Interface bonding dual-mode detection jig and method for photovoltaic junction box EMC potting adhesive

Abstract

The application discloses a photovoltaic junction box EMC potting adhesive interface bonding dual-mode detection jig and method, and belongs to the technical field of photovoltaic module manufacturing quality detection. The jig comprises a small sample preparation mold, a positioning base, a push shear cutter head, a pull column and a positioning ring; the small sample preparation mold is internally provided with a limited height step for controlling the bonding area of the EMC small sample and the potting adhesive and the thickness of the potting adhesive layer; the positioning base is provided with a positioning groove which is open and penetrates through one side of the push shear direction, and the positioning base is provided with a guide groove; the push shear cutter head is provided with a guide part in sliding cooperation with the guide groove; and the positioning ring is provided with a guide hole for the pull column to pass through. The detection method comprises the steps of preparing a standard small sample, push shear testing, pull testing and determining; when determining, the failure mode is given priority to, and the ratio of the shear strength and the tensile strength can be calculated; when the ratio exceeds 1.5-2.5, a warning is given. The application integrates the push shear and pull two modes in the same platform, and realizes the dual-mode quantitative detection of the EMC and potting adhesive interface bonding performance.

Description

Technical Field

[0001] This invention relates to the technical field of photovoltaic module manufacturing quality inspection, and in particular to a dual-mode testing fixture and method for testing the interfacial bonding performance between EMC (epoxy molding compound) encapsulated diode modules and potting sealant inside photovoltaic junction boxes. Background Technology

[0002] Photovoltaic junction boxes are crucial components for current conduction and bypass protection in photovoltaic modules. Common photovoltaic junction boxes contain EMC-encapsulated diode modules. During installation, module manufacturers typically solder the busbar to the diode module leads and then fill the junction box cavity with potting compound to achieve sealing, waterproofing, insulation, and heat dissipation. The reliability of the interface adhesion between the EMC package and the potting compound directly affects the effective heat conduction during diode operation and the long-term lifespan of the junction box.

[0003] In actual production, the interfacial adhesion between the EMC package and the potting compound is easily affected by a variety of factors. The EMC package has low surface energy and may have residual release agent on its surface; flux residue from the soldering process may contaminate the EMC surface; the surface properties of different batches of EMC materials fluctuate due to differences in the amount of release agent, degree of curing, and resin formulation; and the compatibility of different batches of potting compound with EMC lacks systematic verification due to differences in viscosity and curing agent activity.

[0004] Current testing methods mainly rely on environmental reliability testing after the finished junction box is assembled, which results in problems being detected relatively late. Although general tensile testing equipment can provide load and displacement data, the lack of standardized preparation molds and dedicated positioning fixtures for EMC potting compound interface samples makes it difficult to ensure consistency in sample interface area, potting compound layer thickness, loading direction, and failure mode determination, leading to insufficient repeatability and comparability of test results.

[0005] Therefore, there is a need in the field for a standardized testing device and method that can perform a preliminary quantitative assessment of the bonding quality between the EMC module and the potting compound. Summary of the Invention

[0006] To address the shortcomings of the existing technologies, this invention aims to solve the following technical problems: It addresses the lack of standardized methods for preparing EMC potting compound interface samples in existing testing methods, eliminating the incomparability of test results due to inconsistent sample geometry. It solves the problem that existing general-purpose tensile testing equipment cannot simultaneously characterize the interfacial bonding state from both shear and tensile directions, enabling a comprehensive evaluation of interfacial bonding performance. It also solves the problems in existing testing methods where the loading direction is difficult to precisely align with the interface layer during push-shear testing and the pull column is prone to skewness during pull-out testing, leading to invalid data, thereby improving testing accuracy and data validity.

[0007] To achieve the above objectives, the present invention provides a dual-mode testing fixture for the interface bonding of EMC potting compound in photovoltaic junction boxes, employing the following technical solution: A dual-mode testing fixture for EMC potting compound interface adhesion of photovoltaic junction boxes, comprising: The sample preparation mold has a height limiting step inside. The height limiting step is used to control the bonding area between the EMC sample and the potting compound and the thickness of the potting compound layer, so as to ensure that the samples prepared each time are completely consistent in geometric parameters. The positioning base has a positioning groove for fixing the EMC sample. The positioning groove is open and through on one side in the shearing direction, allowing the shearing head to enter without obstruction. The positioning base has a guide groove corresponding to the shearing direction to guide the shearing head to move smoothly in the horizontal direction. The shear head has a height at the force-applying end that is adapted to the thickness of the potting compound layer. The shear head is provided with a guide part that slides with the guide groove to guide the shear head to move in the horizontal direction, ensuring that the shearing force is accurately applied to the interface layer. Pull-up posts are used to adhere to the surface of a potting compound to apply a vertical tensile force. The positioning ring has a guide hole in its center for the pull post to pass through, which guides the pull post to be bonded perpendicularly to the surface of the potting adhesive layer, so as to avoid the pull post being skewed and causing invalid test data. The gap between the inner diameter of the guide hole of the positioning ring and the outer diameter of the pull post is 0.05mm. The positioning base is compatible with the positioning and loading of the push-shear head and the pull column, forming a dual-mode detection platform that can be used for both push-shear and pull-out modes.

[0008] Preferably, the sample preparation mold is made of PTFE material and has a multi-cavity structure.

[0009] By adopting the above technical solution, PTFE material and potting compound have low adhesion, which facilitates the demolding of small samples after curing without damage; the multi-cavity structure of one mold can prepare multiple standard samples at the same time, which improves the sample preparation efficiency and ensures the consistency between samples in the same batch.

[0010] Preferably, the pusher head is provided with a height adjustment mechanism, which is a precision threaded adjustment structure and is provided with a locking element for locking.

[0011] By adopting the above technical solution, the height of the force-applying end can be precisely adjusted to address the slight differences in the thickness of the potting compound layer in different batches, ensuring that the force-applying end is perfectly aligned with the side of the potting compound layer. At the same time, the locking component can prevent the height from loosening due to vibration during the test, thus ensuring the stability and repeatability of the test.

[0012] Preferably, in order to improve testing efficiency and ease of operation, a quick-locking component for pressing the sample is provided inside the positioning base on one side of the positioning groove.

[0013] Preferably, the quick-locking assembly includes a spring and a side pressure block. One end of the spring is fixed in the positioning groove on the side wall parallel to the direction of movement of the push scissor head. The side pressure block is fixed to the end of the spring and is used to press the sample into the positioning groove under the elastic force of the spring.

[0014] By adopting the above technical solution, the elastic pressure provided by the spring is uniform and constant, avoiding the damage that rigid clamping may cause to the sample, while ensuring the consistency of the sample's positioning and clamping force in each test.

[0015] Based on the above-mentioned testing fixture, the present invention also provides a method for testing the interfacial adhesion performance between the photovoltaic junction box EMC module and the potting compound, comprising the following steps: Sample preparation steps: Use the sample preparation mold to prepare standard samples of EMC potting compound, wherein the thickness of the potting compound layer of the standard sample is controlled by the height limiting step; Push-shear test procedure: Fix the standard sample to the positioning base, apply shear force to the side of the potting compound layer in the horizontal direction using the push-shear head, record the peak shear force and calculate the shear strength; Pull-out test procedure: The pull post is vertically bonded to the surface of the potting compound layer through the positioning ring, a tensile force is applied in the vertical direction, the peak tensile force is recorded and the tensile strength is calculated; Judgment steps: Record the damage mode of the interface after the test. When the damage mode is interface damage, it is directly judged as unqualified.

[0016] Preferably, the failure mode includes cohesive failure, interface failure, and mixed failure; in the determination step: When the failure mode is cohesive failure, it is deemed acceptable; When the damage mode is interface damage, it is deemed unqualified; When the failure mode is mixed failure, if the area of ​​cohesive failure accounts for not less than 70%, it is deemed qualified; otherwise, it is deemed unqualified.

[0017] By adopting the above technical solutions, the specific criteria for determining the three damage modes were clarified, transforming qualitative observation into quantifiable judgment criteria.

[0018] The determination step further includes calculating the ratio of the shear strength to the tensile strength, and issuing a warning signal when the ratio is less than 1.5 or greater than 2.5.

[0019] The beneficial effects of this invention are: This invention employs a height-limited stepped mold structure to ensure that the thickness of the potting compound layer and the bonding area remain consistent in each sample preparation, eliminating the impact of human operational differences on test results and achieving cross-comparison of test results between batches.

[0020] This invention integrates the two mechanical testing modes of push-shear and pull-pull into the same testing platform for the first time by using a positioning base that is compatible with the positioning and loading of push-shear heads and pull columns. It comprehensively evaluates the interface bonding quality from both horizontal and vertical directions, avoiding misjudgments that may be caused by testing in only one direction.

[0021] This invention improves the effectiveness and repeatability of test data by setting guide grooves on the positioning base and guide parts on the push scissor head, so that the thrust is accurately applied to the interface layer; and by guiding the pull column to be vertically bonded by the positioning ring.

[0022] Furthermore, this invention introduces a judgment logic that prioritizes failure mode over strength value, which can predict long-term reliability risks earlier and more accurately, and has significant industrial application value. Attached Figure Description

[0023] Figure 1 This is a schematic diagram illustrating the structure of the sample preparation mold in an embodiment of the present invention.

[0024] Figure 2 This is a schematic diagram illustrating the sample preparation mold taking out a sample in an embodiment of the present invention.

[0025] Figure 3 This is a structural schematic diagram illustrating the positioning base in an embodiment of the present invention.

[0026] Figure 4 This is a schematic diagram illustrating the working state of the push-scissor head in an embodiment of the present invention.

[0027] Figure 5 This is a schematic diagram illustrating the structure of the push-button scissor head in an embodiment of the present invention.

[0028] Figure 6 This is an exploded structural diagram illustrating the pulling assembly in an embodiment of the present invention.

[0029] Figure 7 This is a schematic diagram illustrating the working state of the pulling component in an embodiment of the present invention.

[0030] Figure 8 This is a schematic flowchart of the detection method of the present invention.

[0031] Explanation of reference numerals in the attached drawings: 1. Sample preparation mold; 11. Height-limiting step; 12. Height-limiting step surface; 13. Removable side plate; 2. Positioning base; 21. Positioning groove; 22. Guide groove; 3. Push scissor head; 31. Force-applying end; 32. Locking screw; 33. Guide part; 4. Pull column; 5. Positioning ring; 51. Guide hole; 6. Counterweight; 7. EMC sample; 8. Encapsulating layer; 9. Spring; 10. Side pressure block. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of protection of this invention. Features in different embodiments can be combined with each other unless otherwise specified.

[0033] Example 1: Testing the structure of the fixture This embodiment provides a dual-mode testing fixture, which mainly consists of a sample preparation mold 1, a positioning base 2, a pusher head 3, and a pull assembly, wherein the pull assembly includes a pull post 4 and a positioning ring 5.

[0034] Sample preparation mold like Figure 1 and Figure 2 As shown, the sample preparation mold 1 is used to prepare EMC potting compound adhesive samples with standardized geometric dimensions. The sample preparation mold 1 is made of a material that is non-adhesive or has low adhesion to the potting compound, preferably polytetrafluoroethylene (PTFE), to facilitate demolding and avoid residues affecting subsequent testing. The mold has a six-cavity structure for simultaneously preparing six standard samples, ensuring consistency within the same batch.

[0035] The key structure of the sample preparation mold 1 lies in its internal height-limiting step 11, which has a precisely positioned height-limiting step surface 12. During sample preparation, liquid potting compound is injected into the mold cavity until it is flush with the height-limiting step surface 12. After curing, a potting compound layer 8 with a precisely controllable thickness is obtained. The thickness of this potting compound layer is determined according to the actual potting process of the photovoltaic junction box, and is usually selected from the range of 3mm to 5mm. After testing and verification, 4mm is preferred. At this thickness, it can accurately reflect the actual working conditions and ensure that the dispersion coefficient of the test data is minimized. The setting of the height-limiting step 11 eliminates the error caused by manually controlling the thickness of the compound layer.

[0036] To facilitate the non-destructive removal of the cured sample, detachable side plates 13 are provided on both sides of the sample preparation mold 1. After removing the side plates, the sample can be removed by sliding it laterally, avoiding damage to the bonding interface caused by vertical ejection.

[0037] Positioning base like Figure 3 As shown, the positioning base 2 is a common platform for the entire dual-mode testing fixture, used to fix the EMC sample 7 in push-shear and pull-out tests, and to provide precise guidance for the force application tool.

[0038] The positioning base 2 is provided with a positioning groove 21 for accommodating and fixing the EMC sample 7. The inner dimensions of the positioning groove 21 are adapted to the outer dimensions of the standard EMC sample 7, forming a sliding fit relationship, so as to reliably position the sample while facilitating its placement and removal. The positioning groove 21 is designed with an open and through structure on one side in the push-shear direction, allowing the push-shear head 3 to enter horizontally without obstruction and apply force to the side of the potting compound layer 8.

[0039] The positioning base 2 has a guide groove 22 on one side of the opening of the positioning groove 21. The guide groove 22 extends along the shearing direction and is used to cooperate with the corresponding structure on the shear head 3 to guide the shear head 3 to move strictly in the horizontal direction, ensuring that the shearing force is accurately applied to the bonding interface and guaranteeing the accuracy of the test results.

[0040] To facilitate the fixing of the EMC sample 7, a quick-locking assembly is provided in the positioning groove 21, specifically consisting of a spring 9 and a side pressure block 10. The end of the spring 9 is fixed to the side wall of the positioning groove 21 parallel to the direction of movement of the pusher head, and the side pressure block 10 is fixed to the end of the spring 9. Under the elastic force of the spring 9, the EMC sample 7 is pressed firmly into the positioning groove 21, eliminating the need for additional tools and improving operational efficiency. The positioning base 2 is also provided with fixing screw holes for securely mounting the positioning base onto the worktable of the testing machine.

[0041] Push scissor head like Figure 4 and Figure 5 As shown, the push-shear head 3 is used to apply a horizontal shear force to the side of the potting compound layer 8 during the push-shear test.

[0042] The push-shear head 3 has a force-applying end 31, the height of which is configured to match the thickness of the potting compound layer 8, such that during push-shearing, the bottom edge of the force-applying end 31 is substantially flush with the top surface of the EMC sample 7, and the top edge is substantially flush with the top surface of the potting compound layer 8. This structure ensures that the pushing force can be applied completely and evenly to the entire side of the potting compound layer 8 without applying additional torque to the EMC sample 7.

[0043] To accommodate slight variations in potting compound thickness that may exist between different batches of products, the pusher head 3 can adopt a height-adjustable split structure. For example, the vertical position of the force-applying end 31 relative to the positioning base 2 can be adjusted by precisely adjusting the threaded connection between the upper and lower parts. After adjustment, it can be locked with a locking component (such as a locking screw 32) to prevent loosening and displacement during testing. This design makes the fixture more adaptable to process fluctuations.

[0044] The bottom of the pusher head 3 is provided with a guide part 33, which is used to slide and engage with the guide groove 22 on the positioning base 2. Through the precise engagement between the guide part 33 and the guide groove 22, the movement trajectory of the pusher head 3 is constrained, further ensuring that the pushing and shearing direction is always horizontal.

[0045] Pulling components like Figure 6 and Figure 7 As shown, the pull-out assembly is used to apply a vertical tensile force to the surface of the potting compound layer 8 during a pull-out test. Its core function is to ensure that the direction of the tensile force is strictly perpendicular to the bonding interface.

[0046] The pull post 4 has a bottom surface for fixed connection with the surface of the potting compound layer 8. This bottom surface is treated with increased roughness to enhance its anchoring force with the test adhesive. The top of the pull post 4 has a connecting structure for connection with the clamp of the testing machine.

[0047] The positioning ring 5 is a key component ensuring vertical force application. The positioning ring 5 has a positioning cavity for fitting around the EMC sample 7 and a vertically penetrating guide hole 51. A tiny, precise clearance fit is formed between the inner diameter of the guide hole 51 and the outer diameter of the pull post 4. This clearance is sufficient to allow the pull post 4 to slide freely while strictly limiting its tilt, thus guiding the pull post 4 to remain parallel to the surface of the potting compound layer 8 during bonding and perpendicular to the interface during pull-out. This guiding mechanism effectively solves the problem of additional bending moment caused by misalignment of the pull post bonding, which leads to invalid test data.

[0048] When bonding the tie rod 4, a counterweight 6 can be placed on the top of the tie rod 4 to provide standardized and uniform pressure, ensuring a thin and uniform adhesive layer and expelling air bubbles. This further eliminates human error in the bonding process.

[0049] It can be seen that the positioning base 2, the push shear head 3, and the pull assembly consisting of the pull column 4 and the positioning ring 5 together constitute a dual-mode mechanical loading platform that is compatible with both push shear and pull test modes. This enables a comprehensive quantitative evaluation of the interfacial bonding performance of the same batch of samples from both shear and tensile directions under the same standardized positioning reference.

[0050] Example 2: Standard Sample Preparation Method This embodiment provides a method for preparing standard EMC potting compound samples before testing using the above-mentioned testing fixture.

[0051] First, standard EMC samples with uniform dimensions are obtained from the EMC modules of the batch to be inspected by cutting. The cutting process should avoid thermal damage or mechanical stress that may alter the surface properties of the EMC, so as to preserve the original surface condition consistent with the production line.

[0052] Secondly, the surfaces of EMC sample 7 to be bonded undergo standardized cleaning to remove oil, mold release agent, or dust. The cleaning method can be selected based on the actual production line conditions; for example, wiping with organic solvents such as isopropyl alcohol (IPA) is acceptable, ensuring complete solvent evaporation. After cleaning, the surface condition can be verified to confirm that it meets the preset standards. If the production line process involves a primer coating step, the samples should be treated according to the same production line specifications.

[0053] Then, the prepared EMC sample 7 is placed into the cavity of the sample preparation mold 1. The potting compound from the same batch of the production line is mixed evenly according to the specified ratio and degassed, then injected into the mold cavity until it is flush with the height limit step surface 12.

[0054] Finally, the sample preparation mold 1 is placed under specified conditions to allow the potting compound to fully cure. The curing conditions (temperature and time) should be consistent with the production line process. After curing, the sample is cooled to room temperature, the removable side panel 13 is removed, and the sample is taken out laterally. Each sample is visually inspected to confirm that the potting compound layer 8 is free of defects such as bubbles, pinholes, and cracks; unqualified samples are discarded. In this way, a batch of standardized test samples with uniform potting compound layer thickness and consistent interface conditions is prepared.

[0055] Example 3: Push-shear test method This embodiment provides a method for performing a push-shear test using the above-described testing fixture.

[0056] At least one sample prepared in Example 2 is used as the push-shear test sample and placed in the positioning groove 21 of the positioning base 2 and fixed. The push-shear head 3 is installed on the clamp of the testing machine. According to the actual thickness of the potting adhesive layer 8 of the sample to be tested, the height of the force-applying end 31 of the push-shear head 3 is adjusted to match it, and the adjustment mechanism is locked.

[0057] Move the crossbeam of the test machine so that the force-applying end 31 slowly approaches and gently contacts the side of the potting compound layer 8, confirming that the bottom edge of the pusher head 3 is flush with the top surface of the EMC sample 7, and that the guide part 33 has correctly entered the guide groove 22 of the positioning base 2. Zero the force and displacement values.

[0058] Using a quasi-static loading method (e.g., the loading speed can be set in the range of 0.5 mm / min to 2.0 mm / min, preferably 1.0 mm / min), the pusher head 3 is driven horizontally to apply shear force to the side of the potting compound layer 8 until the interface is damaged. The peak shear force Fs during this process is recorded, and the shear strength τ is calculated based on the bonding area (EMC sample length × width).

[0059] Immediately after the test, take a photo of the damaged interface to record it for subsequent damage mode determination.

[0060] Example 4: Pull-out test method This embodiment provides a method for performing pull-out tests using the above-described testing fixture. The bonding of the pull posts must be completed before the pull-out test.

[0061] At least one other sample prepared in Example 2 was placed in the positioning groove 21 of the positioning base 2 and fixed as a pull-out test sample. The positioning ring 5 was then placed around the EMC sample 7 and positioned.

[0062] Apply a thin layer of fast-drying adhesive (such as cyanoacrylate adhesive) to the bottom surface of the pull post 4, then insert the pull post 4 into the guide hole 51 of the positioning ring 5, so that the bottom surface of the pull post 4 contacts the top surface of the potting compound layer 8. Place a counterweight 6 at the top of the pull post 4 to apply standardized and uniform pressure, ensuring that the adhesive layer is thin and uniform. Allow it to cure at room temperature for a sufficient time to ensure that the adhesive is fully cured.

[0063] The entire assembly with the bonded tie rods transferred to the testing machine and connected to the machine clamps via the connecting structure at the top of tie rod 4. A tensile force was applied in a quasi-static loading manner, strictly perpendicular to the bonded interface, until failure. The peak tensile force Ft was recorded, and the tensile strength σ was calculated based on the nominal area of ​​the bottom surface of tie rod 4.

[0064] Similarly, the failure mode should be photographed and recorded immediately after the test. If the failure occurs between the tie post and the potting compound (i.e., tie post adhesion failure) or there are obvious signs of tie post tilting, the test data should be considered invalid and a new sample should be prepared for testing.

[0065] Example 5: Judgment Method and Full-Process Quality Control This embodiment provides a comprehensive judgment method and its application in full-process quality control.

[0066] Destruction mode determination Failure mode is the most direct reflection of interfacial bond quality, and its determination takes precedence over strength value. Failure modes can be divided into three categories: Cohesive failure: Failure occurs within the potting compound itself, with potting compound residue remaining on the EMC surface. This indicates that the interfacial bond strength is higher than the bulk strength of the potting compound, which is a acceptable mode.

[0067] Interface failure: Failure occurs at the bonding interface between the EMC and the potting compound, with a smooth EMC surface free of residue. This indicates that the interfacial bond strength is lower than the bulk strength of the potting compound, which is a non-compliant mode. Once pure interface failure occurs, regardless of the strength value, it should be directly deemed a non-compliant mode.

[0068] Mixed failure: The above two modes coexist. When the proportion of the area of cohesive failure in the total bonding area is not less than 70%, it is judged as qualified; when it is less than 70%, it is judged as unqualified. Through a large number of accelerated aging tests (such as the double 85 test of 85°C / 85%RH), it is verified that the retention rate of interface strength of samples with a proportion of cohesive failure less than 70% decreases significantly after long-term aging and cannot meet the reliability requirements for the 25-year service life of photovoltaic modules, while samples reaching more than 70% show sufficient reliability margins.

[0069] Strength data assisted determination and warning On the premise that the failure mode is qualified (cohesive failure or mixed failure dominated by cohesion), further analyze the strength data. A large number of tests show that the ratio (τ / σ) of the shear strength τ to the tensile strength σ of a normal bonding interface usually falls within a stable range, for example, between 1.5 and 2.5.

[0070] When this ratio is abnormally low, it may indicate that there are local bubbles or insufficient filling of the encapsulant at the interface, resulting in abnormally weak shear resistance; when the ratio is abnormally high, it may indicate problems such as uneven distribution of the primer or locally low surface energy of the EMC at the interface, resulting in abnormally weak tensile resistance. Therefore, even if the absolute value of the strength is within the qualified range, once the τ / σ ratio exceeds the preset warning range, a warning should be issued to trigger enhanced inspection of the corresponding batch of materials and process troubleshooting to detect potential systematic risks as early as possible.

[0071] Full-process quality control application The detection fixture and method of the present invention can be used as a quality gate control tool for the entire production process of photovoltaic junction boxes and play a role at three key nodes: Incoming inspection of the EMC module: For newly incoming batches of EMC modules, verify the surface energy and residual release agent, and conduct spot checks on the bonding performance according to the method of the present invention to ensure the quality of the materials is qualified.

[0072] In-process inspection before encapsulation: After the busbar welding process and before the encapsulation process, re-inspect the surface cleanliness of the EMC and the coating effect of the primer to ensure that the bonding interface is in the best state.

[0073] Final inspection before product shipment: After the encapsulation and curing of the junction box, conduct spot checks on the finished products. In addition to visual inspection and cross-section inspection, use the dual-mode detection method of the present invention for destructive spot checks, release batches according to the above judgment criteria, and establish a statistical process control (SPC) chart for quality trend monitoring.

[0074] The above are all preferred embodiments of the present invention, and do not limit the protection scope of this application accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A dual-mode testing fixture for EMC potting compound interface bonding in photovoltaic junction boxes, characterized in that, include: The sample preparation mold has a height limiting step inside, which is used to control the bonding area between the EMC sample and the potting compound and the thickness of the potting compound layer. A positioning base is provided with a positioning groove for fixing an EMC sample. The positioning groove is open and through on one side in the shearing direction. A guide groove is provided on the positioning base corresponding to the shearing direction. The push-scissor head has a height at the force-applying end that is adapted to the thickness of the potting compound layer. The push-scissor head is provided with a guide part that slides with the guide groove to guide the push-scissor head to move in the horizontal direction. Pull-up posts are used to adhere to the surface of a potting compound to apply a vertical tensile force. The positioning ring has a guide hole in its center for the pull post to pass through, which is used to guide the pull post to be bonded perpendicular to the surface of the potting adhesive layer; The positioning base is compatible with the positioning and loading of the push-scissor head and the pull column.

2. The testing fixture according to claim 1, characterized in that: The sample preparation mold is made of PTFE material and has a multi-cavity structure.

3. The testing fixture according to claim 1, characterized in that: The pusher head is equipped with a height adjustment mechanism, which is a precision threaded adjustment structure and has a locking element for locking.

4. The testing fixture according to claim 1, characterized in that: The positioning base is equipped with a quick-locking component for pressing the sample on one side of the positioning groove.

5. The testing fixture according to claim 4, characterized in that: The quick-locking assembly includes a spring and a side pressure block. One end of the spring is fixed in the positioning groove on the side wall parallel to the direction of movement of the push scissor head. The side pressure block is fixed to the end of the spring and is used to press the sample into the positioning groove under the elastic force of the spring.

6. The testing fixture according to claim 1, characterized in that, The gap between the inner diameter of the guide hole of the positioning ring and the outer diameter of the pull column is 0.05 mm.

7. A detection method based on the detection fixture according to any one of claims 1 to 6, characterized in that, Includes the following steps: Sample preparation steps: Use the sample preparation mold to prepare standard samples of EMC potting compound, wherein the thickness of the potting compound layer of the standard sample is controlled by the height limiting step; Push-shear test procedure: Fix the standard sample to the positioning base, apply shear force to the side of the potting compound layer in the horizontal direction using the push-shear head, record the peak shear force and calculate the shear strength; Pull-out test procedure: The pull post is vertically bonded to the surface of the potting compound layer through the positioning ring, a tensile force is applied in the vertical direction, the peak tensile force is recorded and the tensile strength is calculated; Judgment steps: Record the damage mode of the interface after the test. When the damage mode is interface damage, it is directly judged as unqualified.

8. The detection method according to claim 7, characterized in that: The failure modes include cohesive failure, interface failure, and mixed failure; in the determination step: When the failure mode is cohesive failure, it is deemed acceptable; When the damage mode is interface damage, it is deemed unqualified; When the failure mode is mixed failure, if the area of ​​cohesive failure accounts for not less than 70%, it is deemed qualified; otherwise, it is deemed unqualified.

9. The detection method according to claim 7, characterized in that: The determination step further includes calculating the ratio of the shear strength to the tensile strength, and issuing a warning signal when the ratio is less than 1.5 or greater than 2.5.

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