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CN-121978894-A - Laser precision cutting and heat affected zone control method and system for phosphoric acid fuel cell electrode

CN121978894ACN 121978894 ACN121978894 ACN 121978894ACN-121978894-A

Abstract

The invention discloses a laser precision cutting and heat affected zone control method and system for a phosphoric acid fuel cell electrode, comprising the steps of obtaining an electrode original image, identifying an actual alignment mark, calculating a sub-pixel level centroid coordinate by utilizing a geometric moment, carrying out coordinate mapping on a standard cutting path by combining a two-dimensional affine transformation model to generate a corrected cutting path, collecting a microscopic image of a laser action zone in real time during cutting, calculating a heat damage index based on the width of a kerf heat affected zone and an edge carbonization mean value, and dynamically adjusting a cooling wind speed by a PID algorithm according to the deviation of the heat damage index and a preset threshold value, and triggering a secondary inhibition strategy for reducing laser energy when the wind speed reaches a limit. The invention solves the path deviation through visual positioning compensation, and utilizes visual thermal field feedback to cooperatively adjust cooling and laser parameters, thereby effectively inhibiting heat accumulation and carbonization phenomena in the electrode processing of the phosphoric acid fuel cell.

Inventors

  • LU CONG

Assignees

  • 中科润谷智慧能源科技(佛山)有限公司

Dates

Publication Date
20260505
Application Date
20260210

Claims (10)

  1. 1. The laser precision cutting and heat affected zone control method for the phosphoric acid fuel cell electrode is characterized by comprising the following steps of: Acquiring an original digital image of an electrode of a phosphoric acid fuel cell to be processed, and processing the original digital image to identify an electrode unique identifier ID and an actual alignment mark; Invoking a standard cutting path file and a theoretical alignment mark coordinate set according to the unique electrode identifier ID, and calculating optimal affine transformation parameters by comparing the actual alignment mark with the theoretical alignment mark coordinate set; Performing coordinate transformation on the standard cutting path file by utilizing the optimal affine transformation parameters to generate a corrected cutting path containing actual machining coordinates; controlling the laser cutting module to execute cutting operation according to the corrected cutting path, and simultaneously controlling the cooling module to convey air flow to an action area of the laser cutting module; In the cutting process, acquiring a real-time microscopic image of an action area of a laser cutting module in real time, and calculating a thermal damage index at the current moment based on the real-time microscopic image; And comparing the thermal damage index with a preset thermal damage threshold, and dynamically adjusting the cooling intensity of the cooling module and the output parameter of the laser cutting module according to the comparison result.
  2. 2. The method for controlling laser precision cutting and heat affected zone of a phosphoric acid fuel cell electrode according to claim 1, wherein the processing the raw digital image to identify the electrode unique identifier ID and the actual alignment mark specifically comprises: Performing median filtering processing on the original digital image, defining a sliding window with a size selected from 3×3 pixels or 5×5 pixels on a pixel matrix, and replacing the original gray value of the pixel at the central position with the intermediate value after the gray sequencing of the pixels in the sliding window; Performing histogram equalization processing on the image subjected to median filtering processing, and establishing a gray mapping relation by using a cumulative distribution function; Performing binarization processing on the image by adopting an Otsu algorithm of the Otsu method, and selecting a candidate threshold value which enables the variance between the foreground pixel set and the background pixel set to reach the maximum value as an optimal segmentation threshold value to obtain image data after the binarization processing; searching a closed contour with concentric square geometric characteristics in the binarized image data to position a two-dimensional code, and analyzing the unique electrode identifier ID; And extracting a boundary pixel sequence of the connected region in the binarized image data, and screening and confirming the boundary pixel sequence as an actual alignment mark according to a preset geometric characteristic parameter of the alignment mark.
  3. 3. The method for controlling laser precision cutting and heat affected zone of a phosphoric acid fuel cell electrode according to claim 2, wherein the calculating optimal affine transformation parameters by comparing the actual alignment mark with the theoretical alignment mark coordinate set specifically comprises: Generating a mask region containing all pixels in the actual alignment mark according to the boundary of the actual alignment mark; Calculating zero-order moment, first-order moment in horizontal direction and first-order moment in vertical direction of the actual alignment mark, dividing the first-order moment in horizontal direction by the zero-order moment to obtain horizontal coordinates of the mass center, dividing the first-order moment in vertical direction by the zero-order moment to obtain vertical coordinates of the mass center, and thus obtaining actual alignment mark coordinates with sub-pixel level precision; pairing the theoretical alignment mark coordinate set with an actual coordinate set formed by actual alignment mark coordinates by adopting a nearest neighbor algorithm, and determining effective matching point pairs; And establishing a two-dimensional affine transformation model, constructing an objective function defined as the sum of squares of position residual errors of all effective matching point pairs after coordinate transformation, and solving the optimal affine transformation parameters by using a least square method.
  4. 4. The method for controlling laser precision cutting and heat affected zone of a phosphoric acid fuel cell electrode according to claim 3, wherein the coordinate transformation of the standard cutting path file by using the optimal affine transformation parameters specifically comprises: Reading the standard cutting path file, wherein the coordinates of discrete path points in the standard cutting path file are defined based on a design coordinate system; determining a mapping relation from a design coordinate system to an actual machining coordinate system by utilizing the optimal affine transformation parameters; mapping the discrete path point coordinates in the standard cutting path file into actual processing coordinates suitable for the actual placing state of the current phosphoric acid fuel cell electrode, and generating the corrected cutting path; And the control module executes motion interpolation operation on the corrected cutting path and converts the motion interpolation operation into standard motion control codes which can be executed by the laser cutting module.
  5. 5. The method for controlling a laser precision cutting and heat affected zone of a phosphoric acid fuel cell electrode according to claim 1, wherein the calculating the heat damage index at the current time based on the real-time microscopic image specifically comprises: acquiring a current cutting feed direction vector of a control module, and determining a rear area of a laser beam focus in the real-time microscopic image based on the cutting feed direction vector; Intercepting a region of interest (ROI) in a region behind the laser beam focus, wherein the ROI takes the center track of a processed kerf as a symmetry axis; Invoking a preset heat damage gray level threshold, and screening out pixel points with gray level values lower than the heat damage gray level threshold in the region of interest (ROI) to form a heat damage pixel set; calculating the maximum pixel span of the heat damage pixel set in the direction perpendicular to the joint-cutting center track, and defining the maximum pixel span as the width of a joint-cutting heat affected zone; calculating arithmetic average gray values of all pixel points in the heat damage pixel set, and defining the arithmetic average gray values as edge carbonization average values; and calculating the heat damage index according to the width of the kerf heat affected zone and the edge carbonization average value.
  6. 6. The method for controlling a laser precision cutting and heat affected zone of a phosphoric acid fuel cell electrode according to claim 5, wherein the heat damage index is calculated according to the kerf heat affected zone width and the edge carbonization average value by: invoking a weight coefficient stored in an internal storage unit; multiplying the width of the kerf heat affected zone by a first weight coefficient to obtain a width component; calculating a chrominance component based on a contrast difference between the edge carbonization average value and a reference gray value of the non-damaged area; The width component is added to the chromaticity component to obtain the thermal damage index.
  7. 7. The method for controlling a laser precision cutting and heat affected zone of a phosphoric acid fuel cell electrode according to claim 1, wherein the dynamic adjustment of the cooling strength of the cooling module according to the comparison result comprises: Subtracting the thermal damage index from the preset thermal damage threshold to obtain a real-time deviation value; inputting the real-time deviation value into a built-in PID controller, executing proportional operation, integral operation and differential operation according to the real-time deviation value, and outputting a cooling wind speed regulating signal; And when the real-time deviation value is a positive number, the cooling module responds to the cooling wind speed adjusting signal to linearly adjust the driving voltage or the driving frequency of the high-pressure air blower and improve the rotating speed of the high-pressure air blower.
  8. 8. The method for controlling a laser precision cutting and heat affected zone of a phosphoric acid fuel cell electrode according to claim 7, wherein dynamically adjusting the output parameters of the laser cutting module according to the comparison result comprises triggering a secondary suppression strategy: judging whether the current rotating speed of the high-pressure air blower reaches the maximum rated rotating speed or not; if the current rotating speed of the high-pressure air blower reaches the maximum rated rotating speed, and the real-time deviation value is continuously kept as a positive number in a preset judging period, an energy modulation instruction is sent to the laser cutting module; the laser cutting module responds to the energy modulation instruction to reduce the repetition frequency of laser pulses or reduce the single pulse energy of a laser.
  9. 9. The method for controlling a laser precision cutting and heat affected zone of a phosphoric acid fuel cell electrode according to claim 8, further comprising, after sending an energy modulation command to the laser cutting module: Stopping sending the energy modulation instruction when the real-time deviation value is recovered to be negative and the absolute value of the real-time deviation value exceeds a preset dead zone threshold value; And controlling the laser cutting module to restore to the preset standard processing parameters.
  10. 10. A laser precision cutting and heat affected zone control system for a phosphoric acid fuel cell electrode, comprising: The laser cutting module is used for scanning and cutting the electrode of the phosphoric acid fuel cell and selecting a short pulse laser or an ultrashort pulse laser as a light source; The image acquisition module comprises a Charge Coupled Device (CCD) camera which is arranged on a cutting head of the laser cutting module, and an acquisition visual field of the CCD camera moves synchronously with the laser cutting module and is used for acquiring an original digital image and a real-time microscopic image; The image processing module is used for receiving the image data, performing image preprocessing and feature recognition, calculating optimal affine transformation parameters based on the unique electrode identifier ID and the actual alignment mark, generating a corrected cutting path, and calculating a thermal damage index in the cutting process; The cooling module comprises a high-pressure air blower and an air guide nozzle connected with an air outlet of the high-pressure air blower, and is used for conveying air flow to an action area of the laser cutting module; The control module is respectively connected with the laser cutting module, the image acquisition module, the image processing module and the cooling module, and is used for controlling the laser cutting module according to the corrected cutting path and adjusting pulse parameters of the laser cutting module and cooling intensity of the cooling module according to the thermal damage index.

Description

Laser precision cutting and heat affected zone control method and system for phosphoric acid fuel cell electrode Technical Field The invention relates to the technical field of fuel cell manufacturing, in particular to a laser precision cutting and heat affected zone control method and system for a phosphoric acid fuel cell electrode. Background Phosphoric acid fuel cells are used as a mature chemical energy generating device, and carbon fiber paper or carbon cloth is generally used as a base material of a gas diffusion layer as a core component electrode. In the industrial production process of the electrode, the rolled or large-sized electrode substrate must be cut into a geometric shape with a specific contour according to the structural design requirements of the galvanic pile. The laser cutting technology replaces the traditional mechanical die cutting technology by virtue of the technical advantages of non-contact processing, high flexibility, capability of processing complex curve tracks and the like, and becomes a mainstream precision processing mode of the porous carbon-based material. The existing laser processing equipment is generally provided with a motion control system and an auxiliary air supply device, controls a laser beam to move along a set path according to a pre-programmed numerical control program, and utilizes a high-energy beam to gasify or fuse and separate materials. However, in actual cutting operations for heat-sensitive porous materials such as carbon fiber paper, existing laser cutting systems generally employ an open-loop control mode based on empirical values, i.e., maintaining constant laser output power, pulse frequency, and assist gas flow rate throughout the process. The control mode of the fixed parameters lacks a sensing and feedback mechanism for microscopic thermal effect of a processing site, and cannot adapt to the dynamic change of a thermal field caused by the change of curvature of a path (such as the increase of heat input per unit area caused by the reduction of speed at a corner) or the fluctuation of local density of a material in the cutting process. Because the heat accumulation at the joint can not be monitored and inhibited in real time, uncontrollable carbonization area expansion or heat affected zone exceeding is easy to occur at the edge of the electrode, the structural strength of the electrode is reduced, gas micropores can be blocked by particles generated by carbonization, and the subsequent electrochemical reaction efficiency and the service life of the fuel cell are seriously affected. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a laser precise cutting and heat affected zone control method and a system for a phosphoric acid fuel cell electrode, which solve the problem that the prior art is difficult to simultaneously realize high-precision path alignment and low-heat damage control in the process of machining the phosphoric acid fuel cell electrode. In order to achieve the above object, the present invention is achieved by the following technical scheme, wherein the first aspect of the present invention provides a laser precision cutting and heat affected zone control method for a phosphoric acid fuel cell electrode, the method comprising the steps of: An original digital image of the electrode of the phosphoric acid fuel cell to be processed is obtained, and the original digital image is processed to identify the unique electrode identifier ID and the actual alignment mark. And calling a standard cutting path file and a theoretical alignment mark coordinate set according to the unique electrode identifier ID, and calculating optimal affine transformation parameters by comparing the actual alignment mark with the theoretical alignment mark coordinate set. And carrying out coordinate transformation on the standard cutting path file by utilizing the optimal affine transformation parameters to generate a corrected cutting path containing actual machining coordinates. And controlling the laser cutting module to execute cutting operation according to the corrected cutting path, and simultaneously controlling the cooling module to convey air flow to the action area of the laser cutting module. In the cutting process, a real-time microscopic image of an action area of the laser cutting module is acquired in real time, and a thermal damage index at the current moment is calculated based on the real-time microscopic image. And comparing the thermal damage index with a preset thermal damage threshold, and dynamically adjusting the cooling strength of the cooling module and the output parameters of the laser cutting module according to the comparison result. Further, in the above method, the process of processing the original digital image takes specific steps to remove noise and enhance features. Specifically, the method comprises the steps of performing median filtering processing on an original digital image, a