Method, device, system and storage medium for detecting photovoltaic module

Abstract

The present application relates to the field of photovoltaic detection, and discloses a photovoltaic module detection method, device, system and storage medium. The present application comprises: using a plurality of probe groups to perform multi-position measurement on the conductive connection part of the photovoltaic module, and obtaining the contact resistance values of each measurement position; determining the virtual welding area of the conductive connection part according to the contact resistance values of each measurement position and a pre-constructed mapping relationship; and determining the welding quality of the conductive connection part based on the virtual welding area. The present application solves the problem that the connection state inside the conductive connection part is difficult to effectively identify in related technologies, and there is a risk of virtual welding missing detection.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic testing, and particularly to testing methods, apparatus, systems and storage media for photovoltaic modules. Background Technology

[0002] Photovoltaic modules are the core components of photovoltaic power generation systems, converting solar energy into electrical energy. Their power generation performance and lifespan are closely related to the quality of their internal electrical connections. During the manufacturing process of photovoltaic modules, the internal electrical connections are typically formed by welding to create conductive connection points, which constitute the current conduction path within the module. The connection status of these conductive connection points affects the electrical performance output and long-term operational reliability of the photovoltaic module.

[0003] In related technologies, the welding quality of conductive connection parts of photovoltaic modules is usually evaluated using visual inspection methods. This involves acquiring surface morphology information of the conductive connection parts through image acquisition devices and judging the welding quality accordingly. However, when using this type of visual inspection method to evaluate the welding quality of conductive connection parts, it is difficult to effectively identify the internal connection status of the conductive connection parts, resulting in the risk of missing faulty welds. Summary of the Invention

[0004] The purpose of this invention is to provide a method, apparatus, system and storage medium for testing photovoltaic modules, so as to solve the problem in related technologies that it is difficult to effectively identify the connection status inside the conductive connection parts and there is a risk of missing the detection of poor solder joints.

[0005] To address the aforementioned technical problems, this invention provides a method for testing photovoltaic modules, comprising: using a multi-probe group to perform multi-position measurements on the conductive connection parts of the photovoltaic module to obtain the contact resistance value at each measurement position; determining the area of ​​poor solder joints in the conductive connection parts based on the contact resistance value at each measurement position and a pre-constructed mapping relationship; and determining the welding quality of the conductive connection parts based on the area of ​​poor solder joints.

[0006] The present invention also provides a testing device for photovoltaic modules, comprising: a resistance measurement module configured to perform multi-position measurements on the conductive connection parts of the photovoltaic module using a multi-probe group to obtain the contact resistance value at each measurement position; an area determination module configured to determine the area of ​​the poor solder joint of the conductive connection part based on the contact resistance value at each measurement position and a pre-constructed mapping relationship; and a quality judgment module configured to judge the welding quality of the conductive connection part based on the area of ​​the poor solder joint.

[0007] The present invention also provides a photovoltaic module testing system, comprising: a photovoltaic module testing device as described above; a positioning mechanism configured to fix the photovoltaic module to be tested at the testing position and to electrically connect the multi-probe group of the resistance measurement module to the conductive connection part of the photovoltaic module.

[0008] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described method for detecting photovoltaic modules.

[0009] In this invention, by employing a multi-probe array to perform multi-location measurements on the conductive connection, the contact resistance values ​​at each measurement location can reflect the internal electrical connection state of the conductive connection from multiple sub-regions. The evaluation of welding quality is expanded from observing the surface morphology of the conductive connection to the electrical characterization of its internal connection state. Simultaneously, through a pre-constructed mapping relationship between contact resistance values ​​and the area of ​​the poor weld, the contact resistance values ​​at each measurement location can be converted into a quantifiable indicator of the poor weld area. The criteria for judging welding quality shift from qualitative identification of the welding morphology to quantitative assessment of the poor weld area. This reduces the risk of missing poor weld defects within the conductive connection, improves the precision and objectivity of the welding quality assessment results, and is beneficial for improving the power generation performance and reliability of photovoltaic modules during long-term operation. Attached Figure Description

[0010] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0011] Figure 1 A flowchart illustrating a method for testing photovoltaic modules according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a multi-probe group arranged along a conductive connection portion according to an embodiment of the present invention; Figure 3 This is a mapping curve between contact resistance value and poor solder joint area provided in one embodiment of the present invention; Figure 4 This is a structural block diagram of a photovoltaic module testing device provided in one embodiment of the present invention. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0013] In this invention, "electrical connection" refers to the interconnection of two structures via a conductive material, where current flows between the connected structures when the device is powered on or operating. The directional terms "first direction," "second direction," etc., used in this invention are used to distinguish different reference directions in space and are not used to define the absolute orientation of the structures. The terms "same" and "equal" used in this invention should be considered substantially the same within the range of engineering measurement tolerances or manufacturing errors.

[0014] Photovoltaic modules typically include structural components such as a glass cover, encapsulant film, cell array, busbars, jumpers, junction boxes, and a backsheet. The cell array consists of multiple cells connected in series along a first direction via solder strips to form a cell string. Adjacent cell strings and the cell string itself are electrically connected along a second direction via busbars and jumpers, thus forming the current conduction path within the photovoltaic module. Several conductive connection points formed by welding exist along these current conduction paths, such as the welding area between the busbar and the jumper, the welding area between the solder strip on the front of the cell and the busbar, and the welding area between the cell string lead-out end and the busbar. In actual production, the detection method, detection device, detection system, and storage medium of this invention are applicable to evaluating the welding quality of any of the aforementioned conductive connection points.

[0015] Although photovoltaic modules can pass basic screening during factory electroluminescence testing, they still exhibit localized hot spots, slow power decay, and even junction box burnout during long-term field operation. Disassembly and analysis of defective modules revealed that a significant proportion of faults originated at the conductive connection between the busbar and jumper wire, manifesting as localized discontinuities at the welding interface.

[0016] Existing welding quality assessment methods in this field are mainly divided into two categories. One category is image-based visual inspection methods such as Automated Optical Inspection (AOI), which judge welding quality by identifying the solder creep pattern on the welding surface. The other category is threshold-based assessment methods based on single-point resistance measurement, which give a qualitative conclusion on whether the welding is qualified by comparing the measured resistance value with a preset threshold. For the former, since the image information comes from the outer surface of the welding area, it is difficult to form significant features on the image for the interface discontinuity phenomenon encapsulated under the solder ribbon, thus resulting in missed detections of appearance qualified but internal cold solder joints. For the latter, the single-point resistance is affected by various factors such as the randomness of the probe position, the contact impedance of the fixture, and the impedance of the wire. Even if the measured value is higher than the threshold, it is difficult to determine the spatial distribution and area ratio of cold solder joints in the welding area, and it is impossible to obtain a judgment conclusion that quantitatively corresponds to the welding quality level.

[0017] From a mechanistic perspective, the welding interface between the busbar and the jumper is not an ideal uniform alloy layer, but a complex interface composed of several micro-regions of alloy and non-alloy connections. When the proportion of non-alloy connection areas in the interface increases, the effective conductive channel cross-sectional area decreases, and the macroscopic contact resistance increases accordingly. When the area of ​​the cold weld reaches a certain proportion, under long-term thermal cycling and current load, the welding interface will experience a coupling effect of current density concentration and stress concentration at the edge of the non-alloy region, inducing local overheating and microcrack propagation, ultimately leading to power attenuation or burnout. However, the relationship between the increase in contact resistance and the proportion of the cold weld area is not a simple linear one-to-one correspondence, but rather a nonlinear relationship related to the distribution of the interface alloy layer. This quantitative correspondence has not been systematically established in related technologies for a long time. This invention identifies the lack of such a quantitative correspondence and proposes a technical approach of performing multi-location contact resistance measurements within the welding area and quantitatively judging the welding quality based on the calibrated mapping relationship between the contact resistance value and the cold weld area.

[0018] Example 1 Figure 1 A flowchart illustrating a method for testing photovoltaic modules according to an embodiment of the present invention. See also... Figure 1 The detection method includes steps S101 to S103.

[0019] Step S101: Use a multi-probe group to perform multi-position measurements on the conductive connection parts of the photovoltaic module to obtain the contact resistance value at each measurement position.

[0020] Conductive connection points refer to the connection areas in photovoltaic modules formed by welding to carry current, such as the welding area between busbars and jumpers. A multi-probe group refers to two or more probes arranged spatially, each with independent current injection and voltage acquisition capabilities. Each probe corresponds to a measurement position on the conductive connection point. In one example, the multi-probe group includes N probes, where N is an integer greater than or equal to 2, and optionally N can be 2, 3, 4, 5, 6, 8, or 10.

[0021] Obtaining the contact resistance value at each measurement location can be achieved using a measurement structure with independent current and voltage paths. In one example, for any measurement location in the conductive connection, a constant current I0 is applied to the conductive connection through an independent current injection path, and the voltage drop ΔU on the conductive connection is acquired through a voltage acquisition path independent of the current injection path. The contact resistance value R at that measurement location is determined according to Ohm's law based on the constant current I0 and the voltage drop ΔU, i.e., R = ΔU / I0, where the unit of R is ohms (Ω), the unit of ΔU is volts (V), and the unit of I0 is amperes (A). Thus, current injection and voltage acquisition are completed through independent paths, and the impedance of the connecting wire itself and the probe contact impedance are excluded from the voltage acquisition circuit, enabling stable measurement results even in the micro-ohm to milliohm range of contact resistance. In one example, the constant current I0 can range from 1A to 100A, such as 5A, 10A, 30A or 50A; at this current level, the measurement accuracy of the micro-ohm contact resistance can reach 0.01μΩ.

[0022] See Figure 2 In one example, the multi-probe group includes multiple probes spaced apart along the conductive connection, with the measurement positions of the multiple probes located in different sub-regions of the conductive connection, and the combination of the measurement positions covering the welding area of ​​the conductive connection.

[0023] Optionally, adjacent probes are spaced apart along the extension direction of the conductive connection (denoted as the first direction). The spacing between adjacent probes can be from 1 mm to 20 mm, for example, 2 mm, 5 mm, 8 mm, or 10 mm. In one example, the spacing between adjacent probes is the quotient obtained by dividing the length of the conductive connection along the first direction by the number of probes N. That is, the sub-regions corresponding to each probe are roughly evenly divided along the first direction, and the combination of each measurement position covers the welding area of ​​the conductive connection along the first direction.

[0024] In one embodiment of the invention, each probe is further equipped with a pressure sensor and a pressure adjustment mechanism. The pressure sensor is configured to acquire the pressure of the probe relative to the conductive connection in real time, and the pressure adjustment mechanism is configured to stabilize the pressure near a preset target value. The preset target value of the pressure can be from 1N to 10N, for example, 1N, 2N, 3N, or 10N; the closed-loop fluctuation range of the pressure can be controlled within ±0.2N. This closed-loop adjustment method can reduce the influence of probe pressure fluctuation on contact impedance, and helps to make the contact resistance values ​​at each measurement location comparable.

[0025] Step S102: Determine the area of ​​the poor solder joint in the conductive connection part based on the contact resistance value at each measurement location and the pre-built mapping relationship.

[0026] The area of ​​a poorly welded joint refers to the quantified area within the welded region where no effective alloy bond has formed at the weld interface. It can be expressed as an absolute area (mm²) or a relative percentage (%). A pre-built mapping relationship characterizes the correspondence between contact resistance values ​​and the area of ​​the poorly welded joint. This mapping can be stored in the processing unit in various forms, such as piecewise linear functions, polynomial fitting functions, or lookup tables.

[0027] See Figure 3 In one example, the pre-built mapping relationship is established by obtaining the contact resistance value of the conductive connection part of each calibration sample in multiple calibration samples; and constructing the mapping relationship between the contact resistance value and the poor solder area based on the poor solder area and contact resistance value of each of the multiple calibration samples.

[0028] Optionally, the proportion of poor solder joint area for multiple calibration samples covers six levels: 0%, 10%, 15%, 20%, 25%, and 30%, and can also be extended to other levels within the range of 0% to 50% as needed. At least one calibration sample is prepared for the poor solder joint area at each level, and its corresponding contact resistance value is measured. The calibration data is fitted with the proportion of poor solder joint area as the abscissa and the relative increase in the corresponding contact resistance value (ΔR / R0, where R0 is the reference contact resistance value when the poor solder joint area is zero) as the ordinate to obtain the mapping relationship between the contact resistance value and the poor solder joint area.

[0029] Based on the pre-constructed mapping relationship, the contact resistance values ​​of each measurement position obtained in step S101 are substituted into the mapping relationship, and the proportion of the false solder area corresponding to each sub-region is calculated point by point. Then, the false solder area of ​​each sub-region is weighted and summarized to obtain the overall false solder area of ​​the conductive connection part.

[0030] Furthermore, in one example, while determining the overall area of ​​the poor solder joint in the conductive connection, the spatial distribution characteristics of the contact resistance values ​​at each measurement location can also be used to determine the location of the poor solder joint area within the conductive connection: the contact resistance values ​​of two adjacent measurement locations are compared to obtain the difference in contact resistance values ​​between adjacent measurement locations; the area between adjacent measurement locations where the contact resistance difference is greater than a preset difference threshold is defined as the boundary region of the poor solder joint area; based on the boundary region, the center position and extension range of the poor solder joint area within the conductive connection are determined. The preset difference threshold can be 5% to 20% (e.g., 10% or 15%) of the reference resistance R0. Thus, in addition to obtaining the quantitative result of the poor solder joint area, spatial distribution information of the poor solder joint area within the conductive connection can also be obtained, providing a more targeted adjustment basis for subsequent process feedback.

[0031] Step S103: Determine the welding quality of the conductive connection based on the area of ​​the poor weld.

[0032] In one example, step S103 includes: comparing the area of ​​the poor weld with a preset critical area; if the area of ​​the poor weld is less than the preset critical area, determining that the welding quality of the conductive connection is qualified; if the area of ​​the poor weld is greater than or equal to the preset critical area, determining that the welding quality of the conductive connection is unqualified.

[0033] The preset critical area refers to the upper limit of the allowable area of ​​poor solder joints. Its specific value can be determined comprehensively based on the long-term reliability requirements of the photovoltaic module and the soldering process capabilities. In one example, the preset critical area is expressed as a percentage of the poor solder joint area, and its value can range from 15% to 35%, for example, 15%, 20%, 25%, or 35%. Figure 3 As shown, with 25% as an example value, the corresponding relative increase threshold of contact resistance is approximately 14.92%. That is, when the measured increase of contact resistance relative to the reference value R0 is greater than or equal to 14.92%, the welding quality of the conductive connection is deemed unqualified.

[0034] Furthermore, in one example, in addition to quantitatively judging the overall welding quality based on the area of ​​the cold weld, local cold weld defects can also be identified based on the dispersion of contact resistance values ​​at each measurement location: Based on the contact resistance values ​​at each measurement location, a dispersion index is determined for the contact resistance values ​​between multiple measurement locations; if the dispersion index is greater than a preset dispersion threshold, a local cold weld defect is determined to exist in the conductive connection. The dispersion index can be characterized using statistical quantities such as standard deviation, coefficient of variation, or range: taking the coefficient of variation CV as an example, CV = σ / μ, where σ is the standard deviation (in Ω) of the contact resistance values ​​at multiple measurement locations, μ is the arithmetic mean (in Ω) of the contact resistance values ​​at multiple measurement locations, and CV is a dimensionless quantity. When the overall cold weld area of ​​the conductive connection does not exceed a preset critical area, but the dispersion index exceeds a preset dispersion threshold, locally concentrated cold welds can still be identified, which helps to further discover locally concentrated defects beyond the overall judgment.

[0035] Example 2 The difference between this embodiment and Embodiment 1 is that the conductive connection part is specifically the welding area between the busbar and the jumper in the photovoltaic module.

[0036] See Figure 2In one example, a busbar in the photovoltaic module extends along a first direction and is electrically connected to the leads of the cell string. A jumper extends along a second direction and overlaps with the busbar for welding, forming a conductive connection in the overlap area of ​​the busbar and the jumper. The length of this welding area along the first direction can be 5 mm to 50 mm (e.g., 5 mm, 10 mm, 20 mm, or 50 mm), and the width along the second direction can be 3 mm to 15 mm (e.g., 3 mm, 5 mm, 8 mm, or 15 mm).

[0037] For the aforementioned welding area, the multi-probe group includes N probes spaced apart along a first direction, with N taken as an example value of 4. Each probe corresponds to one of the four sub-regions evenly divided along the first direction of the welding area. The contact resistance value of each probe is substituted into the mapping relationship to calculate the area of ​​the poor weld in each sub-region, and the total of these values ​​is used to obtain the proportion of the overall poor weld area of ​​the welding area. By comparing this proportion with a preset critical area ratio of 25%, the welding quality between the busbar and the jumper can be determined to be acceptable.

[0038] In one embodiment of the present invention, the number N of the multi-probe group and the spacing between adjacent probes satisfy the following relationship with the length of the welding area along the first direction: Spacing between adjacent probes = Length of the welding area along the first direction / N. Therefore, in photovoltaic modules with different specifications of solder strips or different busbar sizes, the coverage of each sub-region remains consistent along the first direction, and the same mapping relationship has good portability between different production lines.

[0039] Furthermore, in one example, before performing multi-position measurements on the soldered area between the busbar and jumper using a multi-probe group, the measurement errors of contact resistance caused by several influencing factors are calibrated: the measurement errors of contact resistance are calibrated for the following influencing factors, including material differences (differences in busbars, jumpers, and solder from different manufacturers and batches of the same specification), equipment measurement accuracy (display error and drift of the measuring instrument itself), probe pressure (the deviation of the probe's pressure relative to the conductive connection), and probe measurement position error (the deviation of the probe's landing point from the designed position, e.g., ±0.2mm). For each influencing factor, at least 20 samples are sampled and tested, the fluctuation range of the contact resistance measurement is recorded, and converted into the corresponding accuracy ratio. Table 1 shows the error calibration results of four influencing factors in one example:

[0040] As shown in Table 1, the relative fluctuation of contact resistance caused by the above four influencing factors is approximately ±3.52%. When setting the critical contact resistance increase for determining a poor solder joint, this total error level can be written as a safety margin into the threshold. That is, a margin of not less than 3.52% is reserved on the basis of the benchmark critical increase of 14.92% to ensure that the threshold determination result has sufficient robustness under mass production conditions.

[0041] Example 3 The difference between this embodiment and Embodiment 1 is that, in addition to judging the welding quality, the dynamic response data of contact resistance during the welding cooling period is also used to verify the judgment result.

[0042] In one example, during a preset cooling period after the conductive connection is welded, a multi-probe group is used to measure the conductive connection multiple times at preset time intervals to obtain dynamic response data of the contact resistance value changing over time. The welding quality is then verified based on the comparison between the dynamic response data and the preset change characteristics.

[0043] The preset cooling time period can range from 10s to 120s, for example, 10s, 20s, 30s, or 120s; the preset time interval can range from 0.1s to 5s, for example, 0.1s, 0.5s, or 5s. The dynamic response data's variation characteristics can include the decay rate of the contact resistance value, the time constant τ, and the steady-state value during the cooling period. In one example, the typical value of the time constant τ corresponding to a qualified weld falls within a preset range (e.g., 2s to 15s). When the measured time constant τ significantly deviates from this preset range (deviation greater than 30%), the judgment result of step S103 needs to be reviewed. This time-domain characteristic verification does not rely on the absolute value of the resistance at a single moment and has a good suppression effect on occasional interference during the measurement process.

[0044] Example 4 The difference between this embodiment and Embodiment 1 is that, after determining the welding quality, the welding process is further adjusted based on the determination result.

[0045] In one example, after determining the welding quality of the conductive connection based on the area of ​​the poor weld, the process further includes: generating welding process feedback data based on the welding quality determination result; adjusting the welding process parameters of the conductive connection in the photovoltaic module according to the welding process feedback data; wherein the welding process parameters include at least one of welding temperature, welding time, and welding pressure.

[0046] Welding process feedback data can include the quantitative value of the cold weld area corresponding to the non-conformity judgment, the distribution information of the cold weld area in the welding area, and the corresponding process adjustment suggestions. Welding process parameters can be adjusted using one or a combination of the following rules: when the proportion of cold weld area is greater than or equal to the critical area proportion and is concentrated in the initial segment of the welding area along the first direction, the welding temperature can be increased by 2°C to 10°C (e.g., 5°C) or the welding time can be extended by 0.1s to 1s (e.g., 0.3s) based on the original setting; when the proportion of cold weld area is greater than or equal to the critical area proportion and is relatively dispersed, the welding pressure can be increased by 0.1MPa to 0.5MPa (e.g., 0.2MPa) based on the original setting. Welding process feedback data can be transmitted to the upstream welding station through the production execution system, where the control unit of the upstream welding station automatically updates the welding process parameters, forming a closed-loop feedback between the welding process and the inspection process.

[0047] Example 5 Figure 4 This is a structural block diagram of a photovoltaic module testing device according to an embodiment of the present invention. See also... Figure 4 The detection device includes a resistance measurement module, an area determination module, and a quality judgment module.

[0048] The resistance measurement module is configured to perform multi-point measurements on the conductive connection parts of the photovoltaic module using a multi-probe group to obtain the contact resistance value at each measurement location. The resistance measurement module hardware may include a constant current source, a voltage acquisition circuit, an analog-to-digital converter circuit, and N sets of multi-probe groups (N is an integer greater than or equal to 2). The two ends of the constant current source are electrically connected to the current injection probes of each probe through current injection paths. The two ends of the voltage acquisition circuit are electrically connected to the voltage acquisition probes of each probe through voltage acquisition paths. The analog-to-digital converter circuit is electrically connected to the output of the voltage acquisition circuit and converts the analog voltage signal into a digital signal, which is then output to the area determination module.

[0049] The area determination module is configured to determine the area of ​​the poor solder joint in the conductive connection based on the contact resistance values ​​at each measurement location and a pre-built mapping relationship. The area determination module can be implemented in hardware using a processor and memory: the memory stores the mapping relationship between contact resistance values ​​and poor solder joint areas, represented in the form of a data table or function; the processor retrieves the mapping relationship from memory and converts the digital contact resistance signal output by the resistance measurement module to obtain the component of the poor solder joint area corresponding to each measurement location and the overall area of ​​the poor solder joint in the conductive connection.

[0050] The quality assessment module is configured to determine the welding quality of conductive connections based on the area of ​​the cold solder joint. The quality assessment module can share the same processor as the area determination module, comparing the cold solder joint area output by the area determination module with a preset critical area, and outputting a welding quality assessment result including a pass / fail conclusion.

[0051] The processor can be implemented using one or more of the following: a central processing unit, a microcontroller unit, a digital signal processor, a field-programmable gate array, or an application-specific integrated circuit. The memory can be implemented using one or more of the following: random access memory, read-only memory, flash memory, or solid-state memory.

[0052] Example 6 In this embodiment of the invention, the detection system includes the photovoltaic module detection device and positioning mechanism as described above.

[0053] The positioning mechanism is configured to fix the photovoltaic module to be tested at the testing position and electrically connect the multi-probe group of the resistance measurement module to the conductive connection part of the photovoltaic module. Structurally, the positioning mechanism may include a support platform, a clamp, and a lifting mechanism: the support platform supports the photovoltaic module and provides a positioning structure on the support surface that matches the contour of the photovoltaic module; the clamp limits the photovoltaic module on the support surface along a first direction and a second direction; the lifting mechanism drives the multi-probe group to move up and down relative to the support surface along a third direction that intersects both the first and second directions, so that the multi-probe group forms an electrical connection with the conductive connection part in the photovoltaic module after descending to the correct position, and rises to reset after the measurement is completed.

[0054] In one example, the detection system can also interact with the welding station, electroluminescence detection station, or electrical performance testing station on the photovoltaic module production line through the production execution system. The welding quality judgment results output by the detection system and the welding process feedback data are transmitted to the upstream welding station to guide the closed-loop adjustment of welding process parameters.

[0055] Example 7 This embodiment provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the photovoltaic module detection method described above.

[0056] Computer-readable storage media can be implemented using volatile or non-volatile memory, such as one or more combinations of random access memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, flash memory, disk storage, optical disk storage, or solid-state storage. In one example, the computer-readable storage medium is integrated into the memory of the aforementioned detection device and is invoked and executed by the processor of the detection device.

[0057] The photovoltaic module testing method, apparatus, system, and storage medium provided in the above embodiments can expand the evaluation criteria for welding quality from the observation of the surface morphology of conductive connection parts to the electrical characterization of the internal connection state of conductive connection parts. By using the pre-constructed mapping relationship between contact resistance value and cold solder area, the contact resistance measurement data can be converted into a quantifiable cold solder area index, and then the welding quality can be quantitatively judged. This reduces the risk of missing the detection of cold solder defects inside conductive connection parts, improves the precision and objectivity of welding quality judgment results, and is conducive to improving the power generation performance and reliability of photovoltaic modules in long-term operation.

[0058] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing the present invention, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the present invention.

Claims

1. A method for testing photovoltaic modules, characterized in that, include: A multi-probe array is used to measure the conductive connection parts of the photovoltaic module at multiple locations to obtain the contact resistance value at each measurement location. Based on the contact resistance values ​​at each measurement location and the pre-established mapping relationship, the area of ​​the poor solder joint at the conductive connection is determined. The welding quality of the conductive connection is determined based on the area of ​​the poor weld.

2. The method for testing photovoltaic modules according to claim 1, characterized in that, The method of using a multi-probe group to perform multi-location measurements on the conductive connection parts of the photovoltaic module to obtain the contact resistance value at each measurement location includes: A constant current is applied to the conductive connection through an independent current injection path, and the voltage drop on the conductive connection is acquired through a voltage acquisition path independent of the current injection path. The contact resistance value at each measurement location is determined based on the constant current and the voltage drop.

3. The method for testing photovoltaic modules according to claim 1, characterized in that, The multi-probe group includes multiple probes arranged at intervals along the conductive connection portion. The measurement positions of the multiple probes are located in different sub-regions of the conductive connection portion, and the combination of the measurement positions covers the welding area of ​​the conductive connection portion.

4. The method for testing photovoltaic modules according to claim 1, characterized in that, The pre-built mapping relationship is established in the following way: Obtain the contact resistance value of the conductive connection portion of each of the multiple calibration samples; Based on the poor solder joint area and the contact resistance value of each of the multiple calibration samples, a mapping relationship between the contact resistance value and the poor solder joint area is constructed.

5. The method for testing photovoltaic modules according to claim 1, characterized in that, The determination of the welding quality of the conductive connection based on the area of ​​the poor weld includes: Compare the area of ​​the poor weld with the preset critical area; If the area of ​​the poor weld is less than the preset critical area, the welding quality of the conductive connection is deemed to be qualified. If the area of ​​the poor weld is greater than or equal to the preset critical area, the welding quality of the conductive connection is determined to be unqualified.

6. The method for testing photovoltaic modules according to claim 1, characterized in that, Also includes: During a preset cooling period after the welding of the conductive connection part is completed, the conductive connection part is measured multiple times at preset time intervals using the multi-probe group to obtain dynamic response data of the contact resistance value changing over time. The welding quality judgment result is verified based on the comparison results between the change characteristics of the dynamic response data and the preset change characteristics.

7. The method for testing photovoltaic modules according to claim 1, characterized in that, After determining the welding quality of the conductive connection based on the area of ​​the poor weld, the method further includes: Welding process feedback data is generated based on the welding quality assessment results; The welding process parameters of the conductive connection parts in the photovoltaic module are adjusted according to the welding process feedback data; wherein, the welding process parameters include at least one of welding temperature, welding time and welding pressure.

8. The method for testing photovoltaic modules according to any one of claims 1 to 7, characterized in that, The conductive connection portion of the photovoltaic module includes the welding area between the busbar and the jumper wire in the photovoltaic module.

9. A testing device for photovoltaic modules, characterized in that, include: The resistance measurement module is configured to use a multi-probe group to perform multi-position measurements on the conductive connection parts of the photovoltaic module to obtain the contact resistance value at each measurement position. The area determination module is configured to determine the area of ​​the poor solder joint of the conductive connection part based on the contact resistance value at each measurement location and a pre-built mapping relationship. The quality assessment module is configured to determine the welding quality of the conductive connection based on the area of ​​the poor weld.

10. A testing system for photovoltaic modules, characterized in that, include: The testing device for photovoltaic modules as described in claim 9; The positioning mechanism is configured to fix the photovoltaic module to be tested at the testing position and to electrically connect the multi-probe group of the resistance measurement module to the conductive connection portion of the photovoltaic module.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the photovoltaic module detection method as described in any one of claims 1 to 8.

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