Photovoltaic cell panel invisible defect detection device based on polarization imaging

Abstract

The invention relates to a photovoltaic cell panel invisible defect detection device based on polarized light imaging. The photovoltaic cell panel invisible defect detection device comprises a light source assembly and a detection assembly, wherein the light source assembly induces a photovoltaic cell panel to emit polarized light in a first direction; and the receiving assembly receives the polarized light in the first direction and performs imaging on the photovoltaic cell panel so as to detect the defects of the photovoltaic cell panel. According to the method, the invisible defects of the photovoltaic cell panel can be effectively detected in the sunlight environment, and the problem that the imaging quality of a traditional detection method is poor in the sunlight environment is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic panel detection, and particularly to a device for detecting invisible defects of photovoltaic panels based on polarization imaging Background Art

[0002] At present, as an important part of renewable energy, photovoltaic panels play an increasingly important role in the energy field. However, during the production, transportation, and installation of photovoltaic panels, invisible defects may occur due to various reasons, such as microcracks, internal bubbles, stains, etc. These invisible defects not only affect the appearance of photovoltaic panels, but more importantly, they will reduce their photoelectric conversion efficiency, shorten the service life, and even pose potential safety hazards. Traditional detection methods, such as visual inspection and infrared thermal imaging, can detect some defects to a certain extent, but for some small or deep invisible defects, the detection effect is not ideal

[0003] In the prior art, the patent document with the application number CN202410245995.1 provides a photovoltaic panel photoluminescence imaging system and method based on a linear array InGaAs camera, including a linear array InGaAs camera, a dual filter structure, a programmable power supply, a linear array light source, an adjustable-speed conveyor belt, a test host computer, and a photovoltaic panel to be tested. The host computer is used to control the programmable power supply to drive the linear array light source to excite the photovoltaic panel to be tested to generate a photoluminescence phenomenon. The optical signal generated by the photovoltaic panel to be tested enters the linear array InGaAs camera through the dual filter structure, and the photoluminescence signal is captured by the linear array InGaAs camera, and after signal noise reduction processing, it is transmitted to the host computer for display, so as to perform defect detection

[0004] However, for photovoltaic panels made of silicon crystal materials, the spectral energy of photoluminescence mainly concentrates in the short-wave infrared range with wavelengths from 1050nm to 1250nm; since the sunlight radiated to the ground during the day has a high spectral irradiance in the short-wave infrared range, therefore, in a daylight environment, the quality of photoluminescence fluorescence imaging will be interfered by sunlight, resulting in an inability to obtain clear defect images Summary of the Invention

[0005] In order to solve the above problems, the present invention proposes a device for detecting invisible defects of photovoltaic panels based on polarization imaging, aiming to provide a method for effectively detecting invisible defects of photovoltaic panels in a daylight environment. The detection device of the present invention uses polarization imaging technology to reduce the interference of sunlight on photoluminescence imaging, improve the imaging quality, and thus achieve precise detection of invisible defects of photovoltaic panels

[0006] The specific technical solution of the present application is as follows: A device for detecting invisible defects of photovoltaic panels based on polarized light imaging, including:

[0007] Light source assembly: The light source assembly induces the photovoltaic panel to emit polarized light in a first direction.

[0008] Receiving assembly: The receiving assembly receives the polarized light in the first direction, images the photovoltaic panel, and detects defects of the photovoltaic panel.

[0009] Further, the light source assembly includes: an LED light source, a linear polarizer, and a beam expander lens. The linear polarizer is disposed between the LED light source and the beam expander lens. The LED light source emits light, which forms polarized light in the first direction after passing through the linear polarizer. The beam expander lens uniformly irradiates the polarized light in the first direction on the photovoltaic panel.

[0010] Further, the light source assembly includes a linearly polarized laser and a beam expander lens. The linearly polarized laser generates polarized light in the first direction, and the beam expander lens uniformly irradiates and disperses the polarized light in the first direction on the photovoltaic panel.

[0011] Further, the receiving assembly includes: an analyzer and an image processing unit. The analyzer can only receive the polarized light in the first direction. The image processing unit is connected to the analyzer and is used to process the polarized light signal received by the analyzer to generate an image of the photovoltaic panel.

[0012] Further, the image processing unit includes a near-infrared or short-wave infrared camera and a microcomputer. The near-infrared or short-wave infrared camera is connected to the microcomputer. The near-infrared or short-wave infrared camera receives the polarized light in the first direction filtered by the analyzer, converts it into an electrical signal, and transmits it to the microcomputer. The microcomputer performs image reconstruction and processing on the received electrical signal, and identifies and marks invisible defects on the photovoltaic panel through a specific algorithm.

[0013] Further, the near-infrared or short-wave infrared camera is an InGaAs camera.

[0014] Further, the device further includes a calibration assembly, and the calibration assembly includes

[0015] a calibration light source and a standard photovoltaic panel. The calibration light source emits polarized light with a known direction and wavelength, and the standard photovoltaic panel has a known defect-free state.

[0016] Further, the device further includes a moving platform. The moving platform is used to carry the photovoltaic panel and move it relative to the light source assembly and the receiving assembly. The moving platform includes a stepper motor and a guide rail. The guide rail is connected to the bracket of the photovoltaic panel, and the stepper motor drives the guide rail to move.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] The photovoltaic panel invisible defect detection device based on polarized light imaging of the present application can effectively detect the invisible defects of photovoltaic panels in daylight environment, overcoming the problem of poor imaging quality of traditional detection methods in daylight environment. By using polarized imaging technology, the present invention significantly improves the imaging quality and makes the detection more accurate. In addition, the detection device of the present invention has a relatively simple structure and convenient operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 : Schematic diagram of the principle of the photovoltaic panel invisible defect detection device based on polarized imaging of the present application;

[0020] Figure 2 : Schematic diagram of the principle of an embodiment of the photovoltaic panel invisible defect detection device based on polarized imaging of the present application;

[0021] Figure 3 : Schematic diagram of the principle of another embodiment of the photovoltaic panel invisible defect detection device based on polarized imaging of the present application;

[0022] Figure 4 : Schematic diagram of the principle of an embodiment of the light source assembly of the photovoltaic panel invisible defect detection device based on polarized imaging of the present application;

[0023] Figure 5 : Schematic diagram of the spectral sensitivity curve of the InGaAS camera and the photoluminescence spectrum curve of the crystalline silicon photovoltaic panel provided by the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] Term explanations in the present application:

[0025] Polarized light: It refers to the asymmetry of the vibration direction of the electric vector of the light wave with respect to the propagation direction. That is, the asymmetry of the vibration direction of the electric vector of the light wave with respect to the propagation direction is called the polarization of light. Only transverse waves have polarization phenomena, and longitudinal waves do not undergo polarization. Polarized light can be divided into elliptically polarized light, linearly polarized light, and circularly polarized light. The polarized light mentioned in the present application refers to linearly polarized light, that is, the light in which the vibration direction of the electric vector in the light wave always remains in a certain determined direction.

[0026] An InGaAs camera refers to a camera based on indium gallium arsenide (InGaAs) material, which features high sensitivity and high resolution in the near-infrared spectral range. InGaAs cameras are commonly used to capture near-infrared light images, especially suitable for environments with weak light or scenes that require detection of near-infrared radiation. In this application, the InGaAs camera is used to receive light that has undergone specific polarization screening to achieve high-precision detection of invisible defects in photovoltaic panels. By converting the received near-infrared polarized light into an electrical signal, the InGaAs camera provides key data for subsequent image reconstruction and processing.

[0027] In some embodiments, as Figure 1 shown, a device for detecting invisible defects in photovoltaic panels based on polarized light imaging includes:

[0028] A light source assembly 1. The light source assembly 1 induces the photovoltaic panel 3 to emit polarized light 4 in a first direction.

[0029] A receiving assembly 2. The receiving assembly 2 receives the polarized light 4 in the first direction, images the photovoltaic panel 3, and detects defects in the photovoltaic panel 3.

[0030] Since sunlight 5 is natural light, containing polarized light components in various directions, and the detection device of the present invention generates polarized light in a specific direction (i.e., the first direction) through the light source assembly and uses the receiving assembly to only receive polarized light in this direction. In this way, in a sunlight environment, most of the polarized light components in sunlight are inconsistent with the polarized light direction used by the detection device, so they will not be received by the receiving assembly, thus effectively reducing the interference of sunlight on photoluminescence imaging.

[0031] Specifically, in some embodiments, as Figure 2 or Figure 3 shown, the light source assembly 1 includes: an LED light source 101, a linear polarizer 102, and a beam expander lens 103. The linear polarizer 102 is disposed between the LED light source 101 and the beam expander lens 103. The LED light source 101 emits light, which forms polarized light in the first direction after passing through the linear polarizer 102, and the beam expander lens 103 uniformly irradiates the polarized light in the first direction on the photovoltaic panel 3.

[0032] In this embodiment, an LED light source is used to generate stable and high-intensity light. This light is modulated by the linear polarizer 102 to form polarized light with a specific polarization direction (i.e., the first direction). This polarized light is then further processed by the beam expander lens 103 to ensure that the light can be uniformly and accurately irradiated on the surface of the photovoltaic panel 3. This design not only improves the utilization rate of light but also ensures the stability and accuracy of the detection device during the detection process.

[0033] In some specific embodiments, the wavelength of the LED light source is 850 nm. The light of this wavelength is in the near-infrared spectrum range and is suitable for use with an InGaAs camera. The 850-nm LED light source can not only provide sufficient brightness to excite the photoluminescence effect of the photovoltaic panel but also reduce the sensitivity to ambient light and improve the detection accuracy. In addition, the 850-nm wavelength can effectively penetrate the slight contamination or occlusion on the surface of the photovoltaic panel, enabling the detection device to capture more real and detailed internal information of the panel. In this way, the detection device can achieve high-precision and high-efficiency detection of invisible defects in the photovoltaic panel.

[0034] In some embodiments, as Figure 4 shown, the light source assembly includes a linearly polarized laser 104 and a beam expander. The linearly polarized laser 104 generates polarized light in a first direction, and the beam expander disperses and uniformly irradiates the polarized light in the first direction on the photovoltaic panel to ensure the uniformity and directivity of the light.

[0035] In some embodiments, the wavelength of the linearly polarized laser is 808 nm.

[0036] Through multiple experimental verifications, the selection of this wavelength is also based on its excellent performance in the near-infrared spectrum range and good compatibility with the camera. The 808-nm linearly polarized laser can not only provide a stable polarized light source but also reduce the interference of the external environment on the detection process, further improving the detection accuracy and efficiency.

[0037] Different from the above embodiments, a linearly polarized laser is used as the light source in this embodiment. Compared with the LED light source, the linearly polarized laser can generate purer and stronger polarized light. This high-intensity polarized light not only improves the detection efficiency but also eliminates the modulation step of the linear polarizer 102, simplifying the structure of the light source assembly. At the same time, the polarized light generated by the linearly polarized laser has better directivity, which can further improve the detection accuracy of the detection device for invisible defects in the photovoltaic panel.

[0038] In some embodiments, as Figures 2 - 4 shown, the receiving assembly 2 includes: a polarizer 201 and an image processing unit. The polarizer 201 can only receive the polarized light in the first direction, and the image processing unit is connected to the polarizer 201 and is used to process the polarized light signal received by the polarizer 201 to generate an image of the photovoltaic panel.

[0039] Through the precise filtering of the analyzer, only the light rays that match the first-direction polarized light generated by the light source assembly 1 are allowed to pass through. This feature ensures that the receiving assembly 2 can capture the photoluminescence signal with a specific polarization direction emitted by the photovoltaic panel, effectively excluding the interference of polarized light in other directions in sunlight. Subsequently, the polarized light signal filtered by the analyzer is transmitted to the image processing unit for further processing.

[0040] Further, in some embodiments, as Figures 2 - 4 shown, the image processing unit includes a near-infrared or short-wave infrared camera 202 and a microcomputer 203. The near-infrared or short-wave infrared camera 202 is connected to the microcomputer 203. The near-infrared or short-wave infrared camera 202 receives the first-direction polarized light filtered by the analyzer 201, converts it into an electrical signal, and transmits it to the microcomputer 203. The microcomputer 203 performs image reconstruction and processing on the received electrical signal, and identifies and marks the invisible defects on the photovoltaic panel through a specific algorithm.

[0041] In this embodiment, the near-infrared or short-wave infrared camera precisely captures the received polarized light signal in the near-infrared spectral range with its advantages of high sensitivity and high resolution. These signals are then converted into electrical signals, providing a high-quality data basis for subsequent image reconstruction and processing. The microcomputer, as the processing core, is responsible for receiving the electrical signals from the near-infrared or short-wave infrared camera and converting these signals into clear and accurate images of the photovoltaic panel through advanced image reconstruction algorithms.

[0042] In some embodiments, the near-infrared or short-wave infrared camera is an InGaAS camera.

[0043] As Figure 5 shown, it is a schematic diagram of the spectral sensitivity curve of the InGaAS camera and the photoluminescence spectrum curve of the crystalline silicon photovoltaic panel provided in this embodiment. The InGaAS camera has high sensitivity in the wavelength range of 1050nm to 1250nm. It performs excellently in the near-infrared spectral range and is particularly suitable for capturing the light rays filtered by specific polarization. Against the backdrop of this polarized fluorescence, the defect images inside and on the surface of the photovoltaic panel are revealed. In this embodiment, the InGaAs camera, as a key component of the image processing unit, is responsible for receiving the first-direction polarized light filtered by the analyzer. The camera can efficiently convert the received polarized light signal into an electrical signal and transmit it to the microcomputer for further processing.

[0044] To achieve high-precision identification of invisible defects in photovoltaic panels, the microcomputer is also equipped with a specific defect identification algorithm. This algorithm can intelligently analyze the subtle differences in the image, accurately identify invisible defects such as cracks, stains, and broken wires on the panel, and clearly mark these defects on the image through the marking function. This greatly improves the detection efficiency.

[0045] In some embodiments, the device further includes a calibration component. The calibration component includes a calibration light source and a standard photovoltaic panel. The calibration light source emits polarized light with a known direction and wavelength, and the standard photovoltaic panel has a known defect-free state.

[0046] By using the calibration component, the accuracy and reliability of the detection device can be further improved. During initial installation or regular maintenance, the calibration component can be used to calibrate the detection device to ensure the stability and consistency of its performance. Specifically, the calibration light source emits polarized light with a known direction and wavelength, and this polarized light irradiates on the standard photovoltaic panel which has a known defect-free state. By comparing the detection result of the detection device on the standard photovoltaic panel with the known defect-free state, the accuracy and precision of the detection device can be evaluated, and necessary adjustments and optimizations can be made. This calibration process can ensure that the detection device always maintains high performance during long-term use, thereby improving the reliability and accuracy of the detection of invisible defects in photovoltaic panels.

[0047] In some embodiments, to better detect the entire surface of the photovoltaic cell, the device further includes a moving platform. The moving platform is used to carry the photovoltaic panel and move it relative to the light source component and the receiving component. The moving platform includes a stepper motor and a guide rail. The guide rail is connected to the bracket of the photovoltaic panel, and the stepper motor drives the guide rail to move.

[0048] By setting up the moving platform, the detection device can achieve high-precision scanning of the entire surface of the photovoltaic panel. The stepper motor serves as the driving source, providing precise and stable movement control, and the guide rail ensures the smoothness and accuracy of the photovoltaic panel during movement. This design not only improves the detection efficiency but also ensures the comprehensiveness and consistency of the detection results.

[0049] In the specific implementation process, the moving platform can automatically move the photovoltaic panel from the entrance to the exit of the detection device according to the preset scanning path and speed. During the movement, the light source component and the receiving component always maintain the irradiation and receiving states of the photovoltaic panel, and capture and process the polarized light signals emitted by the panel in real time. By reconstructing and processing the electrical signals received by the microcomputer, a full-surface image of the photovoltaic panel can be generated, and through a specific defect identification algorithm, the invisible defects on the panel can be accurately identified and marked.

[0050] In addition, the design of the mobile platform also takes into account the convenience and flexibility of operation. Users can adjust parameters such as the scanning path, speed, and accuracy of the mobile platform according to actual needs to adapt to the detection requirements of photovoltaic panels of different specifications and types. At the same time, the mobile platform also has functions such as automatic reset and fault alarm, ensuring the stability and safety of the detection process.

[0051] In summary, the present application provides a photovoltaic panel invisible defect detection device based on polarized light imaging. The device realizes high-precision detection of invisible defects on photovoltaic panels in daylight environment by precisely controlling the direction of polarized light generated by the light source assembly, and by using a highly sensitive InGaAs camera and advanced image processing technology.

[0052] Although this specification contains many specific implementation details, these should not be construed as limitations on the scope of any invention or on the scope of what can be claimed, but rather as illustrations of features that can make a particular implementation of a particular invention specific. The specific features described in the context of separate implementations in this specification can also be implemented in combination with a single implementation. Conversely, the various features described in the context of a single implementation can also be implemented independently in multiple implementations, or in any suitable sub-combination. In addition, although the features above can be described as acting in combination and even initially claimed as such, one or more features from the claimed combination can in some cases be removed from the combination, and the claimed combination can be directed to a sub-combination or a variation of a sub-combination.

Claims

1. A photovoltaic panel invisible defect detection device based on polarized light imaging, characterized in that: The device comprises: The light source assembly induces the photovoltaic panel to emit polarized light in a first direction; Receiving Component The receiving component receives polarized light in the first direction, images the photovoltaic panel, and detects defects of the photovoltaic panel.

2. The photovoltaic panel invisible defect detection device based on polarized light imaging according to claim 1, characterized in that: The light source assembly comprises: An LED light source, a linear polarizer and a collimator lens, wherein the linear polarizer is arranged between the LED light source and the collimator lens, the LED light source emits light, which passes through the linear polarizer to form polarized light in a first direction, and the collimator lens evenly irradiates the polarized light in the first direction onto the photovoltaic cell panel.

3. The photovoltaic panel invisible defect detection device based on polarized light imaging according to claim 1, characterized in that: The wavelength of the LED light source is 850nm.

4. The photovoltaic panel invisible defect detection device based on polarized light imaging according to claim 1, characterized in that: The light source assembly comprises: a linear polarization laser and a beam expander lens, wherein the linear polarization laser generates polarized light in a first direction, and the beam expander lens disperses and evenly irradiates the first direction onto the photovoltaic cell panel.

5. The photovoltaic panel invisible defect detection device based on polarized light imaging according to claim 4, characterized in that: The linearly polarized laser generates polarized light in a first direction with a wavelength of 808 nm.

6. The photovoltaic panel invisible defect detection device based on polarized light imaging according to claim 1, characterized in that: The receiving component includes: an analyzer and an image processing unit. The analyzer can only receive polarized light in the first direction, and the image processing unit is connected to the analyzer and is used to process the polarized light signal received by the analyzer to generate an image of the photovoltaic panel.

7. The photovoltaic panel invisible defect detection device based on polarized light imaging according to claim 6, characterized in that: The image processing unit includes a near-infrared or short-wave infrared camera and a microcomputer. The near-infrared or short-wave infrared camera is connected to the microcomputer. The near-infrared or short-wave infrared camera receives the first-direction polarized light filtered by the analyzer, converts it into an electrical signal, and transmits it to the microcomputer. The microcomputer reconstructs and processes the received electrical signal, and identifies and marks invisible defects on the photovoltaic panel through a specific algorithm.

8. The photovoltaic panel invisible defect detection device based on polarized light imaging according to claim 7, characterized in that: The near infrared or short wave infrared camera is an InGaAS camera.

9. The photovoltaic panel invisible defect detection device based on polarized light imaging according to claim 1, characterized in that: The device also includes a calibration component, which includes a calibration light source and a standard photovoltaic panel. The calibration light source emits polarized light with a known direction and wavelength, and the standard photovoltaic panel has a known defect-free state.

10. The photovoltaic panel invisible defect detection device based on polarized light imaging according to claim 1, characterized in that: The device also includes a moving platform, which is used to carry the photovoltaic panel so that it can move relative to the light source assembly and the receiving assembly. The moving platform includes a stepper motor and a guide rail, which is connected to the bracket of the photovoltaic panel, and the stepper motor drives the guide rail to move.

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