阅读说明：本技术 一种铝电解电容器用电极箔接触电阻的测量方法 (Method for measuring contact resistance of electrode foil for aluminum electrolytic capacitor ) 是由 周小兵 陆云龙 刘慧� 周红炎 于 2021-09-13 设计创作，主要内容包括：本发明公开一种铝电解电容器用电极箔接触电阻的测量方法,将制好的待测电极箔样品使用场效应成像方法测试,同时在场效应样品测试台上放置已知电阻的样品作为参照样本,一起场效应成像；成像后得到待测样品和参照样品的图像,观察待测电极箔样品与已知电阻样品的电阻分布,对图像利用灰度值进行数字化处理,同时对比参照样品成像的明暗度,形成函数关系,将待测试样品的图像数字化转化成对应电阻数据。该测量方法对测试样品没有物理损伤,有利于测量的重复性和再现性,从明暗度关系可以直观体现铆接范围内接触电阻的分布,为分析和改善接触电阻提供了方向,进而用于分析接触电阻不良的原因和工艺改善,有利于工艺制程的提升。(The invention discloses a method for measuring electrode foil contact resistance for an aluminum electrolytic capacitor, which comprises the steps of testing a prepared electrode foil sample to be tested by using a field effect imaging method, placing a sample with known resistance on a field effect sample test board as a reference sample, and carrying out field effect imaging together; and obtaining images of the sample to be detected and the reference sample after imaging, observing the resistance distribution of the electrode foil sample to be detected and the known resistance sample, carrying out digital processing on the images by utilizing gray values, simultaneously comparing the brightness of the imaging of the reference sample to form a functional relation, and converting the images of the sample to be detected into corresponding resistance data in a digital mode. The measuring method has no physical damage to a test sample, is favorable for measuring repeatability and reproducibility, can visually reflect the distribution of the contact resistance in the riveting range from the brightness relation, provides directions for analyzing and improving the contact resistance, is further used for analyzing the reason of poor contact resistance and improving the process, and is favorable for improving the process.)

1. A method for measuring contact resistance of an electrode foil for an aluminum electrolytic capacitor is characterized by comprising the following steps:

s1, cleaning the electrode foil to be detected with pure water, and drying for later use;

s2, drawing a first cutting reference line and a second cutting reference line towards two sides respectively at equal intervals by taking the riveting needle as a center line; cutting along the first cutting reference line and the second cutting reference line to obtain a strip-shaped electrode foil sample to be measured;

s3, cleaning residues left on the electrode foil sample to be detected;

s4, coating a conductive adhesive layer only on the rivet pin arrangement area of the electrode foil sample to be tested so as to fix the electrode foil sample to the field effect sample test board, wherein the non-adhesive area of the electrode foil sample to be tested is dissociated right above the test platform;

s5, testing the electrode foil sample piece to be tested by a field effect imaging method, and simultaneously placing a known resistance sample on the field effect sample test board as a reference sample to perform field effect imaging operation together;

s6, obtaining appearance images of the electrode foil sample to be detected and the known resistance sample simultaneously after field effect imaging, observing the resistance distribution of the electrode foil sample to be detected and the known resistance sample, and indirectly obtaining the size and the distribution of the contact resistance through the brightness of an electron microscope picture;

and S7, carrying out digital processing on the image by utilizing the gray value, simultaneously comparing the brightness of the image of the known resistance sample to form a functional relation, and converting the image of the sample to be tested into corresponding resistance data in a digital mode.

2. The method for measuring contact resistance of an electrode foil for an aluminum electrolytic capacitor as recited in claim 1, wherein the function relationship in S7 is:where S, A represents the integrated area of the resultant image; a. b represents the intensity value (e.g., gray scale value) of a single point of the pixel;R（x）、r (y) represents the single-point resistance values under the intensity values corresponding to a and b.

3. The method for measuring contact resistance of an electrode foil for an aluminum electrolytic capacitor as recited in claim 1, wherein in said S5, field effect imaging is performed by means of a scanning electron microscope.

4. The method of measuring contact resistance of electrode foil for an aluminum electrolytic capacitor as recited in claim 1, wherein 5D ≦ 10D assuming that the outer diameter dimension of the rivet pin is D and the distance between the first clipping reference line and the second clipping reference line is 2D.

Technical Field

The invention relates to the technical field of electrode foil manufacturing, in particular to a method for measuring contact resistance of an electrode foil for an aluminum electrolytic capacitor.

Background

The electrode foil is used as a core material in the aluminum electrolytic capacitor and plays a decisive role in various characteristics of the aluminum electrolytic capacitor. The preparation of the electrode foil comprises two links of corrosion and formation, specifically, a specially-made high-purity aluminum foil is subjected to electrochemical and chemical corrosion to enlarge the surface area to prepare a corrosion foil, and then the corrosion foil is subjected to electrochemical formation to form an oxide film (aluminum oxide) on the surface.

After the electrode foil is off-line, sampling is needed to detect the product performance, and a small sample obtained according to a specified position can accurately reflect the performance level of the roll of electrode foil. The contact resistance is an important index reflecting the quality of the finished electrode foil product and has a crucial influence on the subsequent practical application performance of the electrode foil product. Therefore, it is necessary to find a suitable method for measuring the contact resistance, and the quality of the electrode foil forming process is judged by the measured contact resistance parameter, so that the electrode foil forming process can be optimized to achieve the purpose of process control. For example: patent No. CN104678174A discloses a method for measuring the resistance value of a composite material part, comprising the steps of: step one, taking a measured contact point as a center, cleaning and polishing off a paint layer and floating glue on the surface of a composite material part, and exposing an internal copper mesh; secondly, gluing a copper mesh with copper foil paper by using a conductive adhesive; and thirdly, taking the two copper foil papers as contact points to measure the resistance. In the contact resistance measuring method, a resistance measuring needle or a measuring jig is required to be connected to both ends of the contact electrode and the aluminum foil, respectively, as shown in fig. 4. When the four-wire method is used for testing, the clamp test points are additionally added, the resistance of the test guide pin pressure points or the clamp points has certain influence on the finally obtained contact resistance, and meanwhile, the aluminum foil or the riveting needle is easy to deform due to the pressure points or the clamp points, so that certain physical damage is caused, and repeated measurement and reproduction are not facilitated. Thus, a skilled person is urgently needed to solve the above problems.

Disclosure of Invention

Therefore, in view of the above-mentioned problems and drawbacks, the present inventors have collected relevant information, evaluated and considered in many ways, and continuously conducted experiments and modifications by skilled technicians working in this field for years of research and development, which finally resulted in the appearance of the method for measuring the contact resistance of the electrode foil for the aluminum electrolytic capacitor.

In order to solve the above technical problem, the present invention relates to a method for measuring contact resistance of an electrode foil for an aluminum electrolytic capacitor, comprising the steps of:

s1, cleaning the electrode foil to be detected with pure water, and drying for later use;

and S2, drawing a first cutting reference line and a second cutting reference line towards two sides at equal intervals by taking the riveting needle as a center line. Cutting along the first cutting reference line and the second cutting reference line to obtain a strip-shaped electrode foil sample to be measured;

s3, cleaning residues left on the electrode foil sample to be detected;

s4, coating a conductive adhesive layer only on the rivet pin arrangement area of the electrode foil sample to be tested so as to fix the electrode foil sample to the field effect sample test board, wherein the non-adhesive area of the electrode foil sample to be tested is dissociated right above the test platform;

s5, testing the electrode foil sample piece to be tested by a field effect imaging method, and simultaneously placing a known resistance sample on the field effect sample test board as a reference sample to perform field effect imaging operation together;

s6, obtaining appearance images of the electrode foil sample to be detected and the known resistance sample simultaneously after field effect imaging, observing the resistance distribution of the electrode foil sample to be detected and the known resistance sample, and indirectly obtaining the size and the distribution of the contact resistance through the brightness of an electron microscope picture;

and S7, carrying out digital processing on the image by utilizing the gray value, simultaneously comparing the brightness of the image of the known resistance sample to form a functional relation, and converting the image of the sample to be tested into corresponding resistance data in a digital mode.

As a specific case in the technical solution of the present invention, the relationship of the luminance transformation function in S7 is:where S, A represents the integrated area of the resultant image; a, b represent the intensity value (such as grey scale value) of a single point of the pixel;R（x）、r (y) represents the single-point resistance values under the intensity values corresponding to a and b.

As a further improvement of the present invention, in S5, field effect imaging is preferably performed by a scanning electron microscope.

As a further improvement of the technical scheme of the invention, if the outer diameter of the riveting needle is D and the distance between the first cutting reference line and the second cutting reference line is 2D, D is more than or equal to 5D and less than or equal to 10D.

Compared with the traditional method for measuring the contact resistance of the electrode foil for the aluminum electrolytic capacitor, in the technical scheme disclosed by the invention, the test method is relatively simple, the reading, the graphic processing and the analysis are all completed by a computer, the repeatability and the reproducibility of the measurement are facilitated, and more importantly, the electrode foil sample to be measured is not subjected to the action of the pressure contact force in the whole test process, so that the physical damage phenomenon caused by stress is avoided, and the accuracy of the measured contact resistance data is also ensured.

Moreover, the image obtained by the field effect imaging method can visually represent the distribution of the contact resistance in the electrode foil riveting area from the brightness and darkness relation, provides directions for analyzing and improving the contact resistance, is further used for analyzing the reason of poor contact resistance and improving the process, and is beneficial to the improvement of the process.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic structural flow diagram of a measurement method according to the present invention.

FIG. 2 is a schematic diagram of the mutual positions of electrode foil samples to be tested when they are placed on a field effect test station.

Fig. 3 is a test picture obtained by using a scanning electron microscope as an image capturing device.

Fig. 4 is a schematic diagram of the measurement of contact resistance in the prior art.

1-riveting a needle; 2-electrode foil; 3-conductive adhesive; 4-field effect sample test station.

Detailed Description

For the purpose of enhancing understanding of the present invention, the present invention will be further described in detail with reference to the following examples, which are provided for illustration only and are not to be construed as limiting the scope of the present invention. The methods are conventional methods, not specifically described.

The following detailed description of the preferred embodiments of the present invention, with reference to the accompanying drawings 1,2 and 3, will make the advantages and features of the present invention more easily understood by those skilled in the art, and thus, the scope of the present invention will be clearly and clearly defined.

A method for measuring contact resistance of electrode foil for aluminum electrolytic capacitor comprises the following steps:

s1, cleaning the electrode foil to be detected with pure water, and drying for later use;

and S2, drawing a first cutting reference line and a second cutting reference line towards two sides at equal intervals by taking the riveting needle as a center line. Cutting along the first cutting reference line and the second cutting reference line to obtain a strip-shaped electrode foil sample to be measured;

s3, cleaning residues left on the electrode foil sample to be detected;

s4, coating a conductive adhesive layer only on the rivet pin arrangement area of the electrode foil sample to be tested so as to fix the electrode foil sample to the field effect sample test board, wherein the non-adhesive area of the electrode foil sample to be tested is dissociated right above the test platform;

s5, testing the electrode foil sample piece to be tested by a field effect imaging method, and simultaneously placing a known resistance sample on the field effect sample test board as a reference sample to perform field effect imaging operation together;

s6, obtaining appearance images of the electrode foil sample to be detected and the known resistance sample simultaneously after field effect imaging, observing the resistance distribution of the electrode foil sample to be detected and the known resistance sample, and indirectly obtaining the size and the distribution of the contact resistance through the brightness of an electron microscope picture;

and S7, carrying out digital processing on the image by utilizing the gray value, simultaneously comparing the brightness of the image of the known resistance sample to form a functional relation, and converting the image of the sample to be tested into corresponding resistance data in a digital mode.

As a specific case in the technical solution of the present invention, the relationship of the luminance transformation function in S7 is:where S, A represents the integrated area of the resultant image; a. b represents the intensity value (e.g., gray scale value) of a single point of the pixel;R（x）、r (y) represents the single-point resistance values under the intensity values corresponding to a and b.

Example 1

1. Obtaining the electrode foil to be tested after the nailing from the winding process, cleaning the electrode foil to be tested with pure water, and drying for later use;

2. and respectively drawing a first cutting reference line and a second cutting reference line towards two sides at equal intervals by taking the riveting needle as a central line. And cutting along the first cutting reference line and the second cutting reference line to obtain a strip-shaped electrode foil sample to be measured, wherein the size of the strip-shaped electrode foil sample is 0.5cm x 0.6 cm.

3. Cleaning residual slag on an electrode foil sample to be tested, and then coating a conductive adhesive layer only on a rivet pin arrangement area of the electrode foil sample to be tested so as to fix the electrode foil sample to the field effect sample test bench, wherein at the moment, a non-adhesive area of the electrode foil sample to be tested dissociates right above the test platform (the electrode foil sample is ensured not to be contacted with the field effect sample test bench);

4. imaging an electrode foil sample to be tested by using a scanning electron microscope, wherein the testing condition is preferably 15kV, the magnification is X30 times, and meanwhile, a known resistance sample with the resistance value of 0.128m omega is placed on a testing platform to be used as a reference sample and imaged by using the scanning electron microscope;

5. and images of the sample to be detected and the known resistance sample are obtained after imaging, the brightness of the imaging correspondingly generates difference due to different resistances, and the resistances of the sample to be detected are visually embodied at the same time.

As shown in fig. 3, the size and distribution of the contact resistance are represented by the brightness of the electron microscope picture, that is, the resistance of the brighter area is larger;

6. in the RGB model, if R = G = B, the color represents a gray color, where the value of R = G = B is called gray value, and the gray value range is 0 to 255. For the gray value of the image pixel point, the gray value can be converted into a functional relation of the sample resistance value by using the gray value of the known resistance image pixel point. Given that the pixel points of a 0.128m Ω resistance image are 250000 pixels, RGB is (127,127,127), and the resistance value of each pixel point is defined as:；

here brought in，To obtain，

250000 pixels of the unknown resistance image and (157 ) of GRB, the resistance value of the image is

Example 2

1. Obtaining the electrode foil to be tested after the nailing from the winding process, cleaning the electrode foil to be tested with pure water, and drying for later use;

2. and respectively drawing a first cutting reference line and a second cutting reference line towards two sides at equal intervals by taking the riveting needle as a central line. And cutting along the first cutting reference line and the second cutting reference line to obtain a strip-shaped electrode foil sample to be measured, wherein the size of the strip-shaped electrode foil sample is 0.8cm x 1 cm.

3. Cleaning residual slag on an electrode foil sample to be tested, and then coating a conductive adhesive layer only on a rivet pin arrangement area of the electrode foil sample to be tested so as to fix the electrode foil sample to the field effect sample test bench, wherein at the moment, a non-adhesive area of the electrode foil sample to be tested dissociates right above the test platform (the electrode foil sample is ensured not to be contacted with the field effect sample test bench);

4. imaging an electrode foil sample to be tested by using a scanning electron microscope, wherein the testing condition is preferably 15kV, the magnification is X25 times, and meanwhile, a known resistance sample with the resistance value of 0.790m omega is placed on a testing platform to be used as a reference sample and imaged by using the scanning electron microscope;

5. images of the sample to be detected and the known resistance sample are obtained after imaging, and due to the difference of the resistance, the imaging brightness and darkness correspondingly generate difference, and meanwhile, the resistance of the sample to be detected is also visually reflected at the moment;

6. in the RGB image model, if R = G = B, the color represents a gray color, where the value of R = G = B is called a gray value, and the gray value range is 0 to 255. For the gray value of the image pixel point, the gray value can be converted into a functional relation of the sample resistance value by using the gray value of the known resistance image pixel point. Given that the pixel points of a certain 0.790m Ω resistance image are 250000 pixels, RGB is (221,221,221), and the resistance value of each pixel point is defined as:

；

here brought in，To obtain，

250000 pixels of the unknown resistance image and GRB (230 ), the resistance value of the image is

。

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.