third exemplary embodiment, the process of obtaining the cycle ratio is as follows:

[0094] Get the number of time intervals with unstable speed and the number of change values ​​of adjacent elements in the time intervals with unstable speed, and calculate the cycle ratio through the formula. The formula is as follows:

[0095]

[0096] Among them, m represents the number of time intervals with unstable speed, n represents the number of change values ​​of adjacent elements in the time interval with unstable speed, and N represents the number of all elements in the speed time series;

[0097] The technical solution of the embodiment of the present invention includes: collecting the moving speed of the coil line; performing state recognition analysis based on the moving speed time series to determine the stability of the moving speed of the coil line; regulating the rotating mirror speed according to the determined stability of the moving speed of the coil line; during the high-speed laser drilling of the composite current collector PP film, real-time monitoring and analysis of the movement speed of the assembly line is performed to determine the stability of the moving speed of the coil line, and when the movement speed of the assembly line is unstable, a corresponding matching solution is made to ensure the uniformity of laser drilling of the composite current collector PP film.

[0098] The above formulas are all dimensionless and numerical calculations. The formula is a formula for the most recent real situation obtained by collecting a large amount of data and performing software simulation. The preset parameters in the formula are set by technicians in this field according to actual conditions.

[0099] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for high-speed laser drilling of composite current collector PP film, characterized in that: The following steps are involved: It uses a 25W ultraviolet nanosecond laser with a wavelength of 355nm, a pulse energy of >500uj, a repetition frequency of 40-300KHZ, a pulse width of <20ns, and a beam quality of M 2 <1.2; The vertical point spacing is controlled by the movement speed of the assembly line and the mirror rotation speed, which specifically includes the following steps: S1, collecting the moving speed of the coil line, constructing a sequence of the moving speed of the coil line during processing time, and recording it as a moving speed time sequence; S2. Perform state recognition analysis based on the speed sequence to determine the stability of the speed of the coil line, perform difference calculation on adjacent elements of the speed sequence to obtain a speed difference sequence, and determine whether there is a non-zero element in the speed difference sequence; If there is a non-zero element in the speed difference sequence, a signal of unqualified speed of the coil line is generated; When a signal of unqualified moving speed of the coil line is obtained, the time points corresponding to the non-zero elements in the moving speed difference sequence are extracted, and the time interval in which the moving speed of the coil line is unstable is determined according to the time continuity; Based on the time interval during which the moving speed of the coil line is unstable, the unstable time period value and the unstable moving speed period value are analyzed and obtained; Obtain the time intervals during the drilling process when the moving speed of all coil wire bodies is unstable, record them as unstable moving speed time intervals, analyze the lengths of all unstable moving speed time intervals and the time intervals between adjacent unstable moving speed time intervals, and generate a time period signal if they meet the requirements; When the time period signal is obtained, the similarity in each unstable speed time interval is calculated by the correlation coefficient; the similarity in each unstable speed time interval is averaged, and if it is consistent, a drilling uniform fluctuation signal is generated; if it is not consistent, a drilling uneven fluctuation signal is generated; S3. According to the stability of the moving speed of the coiled material line, the mirror speed is regulated. When the uneven drilling fluctuation signal is obtained, the matching difficulty coefficient is analyzed through the synchronous fluctuation coefficient, the simultaneous fluctuation coefficient and the cycle proportion; according to the size of the matching difficulty coefficient, the regulation scheme is determined; Among them, the analysis process of the matching difficulty coefficient is: Obtain the same period volatility coefficient, simultaneous volatility coefficient and cycle proportion, and mark them as XT, XS and BT respectively. , calculate the matching difficulty coefficient XP.

2. The method for high-speed laser drilling of composite current collector PP film according to claim 1, characterized in that: The process of obtaining the speed difference sequence is as follows: Get any two adjacent elements of the speed sequence, calculate the difference between the speed sequence at the later time and the speed sequence at the earlier time to obtain the speed difference, arrange all the speed differences in chronological order to obtain a speed difference sequence.

3. The method for high-speed laser drilling of composite current collector PP film according to claim 2, characterized in that: The generation process of the time period signal is: Get the length of all unstable time intervals, and calculate the variance to get the length variance of the unstable time intervals; Obtain the time intervals of all the adjacent unstable time intervals, and obtain the interval variance of the unstable time intervals through variance calculation; The length variance of the unstable time interval and the interval variance of the unstable time interval are averaged to obtain the unstable time period value; If the unstable time period value is less than the unstable time period threshold, a time period signal is generated.

4. The method for high-speed laser drilling of composite current collector PP film according to claim 3, characterized in that: The generation process of drilling uneven fluctuation signal is: Extract any two time intervals of unstable speed, calculate the difference of the elements in any two time intervals of unstable speed in order, obtain the difference of each equal sequence, average the difference of all equal sequences, and obtain the similarity of any two time intervals of unstable speed; calculate the average of the similarities in each time interval of unstable speed, and obtain the unstable speed period value; If the unstable speed cycle value is less than the unstable speed cycle threshold, an uneven drilling fluctuation signal is generated.

5. The method for high-speed laser drilling of composite current collector PP film according to claim 4, characterized in that: When the matching difficulty coefficient is small, extract the speed differences in all unstable speed time intervals, calculate the average of the speeds of the same sequence number in all unstable speed time intervals, obtain the average of the speeds of the same sequence number, and construct a sequence of the average speeds of the unstable speed time intervals {V1, V2, ..., V m }, according to the preset proportional coefficient K between the movement speed of the assembly line and the mirror speed, the mirror speed corresponding to the unstable speed time interval is controlled by a sequence {K*V1, K*V2, ..., K*V m }.

6. The method for high-speed laser drilling of composite current collector PP film according to claim 5, characterized in that: The process of obtaining the volatility coefficient during the same period is as follows: Extract each speed difference in the unstable speed time interval, calculate the difference between each speed difference in the unstable speed time interval and its adjacent speed difference, and obtain the change value of the adjacent element; calculate the fluctuation coefficient of the same period of each unstable speed time interval through the formula, the formula is as follows: , where i=1,2,...,n, n represents the number of changes in the adjacent elements in the time interval of unstable speed, Z i Indicates the change value of the i-th adjacent element, represents the mean of all the adjacent element change values ​​in the unstable speed time interval, and w represents the allowable error value of the adjacent element change values ​​in the set unstable speed time interval; The mean of the concurrent fluctuation coefficients of all unstable speed time intervals is calculated to obtain the concurrent fluctuation coefficient.

7. The method for high-speed laser drilling of composite current collector PP film according to claim 6, characterized in that: At the same time, the process of obtaining the volatility coefficient is: Extract all speed differences in all unstable speed time intervals, and calculate the speed differences of each same serial number in all unstable speed time intervals through the formula to obtain the simultaneous fluctuation coefficient of each same serial number. The formula is as follows: , where j = 1, 2, ..., m, where m represents the number of time intervals with unstable speed, and X j Indicates the speed difference of the jth same sequence number, represents the mean of the speed differences of the jth items with the same sequence number; Calculate the mean of all simultaneous fluctuation coefficients with the same serial number to obtain the simultaneous fluctuation coefficient.

8. The method for high-speed laser drilling of composite current collector PP film according to claim 7, characterized in that: The process of obtaining the cycle ratio is as follows: Get the number of time intervals with unstable speed and the number of change values ​​of adjacent elements in the time intervals with unstable speed, and calculate the cycle ratio through the formula. The formula is as follows: Wherein, N represents the number of all elements in the speed time series.

Images