One]The present invention relates to a method for quantifying and diagnosing the quality of a manufacturing facility.
[2]
This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0097050 on August 9, 2019, and all contents disclosed in the literature of the Korean patent application are incorporated as a part of this specification.
background
[3]
Recently, a rechargeable battery capable of charging and discharging has been widely used as an energy source for a wireless mobile device. In addition, secondary batteries are attracting attention as power sources for electric vehicles (EVs) and hybrid electric vehicles (HEVs), which are proposed as a way to solve air pollution, such as conventional gasoline and diesel vehicles using fossil fuels. there is.
[4]
Therefore, the types of applications using secondary batteries are being diversified due to the advantages of secondary batteries, and it is expected that secondary batteries will be applied to more fields and products in the future than now.
[5]
While small mobile devices use one or a small number of battery cells per device, mid-to-large-sized battery modules electrically connecting a plurality of battery cells are used in mid-to-large devices such as automobiles due to the need for high output and large capacity.
[6]
On the other hand, if the defect rate is high as a result of quality inspection of the manufactured secondary battery, diagnosis and supplementation of the above manufacturing equipment are required. However, equipment for manufacturing secondary batteries includes various production factors. Therefore, in order to identify a production factor that causes product failure, an overall diagnosis of the entire manufacturing facility is required. This causes a decrease in process efficiency for the secondary battery.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[7]
An object of the present invention is to solve the problems of the prior art and the technical problems that have been requested from the past. An object of the present invention relates to a method for quantifying and diagnosing the quality of a manufacturing plant with a plurality of production factors at once.
means of solving the problem
[8]
In order to achieve this object, the diagnostic method for quantifying manufacturing equipment quality according to the present invention,
[9]
acquiring successive inspection values ​​for a target product;
[10]
deriving a conversion peak per frequency indicating an expression level per production cycle by separating the continuously acquired test values ​​for each frequency band;
[11]
securing a natural frequency expressed per production cycle for each production factor; and
[12]
and diagnosing the quality of each production element by comparing the natural frequency for each production element and the conversion peak per frequency.
[13]
In one example, in the manufacturing facility quality quantification diagnostic method according to the present invention, the step of acquiring a continuous inspection value for a target product includes examining a specific element of the target product, and comparing the inspection result against a reference value to the inspection value is continuously acquired and performed.
[14]
Specifically, the step of acquiring continuous inspection values ​​for the target product includes:
[15]
Inspect for specific elements of the subject product,
[16]
If the test result exceeds the standard value, it is quantified as a positive (+) number,
[17]
If the test result does not meet the standard, it is quantified as a negative (-) number,
[18]
The quantified values ​​are continuously acquired and performed.
[19]
For example, in the step of acquiring successive inspection values ​​for the target product, the target product is an electrochemical device. In the present invention, the electrochemical device includes not only unit cells such as batteries or capacitors, but also battery modules or battery packs. Specifically, the electrochemical device is a secondary battery, for example, a lithium secondary battery.
[20]
In one example of the present invention, the step of deriving a transformation peak per frequency indicating the expression level per production cycle by separating the continuously acquired inspection values ​​by frequency band is performed through a Fast Fourier Transform (FFT) technique. carry out
[21]
In one example, the step of securing the natural frequency expressed per production cycle for each production factor is to derive the production factors that affect the production of the target product, and each derived production factor is unique based on the number of times it is expressed per production cycle secure the frequency.
[22]
Specifically, the number of occurrences per production cycle for each production factor is a result of extracting the frequency at which the inspection value for a specific factor of the target product deviates from the reference value due to the influence of each production factor.
[23]
In addition, the said production element is an equipment element involved in target product production. For example, the equipment element is an electrochemical device manufacturing equipment element.
[24]
In one example, the step of diagnosing the quality of each production factor by preparing the natural frequency for each production factor and the conversion peak per frequency is, It is characterized in that the production factor of the natural frequency corresponding to the frequency is selected as a quality improvement target.
[25]
In another example, in contrast to the conversion peak per frequency for each natural frequency of each preset production factor, the production factor of the natural frequency corresponding to the frequency at which the conversion peak appears higher than a specific value is selected as a quality complementation target, and the conversion peak It is characterized in that the production factor of the natural frequency corresponding to the frequency in which is lower than a specific value is excluded from the quality improvement target.
[26]
In another example, the present invention prepares the natural frequency for each production element and the conversion peak per frequency, and after the step of diagnosing the quality for each production element, the step of supplementing or replacing the production element selected as the quality complementation target include more
Effects of the Invention
[27]
The quantification diagnostic method for manufacturing equipment quality according to the present invention can quantify and diagnose the quality of a manufacturing equipment having a plurality of production factors at once.
Brief description of the drawing
[28]
1 is a schematic diagram schematically illustrating a manufacturing facility quality quantification diagnostic method according to an embodiment of the present invention.
[29]
2 is a graph showing a result of obtaining continuous inspection values ​​for a target product.
[30]
3 is a graph showing a result of deriving a conversion peak per frequency indicating the expression level per production cycle by separating continuously acquired test values ​​for each frequency band.
[31]
4 is a graph showing the result of comparing the natural frequency for each production element and the conversion peak per frequency.
Modes for carrying out the invention
[32]
Hereinafter, the present invention will be described in detail. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. It should be interpreted as meaning and concept consistent with the technical idea of ​​the present invention based on the principle that it can be defined as
[33]
[34]
The present invention relates to a manufacturing facility quality quantification diagnostic method,
[35]
acquiring successive inspection values ​​for a target product;
[36]
deriving a conversion peak per frequency indicating an expression level per production cycle by separating the continuously acquired test values ​​for each frequency band;
[37]
securing a natural frequency expressed per production cycle for each production factor; and
[38]
and diagnosing the quality of each production element by comparing the natural frequency for each production element and the conversion peak per frequency.
[39]
In each of the above steps, the step of securing the natural frequency expressed per production cycle for each production factor can be performed separately regardless of before or after performing other steps. For example, in the step of securing the natural frequency expressed per production cycle for each production factor, before performing the diagnostic method according to the present invention, it is possible to secure the natural frequency expressed per production cycle for each production factor in advance.
[40]
In one example, in the manufacturing facility quality quantification diagnostic method according to the present invention, the step of acquiring a continuous inspection value for a target product includes examining a specific element of the target product, and comparing the inspection result against a reference value to the inspection value is continuously acquired and performed. In the present invention, inspection values ​​are continuously acquired for a target product. This means that the quality inspection of the target product is continuously performed at the middle or end of the production line. For example, shape, size, or physical properties of a target product are continuously inspected, and this data is built. In the present invention, successively acquiring inspection values ​​means performing a complete inspection on a target product or performing a sample inspection at regular intervals, and the process is performed at regular intervals.
[41]
Specifically, in the step of acquiring a continuous inspection value for the target product, a specific element of the target product is inspected, and when the inspection result exceeds the reference value, it is quantified as a positive (+) number, and the inspection result is If the standard value is not met, it is quantified as a negative (-) number, and the quantified values ​​are continuously acquired and performed. A method of obtaining an inspection value for a target product is not particularly limited as long as the result can be obtained as a quantified graph. As an example, an inspection value is acquired with respect to a specific element of a target product, for example, a thickness or a physical property value of a specific part. In this case, a reference value that can be determined as a normal product is set in advance, and a (+) or (-) sign is added to the delta value of the reference value and the inspection value of the target product to quantify it.
[42]
In the step of acquiring successive inspection values ​​for the target product, the target product is an electrochemical device. In the present invention, the electrochemical device includes not only unit cells such as batteries or capacitors, but also battery modules or battery packs. Specifically, the electrochemical device is a secondary battery, for example, a lithium secondary battery. In one example, a manufacturing facility subject to the present invention is a facility for manufacturing a secondary battery unit cell or a secondary battery module. In this case, the inspection value for the target product includes, for example, a battery size standard, low or high temperature stability, charge/discharge capacity, or charge/discharge cycle characteristics.
[43]
In one example, the step of deriving a transformation peak per frequency indicating the expression level per production cycle by separating the continuously acquired inspection values ​​for each frequency band is performed through a Fast Fourier Transform (FFT) technique. In the present invention, if it is possible to separate for each frequency band from a graph indicating continuously acquired check values, the conversion technique is variously applicable. As an example, Fast Fourier Transform (FFT) is an algorithm that computes the Discrete Fourier Transform (DFT) or inverse (IDFT) of a sequence. Fourier analysis transforms a signal from its original domain (often in time or space) to a representation in the frequency domain, and vice versa. A discrete Fourier transform (DFT) is obtained by decomposing a series of values ​​into components of different frequencies.
[44]
A brief description of the fast Fourier transform is as follows. However, the following description is only for a general understanding of the fast Fourier transform, and the present invention is not limited thereto. In addition, the fast Fourier transform can be described through various papers, and the present invention includes all of them.
[45]
The Fast Fourier Transform is an algorithm for calculating the approximate value of a function, and it is designed to reduce the number of operations when calculating the Discrete Fourier Transform using an approximation formula based on the Fourier Transform.
[46]
The fast Fourier transform was generally known by JW Coley and JW Turkey in the mid-1960s, and has been independently discovered and used by some people about 20 years before that.
[47]
For example, when h m (0≤m≤N-1) is a set of complex numbers, the discrete Fourier transform of the sequence {h m } is as follows.
[48]
[Equation 1]
[49]

[50]
In the same way as in the continuous Fourier transform, the inverse transform can be obtained for the discrete transform as follows.
[51]
[52]
[Equation 2]
[53]

[54]
h n is called the inverse Fourier transform coefficient. The algorithm of the fast Fourier transform is based on the fact that when calculating Equation 1, it can be performed in stages using direct product decomposition.
[55]
When N=N 1 N 2 , N 1 and N 2 are prime to each other, a two-dimensional Fourier transform coefficient is given as an example.
[56]

[57]
When complex multiplication and complex addition are one basic operation, when Horner's method is used, the operation of N 2 , that is, (N 1 N 2 ) 2 is required, but when using the direct decomposition method, H n1 , n2 can be calculated by the operation of N 1 N 2 (N 1 +N 2 ). Since the matrix corresponding to the above transformation is a direct product of the N 1 ХN 1 and N 2 ХN 2 matrices, the calculation is performed by dividing it into the following two steps.
[58]
As a first step, for 0≤m1≤N1-1 and 0≤n2≤N2-1
[59]
[Equation 3]
[60]

[61]
to calculate,
[62]
Next, 0≤n1≤N1-1 and 0≤n2≤N2-1
[63]
[Equation 4]
[64]

[65]
to calculate
[66]
[67]
In one example, the step of securing the natural frequency expressed per production cycle for each production factor is to derive the production factors that affect the production of the target product, and each derived production factor is unique based on the number of times it is expressed per production cycle secure the frequency. Specifically, the number of occurrences per production cycle for each production factor is a result of extracting the frequency at which the inspection value for a specific factor of the target product deviates from the reference value due to the influence of each production factor. In addition, the said production element is an equipment element involved in target product production. For example, the equipment element is an electrochemical device manufacturing equipment element. In a facility for manufacturing a lithium secondary battery unit cell, for example, a raw material supply unit, various rollers, or a conveying belt are production factors, and they affect the production of a target product. Among these production factors, certain parts of the product are defective within a given repetition period, frequently and at short intervals. Another factor of production is the failure of certain parts of the product with relatively few and long cycles. The step of securing the natural frequency in the present invention secures the natural frequency expressed per production cycle for each of the various production factors including the production factors exemplified above.
[68]
In one example, the step of diagnosing the quality of each production factor by preparing the natural frequency for each production factor and the conversion peak per frequency is, The production factor of the natural frequency corresponding to the frequency is selected for quality improvement. In another example, in contrast to the conversion peak per frequency for each natural frequency of each preset production factor, the production factor of the natural frequency corresponding to the frequency at which the conversion peak appears higher than a specific value is selected as a quality complementation target, and the conversion peak It is possible to exclude the production factor of the natural frequency corresponding to the frequency where is lower than a specific value from the target of quality improvement. Furthermore, the present invention may further include the step of supplementing or replacing the production element selected as a quality complementation target after the step of diagnosing the quality of each production element in preparation for the natural frequency for each production element and the conversion peak per frequency .
[69]
[70]
Hereinafter, the present invention will be described in more detail with reference to drawings, etc., but these are only specific examples of the present invention, and the scope of the present invention is not limited thereto.
[71]
1 is a schematic diagram schematically illustrating a manufacturing facility quality quantification diagnostic method according to the present invention. 2 is a graph showing a result of obtaining continuous inspection values ​​for a target product. 3 is a graph showing a result of deriving a conversion peak per frequency indicating the expression level per production cycle by separating continuously acquired test values ​​for each frequency band. In addition, FIG. 4 is a graph showing the result of comparing the natural frequency for each production element and the conversion peak per frequency.
[72]
In FIG. 1 , a product inspection is first performed. The product inspection is a process of acquiring continuous product inspection values ​​for a target product. For example, when manufacturing a unit cell of a secondary battery, a specific element of a target product is inspected, and an inspection value is continuously acquired by comparing the inspection result against a reference value. Here, a specific element of the target product may be selected from among product quality evaluation items, and it is also possible to consider any one element or a plurality of elements in combination. Referring to FIG. 2 , a specific element of a target product is continuously inspected and product inspection values ​​derived therefrom are shown.
[73]
Then, frequency analysis is performed on the obtained product inspection results. In this case, the successively acquired inspection values ​​are separated for each frequency band by using a fast Fourier transform or the like, and a transformation peak per frequency indicating the expression level per production cycle is derived therefrom. Referring to FIG. 1 , an inspection value derived from a product inspection process is separated for each frequency band (refer to waves 1 to 3). Then, a conversion peak per frequency indicating the expression level per production cycle is derived from the graph separated by frequency band. 3 is a result of deriving the conversion peak per frequency indicating the expression level per production cycle after separating the product inspection value derived in FIG. 2 for each frequency band through the fast Fourier transform.
[74]
Next, a process of matching with the natural frequency of each unit is performed. This is a step of diagnosing the quality of each production element by preparing the natural frequency for each production element and the conversion peak per frequency. In this case, in contrast to the conversion peak per frequency for each natural frequency of each preset production element, a production element of a natural frequency corresponding to a frequency at which the conversion peak appears high is selected as a quality improvement target.
[75]
Referring to FIG. 4 , a result of comparing the natural frequency for each production element and the conversion peak per frequency can be confirmed. In a production facility for manufacturing a secondary battery unit cell, for example, a feeder unit, anode idle roller, anode feeding C/V belt, anode feed C Production factors expressed per production cycle by production factors such as /V belt (Cathode feeding C/V belt), Merge C/V belt, or Align C/V belt The natural frequency of each star was secured in advance. Then, it is compared with the conversion peak per frequency indicating the expression level per production cycle.
[76]
Referring to the results of FIG. 4 , in the case of the cathode feeding C/V belt, the natural frequency expressed per production cycle was about 7.91, and it was confirmed that the expression level was the highest. On the contrary, in the case of the feeder unit, the natural frequency expressed per production cycle was about 2, and it was confirmed that the expression level was very low. Accordingly, in the facility of FIG. 4 , the anode supply C/V belt is a priority complementation target, and the raw material supply unit becomes a subordinate complementation target. For production factors selected for quality improvement, follow-up measures are taken to supplement or replace them.

WE CLAIMS

acquiring successive inspection values ​​for a target product; deriving a conversion peak per frequency indicating an expression level per production cycle by separating the continuously acquired test values ​​for each frequency band; securing a natural frequency for each production factor expressed per production cycle for each production factor; and diagnosing the quality of each production factor by comparing the natural frequency for each production factor and the conversion peak per frequency.
[Claim 2]
The method according to claim 1, wherein the step of acquiring the continuous inspection value for the target product is performed by continuously acquiring inspection values ​​by examining a specific element of the target product and comparing the inspection result against the reference value. Manufacturing equipment quality quantification diagnostic method.
[Claim 3]
The method of claim 1, wherein the step of acquiring a continuous inspection value for the target product includes testing a specific element of the target product, but if the inspection result exceeds a reference value, quantifying it as a positive number, and testing A diagnostic method for quantifying manufacturing equipment quality, characterized in that, when one result value is less than a standard value, it is quantified as a negative number, and the quantified values ​​are continuously acquired and performed.
[Claim 4]
The method according to claim 1, wherein in the step of acquiring successive inspection values ​​for the target product, the target product is an electrochemical device.
[Claim 5]
The method of claim 1, wherein the step of deriving a transformation peak per frequency indicating the expression level per production cycle by separating the continuously acquired inspection values ​​by frequency band is performed through a Fast Fourier Transform (FFT) technique. Manufacturing equipment quality quantification diagnostic method, characterized in that.
[Claim 6]
According to claim 1, wherein the step of securing the natural frequency expressed per production cycle for each production factor is based on the number of times expressed per production cycle by deriving production factors affecting the production of the target product, and for each derived production factor A diagnostic method for quantifying manufacturing equipment quality, characterized in that it secures a natural frequency.
[Claim 7]
The quantification of manufacturing equipment quality according to claim 6, wherein the number of occurrences per production cycle for each production factor is a result of extracting the frequency at which the inspection value for a specific element of the target product deviates from the standard value due to the influence of each production factor. diagnosis.
[Claim 8]
The method according to claim 1, wherein the production factor is an equipment component involved in the production of a target product.
[Claim 9]
The method according to claim 8, wherein the equipment element is an electrochemical device manufacturing equipment element.
[Claim 10]
The method according to claim 1, wherein in the step of diagnosing the quality of each production element by comparing the natural frequency for each production element and the conversion peak per frequency, the conversion peak is higher than the conversion peak per frequency for each natural frequency for each production element set in advance. A manufacturing facility quality quantification diagnostic method, characterized in that the production factor of the natural frequency corresponding to the appearing frequency is selected as a quality complementation target.
[Claim 11]
According to claim 1, In contrast to the conversion peak per frequency for each natural frequency of each preset production element, the production element of the natural frequency corresponding to the frequency at which the conversion peak appears higher than a specific value is selected as a quality improvement target, and the conversion peak is A manufacturing facility quality quantification diagnostic method, characterized in that the production factor of natural frequency corresponding to a frequency appearing lower than a specific value is excluded from quality supplementation.
[Claim 12]
The manufacturing method according to claim 1, further comprising the step of supplementing or replacing a production element selected as a quality complementation target after the step of diagnosing the quality of each production element in preparation for the natural frequency for each production element and the conversion peak per frequency Equipment quality quantification diagnostics.