KR102583022B1 - Apparatus for electrode positioning of secondary battery - Google Patents

Abstract

The present invention relates to an electrode positioning device for a secondary battery, and provides an electrode positioning device for a secondary battery that can accurately and reliably determine the electrode position of a secondary battery stacking process to enable the assembly process to proceed without error. By accurately and reliably determining the electrode positions in the battery stacking process, we can support the assembly process to proceed without error.

Description

Electrode positioning device for secondary battery {APPARATUS FOR ELECTRODE POSITIONING OF SECONDARY BATTERY}

The present invention relates to secondary battery manufacturing and manufacturing support devices, and more specifically, to a secondary battery electrode positioning device that can accurately and reliably determine the electrode positions of the secondary battery stacking process and support the assembly process to proceed without error. will be.

Unlike primary batteries, secondary batteries can be recharged and have been extensively researched and developed in recent years due to their small size and high capacity. As technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing.

Secondary batteries are classified into coin-shaped batteries, cylindrical batteries, square-shaped batteries, and pouch-shaped batteries, depending on the shape of the battery case.

In a secondary battery, the electrode assembly mounted inside the battery case is a power generating element capable of charging and discharging consisting of a stacked structure of electrodes and a separator.

The electrode assembly is a jelly-roll type wound with a separator interposed between a sheet-like positive electrode 11 coated with an active material and a negative electrode, and consists of a plurality of positive electrodes 11 and a negative electrode with a separator interposed therebetween. It can be roughly classified into a stacked type in which cells are sequentially stacked, and a stacked/folded type in which stacked unit cells are wound with a long length of separation film.

However, in the case of the conventional stack/folding type, when the distance between unit cells located on the separation film in the unfolding state is not constant, when the unit cells are folded and stacked, there is a separation between the stacked upper and lower unit cells. There has been a problem of mutually misaligned positional errors occurring, causing precipitation due to underfilling or excessive charging at each misaligned overhang portion.

The present invention is intended to solve the above problems, and its purpose is to provide a device for determining the electrode position of a secondary battery that can accurately and reliably determine the electrode position of the secondary battery stacking process so that the assembly process can proceed without error. there is.

The electrode positioning device for a secondary battery according to an embodiment of the present invention to achieve the above object accurately and reliably determines the electrode position of the secondary battery stacking process to enable the assembly process to proceed without error. It provides an electrode positioning device, and can accurately and reliably determine the electrode position of the secondary battery stacking process to enable the assembly process to proceed without error.

The electrode positioning device for a secondary battery according to an embodiment of the present invention, which has the various technical features described above, can accurately and reliably determine the electrode position of the secondary battery stacking process and support the assembly process to proceed without error.

1 is a diagram showing an electrode positioning device for a secondary battery according to an embodiment of the present invention.
FIG. 2 is a diagram showing a method of setting an edge detecting algorithm of the electrode positioning device shown in FIG. 1.
FIG. 3 is a diagram showing a mask processing algorithm of the electrode positioning device shown in FIG. 1.
FIG. 4 is a diagram showing the results of edge detection processing of the electrode positioning device shown in FIG. 1.
FIG. 5 is a diagram showing the camera calibration results of the electrode positioning device shown in FIG. 1.
FIG. 6 is a elevation view showing the camera position relationship of the electrode positioning device shown in FIG. 1.
FIG. 7 is a block diagram for explaining the algorithm processing logic for each component of the electrode positioning device shown in FIG. 1.

The objectives, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments taken in conjunction with the accompanying drawings. In this specification, when adding reference numbers to components in each drawing, it should be noted that identical components are given the same number as much as possible even if they are shown in different drawings. Additionally, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Also, in describing the present invention, detailed descriptions of related known technologies that may unnecessarily obscure the gist of the present invention will be omitted.

1 is a diagram showing an electrode positioning device for a secondary battery according to an embodiment of the present invention.

Referring to Figure 1, the electrode positioning device of the secondary battery extracts the brightness change of the edge, that is, the brightness change rate by calculating the slope.

Shows the Edge Detect first-order differentiation algorithm. When the change in brightness value is differentiated, the edge portion is expressed as the maximum value (dark pixel → bright pixel) or minimum value (bright pixel → dark pixel). A mask is used to obtain the differential value, and a representative algorithm is the mask shown in Figure 2 used in Sobel Edge Detect.

FIG. 2 is a diagram showing a method of setting an edge detecting algorithm of the electrode positioning device shown in FIG. 1.

Referring to Figure 2, the Edge Detect Tool is Cognex's CogFindLineTool and check the options for settings.

Set a certain number of calipers in the area where you want to find the edge, as shown in <Figure 3>. The direction of the arrow indicates the direction of obtaining the differential value between adjacent pixels and is set from bright pixels to dark pixels.

Specifically, it shows the Edge Detect first-order differentiation algorithm. When the change in brightness value is differentiated, the edge portion is expressed as the maximum value (dark pixel → bright pixel) or minimum value (bright pixel → dark pixel). A mask is used to obtain the differential value, and the representative algorithm is the mask shown in <Figure 2> used in Sobel Edge Detect.

Because general lighting and special lighting must occupy the same space on the stage controlled by the motion controller, the exterior design must be the same.

Special lighting has a superior straight-line component of light compared to general lighting, and the distribution of light quantity is uniform, so it is designed to reduce errors. The View of Angle for general lighting is 120 degrees, and the View of Angle for special lighting is 60 degrees. To ensure uniform light distribution, the density of special lighting LED elements is designed to be twice as high as that of general lighting.

General lighting is designed to be 21 It shows the LED layout for special lighting and general lighting, respectively. These are images of backlight general lighting, special lighting products, lighting controllers, and cables.

Motion controllers, like lighting, are designed to enable parallel and rotational movement in the X and Y axes. The motion controller XYR stage design is shown.

FIG. 3 is a diagram showing a mask processing algorithm of the electrode positioning device shown in FIG. 1. And, FIG. 4 is a diagram showing the results of edge detection processing of the electrode positioning device shown in FIG. 1.

Referring to Figures 3 and 4, the projection data is a graph expressing the brightness of the caliper, and the filtered projection data is a graph obtained by differentiating the change in brightness.

The accuracy of Edge Detect can be increased by finding optimal settings such as appropriate caliper settings, contrast threshold, and filter half-size pixels. In this way, the positioning process begins by obtaining the coordinate value of the upper left or lower right of the secondary battery through the optimal Edge Detect setting.

It shows the screen for extracting the upper left coordinates of the secondary battery through Edge Detect.

FIG. 5 is a diagram showing the camera calibration results of the electrode positioning device shown in FIG. 1.

Research on pattern matching has been conducted for a long time. Algorithms for pattern matching can be broadly divided into two. These are geometric shape pattern matching and correlation coefficient pattern matching.

Geometric shape pattern matching is a method of finding patterns by extracting and comparing feature edges of the model, and correlation coefficient pattern matching is a method of comparing similarity by measuring the correlation coefficient for each pixel.

In this study, we use a geometric pattern matching method that easily finds patterns even when distorted or deformed.

The tool for pattern matching uses Cognex's CogPMAlignTool. Here, pattern matching is the process of registering the shape to be tracked as a model and finding the optimal settings such as model area setting, acceptance threshold, acceptance angle, and ratio.

It shows the result of pattern matching. The result of pattern matching is coordinates and rotation angles that match the model. After extracting the upper left and lower right coordinates and rotation angle of the secondary battery, they can be converted to the master registration position of the secondary battery through a position determination process.

FIG. 6 is a diagram showing the camera position relationship of the electrode positioning device shown in FIG. 1.

The positioning process using a camera begins with camera calibration. Camera calibration is a correction process performed in the process of converting points in a three-dimensional coordinate system into points in a two-dimensional coordinate system such as a camera image.

The correction work consists of perspective distortion correction and radial distortion correction.

The camera calibration tool used in this study is CogCalibCheckboardTool in Cognex's VisionPro product.

The reason perspective distortion occurs is because the camera cannot be installed accurately vertically when fixed and a slight tilt occurs. And radial distortion is due to the properties of the camera lens.

This is the result of camera calibration using cameras installed at different angles.

The calibration result is that the camera is aligned almost vertically. The coefficient DX = 0000123469 indicates the degree of inclination around the X axis, and the coefficient DY = 00000108816 indicates the degree of inclination around the Y axis.

The calibration result is the result of the camera being tilted about 5 degrees on the X-axis and about 7 degrees on the Y-axis.

Compared to the results, the coefficient DX = -0000678454 shows a change in size of about 55 times in absolute value, and the coefficient DY = 0000471829 shows a change in size of about 45 times.

There is no significant difference in the radiation conversion coefficient K value because the same lens was used.

In various configurations of measurement cameras and lenses for precision analysis, the camera should be installed as vertically as possible to improve precision.

Minimizing the RMS error calculated as a result of calibration is one of the factors for improving precision.

This is the result of perspective radial transformation through camera calibration. Once correction is completed through camera calibration, any uncorrected coordinates on the image are converted to raw coordinates through CogCalibCheckerboardTool.

FIG. 7 is a block diagram for explaining the algorithm processing logic for each component of the electrode positioning device shown in FIG. 1.

When camera calibration is completed, the relative positions of the home position of the XYR stage controlled by the motion controller and the calibrated coordinate system viewed by the camera are fixed. The assumption made here is that the accuracy of the motion controller returning to the home position is guaranteed. Therefore, the motion controller's reproduction rate error range is designed and manufactured to be within ±005mm.

Camera position relationship refers to a linear coordinate transformation that links the separate camera-specific coordinate systems of two cameras into one camera coordinate system.

It displays the corrected coordinate systems of Camera 1 and Camera 2 for which calibration has been completed. The (x1, y1) coordinate value is the upper left coordinate value of the master secondary battery measured in the coordinate system of camera 1.

The (x2, y2) coordinate value is the coordinate value of the lower right corner of the master secondary battery measured in the coordinate system of Camera 2. And the (xc, yc) coordinate value is the home position rotation axis coordinate value of the XYR stage. (x1, y1) and (x2, y2) are not correlated with each other, but (xc, yc) is fixed in that it is a certain distance from (xc, yc), and Camera 1 correction coordinate system, Camera 2 correction coordinate system, and The XYR stages exist in the same plane.

In order to obtain the camera position relationship, the linear coordinate conversion equation of (x1, y1) ~ (x2, y2) is obtained by tracking the coordinates of the upper left and lower right of the secondary battery through the angular displacement and parallel movement of the XYR stage rotation axis.

When defining the linear coordinate conversion formula X1 = [R T]X2, R represents the rotation matrix and T represents the translation vector.

We intend to define a data collection method to obtain a linear coordinate transformation equation, implement an algorithm, and periodically monitor the coefficients of the linear coordinate transformation equation.

These coefficients are defined as camera position relationship coefficients, and elements that affect changes in camera position relationship coefficients are tracked to maintain system precision.

We plan to design a linear coordinate transformation algorithm for camera position relationship and design a camera position relationship monitoring process. We also plan to design a lens loosening monitoring process.

The above-described present invention may be subject to various substitutions, modifications, and changes without departing from the technical spirit of the present invention to those skilled in the art to which the present invention pertains. It is not limited by .

Claims (3)

positive electrode current collector,
A positive electrode plate including a positive electrode active material layer formed by coating at least one surface of the positive electrode current collector, and a positive electrode uncoated region that is an area formed by not applying the positive electrode active material layer on both sides of the positive electrode current collector,
cathode current collector,
A negative electrode plate including a negative electrode active material layer formed by coating at least one surface of the negative electrode current collector, and a negative electrode uncoated region, which is an area formed by not applying the negative electrode active material layer on both sides of the negative electrode current collector,
A separator disposed between the positive electrode plate and the negative electrode plate is wound and formed,
The positive electrode non-coated portion forms a short circuit prevention area in which the height of the positive electrode non-coated portion is smaller than the height of the positive electrode active material layer,
It further includes a motion controller capable of parallel movement and rotational movement on the An electrode positioning device for a secondary battery characterized by:
delete According to claim 1,
The positive electrode plate further includes a positive electrode tab attached to the positive electrode non-coated portion, and the negative electrode plate further includes a negative electrode tab attached to the negative electrode non-coated portion,
The electrode positioning device for a secondary battery, wherein the short circuit prevention area is formed in a position corresponding to the area in the anode uncoated area to which the negative electrode tab is attached.