Fuel cell stack assembly detection system and method

Abstract

The present application relates to the technical field of fuel cell, in particular to a fuel cell stack assembly detection system and method. The fuel cell stack assembly detection system comprises a self-positioning stacking unit, a self-limiting pressing unit and a central control unit. The central control unit is used to generate a pressing force-displacement curve according to the pressing force data and the pressing displacement data, and control the driving mechanism to enter the pressure maintaining stage when the inflection point in the pressing force-displacement curve is identified. The pressing process is no longer dependent on the preset fixed pressure value or fixed pressing displacement, but is judged based on the stress state change of the single cell structure in the compression process. When the single cell thickness tolerance, the initial height deviation of the sealing ring or the elastic difference of the membrane electrode leads to the difference in the actual compression process of different stacks, the central control unit can still identify the moment when the positioning structure participates in the bearing through the curve inflection point, which can prevent the single cell from over-pressing, and can also reduce the risk of air tightness failure caused by insufficient compression.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and specifically to a fuel cell stack assembly and testing system and method. Background Technology

[0002] Fuel cell stacks are typically formed by stacking multiple individual cells sequentially along a stacking direction. Each individual cell generally includes a membrane electrode assembly (MEA) and electrode plates located on either side of the MEA. Seal rings are also installed between adjacent cells to achieve sealed isolation between fluid channels such as hydrogen, air, and cooling media after the stack is press-fitted. The stacking precision and press-fitting condition of the fuel cell stack directly affect the compression uniformity of the seal rings, the contact state between the electrode plates and the MEA, and the overall sealing reliability and electrical performance consistency of the fuel cell stack.

[0003] In the fuel cell stack pressing process, existing pressing equipment typically compresses the stack core by controlling the preset pressing force or preset pressing displacement. However, factors such as single cell thickness tolerance, initial height error of the sealing ring, elastic differences between the membrane electrode and the gas diffusion layer, rebound of the sealing material, and creep during the pressing process can all lead to inconsistent actual compression states for different fuel cell stacks under the same pressing force or displacement. Therefore, relying solely on fixed pressure or displacement values ​​to control the pressing process makes it difficult to accurately determine whether the sealing ring has reached the appropriate compression ratio, and also makes it difficult to balance sealing reliability and material protection. Summary of the Invention

[0004] One objective of this invention is to provide a fuel cell stack assembly and testing system to solve the problem that the existing technology relies solely on fixed pressure or displacement values ​​to control the pressing process, making it difficult to accurately determine whether the sealing ring has reached the appropriate compression ratio, and also makes it difficult to balance sealing reliability and material protection. The second objective is to provide a fuel cell stack assembly and testing method.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A fuel cell stack assembly and testing system includes a self-positioning stacking unit, a self-limiting pressing unit, and a central control unit, wherein: The self-positioning stacking unit is used to stack multiple single cells along the stacking direction to form a battery stack core. Each single cell includes a first electrode plate, a membrane electrode, and a second electrode plate arranged sequentially along the stacking direction. A sealing ring is provided between the first electrode plate and the second electrode plate of adjacent single cells. The first electrode plate has a first positioning protrusion, and the corresponding area of ​​the second electrode plate has a second positioning protrusion arranged at intervals. A positioning groove is formed between two second positioning protrusions. When two adjacent single cells are stacked, the first positioning protrusion of one single cell matches and connects with the positioning groove of the other single cell. The initial height of the sealing ring is greater than the height of the first positioning protrusion and the second positioning protrusion. The self-limiting pressing unit includes a driving mechanism, a pressure detection element, and a displacement detection element. The driving mechanism is used to apply pressing force to the stacked fuel cell core. The pressure detection element is used to collect pressing force data. The displacement detection element is used to collect pressing displacement data and send the pressing force data and the pressing displacement data to the central control unit. The central control unit is used to generate a pressing force-displacement curve based on the pressing force data and the pressing displacement data, and when an inflection point is detected in the pressing force-displacement curve, it controls the drive mechanism to enter the pressure holding stage.

[0006] Through the aforementioned technical means, the pressing process no longer relies solely on preset fixed pressure values ​​or fixed pressing displacements, but rather on the changes in the stress state of the individual cell's own structure during compression. When differences in the actual compression process of different cell stacks occur due to variations in individual cell thickness tolerance, initial height deviation of the sealing ring, or elasticity differences in the membrane electrode assembly, the central control unit can still identify the moment when the positioning structure participates in bearing the load through the curve inflection point, thereby controlling the sealing ring compression rate within a reasonable range. This prevents overpressure of the individual cell while reducing permanent deformation, rupture, or accelerated aging of the sealing ring caused by overpressure, and also reduces the risk of airtightness failure due to insufficient compression.

[0007] Furthermore, both the first positioning protrusion and the second positioning protrusion are located in the edge blank area outside the sealing area where the sealing ring is located.

[0008] Through the aforementioned technical means, when the first and second positioning protrusions are positioned within this area, they will not intrude into the compression contact surface of the sealing ring, nor will they alter the flow channel cross-section of the hydrogen cavity, air cavity, or water cavity. Therefore, during the stacking process, the positioning protrusions can perform the lateral positioning function of a single cell, while the sealing ring can still compress and seal according to its original sealing path, avoiding abnormal local stress on the sealing ring, discontinuity of the sealing surface, or obstruction of the fluid channel caused by the positioning structure occupying the sealing area.

[0009] Furthermore, the height of the first positioning protrusion and the accommodating height of the positioning groove are determined based on the initial height of the sealing ring and the preset compression ratio of the sealing ring, so that after the sealing ring is compressed to the preset compression ratio, the first positioning protrusion and / or the second positioning protrusion participate in bearing.

[0010] Through the above technical means, when the remaining height of the sealing ring reaches the height corresponding to the preset compression rate, the first positioning protrusion and the bottom of the positioning groove or the corresponding bearing surface of the second positioning protrusion form an abutment in the stacking direction. At this time, further displacement will cause the electrode plate positioning structure with greater rigidity to share more pressing force, thereby causing the slope of the pressing force-displacement curve to change significantly and an inflection point to appear.

[0011] Furthermore, the heights of the first positioning protrusion and the second positioning protrusion are both h1, the height of the positioning groove is h2, the initial height of the sealing ring is h3, and the optimal compression ratio of the sealing ring is a, satisfying the following: h1=h2; a = (h3 - h1) / h3.

[0012] By employing the aforementioned technical means, the optimal compression ratio of the sealing ring, corresponding to the preset compression ratio, can be matched with the moment when the positioning structure participates in bearing the load and the moment when the sealing ring reaches a relatively optimal sealing compression state. In this way, a correlation is formed between the dimensional parameters of the positioning structure, the compression parameters of the sealing ring, and the inflection point judgment of the central control unit. This allows the positioning structure to not only exist as an alignment structure but also further become a mechanical reference in the press-fitting closed-loop control.

[0013] Furthermore, the self-positioning stacking unit also includes a vision recognition module and a material gripping and conveying mechanism. The vision recognition module is used to identify the outer contour edge of the single battery, and the material gripping and conveying mechanism is used to transfer the identified single battery to the stacking station.

[0014] By employing the aforementioned technical means, the reliance on external high-precision positioning fixtures and high-precision visual repeatability can be reduced, stacking cycle time can be increased, and positioning drift caused by fixture wear during long-term operation can be reduced.

[0015] Furthermore, the central control unit is also used to control the drive mechanism to stop when the pressing displacement data exceeds a preset displacement threshold.

[0016] By introducing displacement threshold protection through the above technical means, the pressing stroke can be limited in advance before the pressure fully reflects the abnormality, reducing the risk of over-compression of the electrode plate, membrane electrode and sealing ring.

[0017] Furthermore, first inclined walls are formed on opposite sides of the first positioning protrusion, and the distance between the two first inclined walls gradually decreases along the direction away from the first electrode plate; second inclined walls are formed on opposite sides of the positioning groove, and the distance between the two second inclined walls gradually increases along the direction away from the second electrode plate.

[0018] Through the aforementioned technical means, when adjacent single cells are close together, even if there is a slight lateral offset between the first positioning protrusion and the positioning groove, the first inclined wall and the second inclined wall can still make contact first and generate a lateral component force during the pressing process, causing the first positioning protrusion to move towards the center of the positioning groove. This guiding process can reduce the impact of placement errors on the final stacking accuracy and reduce the probability of the protrusion end directly colliding with the edge of the second positioning protrusion, leading to electrode plate deformation or coating damage. After pressing, the first positioning protrusion is limited by the positioning groove, and with the frictional force after the sealing ring is compressed, the lateral movement of the single cell during vibration or handling can be further suppressed.

[0019] Furthermore, the fuel cell stack assembly and testing system also includes an online performance testing unit, which is used to perform online performance testing on the stack core during the pressure holding stage.

[0020] By using the above-mentioned technical means, performance testing is carried out at this stage. The test results can better reflect the insulation performance, contact status and sealing reliability of the fuel cell stack under actual assembly conditions, thereby improving the correspondence between test results and assembly quality.

[0021] Furthermore, the online performance testing unit includes an insulation resistance testing system, which is used to detect the insulation performance between the positive and negative electrodes of the fuel cell stack core and the shell.

[0022] Using the above-mentioned technical means, the test is carried out under pressure, and the positional relationship and compression state between individual cells are consistent with the final assembly state. Therefore, it is possible to detect insulation risks caused by plate misalignment, contaminant insertion, membrane electrode damage, or insufficient insulation spacing of the casing more promptly.

[0023] Furthermore, the insulation resistance testing system includes a high-voltage insulation tester, and the central control unit is used to adjust the test voltage of the high-voltage insulation tester according to the number of individual cells in the fuel cell stack core.

[0024] By employing the aforementioned technical methods, unnecessary insulation stress can be avoided on small-scale fuel cell stacks due to fixed high test voltages, while insufficient screening of insulation defects in large-scale fuel cell stacks can be avoided due to fixed low test voltages, thereby improving the adaptability and safety of insulation testing.

[0025] Furthermore, the online performance testing unit includes an internal resistance testing system, which is used to detect the internal resistance between the positive and negative electrodes of the fuel cell stack core.

[0026] By using the above-mentioned technical means, the internal resistance is detected during the pressure holding stage. By combining the internal resistance test results with the pressing force-displacement curve, the central control unit can record and trace the assembly process parameters, and also provide a basis for subsequent optimization of pressing force, pressure holding time or structural dimensions.

[0027] Furthermore, the internal resistance testing system is used to detect the internal resistance between the positive and negative electrodes of the fuel cell stack core using the AC impedance method.

[0028] Using the aforementioned techniques, the AC impedance method provides a relatively small test signal amplitude, eliminating the need for the fuel cell stack to enter power generation operation or for introducing reactive gases to participate in the electrochemical reaction. Therefore, it is suitable for rapid online testing at the assembly and pressure-holding station. This method can reflect the quality of internal conductive contacts of the fuel cell stack without disrupting the press-fitting state, thereby improving the timeliness of assembly defect identification.

[0029] Furthermore, the online performance testing unit includes an airtightness testing system, which is used to detect the airtightness of the fuel cell stack core.

[0030] By employing the aforementioned technical means, since the sealing effect of the sealing ring depends on the compression ratio and the uniformity of force, conducting an airtightness test during the pressure holding stage can directly verify the sealing state formed by the aforementioned self-limiting press fitting process, thus avoiding inconsistent test results caused by changes in clamping force after offline transfer.

[0031] Furthermore, the airtightness testing system includes a test gas source, a flow meter, a test pipeline, a tailpipe pipeline, and a shut-off valve group. The test pipeline is connected to the hydrogen chamber, air chamber, and water chamber of the fuel cell stack core. The shut-off valve group is used to switch the on / off state of the test pipeline and the tailpipe pipeline to perform three-chamber airtightness pressure holding tests of the hydrogen chamber, air chamber, and water chamber, inter-chamber leakage tests of the hydrogen chamber and air chamber relative to the water chamber, and hydrogen chamber leakage tests, respectively. The central control unit is used to determine whether the airtightness of the fuel cell stack core is qualified based on the pressure decay rate or leakage amount after the airtightness test system enters the pressure holding test.

[0032] The above-mentioned technical means can be used to check the sealing reliability of the fuel cell stack core relative to the outside world, identify cross-cavity leakage problems caused by misalignment of sealing rings, damage to the sealing area of ​​the electrode plate, welding or bonding defects, and conduct hydrogen cavity leakage tests separately.

[0033] A fuel cell stack assembly and testing method, applied to a fuel cell stack assembly and testing system, the method comprising: Multiple single cells are transported one by one to the stacking station, and the first positioning protrusion of one of the single cells is inserted into the positioning groove of the adjacent single cell to form the stack core. A pressing force is applied to the fuel cell stack core, and pressing force data and pressing displacement data are collected; Generate a pressing force-displacement curve based on the pressing force data and the pressing displacement data; When an inflection point is detected in the pressure-displacement curve, the pressure holding stage begins.

[0034] The above-mentioned technical means can avoid over-pressure or under-pressure caused by relying solely on fixed pressure or fixed displacement for press-fitting, and can also keep the stack core stable under a more suitable compression state, thereby improving the stacking accuracy of single cells and the compression consistency of the sealing ring.

[0035] Furthermore, during the pressure holding stage, the fuel cell stack core is subjected to online performance testing, which includes at least one of insulation resistance testing, internal resistance testing, and airtightness testing of the fuel cell stack core.

[0036] Through the aforementioned technical means, the entire process of fuel cell stack core assembly, from single-cell stacking and press-fit inflection point identification to pressure holding and online performance testing, can be completed continuously within the same assembly system. Online performance testing is implemented during the pressure holding stage, ensuring that insulation, internal resistance, and airtightness test results reflect the performance of the stack under actual compressed conditions. This improves fuel cell stack assembly consistency, real-time testing, and production cycle time, while reducing the risk of defective products flowing into subsequent processes.

[0037] The beneficial effects of this invention are: (1) The pressing process no longer relies solely on preset fixed pressure values ​​or fixed pressing displacements, but is based on the changes in the stress state of the single cell structure during the compression process. When the actual compression process of different stacks differs due to single cell thickness tolerance, initial height deviation of the sealing ring, or elasticity differences of the membrane electrode, the central control unit can still identify the moment when the positioning structure participates in bearing the load through the curve inflection point, thereby controlling the sealing ring compression rate within a reasonable range. In this way, it can prevent single cell overpressure while reducing permanent deformation, rupture, or accelerated aging caused by sealing ring overpressure, and also reduce the risk of airtightness failure due to insufficient compression.

[0038] (2) The positioning of this application does not rely on external metal positioning pins or clamps that pass through the core of the fuel cell stack. Therefore, it can reduce the interference of external positioning devices on electrical performance testing and reduce the risk of short circuits or misjudgments in insulation testing caused by external metal parts.

[0039] (3) By using the fuel cell stack assembly and testing method, on the one hand, it can avoid over-pressure or under-pressure caused by relying solely on fixed pressure or fixed displacement for press assembly, and on the other hand, it can keep the stack core stable under a more suitable compression state, thereby improving the stacking accuracy of single cells and the compression consistency of sealing rings. Attached Figure Description

[0040] Figure 1 A cross-sectional structural diagram of a single cell provided in an embodiment of this application; Figure 2 A cross-sectional structural diagram of a single cell during the assembly and stacking process provided in an embodiment of this application; Figure 3 A cross-sectional structural diagram of a single cell after assembly and stacking, provided in an embodiment of this application; Figure 4 for Figure 1 A schematic diagram showing the dimensions of the structure is provided. Figure 5 A block diagram showing the connection relationships of the fuel cell stack assembly and testing system and method provided in the embodiments of this application; Figure 6 This is a schematic diagram of the connection relationship of the airtightness testing system provided in the embodiments of this application.

[0041] in, 100. First electrode plate; 110. First positioning protrusion; 111. First inclined wall; 200. Membrane electrode; 300, Second electrode plate; 310, Second positioning protrusion; 320, Positioning groove; 321, Second inclined wall; 400. Sealing ring; 500. Self-positioning stacking unit; 510. Vision recognition module; 520. Gripping and conveying mechanism; 600. Self-limiting press-fitting unit; 610. Drive mechanism; 620. Displacement detection element; 630. Pressure detection element; 700. Central control unit; 800. Online performance testing unit; 810. Insulation resistance testing system; 820. Internal resistance testing system; 830. Air tightness testing system; 831. Test air source; 832. Flow meter; 833. Test pipeline; 834. Tail drain pipeline. Detailed Implementation

[0042] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0043] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0044] For ease of description, spatial relative terms may be used in the text to describe the relative position or movement of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "front," "back," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure undergoes a positional flip, orientation change, or change of motion, these directional indications will change accordingly. For instance, an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0045] This application provides a fuel cell stack assembly and inspection system. This system primarily addresses the problems encountered during the large-scale assembly of fuel cell stacks, such as reliance on external tooling for single-cell stack positioning, easy accumulation of stacking errors, difficulty in accurately controlling the compression ratio of the sealing ring, lack of effective feedback during the pressing process, and the need for offline transfer for post-assembly inspection. The system achieves self-positioning of individual cells during the stacking process by incorporating mutually cooperating positioning structures within each cell. Simultaneously, through the matching relationship between the height of the sealing ring and the height of the positioning structure, the positioning structure participates in load-bearing after the sealing ring reaches a preset compression ratio, resulting in a identifiable stiffness change in the pressing force-displacement curve. The central control unit identifies the pressing inflection point based on this stiffness change and controls the pressing process to enter the pressure holding stage. During this stage, online detection of insulation resistance, internal resistance, and airtightness is further performed. Therefore, this application integrates stack positioning, pressing limit, and online inspection into the same assembly process, thereby reducing the use of external positioning tooling, minimizing errors caused by transfer and repeated clamping, and improving the real-time performance of assembly quality feedback.

[0046] like Figures 1-6 As shown, the fuel cell stack assembly and testing system includes a self-positioning stacking unit 500, a self-limiting pressing unit 600, and a central control unit 700. The self-positioning stacking unit 500 is used to stack multiple single cells along a stacking direction to form a fuel cell stack core. Each single cell includes a first electrode plate 100, a membrane electrode 200, and a second electrode plate 300 arranged sequentially along the stacking direction. A sealing ring 400 is provided between the first electrode plate 100 and the second electrode plate 300 of adjacent single cells. The first electrode plate 100 has a first positioning protrusion 110, and the corresponding area of ​​the second electrode plate 300 has spaced second positioning protrusions 310. A positioning groove 320 is formed between two second positioning protrusions 310. When two adjacent single cells are stacked, the first positioning protrusion 110 of one single cell and the first positioning protrusion 110 of the other single cell... The positioning groove 320 of the single cell is matched and connected. The initial height of the sealing ring 400 is greater than the height of the first positioning protrusion 110 and the second positioning protrusion 310. The self-limiting pressing unit 600 includes a driving mechanism 610, a pressure detection element 630 and a displacement detection element 620. The driving mechanism 610 is used to apply pressing force to the stacked core of the fuel cell stack. The pressure detection element 630 is used to collect pressing force data. The displacement detection element 620 is used to collect pressing displacement data and send the pressing force data and the pressing displacement data to the central control unit 700. The central control unit 700 is used to generate a pressing force-displacement curve based on the pressing force data and the pressing displacement data, and when an inflection point is detected in the pressing force-displacement curve, it controls the driving mechanism 610 to enter the pressure holding stage.

[0047] The self-positioning stacking unit 500 is used to stack multiple single cells sequentially along the stacking direction to form a fuel cell stack core. The first electrode plate 100 and the second electrode plate 300 of each single cell can be the anode plate, cathode plate, or conductive plate corresponding to the functions of the anode plate and cathode plate in the fuel cell, respectively. A membrane electrode 200 is sandwiched between the two. A sealing ring 400 is provided between the first electrode plate 100 and the second electrode plate 300 of adjacent single cells. The sealing ring 400 can be surrounded on the outer periphery of the hydrogen cavity, air cavity, water cavity, or corresponding fluid channel to form a sealed boundary after press-fitting.

[0048] When two adjacent single cells are stacked, the first positioning protrusion 110 of one single cell matches and connects with the positioning groove 320 of the other single cell. Specifically, during the process of placing the upper single cell down to the lower single cell, the first positioning protrusion 110 first enters the positioning groove 320 between the two second positioning protrusions 310. Since the positioning groove 320 limits the first positioning protrusion 110 in a plane perpendicular to the stacking direction, the lateral relative displacement between adjacent single cells is suppressed. In this way, even if there is a certain positional deviation when the material gripping and conveying mechanism 520 places the single cell, the first positioning protrusion 110 can gradually correct the deviation through lateral guidance during the process of entering the positioning groove 320, so that multiple single cells can form a self-centering or self-positioning effect during the stacking process.

[0049] The initial height of the sealing ring 400 is greater than the height of the first positioning protrusion 110 and the second positioning protrusion 310. Thus, during the initial stacking of a single cell and the application of pressure, the sealing ring 400 contacts the adjacent electrode earlier than the positioning protrusions and is the first to bear the compression deformation. As the drive mechanism 610 continuously applies pressure, the sealing ring 400 is gradually compressed, and its height gradually approaches the height corresponding to when the first positioning protrusion 110 and the second positioning protrusion 310 participate in load bearing. When the sealing ring 400 is compressed to near a preset compression ratio, the top of the first positioning protrusion 110 and / or the corresponding bearing surface of the second positioning protrusion 310 begin to participate in the load bearing in the stacking direction. Since the stiffness of the electrode positioning structure is generally greater than the elastic stiffness of the sealing ring 400, the overall stiffness of the stack core changes significantly before and after the positioning structure participates in load bearing. This change can be reflected in the slope change of the pressure-displacement curve. Therefore, the positioning structure is not only used for lateral positioning during single cell stacking but also forms the basis for pressure limiting and inflection point identification together with the compression process of the sealing ring 400.

[0050] The self-limiting press-fit unit 600 includes a drive mechanism 610, a pressure detection element 630, and a displacement detection element 620. The drive mechanism 610 may include a servo motor, hydraulic cylinder, pneumatic-hydraulic pressurization mechanism, electric cylinder, or other actuator capable of applying a controllable press-fit force to the fuel cell stack core. The output end of the drive mechanism 610 can be connected to a pressure head or pressure plate. The pressure head acts on the end plate or press-fit end face of the fuel cell stack core, thereby applying a press-fit force to the fuel cell stack core along the stacking direction. The pressure detection element 630 can be located at the pressure head, pressure plate, output end of the drive mechanism 610, or pressure-bearing platform for real-time acquisition of press-fit force data. The displacement detection element 620 can be a displacement sensor, encoder, linear encoder, or a detection element related to the stroke of the drive mechanism 610 for acquiring press-fit displacement data of the pressure head. Both the pressure detection element 630 and the displacement detection element 620 are communicatively connected to the central control unit 700 to send the acquired press-fit force data and press-fit displacement data to the central control unit 700.

[0051] The central control unit 700 may include an industrial controller, PLC, industrial computer, embedded controller, or a combination thereof. The central control unit 700 receives pressing force data and pressing displacement data, and matches the data according to sampling time, pressing displacement, or pressing stage to generate a pressing force-displacement curve. To reduce the impact of transient interference on curve judgment, the central control unit 700 can filter, remove outliers, or perform moving average processing on the collected data. Subsequently, the central control unit 700 can calculate the pressure increment corresponding to a unit displacement increment, i.e., the curve slope; it can also calculate the slope change or second-order change between consecutive sampling points. When the slope of the pressing force-displacement curve switches from the first slope interval corresponding to the elastic compression stage of the sealing ring 400 to the second slope interval corresponding to the stage where the positioning structure participates in bearing load within multiple consecutive sampling periods, the central control unit 700 identifies an inflection point in the pressing force-displacement curve. This inflection point indicates that the sealing ring 400 has approached or reached a preset compression ratio, and the positioning structure begins to participate in bearing load in the stacking direction. At this time, the central control unit 700 controls the drive mechanism 610 to enter the pressure holding stage, so that the drive mechanism 610 maintains the current pressing force, the current position, or the preset pressure holding range.

[0052] Through the aforementioned control logic, the pressing process no longer relies solely on preset fixed pressure values ​​or fixed pressing displacements, but rather on the changes in the stress state of the individual cell's structure during compression. When differences in the actual compression process of different cell stacks arise due to variations in cell thickness tolerance, initial height deviation of the sealing ring 400, or elasticity differences in the membrane electrode 200, the central control unit 700 can still identify the moment when the positioning structure participates in bearing the load through the curve inflection point, thereby controlling the compression rate of the sealing ring 400 within a reasonable range. This prevents overpressure of the individual cell while reducing permanent deformation, cracking, or accelerated aging caused by overpressure of the sealing ring 400, and also lowers the risk of airtightness failure due to insufficient compression.

[0053] To avoid interference from the positioning structure with the sealing area of ​​the sealing ring 400, in some embodiments, the first positioning protrusion 110 and the second positioning protrusion 310 are both located in the edge blank area outside the sealing area of ​​the sealing ring 400. The edge blank area can be a non-functional flow channel area on the electrode plate located outside the reaction flow field area, cooling flow field area, and the area enclosed by the sealing ring 400. When the first positioning protrusion 110 and the second positioning protrusion 310 are located in this area, they will not intrude into the compression contact surface of the sealing ring 400, nor will they change the flow channel cross-section of the hydrogen cavity, air cavity, or water cavity. Thus, during the stacking process, the positioning protrusions can perform the lateral positioning function of a single cell, while the sealing ring 400 can still perform compression sealing according to the original sealing path, avoiding abnormal local stress on the sealing ring 400, discontinuity of the sealing surface, or obstruction of the fluid channel caused by the positioning structure occupying the sealing area.

[0054] Optionally, the first positioning protrusion 110 and the second positioning protrusion 310 can be formed by stamping, embossing, etching, molding, rolling, or other methods compatible with the electrode plate forming process. Since this positioning structure can be directly formed on the electrode plate itself, there is no need to assemble additional independent positioning blocks or injection-molded positioning parts. This reduces assembly complexity caused by additional parts and minimizes insulation, detachment, or dimensional stability problems caused by improper material selection for independent positioning parts.

[0055] To enable the positioning structure to function as both a positioning and press-fit limiting device, in some embodiments, the height of the first positioning protrusion 110 and the accommodating height of the positioning groove 320 are determined based on the initial height of the sealing ring 400 and a preset compression rate. This ensures that after the sealing ring 400 is compressed to the preset compression rate, the first positioning protrusion 110 and / or the second positioning protrusion 310 participate in bearing the load. Specifically, the sealing ring 400 has an initial height when uncompressed, and during the press-fit process, the sealing ring 400 is gradually compressed from its initial height. When the remaining height of the sealing ring 400 reaches the height corresponding to the preset compression rate, the first positioning protrusion 110 abuts against the bottom of the positioning groove 320 or the corresponding bearing surface of the second positioning protrusion 310 in the stacking direction. At this point, further displacement causes the relatively stiff electrode positioning structure to bear more of the press-fit force, resulting in a significant change in the slope of the press-fit force-displacement curve, creating an inflection point. The central control unit 700 uses the identification of this inflection point to confirm that the sealing ring 400 has reached the target compression state.

[0056] In one alternative embodiment, the heights of the first positioning protrusion 110 and the second positioning protrusion 310 are both h1, the height of the positioning groove 320 is h2, the initial height of the sealing ring 400 is h3, and the optimal compression ratio of the sealing ring 400 is a, which is the aforementioned preset compression ratio of the sealing ring 400, satisfying h1=h2 and a=(h3-h1) / h3. Here, the height of the positioning groove 320 can be understood as the groove depth of the positioning groove 320 in the stacking direction. Since H1 and H2 are equal or substantially equal, when adjacent single cells are compressed in the stacking direction to the state where the first positioning protrusion 110 and the positioning groove 320 abut against each other, the distance between adjacent plates defined by the sealing ring 400 corresponds to h1. At this time, the sealing ring 400 is compressed from the initial height h3 to the height h1, corresponding to a compression ratio of (h3-h1) / h3. By aligning the preset compression rate with the optimal compression rate of the sealing ring 400, the timing of the positioning structure's participation in load-bearing can be matched with the timing of the sealing ring 400 reaching a superior sealing compression state. This establishes a correlation between the dimensional parameters of the positioning structure, the compression parameters of the sealing ring 400, and the inflection point determination of the central control unit 700, preventing the positioning structure from existing merely as a standalone alignment structure, and instead making it a mechanical reference in the press-fitting closed-loop control.

[0057] The optimal compression ratio of the sealing ring 400 can be determined based on its material, cross-sectional shape, operating temperature, medium type, and fuel cell stack operating pressure. For example, the sealing ring 400 can be made of fluororubber, silicone rubber, EPDM rubber, or other elastic sealing materials suitable for the fuel cell operating environment. When determining the parameters of the sealing ring 400, the overall compression requirements of a single cell can be determined first based on the thickness of the membrane electrode 200, carbon paper, or gas diffusion layer and their suitable compression range. Then, the initial height H3 and optimal compression ratio a of the sealing ring 400 can be determined based on the recommended compression ratio range of the sealing material. This allows for the derivation of the height relationship between the first positioning protrusion 110, the second positioning protrusion 310, and the positioning groove 320. Through this parameter-related design, the airtightness of the sealing ring 400 can be ensured while reducing stress concentration caused by overpressure, which is beneficial for improving the consistency of contact resistance and sealing condition after assembly of different batches of fuel cell stacks.

[0058] To further improve automated stacking efficiency, in some embodiments, the self-positioning stacking unit 500 also includes a vision recognition module 510 and a material gripping and conveying mechanism 520. The vision recognition module 510 is used to identify the outer contour edges of a single battery. The vision recognition module 510 may include a camera, a light source, an image acquisition card, and an image processor. The vision recognition module 510 can acquire images of the single battery and identify the outer contour edges of the single battery through edge detection, contour fitting, corner recognition, template matching, or feature point matching, thereby determining the position, orientation, and rotation angle of the single battery. The material gripping and conveying mechanism 520 may include a robotic arm, a vacuum suction cup, grippers, a linear module, a conveyor line, or a combination thereof, for transferring the identified single battery to the stacking station.

[0059] Optionally, during operation, the vision recognition module 510 first acquires an image of the single battery to be stacked and outputs the battery's pose information. The central control unit 700 or the local controller of the self-positioning stacking unit 500 corrects the gripping position and placement path of the material gripping and conveying mechanism 520 based on the pose information. After the material gripping and conveying mechanism 520 moves the single battery to the stacking station, it aligns the first positioning protrusion 110 with the positioning groove 320 of the adjacent single battery within the allowable deviation range. Subsequently, the single battery completes the initial engagement of the positioning protrusion and the positioning groove 320 under its own gravity, the lowering action of the conveying mechanism, or a slight pre-pressure. The residual deviation can be mechanically guided by the positioning structure, so the vision recognition module 510 does not need to bear all the final positioning accuracy requirements. In this way, the dependence on external high-precision positioning fixtures and high-precision visual repeat positioning can be reduced, the stacking cycle can be improved, and the positioning drift caused by fixture wear during long-term operation can be reduced.

[0060] To prevent damage to the fuel cell stack caused by abnormal pressing, in some embodiments, the central control unit 700 is also used to control the drive mechanism 610 to stop when the pressing displacement data exceeds a preset displacement threshold. The preset displacement threshold can be determined based on the number of single cells, the theoretical thickness of a single cell, the initial height of the sealing ring 400, the compression amount of the membrane electrode 200, allowable manufacturing tolerances, and the end plate structure. If the pressing displacement exceeds the preset displacement threshold, it indicates that the fuel cell stack core may have issues such as missing single cells, missing sealing rings 400, incorrect engagement of the positioning structure, sensor malfunction, or abnormal pressing path. Upon detecting this state, the central control unit 700 can immediately stop the drive mechanism 610 from pressing further and trigger an alarm, record abnormal data, or control the assembly process to enter a manual review state. Through this displacement threshold protection, the pressing stroke can be limited in advance before the pressure fully reflects the abnormality, reducing the risk of over-compression of the electrode plates, membrane electrode 200, and sealing ring 400.

[0061] To improve the fault tolerance when the positioning protrusion enters the positioning groove 320, in some embodiments, first inclined walls 111 are formed on opposite sides of the first positioning protrusion 110, and the distance between the two first inclined walls 111 gradually decreases along the direction away from the first electrode plate 100. That is, the first positioning protrusion 110 can have a cross-sectional shape that is narrower at the top and wider at the root. Second inclined walls 321 are formed on opposite sides of the positioning groove 320, and the distance between the two second inclined walls 321 gradually increases along the direction away from the second electrode plate 300. In this way, the positioning groove 320 can have a wider opening and a relatively narrower bottom, that is, a guiding shape that matches the first positioning protrusion 110. When adjacent single cells are close together, even if there is a slight lateral offset between the first positioning protrusion 110 and the positioning groove 320, the first inclined walls 111 and the second inclined walls 321 can still make contact first and generate a lateral component force during the pressing process, causing the first positioning protrusion 110 to move towards the center of the positioning groove 320. This guiding process can reduce the impact of placement errors on the final stacking accuracy and lower the probability of the protruding end directly colliding with the edge of the second positioning protrusion 310, causing electrode plate deformation or coating damage. After pressing, the first positioning protrusion 110 is limited by the positioning groove 320, and with the frictional force after compression of the sealing ring 400, the lateral movement of the single cell during vibration or handling can be further suppressed.

[0062] In some embodiments, the fuel cell stack assembly and testing system further includes an online performance testing unit 800, which is used to perform online performance testing on the stack core during the pressure holding stage. The pressure holding stage is the stage entered based on the inflection point of the pressure-displacement curve. At this time, the sealing ring 400 has been compressed to near the preset compression ratio, the positioning structure has participated or is about to participate in load bearing, and the compression state of the stack core is relatively stable. Therefore, performance testing at this stage can better reflect the insulation performance, contact state, and sealing reliability of the stack under actual assembly conditions. If testing is performed in an uncompressed state, the sealing ring 400 has not yet formed a stable seal, and the contact state between the electrode plates and the membrane electrode 200 is not stable, making it easy for the test results to deviate from the actual use state. If testing is performed after the stack is transferred to an offline workstation, it will introduce problems such as repeated clamping, pipeline reconnection, and state changes. This application sets the online performance testing in the pressure holding stage, which can unify the pressure holding state and the testing state, thereby improving the correspondence between the test results and the assembly quality.

[0063] The online performance testing unit 800 may include one or more of an insulation resistance testing system 810, an internal resistance testing system 820, and an airtightness testing system 830. The central control unit 700 can schedule the operation of each testing system according to the order of testing items, testing time, equipment status, and safety interlock conditions. Optionally, insulation resistance testing and internal resistance testing can be performed before pressurization for airtightness testing, or they can be set between different stages of airtightness testing according to safety requirements; airtightness testing can be completed in steps during the pressure holding stage. Since the fuel cell stack core remains in a stable compressed state during the pressure holding process, and the positioning in this application does not rely on external metal positioning pins or clamps passing through the fuel cell stack core, interference from external positioning devices on electrical performance testing can be reduced, and the risk of short circuits or misjudgments in insulation testing caused by external metal parts can also be reduced.

[0064] In some embodiments, the online performance testing unit 800 includes an insulation resistance testing system 810, which is used to detect the insulation performance between the positive and negative electrodes of the fuel cell stack core and the casing. The insulation resistance testing system 810 may include a high-voltage insulation tester, a test harness, a switching relay, contact probes, or connection clamps. During testing, one end of the high-voltage insulation tester can be connected to the positive or negative electrode of the fuel cell stack core, and the other end can be connected to the casing or the reference end of the insulation to be tested. The central control unit 700 controls the high-voltage insulation tester to apply a test voltage and collects leakage current, insulation resistance values, or test pass signals. If the measured insulation resistance is lower than a preset insulation threshold, the central control unit 700 can determine that there is an insulation abnormality in the fuel cell stack core and stop the subsequent assembly process or output an alarm message. Because this detection is performed under pressure holding conditions, the positional relationship and compression state between individual cells are consistent with the final assembly state, thus enabling more timely detection of insulation risks caused by plate misalignment, contaminant insertion, membrane electrode 200 damage, or insufficient casing insulation spacing.

[0065] Preferably, the insulation resistance testing system 810 includes a high-voltage insulation tester, and a central control unit 700 is used to adjust the test voltage of the high-voltage insulation tester according to the number of individual cells in the fuel cell stack core. Specifically, the central control unit 700 can determine the number of individual cells based on production task information, barcode scanning information, or stack counting results, and call the corresponding test voltage according to the number of individual cells. The more individual cells there are, the higher the rated voltage or test level of the fuel cell stack may be. The central control unit 700 can determine the test voltage by looking up a table, linear calculation, or segmented rules. For example, the test voltage can be increased within the allowable range as the number of individual cells increases, but it cannot exceed the upper limit allowed by the high-voltage insulation tester and the fuel cell stack insulation design. In this way, it is possible to avoid unnecessary insulation stress on small-scale fuel cell stacks by fixing a high test voltage, and it is also possible to avoid insufficient screening of insulation defects in large-scale fuel cell stacks by fixing a low test voltage, thereby improving the adaptability and safety of insulation testing.

[0066] In some embodiments, the online performance testing unit 800 includes an internal resistance testing system 820, which is used to detect the internal resistance between the positive and negative electrodes of the fuel cell stack core. The internal resistance testing system 820 may include an internal resistance tester, a current injection unit, a voltage acquisition unit, a test harness, and a switching switch. During testing, the internal resistance testing system 820 applies a test signal between the positive and negative electrodes of the fuel cell stack core and acquires the corresponding voltage, current, or impedance response. Since the internal resistance of the fuel cell stack is related to the contact state of the electrode plates, the compression state of the membrane electrode 200, the degree of compression of the gas diffusion layer, and the distribution of clamping pressure, detecting the internal resistance during the pressure holding stage can determine whether the contact between the individual cells is sufficient under the current pressure-fitting state. If the pressure fitting is insufficient, the contact resistance between the electrode plates and the membrane electrode 200 or the gas diffusion layer may be too high; if the pressure fitting is excessive, it may cause local structural damage or impedance abnormalities. By combining the internal resistance test results with the pressure-displacement curve, the central control unit 700 can record and trace the assembly process parameters, and can also provide a basis for subsequent optimization of pressure fitting force, pressure holding time, or structural dimensions.

[0067] Preferably, the internal resistance testing system 820 can use the AC impedance method to detect the internal resistance between the positive and negative electrodes of the fuel cell stack core. When using the AC impedance method, the internal resistance testing system 820 can apply a small AC current or AC voltage to the fuel cell stack core and measure the amplitude and phase of the response signal to obtain the impedance of the fuel cell stack core. Optionally, one or more frequency points can be selected for testing, and the real part of the high-frequency impedance can be used as a parameter characterizing the contact resistance or ohmic internal resistance. Because the AC impedance method test signal amplitude is small, it does not require the fuel cell stack to enter a power generation operation state, nor does it require the introduction of reactive gases to participate in the electrochemical reaction. Therefore, it is suitable for rapid online detection at the assembly and pressure holding station. This method can reflect the quality of the internal conductive contacts of the fuel cell stack without damaging the press-fit state, thereby improving the timeliness of assembly defect identification.

[0068] In some embodiments, the online performance testing unit 800 includes an airtightness testing system 830, which is used to test the airtightness of the fuel cell stack core. The airtightness testing system 830 can perform the test using differential pressure, pressure decay, flow rate, or a combination thereof. While the fuel cell stack core is kept compressed, the airtightness testing system 830 can introduce test gases into the hydrogen chamber, air chamber, and water chamber respectively, and determine whether the sealing ring 400, the electrode sealing area, and the inter-cavity isolation structure meet the airtightness requirements based on pressure changes or leakage. Since the sealing effect of the sealing ring 400 depends on the compression ratio and the uniformity of force, performing airtightness testing during the pressure holding stage can directly verify the sealing state formed by the aforementioned self-limiting press-fit process, avoiding inconsistent test results caused by changes in clamping force after offline transfer.

[0069] Furthermore, the airtightness testing system 830 includes a test gas source 831, a flow meter 832, a test pipeline 833, a tailpipe 844, and a shut-off valve assembly. The test gas source 831 can be nitrogen, air, helium, or other gases suitable for airtightness testing. The flow meter 832 is located between the test gas source 831 and the test pipeline 833 to detect or control the flow rate of the test gas entering the fuel cell stack core. The test pipeline 833 communicates with the hydrogen chamber, air chamber, and water chamber of the fuel cell stack core. The tailpipe 844 is used to discharge the test gas after purging, depressurization, or testing. The shut-off valve assembly may include a gas source shut-off valve, a hydrogen chamber on / off valve, an air chamber on / off valve, a water chamber on / off valve, a tailpipe valve, and valves required for switching test states between different chambers. The central control unit 700 is communicatively connected to the shut-off valve assembly and is used to control the opening and closing states of each valve according to the current test item.

[0070] Before conducting the airtightness test, the central control unit 700 can first confirm that the drive mechanism 610 has entered the pressure holding stage and that the test pipeline 833 is connected. Subsequently, the central control unit 700 controls the shut-off valve assembly to allow the test gas to enter the test pipeline 833 through the flow meter 832, purging or replacing the hydrogen chamber, air chamber, water chamber, and tailpipe 844 to remove residual air, impurities, or residual gas from the previous test stage. After purging, the central control unit 700 switches the shut-off valve assembly, placing the test pipeline 833 and tailpipe 844 in their corresponding on / off states.

[0071] During the three-chamber airtightness pressure holding test of the hydrogen chamber, air chamber, and water chamber, the central control unit 700 can control the test gas source 831 to simultaneously or separately pressurize the hydrogen chamber, air chamber, and water chamber. Once the pressure reaches the target test pressure, the gas source side valve is closed, putting the three chambers into a pressure holding state. The central control unit 700 collects pressure data in real time and calculates the pressure decay rate or equivalent leakage. If the pressure decay rate or leakage exceeds the corresponding threshold, it can be determined that there is an overall external leakage risk in the three chambers. This test can check the sealing reliability of the fuel cell stack core relative to the external environment.

[0072] During inter-cavity leakage testing of the hydrogen and air cavities relative to the water cavity, the central control unit 700 switches the test pipeline 833 via the shut-off valve assembly to put the hydrogen and air cavities into pressurized or pressure-holding states, while keeping the water cavity in a detection, isolation, or tail-discharge associated state. If abnormal changes occur in the water cavity side pressure, flow rate, or leakage response during the pressure holding process, or if the pressure decay of the hydrogen and air cavities exceeds a threshold, it can be determined that there is a risk of inter-cavity leakage between the hydrogen and air cavities and the water cavity. This test can identify cross-cavity leakage problems caused by misalignment of the sealing ring 400, damage to the electrode sealing area, welding or bonding defects, etc.

[0073] During the hydrogen chamber leakage test, the central control unit 700 controls the shut-off valve assembly to allow test gas to enter the hydrogen chamber and isolates the air chamber and water chamber or places them in a specified exhaust state. After the hydrogen chamber is pressurized to the target pressure, the gas source side valves are closed and pressure is maintained. The central control unit 700 calculates the leakage amount based on the change in hydrogen chamber pressure over time, the flow compensation amount, or the pressure decay rate, and compares it with a preset threshold. If the leakage amount exceeds the threshold, the hydrogen chamber is deemed to be unqualified due to leakage. Because the hydrogen chamber has high safety requirements during fuel cell operation, conducting a separate hydrogen chamber leakage test can improve the ability to identify hydrogen-side sealing defects.

[0074] After the airtightness test is completed, the central control unit 700 controls the tailpipe 844 to open, reducing the pressure in each test chamber to a safe range, and records the test pressure, holding time, pressure decay rate, leakage, valve group status, and test results. By associating and storing these data with the press-fit force-displacement curve, inflection point position, holding pressure, and press-fit displacement, quality traceability data for fuel cell stack assembly inspection can be formed. When the test results are unqualified, the central control unit 700 can prevent entry into the subsequent final assembly process and output the corresponding defect type, such as external leakage, inter-cavity leakage, or hydrogen cavity leakage.

[0075] Specifically, this application provides an online airtightness testing system 830 as shown in the figure. The shut-off valve group includes shut-off valves 1-7, where hydrogen inlet and hydrogen outlet represent the inlet and outlet of the hydrogen chamber, respectively; air inlet and air outlet represent the inlet and outlet of the air chamber, respectively; and water inlet and water outlet represent the inlet and outlet of the water chamber, respectively. A specific operational illustration of the test is shown below: 1. Preparations before testing.

[0076] After the drive mechanism 610 enters the pressure holding stage, all shut-off valves 1~7 are closed. Connect the test air source 831 to ensure that there is no leakage in the pipeline; confirm that the tailpipe pipeline 844 is unobstructed and free from blockage.

[0077] 2. Purge and replacement of the gas path.

[0078] Open the shut-off valves 1-7, and the test gas enters through the flow meter 832: one path enters the hydrogen / air inlet passage through the support plate to purge and replace the hydrogen and air side flow channels; the other path directly merges into the tailpipe 844 to discharge the residual air / impurities.

[0079] 3. Airtight pressurization and pressure maintenance.

[0080] After purging, close shut-off valves 5, 6, and 7, while keeping shut-off valves 1, 2, 3, and 4 open, preparing for pressurization to perform a three-chamber airtightness test (hydrogen, air, and water). Control the test gas flow rate using flow meter 832 to raise the system pressure to the target test pressure. Close shut-off valve 1 to cut off the test gas supply 831, entering the pressure holding phase (typically 5-10 minutes). Monitor system pressure changes in real time; if the pressure drop rate exceeds a threshold, an external leak is detected in the three chambers. After the pressure holding period, keep shut-off valves 5 and 6 open to complete the test gas exhaust.

[0081] After the tail discharge is completed, close shut-off valves 2, 5, and 6, while keeping shut-off valves 1, 3, 4, and 7 open, preparing for pressurization to conduct a pressure holding test on the hydrogen and air chambers. Control the test gas flow rate using flow meter 832 to raise the system pressure to the target test pressure. Close shut-off valve 1 to cut off the test gas supply 831, entering the pressure holding phase (typically 5-10 minutes). Monitor system pressure changes in real time; if the pressure drop rate exceeds a threshold, leakage is determined between the hydrogen / air chambers and the water chamber. After the pressure holding is completed, keep shut-off valve 5 open to complete the test gas tail discharge.

[0082] After the tail discharge is completed, close shut-off valves 2, 4, 5, 6, and 7, while keeping shut-off valves 1 and 3 open, preparing for pressurization to conduct a hydrogen chamber airtightness pressure holding test. Control the test gas flow rate using flow meter 832 to raise the system pressure to the target test pressure. Close shut-off valve 1 to cut off the test gas supply 831, entering the pressure holding phase (typically 5-10 minutes). Monitor system pressure changes in real time; if the pressure drop rate exceeds a threshold, a leak in the hydrogen chamber is determined. After the pressure holding is completed, keep shut-off valve 6 open to complete the test gas tail discharge.

[0083] 4. Depressurization and post-treatment.

[0084] After the test is completed and the system pressure has been confirmed to have dropped to atmospheric pressure, close all valves and disconnect the test gas source 831. Record the pressure change data, generate an airtightness test report, and determine whether the fuel cell stack is qualified.

[0085] This application also provides a fuel cell stack assembly and testing method, which can be applied to any of the aforementioned fuel cell stack assembly and testing systems. The fuel cell stack assembly and testing method includes: conveying multiple single cells one by one to a stacking station, and inserting the first positioning protrusion 110 of one of the single cells into the positioning groove 320 of an adjacent single cell to form a stack core; applying a pressing force to the stack core and collecting pressing force data and pressing displacement data; generating a pressing force-displacement curve based on the pressing force data and the pressing displacement data; and entering a pressure holding stage when an inflection point is detected in the pressing force-displacement curve.

[0086] This method first transports multiple individual cells to a stacking station one by one, and then inserts the first positioning protrusion 110 of one of the individual cells into the positioning groove 320 of an adjacent individual cell to form the stack core. Specifically, the outer contour edge and orientation of the individual cell can be identified first by a vision recognition module 510, and then the individual cell can be picked up by a material gripping and conveying mechanism 520 and placed in the stacking station. During the placement process, the first positioning protrusion 110 and the positioning groove 320 approach and engage with each other. The guiding and limiting effect of the protrusion and groove corrects the positional deviation between adjacent individual cells, thereby forming aligned stack cores one by one.

[0087] After the fuel cell stack core is formed, the drive mechanism 610 applies a pressing force to the core. The pressure detection element 630 collects the pressing force data, and the displacement detection element 620 collects the pressing displacement data. The central control unit 700 generates a pressing force-displacement curve based on the pressing force and displacement data. In the initial pressing stage, elastic structures such as the sealing ring 400 and the membrane electrode 200 are compressed first. When the sealing ring 400 is compressed to near a preset compression ratio, the first positioning protrusion 110 and / or the second positioning protrusion 310 begin to participate in load-bearing in the stacking direction, increasing the overall stiffness of the fuel cell stack core. This causes a significant change in the curve's slope, resulting in an inflection point. When the central control unit 700 detects an inflection point in the pressing force-displacement curve, it controls the drive mechanism 610 to enter the pressure-holding stage.

[0088] During the pressure holding phase, the drive mechanism 610 maintains the fuel cell stack core in a stable and compressed state. Optionally, the central control unit 700 can use a force closed-loop method to maintain the pressing force within the target range, a displacement closed-loop method to maintain the pressure head position, or a force-displacement combined control method to compensate for the springback or material creep of the sealing ring 400. By entering the pressure holding phase after inflection point recognition, the sealing ring 400 can be kept in a state close to the optimal compression ratio, and further over-compression can be limited, thereby ensuring that subsequent detection corresponds to a stable and reasonable assembly state.

[0089] In summary, the above-described fuel cell stack assembly and testing method utilizes the cooperation between the first positioning protrusion 110 and the positioning groove 320 between adjacent cells during the stacking process. This allows each cell to achieve relative positioning based on its own structure after entering the stacking station, reducing reliance on external positioning fixtures and minimizing lateral misalignment and cumulative errors during stacking. During the pressing process, by simultaneously collecting pressing force and displacement data and generating a pressing force-displacement curve, the pressing state can be characterized by real-time mechanical response. When the sealing ring 400 is compressed to a preset compression state and the positioning structure participates in load bearing, the inflection point formed in the curve reflects the transition of the fuel cell stack core from the elastic compression stage to the limited load bearing stage. Therefore, the pressure holding stage can be entered promptly based on this inflection point. This approach avoids over- or under-pressure caused by relying solely on fixed pressure or displacement for pressing, and ensures the fuel cell stack core remains stable under suitable compression conditions, thereby improving the stacking accuracy of individual cells, the compression consistency of the sealing ring 400, and the controllability of the fuel cell stack assembly quality.

[0090] Preferably, the fuel cell stack assembly and testing method further includes: online performance testing of the stack core during the pressure holding stage. Online performance testing includes at least one of insulation resistance testing, internal resistance testing, and airtightness testing of the stack core. Insulation resistance testing involves applying a test voltage between the positive and negative electrodes of the stack core and the casing, and determining whether the insulation performance is qualified based on the leakage current or insulation resistance. Internal resistance testing can employ the AC impedance method, applying an AC test signal between the positive and negative electrodes and calculating the internal resistance or impedance parameters to determine the electrical contact state between individual cells. Airtightness testing involves performing a three-chamber airtightness pressure holding test, inter-chamber leakage test, and hydrogen chamber leakage test on the hydrogen chamber, air chamber, and water chamber using a test gas source 831, flow meter 832, test pipeline 833, tailpipe 844, and shut-off valve assembly, and determining whether the airtightness of the stack core is qualified based on the pressure decay rate or leakage amount.

[0091] Using the above method, the entire process of fuel cell stack core assembly, from single-cell stacking, press-fit inflection point identification, pressure holding, to online performance testing, can be completed continuously within the same assembly system. The self-positioning structure of each single cell reduces the use of external positioning tooling, lowering errors caused by tooling wear, repeated calibration, or transport. The high correlation between the positioning structure and the compression ratio of the sealing ring 400 provides a clear mechanical origin for the press-fit inflection point, facilitating closed-loop judgment of the press-fit status by the central control unit 700. Online performance testing is set during the pressure holding stage, ensuring that insulation, internal resistance, and airtightness test results reflect the performance of the fuel cell stack under actual press-fit conditions. Therefore, this application can improve fuel cell stack assembly consistency, real-time testing, and production cycle time, while reducing the risk of defective products flowing into subsequent processes.

[0092] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0093] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0094] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A fuel cell stack assembly and testing system, characterized in that, It includes a self-positioning stacking unit, a self-limiting pressing unit, and a central control unit, wherein: The self-positioning stacking unit is used to stack multiple single cells along the stacking direction to form a battery stack core. Each single cell includes a first electrode plate, a membrane electrode, and a second electrode plate arranged sequentially along the stacking direction. A sealing ring is provided between the first electrode plate and the second electrode plate of adjacent single cells. The first electrode plate has a first positioning protrusion, and the corresponding area of ​​the second electrode plate has a second positioning protrusion arranged at intervals. A positioning groove is formed between two second positioning protrusions. When two adjacent single cells are stacked, the first positioning protrusion of one single cell matches and connects with the positioning groove of the other single cell. The initial height of the sealing ring is greater than the height of the first positioning protrusion and the second positioning protrusion. The self-limiting pressing unit includes a driving mechanism, a pressure detection element, and a displacement detection element. The driving mechanism is used to apply pressing force to the stacked fuel cell core. The pressure detection element is used to collect pressing force data. The displacement detection element is used to collect pressing displacement data and send the pressing force data and the pressing displacement data to the central control unit. The central control unit is used to generate a pressing force-displacement curve based on the pressing force data and the pressing displacement data, and when an inflection point is detected in the pressing force-displacement curve, it controls the drive mechanism to enter the pressure holding stage.

2. The fuel cell stack assembly and testing system according to claim 1, characterized in that, Both the first positioning protrusion and the second positioning protrusion are located in the blank edge area outside the sealing area where the sealing ring is located.

3. The fuel cell stack assembly and testing system according to claim 1, characterized in that, The height of the first positioning protrusion and the accommodating height of the positioning groove are determined according to the initial height of the sealing ring and the preset compression ratio of the sealing ring, so that after the sealing ring is compressed to the preset compression ratio, the first positioning protrusion and / or the second positioning protrusion participate in bearing.

4. The fuel cell stack assembly and testing system according to claim 3, characterized in that, The heights of the first and second positioning protrusions are both h1, the height of the positioning groove is h2, the initial height of the sealing ring is h3, and the optimal compression ratio of the sealing ring is a, satisfying the following: h1=h2; a = (h3 - h1) / h3.

5. The fuel cell stack assembly and testing system according to claim 1, characterized in that, The self-positioning stacking unit also includes a vision recognition module and a material gripping and conveying mechanism. The vision recognition module is used to identify the outer contour edge of the single battery, and the material gripping and conveying mechanism is used to transfer the identified single battery to the stacking station.

6. The fuel cell stack assembly and testing system according to claim 1, characterized in that, The central control unit is also used to control the drive mechanism to stop when the pressing displacement data exceeds a preset displacement threshold.

7. The fuel cell stack assembly and testing system according to claim 1, characterized in that, The first positioning protrusion forms a first inclined wall on its opposite sides, and the distance between the two first inclined walls gradually decreases along the direction away from the first electrode plate; the positioning groove forms a second inclined wall on its opposite sides, and the distance between the two second inclined walls gradually increases along the direction away from the second electrode plate.

8. The fuel cell stack assembly and testing system according to any one of claims 1-7, characterized in that, It also includes an online performance testing unit, which is used to perform online performance testing on the fuel cell stack core during the pressure holding phase.

9. The fuel cell stack assembly and testing system according to claim 8, characterized in that, The online performance testing unit includes an insulation resistance testing system, which is used to detect the insulation performance between the positive and negative electrodes of the fuel cell stack core and the shell.

10. The fuel cell stack assembly and testing system according to claim 9, characterized in that, The insulation resistance testing system includes a high-voltage insulation tester, and the central control unit is used to adjust the test voltage of the high-voltage insulation tester according to the number of individual cells in the fuel cell stack core.

11. The fuel cell stack assembly and testing system according to claim 8, characterized in that, The online performance testing unit includes an internal resistance testing system, which is used to detect the internal resistance between the positive and negative electrodes of the fuel cell stack core.

12. The fuel cell stack assembly and testing system according to claim 11, characterized in that, The internal resistance testing system is used to detect the internal resistance between the positive and negative electrodes of the fuel cell stack core using the AC impedance method.

13. The fuel cell stack assembly and testing system according to claim 8, characterized in that, The online performance testing unit includes an airtightness testing system, which is used to detect the airtightness of the fuel cell stack core.

14. The fuel cell stack assembly and testing system according to claim 13, characterized in that, The airtightness testing system includes a test gas source, a flow meter, a test pipeline, a tailpipe pipeline, and a shut-off valve group. The test pipeline is connected to the hydrogen chamber, air chamber, and water chamber of the fuel cell stack core. The shut-off valve group is used to switch the on / off state of the test pipeline and the tailpipe pipeline to perform three-chamber airtightness pressure holding tests of the hydrogen chamber, air chamber, and water chamber, inter-chamber leakage tests of the hydrogen chamber and air chamber relative to the water chamber, and hydrogen chamber leakage tests, respectively. The central control unit is used to determine whether the airtightness of the fuel cell stack core is qualified based on the pressure decay rate or leakage amount after the airtightness test system enters the pressure holding test.

15. A method for testing the assembly of a fuel cell stack, characterized in that, The method, applied to the fuel cell stack assembly and testing system according to any one of claims 1 to 14, comprises: Multiple single cells are transported one by one to the stacking station, and the first positioning protrusion of one of the single cells is inserted into the positioning groove of the adjacent single cell to form the stack core. A pressing force is applied to the fuel cell stack core, and pressing force data and pressing displacement data are collected; Generate a pressing force-displacement curve based on the pressing force data and the pressing displacement data; When an inflection point is detected in the pressure-displacement curve, the pressure holding stage begins.

16. The fuel cell stack assembly and testing method according to claim 15, characterized in that, During the pressure holding stage, the fuel cell stack core is subjected to online performance testing, which includes at least one of insulation resistance testing, internal resistance testing, and airtightness testing.

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