KR20200128917A - Defect detecting system and method of electrode sheet - Google Patents

Abstract

The present invention relates to a defect detection system, and a defect detection method for an electrode sheet. The present invention makes data of a reference value from values scanning the entire shape of an electrode balcony of an electrode sheet, which is determined as a good product, and compares the reference value with a measuring value scanning the shape of an electrode balcony to be measured.

Description

Defect detection system and defect detection method for electrode sheet {DEFECT DETECTING SYSTEM AND METHOD OF ELECTRODE SHEET}

The present invention relates to a defect detection system and a defect detection method for an electrode sheet, and more particularly, to a defect detection system and a defect for an electrode sheet capable of preventing the occurrence of a core crack in an electrode balcony part when manufacturing an electrode sheet. It relates to a detection method.

In general, due to the advantage that secondary batteries can be recharged and can be small and large-capacity, their development and use are increasing in recent years. The secondary battery includes an electrode assembly composed of an electrode sheet and a separator, and an exterior material for sealing and receiving the electrode assembly together with an electrolyte.

The electrode assembly of the secondary battery may be formed by winding an electrode sheet and a separator coated with an electrode active material around a core.

In connection with the manufacture of such an electrode for a secondary battery, it has been previously filed with Patent Publication No. 10-2019-0010078 (published on January 30, 2019).

Referring to FIG. 1, an electrode sheet 1 for manufacturing an electrode assembly for a conventional secondary battery includes a first inclined portion 21 and a first protruding portion 23 on one surface of a current collector 10 extending in one direction. The first active material layer 20 including a is formed. In addition, a second active material layer 30 including a second inclined portion 31 and a second protruding portion 33 is formed on the other surface of the current collector 10.

In this case, the first and second inclined portions 21 and 31 mean a drag area formed at the tip of the coating area. In addition, the first and second protrusions 23 and 33 refer to the electrode balcony part B (the coating start part) that is convexly formed at a position spaced apart from the first and second inclined parts 21 and 31. do.

In addition, the electrode sheet 1 has a non-coated portion N on one surface of the current collector 10 to which the first active material layer 20 is not applied so as to secure stability according to winding.

In this case, as the uncoated portion N in which the first active material layer 20 is not provided is formed on one surface of the current collector 10 and the second active material layer 30 is formed on the other surface of the current collector 10, A second protrusion 33 of the second active material layer 30 is positioned in a region of the first active material layer 20 facing the first inclined portion 21.

Through the above-described structure, it is possible to prevent the electrode thickness from rapidly changing in a region facing the first inclined portion 21. That is, the first inclined portion 21 and the second protruding portion 33 can prevent a local rapid increase in the rolling rate, and accordingly, deformation and cracking of the electrode balcony portion can be prevented.

On the other hand, referring to FIGS. 2 and 3, in order to prevent deformation and cracking of the electrode balcony part B as described above, conventionally, a predetermined distance (d) from the coating start part of one surface of the electrode sheet 1 The thickness of the electrode balcony portion (B) was measured (see FIG. 2), and the maximum, minimum, and average values were recorded and managed. That is, in the prior art, when measuring the thickness t (see FIG. 3) of the electrode balcony part B (see FIG. 3), it was determined whether or not defective based on a value obtained by subtracting the average value from the maximum value.

However, the conventional management method for preventing deformation and cracking of the electrode balcony portion (B) has a problem that an accurate indicator cannot be provided when the shape of the electrode balcony portion (B) is severely distributed.

That is, although there is a specification for the thickness (t) of the electrode balcony part (B), it is determined whether it is defective based on the value obtained by subtracting the average value from the maximum value of the thickness (t) of the electrode balcony part (B). However, in the case of applying this method, it is rare that a bad judgment is made.

In other words, since the specifications are collected without considering the distribution of the shape of the electrode balcony part B, there is a problem that it is not appropriate to judge whether the shape of the electrode balcony part B is defective. .

In addition, since the possibility of cracking is different depending on the height and position of the electrode balcony part B, it is difficult to proceed with the entire DOE (Diffractive Optical Element) for these items.

The present invention was conceived to solve the above-described problem, and after converting the whole electrode balcony shape of the electrode sheet determined as good product into data as a reference value, the reference value and the measurement value obtained by scanning the shape of the electrode balcony to be measured are compared. Therefore, it is an object of the present invention to provide a defect detection system and a defect detection method for an electrode sheet that can determine whether there is a defect.

A defect detection system for an electrode sheet according to an embodiment of the present invention for realizing the object as described above includes: a thickness measurement unit for scanning the entire shape of the electrode balcony part of the electrode sheet determined as good; A reference value setting unit that derives the entire shape of the electrode balcony portion measured through the thickness measurement unit as a QLL (qualified limit line) according to a thickness position and converts the data into a reference value; And a defect determination unit that scans the entire shape of the electrode balcony portion of the electrode sheet to be measured to compare whether the measured value deviates from the reference value, and then determines whether the electrode balcony portion is defective.

In this case, the thickness measurement unit may sample and scan the electrode balcony portion after the coating or rolling process during the manufacturing process of the electrode sheet.

In addition, the thickness measurement unit may scan the entire shape from a starting point to a predetermined point of the electrode balcony portion formed on one surface and the other surface of the current collector, respectively.

In addition, the thickness measurement unit may scan at least one of a height, a position, and a shape of the electrode balcony.

In addition, based on the reference value set by the reference value setting unit, the setting spec of the coating process including the rotation speed (RPM) and the spraying speed during the manufacturing process of the electrode sheet may be optimized.

In addition, the defect determination unit can determine the entire shape of the electrode balcony formed on one side and the other side of the current collector through an automatic thickness measurement device installed between the electrode sheet transferred to one side during the coating or rolling process of the measurement target electrode sheet. By scanning as a result, it may be determined whether the electrode balcony is defective.

Meanwhile, in the defect detection method using the defect detection system for an electrode sheet, the method comprising: scanning the entire shape of the electrode balcony part of the electrode sheet determined as good quality through a thickness measuring device; Deriving the entire shape of the scanned electrode balcony part as a QLL (qualified limit line) according to a thickness position and converting the data into a reference value; And comparing whether or not the measured value deviates from the reference value by scanning the entire shape of the electrode balcony part of the electrode sheet to be measured, and then determining whether there is a defect.

In this case, the thickness measuring apparatus may scan the entire shape of the electrode balcony portion formed on one surface of the current collector and the other surface of the electrode sheet from a starting point to a predetermined point, respectively.

The present invention according to the configuration as described above, by scanning the entire shape of the electrode balcony portion formed on one side and the other side of the current collector from the start point to a predetermined point to convert the reference value of the entire shape of the electrode balcony into data, the data converted Based on the reference value, it is possible to compare and determine whether the balcony of the electrode to be measured is defective.

In this case, it is possible to easily establish the shape of the electrode balcony part with high measurement difficulty and the criteria for determining whether or not a defect is defective, thereby improving accuracy in determining whether or not a defect is defective.

In addition, since it is easy to determine whether the electrode balcony is good or bad, it is possible to check the risk of cracking in the state of the electrode immediately after coating.

In addition, it is possible to specify and continuously manage the electrode balcony through the shape of the electrode balcony, and it is possible to optimize the setting specifications of the coating process including the rotational speed (RPM) and the spraying speed through the shape specification of the electrode balcony. .

1 is a side view showing the shape of a general electrode balcony part,
2 is a schematic diagram showing a state of measuring the thickness of the balcony of the electrode of FIG. 1;
3 is a graph showing the thickness of the electrode balcony measured in FIG. 2;
4 is a schematic overall configuration diagram showing a defect detection system for an electrode sheet according to the present invention,
5 is a schematic view showing a state of measuring the thickness of the electrode balcony portion according to the present invention,
6 to 8 are diagrams showing a process of deriving a boundary line (QLL) according to the present invention;
9 and 10 are graphs of an embodiment for determining whether or not an electrode balcony is defective using a reference value set by a defect detection system for an electrode sheet according to the present invention;
11 is a flowchart showing a defect detection process using the defect detection system for an electrode sheet according to the present invention;
12 is a schematic diagram showing a failure detection system for an electrode sheet according to another embodiment of the present invention.

Hereinafter, the configuration and operation of a specific embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Here, in adding reference numerals to elements of each drawing, it should be noted that the same elements are marked with the same numerals as much as possible, even if they are indicated on different drawings.

4 is a schematic overall configuration diagram showing a failure detection system for an electrode sheet according to the present invention, FIG. 5 is a schematic diagram showing a state of measuring the thickness of an electrode balcony part according to the present invention, and FIGS. 6 to 8 are the present invention It is a diagram showing the process of deriving the boundary line (QLL) according to.

First, the structure of the electrode sheet in which the electrode balcony portion B to be measured is formed according to the present invention will be described.

An electrode sheet for manufacturing an electrode assembly for a secondary battery is a first active material layer including a first inclined portion 21 and a first protruding portion 23 on one surface of the current collector 10 (metal foil) extending in one direction (20) is formed. In addition, a second active material layer 30 including a second inclined portion 31 and a second protruding portion 33 is formed on the other surface of the current collector 10 (see FIG. 1 ).

In addition, on one surface of the current collector 10, an uncoated portion N to which the first active material layer 20 is not applied is formed so as to ensure stability according to winding of the electrode sheet.

In this case, the first and second protrusions 23 and 33 refer to the electrode balcony part B (coating start part) formed convexly at a position spaced apart from the first and second inclined parts 21 and 31 do.

Referring to FIG. 4, the defect detection system 100 for an electrode sheet according to an exemplary embodiment of the present invention, which enables it to determine whether the electrode balcony portion B having the above configuration is defective, includes a thickness measurement unit 110 ), a reference value setting unit 120, and a failure determination unit 130.

The configuration of the present invention will be described in detail as follows.

First, the thickness measurement unit 110 measures the thickness of the electrode balcony portion B formed on one side and the other side of the metal foil as the current collector 10, and this thickness measurement unit 110 is an electrode determined as good. The entire shape of the electrode balcony part B of the sheet 1 is scanned.

That is, the thickness measurement unit 110 may be a kind of data collection means for setting the reference value of the electrode balcony unit B, and the thickness measurement unit 110 can scan the entire shape of the electrode balcony unit B. A thickness measuring device (not shown) can be used.

Referring to FIG. 5, the thickness measurement unit 110 scans the entire shape from the start point to a predetermined point of the electrode balcony portion B formed on one side and the other side of the current collector 10, respectively.

In this case, the thickness measurement unit 110 may sample and scan the electrode balcony portion B after the coating or rolling process during the manufacturing process of the electrode sheet. In this case, it is preferable to use a sample after a drying process for the electrode balcony part B to be measured.

In addition, the thickness measuring apparatus constituting the thickness measuring unit 110 may use a rotary caliper capable of easily measuring the thickness of the entire shape of the electrode balcony portion B of the sampled electrode sheet. Of course, the present invention is not limited thereto, and any device capable of easily measuring the thickness of the entire shape of the electrode balcony portion B may be changed and applied in various ways.

When setting the reference value T through the reference value setting unit 120 to be described later by scanning at least one of the height, position, and shape of the electrode balcony unit B, preferably only the shape, the thickness measurement unit 110 having such a configuration It can be used as basic data.

In this case, a common method of measuring thickness using height and position is that it is easy to make a specification because it can be represented by numbers. However, in the case of the electrode balcony portion (B) according to the present invention, the position is not fixed. Therefore, the most accurate method for determining the good or bad of the electrode balcony portion B is to determine the shape. The shape includes the height and position. In particular, in the case of the electrode balcony part (B), it is most suitable to use the shape to determine the good or bad of the balcony part (B) as it consists of continuous height and position data. . For reference, in FIG. 6, the blue line is data of the electrode balcony part B having a clear standard of good quality, and the red line is data of the electrode balcony part B having a clear criterion of defects. And using this data, it is possible to derive a boundary line (QLL) to be described later.

The reference value setting unit 120 serves to derive the entire shape of the electrode balcony part B measured through the thickness measurement unit 110 as a QLL (qualified limit line) according to the thickness position, and convert the data into a reference value.

The reference value setting unit 120 does not convert the thickness position of each point of the electrode balcony portion B measured through the thickness measuring unit 110 into data, but the thickness position (P) of the entire shape of the electrode balcony portion (B). ) (See Fig. 7) is shaped as a boundary line (QLL).

Specifically, as shown in FIG. 8, the reference value setting unit 120 includes data (refer to the blue line) of the electrode balcony unit B having a clear standard of good quality and the electrode balcony unit B having a clear criterion of defects. Data (refer to the red line) is continuously collected. Based on the collected data, a boundary line (QLL) (refer to the yellow-green color part) that distinguishes good and bad products of the electrode balcony part B can be set. That is, the boundary line (QLL) is set to an area behavior within a boundary, not a line value or a specified specification.

The boundary line QLL shaped in this way is used as reference value data that becomes a reference when determining whether the electrode balcony B is good or bad through the defect determination unit 130 to be described later.

The reference value setting unit 120 as described above may improve the accuracy of the reference value used for determination of good or bad by progressing deep learning through application of a tensor flow.

For reference, Tensor Flow is a software developed for use in deep learning and machine learning by performing numerical calculations using a data flow graph. In addition, deep learning is a technology used to cluster or classify objects or data, and its core is prediction through classification.

That is, the present invention establishes a standard for determining the good or bad shape of the electrode balcony part (B) based on the reference value derived through the reference value setting unit 120, and through this, it is easy to reduce crack risk in the electrode sheet of the semi-finished product immediately after coating. It can be discriminated accordingly, and accordingly, additional defects and required costs in the post process can be reduced.

In addition, based on the reference value set by the reference value setting unit 120, the setting spec of the coating process including the rotational speed (RPM) and the spraying speed during the manufacturing process of the electrode sheet may be optimized.

The defect determination unit 130 scans the entire shape of the electrode balcony portion B of the electrode sheet 1 to be measured using a thickness measuring device, and then checks whether the measured measurement value M deviates from the reference value T. Will be compared. The defect determination unit 130 may determine whether the electrode balcony portion B of the electrode sheet to be measured is defective.

That is, as shown in FIG. 9, when the measured value M of the electrode balcony part B deviates from the boundary line QLL of the reference value T (part'A'), the defect determination unit 130 It is determined that the balcony part B of the electrode to be measured is defective.

And, as shown in FIG. 10, when the measured value M of the electrode balcony part B is within the boundary line QLL of the reference value T, the defect determination unit 130 returns the measurement target electrode balcony part B ) Is judged to be a good product.

Then, a defect detection process using the defect detection system for an electrode sheet according to the present invention having the above configuration will be described with reference to FIG. 11.

First, the entire shape of the electrode balcony portion of the electrode sheet determined to be good is scanned (S1).

Then, the entire shape of the scanned electrode balcony part B is derived as a QLL (qualified limit line) according to the thickness position, and data is converted into a reference value T (S3).

Then, after scanning the entire shape of the electrode balcony part B of the electrode sheet 1 to be measured, and comparing whether the measured measurement value M deviated from the reference value T (see FIGS. 9 and 10), It is determined whether the electrode balcony part B is defective (S5).

In the above, the present invention has been illustrated and described with reference to specific specific embodiments, but the present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit of the present invention.

On the other hand, in the present invention, after sampling the electrode balcony portion B of the electrode sheet 1 to be measured, it is determined whether or not good or bad using a thickness measuring device, but is not limited thereto and may be changed and applied in various cases.

For example, as shown in FIG. 12, the thickness of the electrode balcony portion B formed on one side and the other side of the current collector 10 immediately before winding during the coating or rolling process of the electrode sheet 1 transferred to one side is measured in real time. The automatic thickness measurement device 200 may be installed in an in-line manner so as to be able to scan, so that it is possible to determine whether the electrode balcony part B is good or bad. Accordingly, when manufacturing an electrode sheet, all patterned electrodes can be completely inspected, and data for image analysis can be easily secured.

On the other hand, the electrode sheet defect detection system 100 according to the present invention has been described as an example of a case in which the occurrence of a core crack in the electrode balcony part B can be prevented in advance, but is not limited thereto, and the electrode balcony In addition to the core crack of part (B), it can also be applied to analysis of low resistance, foreign matter, and core part active material detachment.

That is, the electrode balcony portion (B) is the most noisy portion of the electrode, and when the height of the electrode balcony portion (B) is high, it is disadvantageous to detachment of the active material due to core bending during winding. Therefore, if the data of the electrode balcony part (B) is collected by dividing it into a sample with high low resistance and a low sample, and then setting the boundary line (QLL) using this, low resistance, foreign matter, and core part active material of the electrode balcony part (B) It can be used for analysis such as tally. In this case, since active material detachment causes foreign matter and low voltage, it can be seen that the control of the electrode balcony part B immediately controls the overall quality of the electrode core part.

1: electrode sheet 10: current collector
20: first active material layer 21: first slope
23: first protrusion 30: second active material layer
31: second slope 33: second protrusion
100: defect detection system for electrode sheet 110: thickness measurement unit
120: reference value setting unit 130: defect determination unit
B: electrode balcony part GLL: border line
M: measured value N: uncoated
T: reference value

Claims (8)

A thickness measuring unit for scanning the entire shape of the electrode balcony portion of the electrode sheet determined to be good;
A reference value setting unit that derives the entire shape of the electrode balcony portion measured through the thickness measurement unit as a QLL (qualified limit line) according to a thickness position and converts the data into a reference value; And
A defect detection system for an electrode sheet comprising: a defect determination unit configured to determine whether or not the electrode balcony is defective after scanning the entire shape of the electrode balcony part of the electrode sheet to be measured and comparing whether the measured value deviates from the reference value .
The method of claim 1,
The thickness measurement unit,
The electrode sheet defect detection system to sample and scan the electrode balcony portion after the coating or rolling process during the manufacturing process of the electrode sheet.
The method of claim 1,
The thickness measurement unit,
A defect detection system for an electrode sheet, which scans the entire shape from a starting point to a predetermined point of the electrode balcony portion formed on one side and the other side of the current collector, respectively.
The method of claim 1,
The thickness measurement unit,
A defect detection system for an electrode sheet that scans at least one of a height, a position, and a shape of the electrode balcony part.
The method of claim 1,
Defect detection system for an electrode sheet to optimize the setting spec of the coating process including the rotational speed (RPM) and spraying speed during the manufacturing process of the electrode sheet based on the reference value set by the reference value setting unit.
The method of claim 1,
The failure determination unit,
During the coating or rolling process of the electrode sheet to be measured, the entire shape of the electrode balcony formed on one side and the other side of the current collector is scanned in real time through an automatic thickness measurement device installed with the electrode sheet transferred to one side therebetween. A defect detection system for electrode sheets that allows it to determine whether there is a negative defect.
In the defect detection method using the defect detection system for electrode sheet,
Scanning the entire shape of the electrode balcony portion of the electrode sheet determined as good product through a thickness measuring device;
Deriving the entire shape of the scanned electrode balcony part as a QLL (qualified limit line) according to a thickness position and converting the data into a reference value; And
Defect detection method using a defect detection system for an electrode sheet comprising a; scanning the entire shape of the electrode balcony portion of the electrode sheet to be measured, comparing whether the measured value is out of the reference value, and then determining whether there is a defect.
The method of claim 7,
The thickness measuring device,
A defect detection method using a block quantity detection system, wherein the entire shape of the electrode balcony part formed on one side of the current collector and the other side of the electrode sheet from a starting point to a predetermined point is respectively scanned.

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