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CN-122000403-A - Full-automatic robot stacking and servo press-fitting forming process of phosphoric acid fuel cell stack

CN122000403ACN 122000403 ACN122000403 ACN 122000403ACN-122000403-A

Abstract

The application relates to the technical field of fuel cell manufacturing, and discloses a full-automatic robot stacking and servo press-fitting forming process of a phosphoric acid fuel cell stack, which comprises the following steps of initializing a substrate and quantifying an acid coating; the method comprises the steps of extracting coating characteristics by using a visual detection unit and calculating a coating distribution density index, controlling a robot execution unit to complete component initial positioning and visual servo fine positioning by using a multi-stage visual feedback, calculating a correction target displacement by a central control unit according to the coating distribution density index when stacking reaches a preset period, driving a servo press-fitting module to execute self-adaptive press-fitting based on feedforward compensation, and circulating the steps until the whole stack is completed. According to the application, the mapping relation between the optical characteristics of the coating and the press-fit displacement is established, so that the microscopic difference of the thickness of the coating is effectively compensated, the fluctuation of contact resistance is eliminated, the closed-loop monitoring of the whole flow data is realized, and the assembly precision and the performance consistency of the galvanic pile are remarkably improved.

Inventors

  • LU CONG

Assignees

  • 中科润谷智慧能源科技(佛山)有限公司

Dates

Publication Date
20260508
Application Date
20260210

Claims (10)

  1. 1. The full-automatic robot stacking and servo press-fitting forming process of the phosphoric acid fuel cell stack is performed based on a full-automatic robot stacking and servo press-fitting system, the system comprises a central control unit, a robot executing unit, a visual detection unit and a coating and weighing unit, and the process comprises the following steps: Step S100, initializing a substrate and detecting the weight of the substrate, wherein a central control unit controls the mass of the substrate before coating of an electronic balance recording assembly; Step 200, quantitative acid coating and coating amount verification, wherein the coating and weighing unit carries out phosphate solution coating on the surface of the component, and the central control unit verifies the actual coating net weight according to the difference value between the coated mass and the substrate mass; step S300, visual detection and feature quantification of coating quality, wherein a central control unit acquires a coating image by utilizing the visual detection unit, extracts an effective coating area and calculates a coating distribution density index for representing a coating microscopic distribution trend; Step S400, component grabbing and initial positioning, wherein the vision detection unit identifies initial position deviation of a component, and the robot execution unit grabs the component according to the initial position deviation; S500, visual servo fine positioning, namely carrying the assembly to a hovering position by the robot execution unit, calculating a fine positioning deviation vector by the central control unit according to the bottom features of the assembly obtained by the visual detection unit, and controlling the robot execution unit to perform fine adjustment stacking; Step 600, self-adaptive servo press fitting based on feedforward compensation, wherein when the number of stacked layers reaches a preset press fitting cycle number, a central control unit is used for calling the coating distribution density indexes corresponding to all components in the press fitting cycle number, and calculating and generating correction target displacement; And S700, whole pile circulating assembly, namely judging whether the current total layer number reaches the total layer number of the electric pile by the central control unit after finishing press mounting, and executing steps S100 to S600 in a circulating way when the current total layer number of the electric pile is not reached.
  2. 2. The fully automated robotic stacking and servo press-fitting process of a phosphoric acid fuel cell stack according to claim 1, wherein in step S300, the specific way of calculating the coating distribution density index is: The central control unit performs Gaussian filtering denoising and threshold segmentation on the coating image to extract the effective coating area, calculates the sum of gray values of all pixel points in the effective coating area, divides the sum of the gray values by the total pixel area of the theoretical coating area to obtain the coating distribution density index, binds the coating distribution density index with the unique identification code of the component, and stores the coating distribution density index into a production data queue.
  3. 3. The fully automated robotic stacking and servo press-fitting process of a phosphoric acid fuel cell stack of claim 2, wherein step S300 further comprises a coating eligibility determination step of: the central control unit divides the effective coating area into a plurality of sub-grids, calculates the local variance of the pixel gray scale in each sub-grid to judge uniformity, counts the ratio of the total number of pixels in the effective coating area to the total number of pixels in the theoretical coating area to judge coverage, and sends out a rejection instruction when the uniformity or the coverage is lower than a preset threshold.
  4. 4. The fully automatic robotic stacking and servo press-fitting process of a phosphoric acid fuel cell stack according to claim 1, wherein in step S500, the specific implementation of the visual servo fine positioning is: The robot execution unit hovers the component above a look-up lens of the visual detection unit, the visual detection unit shoots an image of the bottom of the component, the central control unit calculates image domain deviation of the actual pose of the component relative to the theoretical stacking pose, the central control unit converts the image domain deviation into a motion compensation instruction under a robot base coordinate system by using a hand eye calibration matrix and a deviation transformation matrix, and the robot execution unit drives the end effector to conduct six-degree-of-freedom fine adjustment according to the motion compensation instruction until the center of the component coincides with the stacking center.
  5. 5. The fully automated robotic stacking and servo press-fitting process of a phosphoric acid fuel cell stack of claim 1, wherein in step S600, the specific logic for calculating the generated corrected target displacement is: The central control unit calculates the arithmetic average value of the coating distribution density indexes of all components in the period and records the arithmetic average value as a period average density index, the central control unit calculates the difference value between the period average density index and the density index of a standard reference sample, the central control unit multiplies the difference value by a preset displacement compensation coefficient and superimposes the product result on the nominal press-fitting displacement to obtain the corrected target displacement, wherein the displacement compensation coefficient is used for representing the physical displacement adjustment quantity required by unit density index deviation.
  6. 6. The fully automatic robot stacking and servo press-fitting process of the phosphoric acid fuel cell stack according to claim 5, wherein the step S600 further comprises a pressure monitoring step of driving the rigid press head to press down at a preset speed until the actual displacement fed back by the position detection sensor is equal to the corrected target displacement, a pressure maintaining step of monitoring the actual contact pressure value in real time by the central control unit through the force sensor, and generating an alarm signal and terminating the action when the actual contact pressure value exceeds a preset target pressure range.
  7. 7. The fully automated robotic stacking and servo press-fitting process of a phosphoric acid fuel cell stack of claim 1, wherein in step S700, before the cyclic execution of steps S100-S600, further comprising resetting the robotic execution unit, acid coating the center position of the back of the stack with the coating and weighing unit, and recording the time stamp of the coating operation by the central control unit to monitor electrolyte exposure time.
  8. 8. The fully automated robotic stacking and servo press-fitting process of a phosphoric acid fuel cell stack of claim 4, wherein in step S400, the component grabbing and initial positioning is performed in the following manner: The overlooking lens of the visual detection unit shoots a feeding level image, and the central control unit identifies the model of the component by utilizing a characteristic matching algorithm; the robot execution unit adjusts the grabbing point according to the initial coordinate deviation and absorbs the component by utilizing the vacuum absorption module.
  9. 9. The fully automated robotic stacking and servo press-fitting process for phosphoric acid fuel cell stacks of claims 1-8, further comprising a full flow closed loop control step of: The method comprises the steps that a lower computer of a central control unit collects pressure data and displacement data of a servo press-fitting module in real time, when the pressure data or the displacement data are detected to be abnormal, the lower computer cuts off an enabling signal of a servo driver and sends a fault code to an upper computer of the central control unit, after each press-fitting period is completed, the lower computer returns process result data to the upper computer, and the upper computer combines and stores the process result data with the coating distribution density index.
  10. 10. The fully automated robotic stacking and servo press-fitting process of a phosphoric acid fuel cell stack of claims 1-8, wherein in step S600, the servo press-fitting module performs a press-fitting operation comprising the following mechanical mating steps: The robot execution unit drives the composite end effector to descend, and a vacuum adsorption module on the composite end effector firstly contacts the stacking body; When the composite end effector continues to descend, the vacuum adsorption module is retracted by the elastic floating mechanism under the action of the axial reaction force, the rigid pressure head of the servo press-fitting module protrudes out of the vacuum adsorption module through the retraction action of the elastic floating mechanism, and the rigid pressure head directly applies the vertical plane pressure to the stacked body.

Description

Full-automatic robot stacking and servo press-fitting forming process of phosphoric acid fuel cell stack Technical Field The invention relates to the technical field of fuel cell manufacturing, in particular to a full-automatic robot stacking and servo press-fitting forming process of a phosphoric acid fuel cell stack. Background Phosphoric acid fuel cell stacks are typically formed by stacking hundreds of bipolar plates and membrane electrodes alternately, the quality of the assembly of which directly determines the output power and the service life of the stack. In the automated assembly process, the phosphate coating on the surface of the component not only serves as an electrolyte to transport protons, but also serves to fill microscopic voids at the contact surface to reduce contact resistance. The existing assembly process mostly adopts fixed displacement parameters or constant pressure setting in the press-fitting link, and the control mode ignores microscopic thickness differences and distribution density fluctuation existing in the chemical coating. When the coating is partially thicker or the distribution density is larger, the local contact stress is overlarge due to the adoption of the preset fixed displacement for press mounting, and the porous microstructure of the assembly can be damaged, otherwise, when the coating is thinner, the same press mounting displacement cannot establish enough contact surface pressure, so that the interlayer contact resistance is increased, and the consistency and the electrochemical performance of the overall voltage of the galvanic pile are further affected. The fabrication of stacks involves the sequential vertical stacking of a large number of flexible or brittle sheet assemblies with extremely high requirements on spatial alignment accuracy. The traditional industrial robot grabbing operation mainly relies on teaching coordinates or mechanical limiting to position, and a dynamic correction mechanism for random deviation of incoming material positions and cumulative errors of movement of a mechanical arm is lacked. With the increase of the stacking layers, tiny single-layer alignment errors can be accumulated and amplified layer by layer, so that the geometric center of a galvanic pile is deviated or inclined, and the structural stability and packaging reliability of a finished product are reduced. The existing automatic production line has limitations in terms of data interaction and process monitoring. The upper production management system and the bottom execution mechanism often lack data linkage based on single characteristics, and real-time binding of component physicochemical data and a final press-fitting process result is difficult to realize. In the production process, if abnormal fluctuation of press fitting force or displacement occurs, the system often cannot trigger the safety interlocking logic of the bottom layer rapidly based on real-time feedback data, so that unqualified products flow into subsequent procedures, and accurate tracing and analysis of finished product fault reasons are difficult due to lack of a full life cycle process data chain. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a full-automatic robot stacking and servo press-fitting forming process of a phosphoric acid fuel cell stack, which solves the problems that the prior press-fitting process adopts fixed displacement or pressure parameters and cannot adapt to thickness difference and distribution density fluctuation of a phosphoric acid coating on a microscopic scale, so that consistency of contact resistance among stack components is poor or a microstructure is damaged due to partial overpressure. In order to achieve the above purpose, the invention is realized by the following technical scheme: The invention provides a full-automatic robot stacking and servo press-fitting forming process of a phosphoric acid fuel cell stack, which is used for solving the technical problems of contact resistance fluctuation and poor stacking height consistency caused by uneven coating distribution and component dimensional tolerance in the process of assembling the stack. The invention provides a fully automatic robot stacking and servo press-fitting forming process of a phosphoric acid fuel cell stack, which is executed based on a fully automatic robot stacking and servo press-fitting system comprising a central control unit, a robot execution unit, a visual detection unit and a coating and weighing unit. The process comprises the following steps: Step S100, initializing the substrate and detecting the weight of the substrate, wherein the central control unit controls the electronic balance to record the mass of the substrate before the coating. And step 200, quantitatively acid coating and coating quantity verification, wherein the coating and weighing unit performs phosphate solution coating on the surface of the component, and the central control