Testing method and testing device for photovoltaic module

Abstract

The invention discloses a test method and a test device for a photovoltaic module, and belongs to the field of photovoltaic technology. The method comprises the following steps: acquiring an electroluminescent image of the photovoltaic module; on the basis of the electroluminescence image, under the condition that it is determined that the photovoltaic string test is passed, the current string voltage of the photovoltaic string under the target irradiance is obtained; and based on the current string voltage, determining a test result of the bypass diode connected in parallel with the photovoltaic string. According to the method, the electroluminescence test is performed on the photovoltaic module, whether the photovoltaic string has defects or abnormities is detected, the current string voltage of the photovoltaic string is obtained and the bypass diode connected in parallel with the photovoltaic string is tested under the condition that the photovoltaic string test is passed, so that the missing detection risk of diode short circuit in the test process can be eliminated, and the detection accuracy is improved. And the photovoltaic module passing the test is safer and more reliable.

Description

Technical Field

[0001] The present application belongs to the field of photovoltaic technology, and in particular, relates to a testing method and a testing device for a photovoltaic module. Background Art

[0002] In order to avoid the loss of power generation efficiency and component safety risks caused by the hot spot effect of photovoltaic modules, bypass diodes are usually installed in the photovoltaic junction box of the photovoltaic module.

[0003] During the production process of photovoltaic modules, a series of tests are carried out to ensure the product quality of photovoltaic modules. The electroluminescent (EL) test is to apply voltage to both ends of the photovoltaic module to make the photovoltaic module glow under the action of the electric field, and use a camera to capture the module image to detect internal defects such as cracks and fragments on the photovoltaic module.

[0004] During the electroluminescence test, current flows through the photovoltaic module, and the module emits light under the action of the current. The camera captures the cell light image for judgment. Most photovoltaic modules have multiple strings. The test process usually requires multiple power-ons, and the images of each string are taken in turn for judgment. The static electricity release during power-on and the instantaneous high voltage caused by the instability of the test equipment may cause the bypass diodes connected in parallel to the photovoltaic module to break down and short-circuit. The current EL test method may miss the detection of diode short circuits, affecting the product quality of photovoltaic modules. Summary of the invention

[0005] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a photovoltaic module testing method and testing device, which can eliminate the risk of missed detection of diode short circuits during the testing process.

[0006] In a first aspect, the present application provides a method for testing a photovoltaic assembly, wherein the photovoltaic assembly includes at least one photovoltaic string, wherein the photovoltaic string is connected in parallel with a bypass diode, and the method includes:

[0007] Acquiring an electroluminescent image of the photovoltaic module;

[0008] When it is determined that the photovoltaic string has passed the test based on the electroluminescent image, obtaining a current string voltage of the photovoltaic string under a target irradiance;

[0009] Based on the current string voltage, a test result of the bypass diode connected in parallel with the photovoltaic string is determined.

[0010] According to the photovoltaic module testing method of the present application, by performing an electroluminescence test on the photovoltaic module to detect whether the photovoltaic string has defects or abnormalities, if the photovoltaic string test passes, the current string voltage of the photovoltaic string is obtained, and the bypass diode connected in parallel with the photovoltaic string is tested. This can eliminate the risk of missed detection of diode short circuits during the test, and photovoltaic modules that pass the test are safer and more reliable.

[0011] According to an embodiment of the present application, determining the test result of the bypass diode connected in parallel to the photovoltaic string based on the current string voltage includes:

[0012] Based on the current string voltage and a standard string voltage corresponding to the photovoltaic string under the target irradiance, a test result of the bypass diode connected in parallel with the photovoltaic string is determined.

[0013] According to an embodiment of the present application, determining the test result of the bypass diode connected in parallel to the photovoltaic string based on the current string voltage and the standard string voltage corresponding to the photovoltaic string under the target irradiance includes:

[0014] Based on the standard string voltage, determining a string voltage range, wherein a minimum value of the string voltage range is less than the standard string voltage, and a maximum value of the string voltage range is greater than the standard string voltage;

[0015] When the current string voltage is less than the minimum value of the string voltage range, it is determined that a short circuit fault occurs in the bypass diode connected in parallel to the photovoltaic string.

[0016] According to an embodiment of the present application, determining the test result of the bypass diode connected in parallel to the photovoltaic string based on the current string voltage and the standard string voltage corresponding to the photovoltaic string under the target irradiance includes:

[0017] Based on the standard string voltage, determining a string voltage range, wherein a minimum value of the string voltage range is less than the standard string voltage, and a maximum value of the string voltage range is greater than the standard string voltage;

[0018] When the current string voltage is within the string voltage range, it is determined that the bypass diode connected in parallel with the photovoltaic string has passed the test.

[0019] According to an embodiment of the present application, determining that the photovoltaic string test has passed based on the electroluminescent image includes:

[0020] When there is no string defect feature in the image area corresponding to the photovoltaic string in the electroluminescent image, it is determined that the photovoltaic string test has passed.

[0021] According to one embodiment of the present application, after acquiring the electroluminescent image of the photovoltaic component, the method further includes:

[0022] When there is a black string feature in the image area corresponding to the photovoltaic string in the electroluminescent image, it is determined that the bypass diode connected in parallel with the photovoltaic string has a short circuit fault.

[0023] According to one embodiment of the present application, acquiring the electroluminescent image of the photovoltaic component includes:

[0024] A voltage is applied to the photovoltaic component at least once to make the photovoltaic component emit light and obtain the electroluminescent image, and each application of the voltage corresponds to obtaining one electroluminescent image.

[0025] In a second aspect, the present application provides a photovoltaic module testing device, the device comprising:

[0026] A power supply device, the power supply device is electrically connected to the photovoltaic assembly, the power supply device is used to supply power to the photovoltaic assembly, the photovoltaic assembly includes at least one photovoltaic string, and the photovoltaic string is connected in parallel with a bypass diode;

[0027] A light source device, the light source device is used to provide light for the photovoltaic module;

[0028] An image acquisition device and a voltage acquisition device, wherein the image acquisition device is used to acquire an electroluminescent image of the photovoltaic module, and the voltage acquisition device is used to acquire a string voltage of the photovoltaic module;

[0029] A processing device, the processing device is electrically connected to the image acquisition device and the voltage acquisition device, and the processing device is used to test the photovoltaic string and the bypass diode connected in parallel with the photovoltaic string according to the photovoltaic component testing method described in the first aspect above.

[0030] According to the photovoltaic module testing device of the present application, by performing an electroluminescence test on the photovoltaic module, it is detected whether the photovoltaic string has defects or abnormalities. When the photovoltaic string test passes, the current string voltage of the photovoltaic string is obtained, and the bypass diode connected in parallel with the photovoltaic string is tested. This can eliminate the risk of missed detection of diode short circuits during the test, and photovoltaic modules that pass the test are safer and more reliable.

[0031] According to an embodiment of the present application, the power supply device is electrically connected to the light source device.

[0032] According to one embodiment of the present application, it also includes:

[0033] A temperature control device is electrically connected to the photovoltaic component and is used to control the temperature of the photovoltaic component.

[0034] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0036] Figure 1 This is one of the flow charts of the photovoltaic module testing method provided in the embodiment of the present application;

[0037] Figure 2 This is the second flow chart of the photovoltaic module testing method provided in the embodiment of the present application;

[0038] Figure 3 is a schematic diagram of the structure of a photovoltaic module testing device provided in an embodiment of the present application;

[0039] Figure 4 It is a schematic diagram of the structure of the photovoltaic assembly provided in the embodiment of the present application.

[0040] Reference numerals:

[0041] light source device 310, power supply device 320, first switch 331, second switch 332, temperature control device 340, image acquisition device 350, voltage acquisition device 360, processing device 370,

[0042] Photovoltaic module 400 , photovoltaic string 410 , bypass diode 420 . DETAILED DESCRIPTION

[0043] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0044] Reference below Figure 1-Figure 4 The test method of the photovoltaic module 400 and the test device of the photovoltaic module 400 according to the embodiment of the present application can eliminate the risk of missed detection of diode short circuit during the test process, and the photovoltaic module 400 that passes the test is safer and more reliable.

[0045] The photovoltaic assembly 400 of the embodiment of the present application may include at least one photovoltaic string 410 , and a bypass diode 420 is connected in parallel to the photovoltaic string 410 .

[0046] It is understandable that the photovoltaic assembly 400 may include a plurality of photovoltaic strings 410 , and the plurality of photovoltaic strings 410 may be connected in series or in parallel, and the photovoltaic string 410 may include a plurality of solar cells connected in series.

[0047] Each photovoltaic string 410 is connected in parallel with a bypass diode 420. When the photovoltaic string 410 connected in parallel with the bypass diode 420 cannot work normally due to obstruction, the bypass diode 420 will automatically turn on to bypass this part, so that the current generated by other photovoltaic strings 410 that work normally can bypass the fault point, thereby avoiding the occurrence of hot spot effect and protecting the photovoltaic module 400 from damage.

[0048] like Figure 1 As shown, the testing method of the photovoltaic assembly 400 according to the embodiment of the present application includes step 110 , step 120 and step 130 .

[0049] Step 110 : Acquire an electroluminescent image of the photovoltaic assembly 400 .

[0050] In this step, voltage may be applied to the photovoltaic module 400 , and current flows through the photovoltaic module 400 to generate light. An image of the light emitted by the photovoltaic module 400 is captured by an image acquisition device 350 such as a near-infrared camera to obtain an electroluminescent image of the photovoltaic module 400 .

[0051] In actual implementation, the photovoltaic component 400 includes one or more photovoltaic strings 410. Multiple electroluminescent images can be captured by applying multiple voltages to the photovoltaic component 400. Each electroluminescent image can include image information of light emitted by one or more photovoltaic strings 410.

[0052] In some embodiments, a voltage is applied to the photovoltaic assembly 400 at least once to make the photovoltaic assembly 400 emit light and obtain an electroluminescent image. Each application of the voltage corresponds to obtaining an electroluminescent image.

[0053] In this embodiment, voltage is applied to the photovoltaic module 400, and the photovoltaic module 400 will emit light and become brighter after the current passes through it. The electroluminescent image is collected by the image acquisition device 350, and the status of the photovoltaic string 410 and the bypass diode 420 is determined based on the electroluminescent image.

[0054] It can be understood that the photovoltaic component 400 may include multiple photovoltaic strings 410, and the electroluminescent image captured by the image acquisition device 350 has a limited range. Each time a voltage is applied, an electroluminescent image is obtained (which may only include part of the photovoltaic string 410). Multiple electroluminescent images are obtained by powering on multiple times. The bypass diode 420 is subsequently tested through the current string voltage. This is suitable for the existing EL test image acquisition method without the need to increase the cost of image acquisition.

[0055] For example, Figure 3 As shown, the image acquisition device 350 is composed of four camera lenses arranged vertically. One group of camera lenses can capture two photovoltaic strings 410 at a time, and the photovoltaic assembly 400 includes six photovoltaic strings 410 .

[0056] In this embodiment, voltage is applied to the photovoltaic component 400 three times, and one group of shooting lenses completes 6-string shooting operations three times; voltage is applied to the photovoltaic component 400 twice, and two groups of shooting lenses complete 6-string shooting operations twice; voltage is applied to the photovoltaic component 400 once, and three groups of shooting lenses complete 6-string shooting operations once.

[0057] It can be understood that in the obtained electroluminescent image, when the photovoltaic string 410 is free of defects, the conductivity is good, which is reflected in the high brightness and uniform brightness of the corresponding image area. When there are defects in the photovoltaic string 410, the electroluminescence phenomenon at the defective position is relatively weak, which is reflected in the appearance of black spots, black dots, uneven brightness distribution, etc. in the corresponding battery cell image area.

[0058] It should be noted that the electroluminescence test can be used to detect abnormal phenomena such as internal defects, hidden cracks, fragments, poor solder joints, and broken grids of the battery, that is, the electroluminescence image can be used to determine whether each photovoltaic string 410 has internal defects, hidden cracks, fragments, poor solder joints, broken grids, and other abnormal phenomena. Step 120: When it is determined that the photovoltaic string 410 has passed the test based on the electroluminescence image, the current string voltage of the photovoltaic string 410 under the target irradiance is obtained.

[0059] In this step, the electroluminescent image obtained can be used to determine whether the photovoltaic string 410 has defects. When the photovoltaic string 410 has no defects, that is, the photovoltaic string 410 passes the test, the power supply of the photovoltaic module 400 for the electroluminescent test is cut off, and the photovoltaic module 400 is irradiated with light of the target irradiance to obtain the current string voltage corresponding to the photovoltaic string 410 when the photovoltaic module 400 generates electricity.

[0060] It should be noted that when it is judged based on the electroluminescent image that the photovoltaic string 410 has internal defects, hidden cracks, fragments, poor solder joints, broken grids and other abnormal phenomena, the photovoltaic string 410 fails the test; when it is judged based on the electroluminescent image that the photovoltaic string 410 does not have internal defects, hidden cracks, fragments, poor solder joints, broken grids and other abnormal phenomena, the photovoltaic string 410 passes the test.

[0061] In this embodiment, when it is determined that a photovoltaic string 410 has passed the test based on the electroluminescent image, the photovoltaic component 400 is irradiated with light of the target irradiance to obtain the current string voltage corresponding to the photovoltaic string 410, that is, the potential difference across the photovoltaic string 410.

[0062] In actual implementation, the current string voltage of each photovoltaic string 410 can be collected by a voltage collection device 360 ​​such as an electric meter or an oscilloscope; the target irradiance can be a preset irradiance, for example, the target irradiance can be 1000 watts / square meter (W / m2) corresponding to the standard test conditions (Standard Test Conditions, STC). 2 ).

[0063] Step 130 : Determine the test result of the bypass diode 420 connected in parallel to the photovoltaic string 410 based on the current string voltage.

[0064] It should be noted that, under the premise that the photovoltaic string 410 passes the test, light is provided to the photovoltaic string 410, and the current generated by the photovoltaic string 410 flows from the negative pole to the positive pole. When the bypass diode 420 is normal and has no faults, the bypass diode 420 plays a reverse cutoff role, and the current cannot pass through the bypass diode 420; when the bypass diode 420 has a short circuit fault, the reverse cutoff performance of the bypass diode 420 is affected, and the current can pass through the bypass diode 420.

[0065] It is understandable that when the photovoltaic string 410 generates electricity, the potential difference across the photovoltaic string 410 is different when there is current passing through the bypass diode 420 and when there is no current passing through the bypass diode 420. When there is current passing through the bypass diode 420, the potential difference across the photovoltaic string 410 is reduced. It is possible to determine whether the bypass diode 420 connected in parallel to the photovoltaic string 410 is short-circuited based on the current string voltage corresponding to the photovoltaic string 410.

[0066] In actual implementation, the current string voltage corresponding to a certain photovoltaic string 410 can be compared with the standard value to determine whether the bypass diode 420 connected in parallel to the photovoltaic string 410 is short-circuited. When the current string voltage corresponding to the photovoltaic string 410 is less than the standard value, or the difference between the current string voltage and the standard value exceeds a certain range, it can be determined that the bypass diode 420 connected in parallel to the photovoltaic string 410 is short-circuited.

[0067] In this embodiment, the current string voltages corresponding to the various photovoltaic strings 410 in the photovoltaic assembly 400 can also be compared. For photovoltaic strings 410 of the same specification, when the current string voltage corresponding to a certain photovoltaic string 410 is significantly smaller than the current string voltages corresponding to the remaining photovoltaic strings 410, it can be determined that the bypass diode 420 connected in parallel to the photovoltaic string 410 is short-circuited.

[0068] In the related technology, the mainstream components are mostly designed with 6 strings of batteries. The EL test usually consists of taking three photos, each time taking 2 strings of batteries. The test power supply needs to power on the component three times. When the second or third power-on photo is taken, if the diode corresponding to the battery string photographed in the previous test is short-circuited, it will not affect the image of the current string of batteries, and the diode short-circuit may be missed.

[0069] In the embodiment of the present application, an electroluminescence test is first performed on the photovoltaic module 400, and whether each photovoltaic string 410 has passed the test is determined based on the electroluminescence image. When the photovoltaic string 410 has passed the test, the current string voltage corresponding to the photovoltaic string 410 under the lighting conditions is obtained, and based on the current string voltage, it is determined whether the bypass diode 420 has a breakdown short circuit during the electroluminescence test. This can eliminate the risk of missed detection of diode short circuits during the test, and the photovoltaic module 400 that has passed the test is safer and more reliable.

[0070] For example, Figure 3 As shown, the photovoltaic assembly 400 to be tested is connected to the test device, and the photovoltaic assembly 400 includes three photovoltaic strings 410 connected in series, and each photovoltaic string 410 is connected in parallel with a bypass diode 420 .

[0071] The first switch 331 is closed, the second switch 332 is opened, and voltage is applied to the photovoltaic module 400. The image acquisition device 350 starts to collect electroluminescent images. The power is turned on three times. The image acquisition device 350 collects three electroluminescent images from left to right. The brightness of the electroluminescent images taken three times is uniform, without obvious black spots or black spots, indicating that the three photovoltaic strings 410 are normal.

[0072] The first switch 331 is disconnected, and the second switch 332 is closed. The power supply device 320 supplies power to the light source device 310. The light source device 310 provides a lighting environment with a target irradiance for the photovoltaic module 400. The current string voltages corresponding to the six photovoltaic strings 410 are collected by the voltage collection device 360. According to the current string voltages, it is determined that the bypass diodes 420 connected in parallel to the two photovoltaic strings 410 on the far left are normal, and the bypass diodes 420 connected in parallel to the four photovoltaic strings 410 in the middle and on the far right are short-circuited.

[0073] In this embodiment, after the electroluminescence test, the bypass diode 420 connected in parallel to the photovoltaic string 410 is detected by collecting the current string voltage of the photovoltaic string 410, so as to accurately detect the breakdown short circuit of the bypass diode 420 connected in parallel to the photovoltaic assembly 400, thereby eliminating the risk of missed detection of diode short circuit during the electroluminescence test.

[0074] According to the testing method of the photovoltaic module 400 provided in the embodiment of the present application, by performing an electroluminescence test on the photovoltaic module 400, it is detected whether the photovoltaic string 410 has defects or abnormalities. When the photovoltaic string 410 passes the test, the current string voltage of the photovoltaic string 410 is obtained, and the bypass diode 420 connected in parallel with the photovoltaic string 410 is tested. This can eliminate the risk of missed detection of diode short circuits during the test, and the photovoltaic module 400 that passes the test is safer and more reliable.

[0075] In some embodiments, step 130, determining the test result of the bypass diode 420 connected in parallel to the photovoltaic string 410 based on the current string voltage, may include:

[0076] Based on the current string voltage and the standard string voltage corresponding to the photovoltaic string 410 under the target irradiance, the test result of the bypass diode 420 connected in parallel with the photovoltaic string 410 is determined.

[0077] It should be noted that the standard string voltage refers to the standard potential difference across the string when a standard string of the same specification as the photovoltaic string 410 generates electricity under the target irradiance. Photovoltaic strings 410 of different specifications correspond to different standard string voltages.

[0078] In actual implementation, the bypass diode 420 may not be connected in parallel to the standard string to ensure that the current flows only through the string. The standard potential difference between the two ends of the string when the standard string generates electricity under the target irradiance is collected as the standard string voltage.

[0079] In this embodiment, the current string voltage is compared with the standard string voltage corresponding to the photovoltaic string 410 under the target irradiance, and whether the bypass diode 420 connected in parallel to the photovoltaic string 410 is short-circuited is determined based on the comparison result.

[0080] It is understandable that when the photovoltaic string 410 generates electricity and current passes through the bypass diode 420, the potential difference across the photovoltaic string 410 is reduced. When the current string voltage is less than the standard string voltage, current may pass through the bypass diode 420, and it can be determined that the bypass diode 420 is short-circuited.

[0081] In actual implementation, when the current string voltage of a certain photovoltaic string 410 is equal to 0, it indicates that there is no potential difference between the two ends of the photovoltaic string 410, no current flows through the photovoltaic string 410, and the bypass diode 420 is short-circuited.

[0082] A specific embodiment is described below.

[0083] like Figure 4 As shown, the photovoltaic assembly 400 includes three photovoltaic strings 410 of the same specification connected in series, with a power of 1000W / m 2 Under standard test conditions of 25°C, the standard component opening voltage of the photovoltaic component 400 is 45V, the current flows from the negative pole (-) to the positive pole (+), and the potential distribution from the negative pole to the positive pole is 0V, 15V, 30V, and 45V respectively. The standard string voltage corresponding to each photovoltaic string 410 is 15V.

[0084] In this embodiment, at 1000 W / m 2 Under the standard test conditions of 25℃, when the potential from the negative electrode to the positive electrode is 0V, 15V, 15V, and 30V respectively, the open circuit voltage of the photovoltaic module 400 will drop significantly. According to the current string voltage of the middle photovoltaic string 410 being 0V, it is judged that Figure 4 The bypass diode 420 at the middle position breaks down and short-circuits.

[0085] In some embodiments, based on the current string voltage and the standard string voltage corresponding to the photovoltaic string 410 under the target irradiance, determining the test result of the bypass diode 420 connected in parallel with the photovoltaic string 410 may include:

[0086] Based on the standard string voltage, a string voltage range is determined, wherein the minimum value of the string voltage range is less than the standard string voltage, and the maximum value of the string voltage range is greater than the standard string voltage;

[0087] When the current string voltage is less than the minimum value of the string voltage range, it is determined that the bypass diode 420 connected in parallel to the photovoltaic string 410 has a short circuit fault.

[0088] In other embodiments, determining the test result of the bypass diode 420 connected in parallel to the photovoltaic string 410 based on the current string voltage and the standard string voltage corresponding to the photovoltaic string 410 under the target irradiance may include:

[0089] Based on the standard string voltage, a string voltage range is determined, wherein the minimum value of the string voltage range is less than the standard string voltage, and the maximum value of the string voltage range is greater than the standard string voltage;

[0090] When the current string voltage is within the string voltage range, it is determined that the bypass diode 420 connected in parallel to the photovoltaic string 410 has passed the test.

[0091] In this embodiment, a string voltage range is set according to the standard string voltage to determine whether the current string voltage is within the string voltage range. When the current string voltage is less than the minimum value of the string voltage range, it indicates that current may pass through the bypass diode 420 and a short circuit fault occurs in the parallel bypass diode 420. When the current string voltage is within the string voltage range, it indicates that the parallel bypass diode 420 has no short circuit fault and the test passes.

[0092] It should be noted that the string voltage range may be a range that characterizes voltage fluctuations during normal power generation of the photovoltaic string 410. By setting the string voltage range, false detection of diode short circuits caused by voltage fluctuations during normal power generation of the photovoltaic string 410 can be avoided, and it can be accurately determined whether the bypass diode 420 is short-circuited during the electroluminescence test.

[0093] In actual implementation, the allowable voltage error value can be set based on the standard string voltage to obtain the corresponding string voltage range, or the allowable voltage error ratio can be set based on the standard string voltage to obtain the corresponding string voltage range.

[0094] For example, the standard string voltage is Vs, and the allowable voltage error value V1 is set, and the corresponding string voltage range is (Vs-V1, Vs+V1). The minimum value of the string voltage range is Vs-V1, and the maximum value of the string voltage range is Vs+V1.

[0095] For another example, the standard string voltage is Vs, and the allowable voltage error ratio is set to 0.9-1.1, and the corresponding string voltage range is (0.9Vs, 1.1Vs). The minimum value of the string voltage range is 0.9Vs, and the maximum value of the string voltage range is 1.1Vs.

[0096] In this embodiment, based on the standard string voltage, a 10% voltage fluctuation is allowed, and the string voltage range is (Vs-0.1Vs, Vs+0.1Vs). This can effectively avoid false detection of diode short circuits caused by voltage fluctuations in normal power generation, and at the same time accurately detect whether the bypass diode 420 is short-circuited by breakdown.

[0097] In some embodiments, determining that the photovoltaic string 410 has passed the test based on the electroluminescent image may include:

[0098] When there is no string defect feature in the image region corresponding to the photovoltaic string 410 in the electroluminescent image, it is determined that the photovoltaic string 410 has passed the test.

[0099] Among them, string defect features refer to features such as black spots, black dots, and uneven brightness distribution in the image.

[0100] In this embodiment, when the image area corresponding to the photovoltaic string 410 in the electroluminescent image does not have string defect characteristics such as black spots, black dots, and uneven brightness distribution, it can be determined that the photovoltaic string 410 has passed the test, and the bypass diode 420 is subsequently tested according to the current string voltage under the target irradiance.

[0101] It is understandable that when string defect features appear in the image area corresponding to the photovoltaic string 410 in the electroluminescent image, it can be determined that the photovoltaic string 410 has internal defects, hidden cracks, fragments, poor solder joints, broken grids and other abnormal phenomena, and the photovoltaic string 410 fails the test.

[0102] In some embodiments, after acquiring the electroluminescent image of the photovoltaic assembly 400 , the testing method of the photovoltaic assembly 400 may further include:

[0103] When the image region corresponding to the photovoltaic string 410 in the electroluminescent image has a black string feature, it is determined that the bypass diode 420 connected in parallel with the photovoltaic string 410 has a short circuit fault.

[0104] The black string feature refers to the feature that the photovoltaic string 410 in the image is not emitting light.

[0105] It is understandable that when the photovoltaic string 410 is not emitting light, it indicates that no current flows through the photovoltaic string 410 . At this time, the current can flow through the bypass diode 420 , indicating that the bypass diode 420 connected in parallel with the photovoltaic string 410 has a short circuit fault.

[0106] A specific embodiment is described below.

[0107] like Figure 4 As shown, the photovoltaic assembly 400 includes three photovoltaic strings 410 connected in series. The photovoltaic strings 410 of the photovoltaic assembly 400 are strings of the same specification and have the same standard string voltage. The standard string voltage is first obtained through the standard specification assembly.

[0108] like Figure 2 As shown, connect the standard specification components to Figure 3 In the test device shown in the figure, the temperature control device 340 controls the temperature T0 of the standard specification component to 25°C, and the light source device 310 provides the standard specification component with a light source irradiance E0=1000W / m 2 , the first switch 331 is opened and the second switch 332 is closed for 30s-120s, the output voltage of the standard specification component is recorded as V0=45V, and the standard string voltage of the standard specification string is 15V.

[0109] Connect the photovoltaic module 400 to the Figure 3In the test device shown in the figure, the temperature control device 340 controls the temperature T0 = 25°C, and the light source device 310 provides the light source irradiance E0 = 1000W / m 2 , close the first switch 331 and open the second switch 332, apply voltage to the photovoltaic component 400, and the image acquisition device 350 starts to collect electroluminescent images, completes the image acquisition work of all photovoltaic strings 410 in 3 times, and uploads the electroluminescent images to the processing device 370.

[0110] When the processing device 370 determines that light and dark patches, black dots or black spots appear in the electroluminescent image, it indicates that there is an abnormality in the photovoltaic string 410. When the processing device 370 determines that a black string appears in the electroluminescent image, it indicates that the bypass diode 420 connected in parallel with the photovoltaic string 410 is abnormal. In both cases, the image is judged to be NG (failed the test) and the test can be terminated.

[0111] When the processing device 370 determines that the electroluminescent image has uniform brightness, has no obvious light or dark areas, and has no obvious black dots, black spots, black strings, etc., it determines that the image is OK (passed the test).

[0112] The temperature control device 340 controls the temperature T0 = 25°C, and the light source device 310 provides the light source irradiance E0 = 1000 W / m 2 , open the first switch 331 , 1s-3s later, close the second switch 332 for 30s-120s, the photovoltaic component 400 generates electricity, and the output voltage V1 of the photovoltaic component 400 is recorded and uploaded to the processing device 370 .

[0113] The processing device 370 compares the sizes of V0 and V1. For example, V1=33V, the standard string voltage is V0=45V, the minimum value of the string voltage range is 0.9V0=40.5V, 33V<40.5V, the current string voltage is less than the minimum value of the string voltage range, the test ends, the test is NG, and the bypass diode 420 is short-circuited.

[0114] For example, V1=44.5V, the standard string voltage is V0=45V, the minimum value of the string voltage range is 0.9V0=40.5V, the maximum value of the string voltage range is 1.1V0=49.5V, 40.5V<44.5V<49.5V, the current string voltage is within the string voltage range, the test is completed, the test is OK, and the bypass diode 420 is normal.

[0115] The embodiment of the present application also provides a testing device for a photovoltaic assembly 400 .

[0116] like Figure 3 As shown, the testing device of the photovoltaic assembly 400 includes: a power supply device 320 , a light source device 310 , an image acquisition device 350 , a voltage acquisition device 360 ​​and a processing device 370 .

[0117] The power supply device 320 is electrically connected to the photovoltaic assembly 400 . The power supply device 320 is used to supply power to the photovoltaic assembly 400 . The photovoltaic assembly 400 includes at least one photovoltaic string 410 . A bypass diode 420 is connected in parallel to the photovoltaic string 410 .

[0118] The power supply device 320 may be a voltage-stabilized constant-current power supply, which provides a cross-current power supply for the photovoltaic component 400 to be tested, and the current passes through the photovoltaic string 410 to make it emit light.

[0119] The light source device 310 is used to provide illumination for the photovoltaic module 400. The light source device 310 is a stable light source that can provide the specified irradiance intensity required for the test. For example, the light source device 310 can provide the photovoltaic module 400 with a target irradiance of 1000 W / m 2 irradiation environment.

[0120] The testing device includes two data acquisition modules, an image acquisition device 350 and a voltage acquisition device 360 ​​. The image acquisition device 350 is used to acquire the electroluminescent image of the photovoltaic module 400 , and the voltage acquisition device 360 ​​is used to acquire the string voltage of the photovoltaic module 400 .

[0121] In actual implementation, when current passes through the photovoltaic module 400, it becomes brighter due to electroluminescence, and the electroluminescence image is collected by the image acquisition device 350; when the light source device 310 provides light for the photovoltaic module 400, the photovoltaic module 400 generates electricity, and the current string voltage of the photovoltaic string 410 in the photovoltaic module 400 is collected by the voltage acquisition device 360.

[0122] The processing device 370 is electrically connected to the image acquisition device 350 and the voltage acquisition device 360 ​​, and is used to test the photovoltaic string 410 and the bypass diode 420 connected in parallel with the photovoltaic string 410 according to the above-mentioned testing method of the photovoltaic assembly 400 .

[0123] In this embodiment, the processing device 370 determines whether each photovoltaic string 410 has passed the test based on the electroluminescent image. When the photovoltaic string 410 has passed the test, the current string voltage corresponding to the photovoltaic string 410 under the lighting conditions is obtained. The processing device 370 determines whether the bypass diode 420 has a breakdown short circuit during the electroluminescent test based on the current string voltage. The risk of missing the diode short circuit during the test can be eliminated, and the photovoltaic module 400 that has passed the test is safer and more reliable.

[0124] According to the testing device of the photovoltaic module 400 provided in the embodiment of the present application, by performing an electroluminescence test on the photovoltaic module 400, it is detected whether the photovoltaic string 410 has defects or abnormalities. When the photovoltaic string 410 passes the test, the current string voltage of the photovoltaic string 410 is obtained, and the bypass diode 420 connected in parallel with the photovoltaic string 410 is tested. This can eliminate the risk of missed detection of diode short circuits during the test, and the photovoltaic module 400 that passes the test is safer and more reliable.

[0125] In some embodiments, the power supply device 320 is electrically connected to the light source device 310 .

[0126] In this embodiment, the power supply device 320 can not only provide the power required for the electroluminescence test of the photovoltaic assembly 400 to be tested, but also provide power for the light source device 310 to emit light, which can effectively save the cost of the test device.

[0127] like Figure 3 As shown, the circuit connecting the power supply device 320 and the light source device 310 can be provided with a second switch 332 , and the circuit connecting the power supply device 320 and the photovoltaic assembly 400 to be tested can be provided with a first switch 331 .

[0128] When the first switch 331 is closed and the second switch 332 is opened, the power supply device 320 supplies power to the photovoltaic component 400 to perform an electroluminescence test; when the second switch 332 is closed and the first switch 331 is opened, the power supply device 320 supplies power to the light source device 310, and the light source device 310 provides a lighting environment for the photovoltaic component 400.

[0129] In some embodiments, the testing device may further include a temperature control device 340 , which is electrically connected to the photovoltaic assembly 400 , and is used to control the temperature of the photovoltaic assembly 400 .

[0130] It is understandable that the voltage generated by the same photovoltaic module 400 at different temperatures is different. The test device is provided with a temperature control device 340 to provide a temperature environment for the photovoltaic module 400, control the temperature of the environment in which the photovoltaic module 400 is located, and compare the current string voltage obtained with the corresponding standard string voltage at the same temperature. The test result of the bypass diode 420 is more accurate.

[0131] In actual implementation, the temperature control device 340 can be a thermostat, which can include components such as a temperature sensing element, a comparison element, an actuator and a regulating circuit. It can automatically adjust the temperature of the photovoltaic component 400 according to the temperature changes of the working environment to keep it within the set temperature range.

[0132] A specific embodiment is described below.

[0133] like Figure 3 As shown, the testing device includes: a power supply device 320, a light source device 310, an image acquisition device 350, a voltage acquisition device 360, a temperature control device 340 and a processing device 370. A second switch 332 is set for the circuit connecting the power supply device 320 and the light source device 310, and a first switch 331 is set for the circuit connecting the power supply device 320 and the photovoltaic component 400 to be tested.

[0134] like Figure 4 As shown, the photovoltaic assembly 400 to be tested includes three photovoltaic strings 410 connected in series. The photovoltaic strings 410 of the photovoltaic assembly 400 are of the same specification and have the same standard string voltage. The standard string voltage is first obtained through the standard specification assembly.

[0135] The standard specification component is connected to the test device, the temperature control device 340 controls the temperature of the standard specification component to T0 = 25°C, and the light source device 310 provides the standard specification component with a light source irradiance of E0 = 1000W / m 2 , the first switch 331 is opened and the second switch 332 is closed for 30s-120s, the output voltage of the standard specification component is recorded as V0=45V, and the standard string voltage of the standard specification string is 15V.

[0136] The photovoltaic module 400 to be tested is connected to the test device, the temperature control device 340 controls the temperature T0 = 25°C, and the light source device 310 provides the light source irradiance E0 = 1000W / m 2 , close the first switch 331 and open the second switch 332, apply voltage to the photovoltaic component 400, and the image acquisition device 350 starts to collect electroluminescent images, completes the image acquisition work of all photovoltaic strings 410 in 3 times, and uploads the electroluminescent images to the processing device 370.

[0137] When the processing device 370 determines that light and dark patches, black dots or black spots appear in the electroluminescent image, it indicates that there is an abnormality in the photovoltaic string 410. When the processing device 370 determines that a black string appears in the electroluminescent image, it indicates that the bypass diode 420 connected in parallel with the photovoltaic string 410 is abnormal. In both cases, the image is judged to be NG (failed the test) and the test can be terminated.

[0138] When the processing device 370 determines that the electroluminescent image has uniform brightness, has no obvious light or dark areas, and has no obvious black dots, black spots, black strings, etc., it determines that the image is OK (passed the test).

[0139] The temperature control device 340 controls the temperature T0 = 25°C, and the light source device 310 provides the light source irradiance E0 = 1000 W / m 2, open the first switch 331 , 1s-3s later, close the second switch 332 for 30s-120s, the photovoltaic component 400 generates electricity, and the output voltage V1 of the photovoltaic component 400 is recorded and uploaded to the processing device 370 .

[0140] The processing device 370 compares the sizes of V0 and V1. For example, V1=33V, the standard string voltage is V0=45V, the minimum value of the string voltage range is 0.9V0=40.5V, 33V<40.5V, the current string voltage is less than the minimum value of the string voltage range, the test ends, the test is NG, and the bypass diode 420 is short-circuited.

[0141] For example, V1=44.5V, the standard string voltage is V0=45V, the minimum value of the string voltage range is 0.9V0=40.5V, the maximum value of the string voltage range is 1.1V0=49.5V, 40.5V<44.5V<49.5V, the current string voltage is within the string voltage range, the test is completed, the test is OK, and the bypass diode 420 is normal.

[0142] In this embodiment, the testing device performs an electroluminescence test on the photovoltaic module 400 to detect whether the photovoltaic string 410 has defects or abnormalities. When the photovoltaic string 410 passes the test, the current string voltage of the photovoltaic string 410 is obtained, and the bypass diode 420 connected in parallel with the photovoltaic string 410 is tested. This can eliminate the risk of missing detection of diode short circuits during the test, and the photovoltaic module 400 that passes the test is safer and more reliable.

[0143] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0144] In the description of this application, "first feature" or "second feature" may include one or more of the features.

[0145] In the description of the present application, “plurality” means two or more.

[0146] In the description of the present application, a first feature being “on” or “under” a second feature may include that the first and second features are directly in contact with each other, or may include that the first and second features are not in direct contact with each other but are in contact with each other via another feature therebetween.

[0147] In the description of the present application, “above”, “over” and “above” a first feature to a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature.

[0148] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0149] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for testing a photovoltaic module, characterized in that: The photovoltaic assembly includes at least one photovoltaic string, the photovoltaic string is connected in parallel with a bypass diode, and the method includes: Acquiring an electroluminescent image of the photovoltaic module; When it is determined that the photovoltaic string has passed the test based on the electroluminescent image, obtaining a current string voltage of the photovoltaic string under a target irradiance; Based on the current string voltage, a test result of the bypass diode connected in parallel with the photovoltaic string is determined.

2. The photovoltaic module testing method according to claim 1, characterized in that: The step of determining a test result of the bypass diode connected in parallel to the photovoltaic string based on the current string voltage includes: Based on the current string voltage and a standard string voltage corresponding to the photovoltaic string under the target irradiance, a test result of the bypass diode connected in parallel with the photovoltaic string is determined.

3. The photovoltaic module testing method according to claim 2, characterized in that: The determining, based on the current string voltage and the standard string voltage corresponding to the photovoltaic string under the target irradiance, a test result of the bypass diode connected in parallel to the photovoltaic string comprises: Based on the standard string voltage, determining a string voltage range, wherein a minimum value of the string voltage range is less than the standard string voltage, and a maximum value of the string voltage range is greater than the standard string voltage; When the current string voltage is less than the minimum value of the string voltage range, it is determined that a short circuit fault occurs in the bypass diode connected in parallel to the photovoltaic string.

4. The photovoltaic module testing method according to claim 2, characterized in that: The determining, based on the current string voltage and the standard string voltage corresponding to the photovoltaic string under the target irradiance, a test result of the bypass diode connected in parallel to the photovoltaic string comprises: Based on the standard string voltage, determining a string voltage range, wherein a minimum value of the string voltage range is less than the standard string voltage, and a maximum value of the string voltage range is greater than the standard string voltage; When the current string voltage is within the string voltage range, it is determined that the bypass diode connected in parallel with the photovoltaic string has passed the test.

5. The photovoltaic module testing method according to any one of claims 1 to 4, characterized in that: The step of determining, based on the electroluminescent image, that the photovoltaic string test has passed includes: When there is no string defect feature in the image area corresponding to the photovoltaic string in the electroluminescent image, it is determined that the photovoltaic string test has passed.

6. The photovoltaic module testing method according to any one of claims 1 to 4, characterized in that: After acquiring the electroluminescent image of the photovoltaic component, the method further includes: When there is a black string feature in the image area corresponding to the photovoltaic string in the electroluminescent image, it is determined that the bypass diode connected in parallel with the photovoltaic string has a short circuit fault.

7. The photovoltaic module testing method according to any one of claims 1 to 4, characterized in that: The step of acquiring the electroluminescent image of the photovoltaic module comprises: A voltage is applied to the photovoltaic component at least once to make the photovoltaic component emit light and obtain the electroluminescent image, and each application of the voltage corresponds to obtaining one electroluminescent image.

8. A photovoltaic module testing device, characterized in that: include: A power supply device, the power supply device is electrically connected to the photovoltaic assembly, the power supply device is used to supply power to the photovoltaic assembly, the photovoltaic assembly includes at least one photovoltaic string, and the photovoltaic string is connected in parallel with a bypass diode; A light source device, the light source device is used to provide light for the photovoltaic module; An image acquisition device and a voltage acquisition device, wherein the image acquisition device is used to acquire an electroluminescent image of the photovoltaic module, and the voltage acquisition device is used to acquire a string voltage of the photovoltaic module; A processing device, the processing device is electrically connected to the image acquisition device and the voltage acquisition device, and the processing device is used to test the photovoltaic string and the bypass diode connected in parallel with the photovoltaic string according to the photovoltaic module testing method according to any one of claims 1 to 7.

9. The photovoltaic module testing device according to claim 8, characterized in that: The power supply device is electrically connected to the light source device.

10. The photovoltaic module testing device according to claim 8 or 9, characterized in that: Also includes: A temperature control device is electrically connected to the photovoltaic component and is used to control the temperature of the photovoltaic component.

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