Test method, device and system and storage medium

Abstract

The invention discloses a testing method, device and system and a storage medium, and the testing method employs a photoluminescence resistance testing method and / or an electroluminescent resistance testing method to measure the local resistance of a preset area on a to-be-tested cell, and the local resistance is the thin-layer resistance of the preset area. According to the method, the sheet resistance of the to-be-measured battery piece is calculated according to the local resistance and the transverse transmission path of the carriers in measurement, the sheet resistance of the to-be-measured battery piece is measured, the local resistance is measured based on the photoluminescence resistance test and / or the photoluminescence resistance test, the sheet resistance is calculated in combination with the local resistance and the transverse transmission path of the carriers, and the sheet resistance of the to-be-measured battery piece is measured. Compared with a four-probe method, the test method is simpler, more convenient and easier to implement, is less affected by surface charges compared with a surface photovoltage method, does not need to calibrate the surface charges regularly, and improves the reliability of test results on the basis of reducing the complexity of the test method.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and in particular to a testing method, apparatus, system, and storage medium. Background Technology

[0002] To determine the sheet resistance of a solar cell under test, existing technologies generally employ the four-probe measurement method and the junction-photovoltaic method.

[0003] The four-probe measurement method is a contact measurement method. In order to ensure the accuracy of the measurement results and the integrity of the solar cell, the operation steps are often complicated and it is difficult to detect quickly online. The junction-photovoltaic method is a measurement method that uses light excitation and voltage signal detection to calculate resistance, but it is greatly affected by the surface charge of the solar cell and the calculation is complicated.

[0004] In summary, the two commonly used sheet resistance measurement schemes for solar cells under test in the existing technology are both quite complex, which greatly restricts the development of online rapid testing technology. Summary of the Invention

[0005] This invention provides a testing method, apparatus, system, and storage medium to improve the reliability of test results while reducing the complexity of the testing method.

[0006] According to one aspect of the present invention, a testing method is provided, the testing method comprising:

[0007] The local resistance of a preset area on the battery cell under test is measured using photoluminescence resistance testing and / or electroluminescence resistance testing, wherein the local resistance is the thin-layer resistance of the preset area;

[0008] The sheet resistance of the cell under test is calculated based on the local resistance and the lateral transport path of charge carriers during measurement.

[0009] Optionally, the preset region includes a first sub-region and a second sub-region;

[0010] The method of measuring the local resistance of a preset area on the battery cell under test using photoluminescence resistance testing and / or electroluminescence resistance testing includes:

[0011] When the battery cell under test is locally illuminated, the local potential of the first sub-region and the local potential of the second sub-region are determined according to the grayscale image of the preset area on the battery cell under test.

[0012] The difference between the local potential of the first sub-region and the local potential of the second sub-region is used to calculate the local resistance of the preset region by combining the photocurrent of the preset region.

[0013] Optionally, the irradiated area of ​​the localized illumination is the central circular area of ​​the battery cell under test; the preset area is the concentric ring area outside the central circular area; the first sub-region is the inner edge area of ​​the concentric ring area, and the second sub-region is the outer edge area of ​​the concentric ring area;

[0014] The step of determining the local potential of the first sub-region and the local potential of the second sub-region based on the grayscale image of the preset area on the battery cell under local illumination includes:

[0015] When the central circular region of the battery cell under test is illuminated, a grayscale image of the concentric ring region is acquired.

[0016] Based on the grayscale parameters of the inner edge region and the outer edge region in the grayscale image, the local potential of the inner edge region and the local potential of the outer edge region are determined respectively.

[0017] Optionally, the first sub-region and the second sub-region are arranged adjacent to each other, and the area illuminated by the local illumination is at least a portion of the first sub-region;

[0018] The step of determining the local potential of the first sub-region and the local potential of the second sub-region based on the grayscale image of the preset area on the battery cell under local illumination includes:

[0019] When at least a portion of the first sub-region is illuminated, a grayscale image of the illuminated area in the first sub-region and a grayscale image of the second sub-region are acquired.

[0020] Based on the grayscale images of the illuminated area in the first sub-region and the grayscale images of the second sub-region, the local potentials of the illuminated area in the first sub-region and the second sub-region are determined respectively.

[0021] Optionally, calculating the sheet resistance of the cell under test based on the local resistance and the lateral transport path of charge carriers during measurement includes:

[0022] Obtain the dimensional parameters of the lateral transport path of charge carriers during measurement;

[0023] Based on the functional relationship between the sheet resistance of the battery cell under test and the size parameters and the local resistance, and in conjunction with the local resistance of the preset region, the sheet resistance of the battery cell under test is calculated.

[0024] Optionally, the preset region includes a first sub-region and a second sub-region; the irradiated area of ​​the local illumination in the photoluminescence resistance test method is the central circular region of the battery cell under test; the preset region is a concentric ring region outside the central circular region; the first sub-region is the inner edge region of the concentric ring region, and the second sub-region is the outer edge region of the concentric ring region;

[0025] The step of obtaining the size parameters of the lateral transport path of charge carriers in the measurement includes: when the lateral transport path of charge carriers in the measurement is from the inner edge region to the outer edge region, determining that the size parameters of the lateral transport path include the inner edge diameter and the outer edge diameter of the concentric annular region;

[0026] The calculation of the sheet resistance of the battery cell under test, based on the functional relationship between the sheet resistance and the size parameters and the local resistance, combined with the local resistance of the preset region, includes: substituting the inner edge diameter, the outer edge diameter, and the local resistance into the first relational expression. Calculate the sheet resistance of the battery cell under test; wherein, R is the sheet resistance, d1 is the inner edge diameter, and d2 is the outer edge diameter.

[0027] Optionally, the preset area includes a first sub-region and a second sub-region; the first sub-region and the second sub-region are arranged adjacent to each other, and the irradiated area of ​​the local illumination in the photoluminescence resistance test method is at least a part of the first sub-region;

[0028] The step of obtaining the size parameters of the lateral transport path of charge carriers in the measurement includes: when the lateral transport path of charge carriers in the measurement is from the first sub-region to the second sub-region, determining that the size parameters of the lateral transport path include the width of the solar cell on the lateral transport path and the length of the solar cell on the lateral transport path.

[0029] The step of calculating the sheet resistance of the battery cell under test based on the functional relationship between the sheet resistance of the cell under test and the size parameters and the local resistance, combined with the local resistance of the preset region, includes: calculating the sheet resistance of the battery cell under test based on the local resistance, the width of the battery cell on the lateral transmission path, and the length of the battery cell on the lateral transmission path; wherein the sheet resistance of the battery cell under test is directly proportional to the local resistance and the width of the battery cell on the lateral transmission path, and inversely proportional to the length of the battery cell on the lateral transmission path.

[0030] According to another aspect of the present invention, a testing apparatus is provided, comprising: a processor coupled to a memory for storing a program or instructions, wherein when the program or instructions are executed by the processor, the testing apparatus performs a testing method as described in any of the first aspects.

[0031] According to another aspect of the present invention, a testing system is provided, characterized in that it includes a testing device, an image acquisition component, and a light source, wherein the light source is used to emit light to a local area of ​​the battery cell under test, the image acquisition component is used to acquire a grayscale image of the battery cell under test, and the testing device is used to perform the testing method as described in any of the first aspects.

[0032] According to another aspect of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium storing computer instructions for causing a processor to execute and implement the test method described in any embodiment of the present invention.

[0033] The testing method, apparatus, system, and storage medium of this invention utilize photoluminescence resistance (PRR) and / or electroluminescence resistance (EMR) testing to measure the local resistance of a preset region on a solar cell under test, wherein the local resistance is the thin-layer resistance of the preset region. Based on the local resistance and the lateral transport path of charge carriers during measurement, the sheet resistance of the solar cell under test is calculated, thus realizing the sheet resistance measurement of the solar cell under test. This method, based on PRR and / or EMR testing, measures the local resistance and calculates the sheet resistance by combining the local resistance and the lateral transport path of charge carriers. This testing method is simpler and easier to implement than the four-probe method, and compared to the surface photovoltage method, it is less affected by surface charge and does not require periodic calibration of the surface charge. It improves the reliability of the test results while reducing the complexity of the testing method.

[0034] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram showing the composition and positional relationship of a testing system and a battery cell under test, as proposed in an embodiment of the present invention.

[0037] Figure 2 This is a flowchart illustrating a testing method proposed in an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of the region division of a battery cell under test provided in an embodiment of the present invention;

[0039] Figure 4 A flowchart illustrating another testing method provided in an embodiment of the present invention;

[0040] Figure 5 This is a schematic diagram of another region division of the battery cell to be tested provided in an embodiment of the present invention;

[0041] Figure 6 A flowchart illustrating another testing method provided in an embodiment of the present invention;

[0042] Figure 7 A flowchart illustrating another testing method provided in an embodiment of the present invention;

[0043] Figure 8 This is a schematic diagram of the composition of a speed measuring device provided in an embodiment of the present invention. Detailed Implementation

[0044] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0045] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0046] In existing technologies, the sheet resistance of solar cells is mostly tested using the four-probe method or the junction-photovoltaic voltage method. The four-probe method requires connecting four sets of probes to the solar cell, which is complex to operate and difficult to achieve rapid online testing; while the junction-photovoltaic voltage method is greatly affected by the surface charge of the solar cell, requiring periodic calibration of the surface charge, which is computationally intensive and complex.

[0047] Therefore, to address the aforementioned problems, this application proposes a testing method, apparatus, system, and storage medium for testing the sheet resistance of a solar cell under test. The solar cell under test in this application is a double-sided doped cell, eliminating the need to remove the phosphorus-silicate glass (PSG) and boron-silicate glass (BSG) of the cell. To clearly illustrate the testing principle, before introducing the proposed testing method, a brief description of the basic components of the system implementing the testing method is provided using an embodiment. This invention proposes a testing system... Figure 1 This is a schematic diagram illustrating the composition and positional relationship of a testing system and the battery cell under test, as proposed in an embodiment of the present invention. Figure 1 The testing system 100 includes a target light source 101, an image acquisition component 102, and a testing device 103, wherein the testing device 103 is used to execute the testing methods provided in any embodiment of this application.

[0048] The target light source 101 is used to provide preset illumination conditions for a preset area of ​​the battery cell 104 under test, so that the illuminated area and its related areas of the preset area emit light. The target light source 101 may include a laser array light source or an LED array light source with strong and uniform light. The diameter of the light spot formed by a single laser light source illuminating the battery cell 104 under test can be between 1 mm and 25 mm, while the diameter of the light spot formed by a single LED light source illuminating the battery cell 104 under test can be between 2 mm and 50 mm. The entire array light source can expand the diameter range of the light spot formed by the light source illuminating the battery cell 104 under test to 180 mm to 400 mm. Of course, in other embodiments, the target light source 101 may also sample other types of target light sources 101 and light source sizes, and this application does not impose specific limitations on this.

[0049] In some embodiments, in addition to light-emitting components such as laser array light sources and LED array light sources, the target light source 101 may also include a light-shielding component. The light-shielding component can be disposed between the light-emitting component and the battery cell 104 under test, cooperating with the light-emitting component to illuminate a target area on the battery cell 104 under test. For example, the light-shielding component may include a light-shielding sheet, which can block part of the light emitted by the light-emitting component, so that only the target area on the battery cell 104 under test receives light. Furthermore, the light-shielding component may also include a movement control, which is connected to the testing device 103 and can be controlled by the testing device 103 to move the light-shielding sheet, thereby illuminating different areas of the battery cell 104 under test by the target light source 101.

[0050] The illumination intensity provided by the target light source 101 can be 1 sun, 2 sun, or 3 sun. Preferably, the illumination intensity provided by the target light source 101 can be greater than 1.5 sun. Of course, in other embodiments, the illumination intensity provided by the target light source 101 can also be other values, which can be set according to the actual needs of the local resistance testing method. In addition, the higher the illumination intensity provided by the target light source 101, the better the photoluminescence effect of the battery cell 104 under test in the photoluminescence resistance testing method, which can improve the accuracy of the test.

[0051] The target light source 101 can provide a single-wavelength light source in the range of 300 to 1200 nm. Preferably, in some embodiments, the target light source 101 can provide a long wavelength of 400 to 600 nm, which can just excite the photogenerated carriers on the surface of the doped layer on the cell under test 104, reducing the impact of the light generated by the photogenerated carriers in the base region on the image sampling results of the image acquisition component 102 (e.g., a PL camera), thereby improving the accuracy of the test results. In other embodiments, the target light source 101 can also provide multi-wavelength or continuous spectrum illumination, so that the illumination received by the cell under test 104 during the test is close to the sunlight it receives during actual use, thereby improving the accuracy of the test results.

[0052] The incident angle of the light emitted by the target light source 101 can be from 5° to 90°. For example, the incident angle can be 5°, 15°, 25°, 35°, 45°, 55°, 65°, 75°, 85°, or 90°. This application does not impose any specific limitations on this.

[0053] The image acquisition component 102 is used to acquire images of a preset area of ​​the solar cell 104 under test, to obtain grayscale images of the preset area, and to feed them back to the testing device 103. For example, the image acquisition component 102 can be an image acquisition device capable of detecting the luminescence characteristics of Si-based photovoltaic cells, such as a silicon-based CCD, InGaAs, InSb, or HgCdTd. Alternatively, the image acquisition component 102 can also be an image acquisition device capable of acquiring radiation from other types of semiconductors (e.g., perovskite semiconductors). This application does not impose specific limitations on this.

[0054] The testing device 103 is connected to the image acquisition component 102 and the target light source 101, respectively. As the control center of the testing system 100, it controls the operating status of the target light source 101, the image acquisition component 102, and other controllable components within the device. It also executes the testing methods provided in any embodiment of this application to perform sheet resistance testing on the battery cell under test. Exemplarily, the testing device 103 can be a microcontroller or other chips and controllers capable of data analysis, processing, and external control.

[0055] As an alternative or supplement to the aforementioned image acquisition component 102 and target light source 101, in some embodiments, the test system 100 may further include an infrared camera and a pair of electrodes (not shown in the figure). The electrodes are connected to a power source, and the connection line status is controlled by the test apparatus 103. During the test, the electrodes can be attached to the battery cell under test 104 to apply a test current to the battery cell under test 104. While the test current is applied to the battery cell under test 104, the infrared camera can acquire infrared images of the battery cell under test 104 to test the local resistance of the battery cell under test 104 using the electroluminescent resistor test method.

[0056] In some embodiments, the testing system 100 may further include a stage 105 on which the battery cell 104 to be tested may be placed. Other components in the testing system 100 are arranged around the stage 105 to perform stable testing on the battery cell 104 to be tested. For example, the stage 105 may be a fixed support platform that can provide a fixed and stable test placement area for the battery cell 104 to be tested. The stage 105 may also be a support platform with conveying or rotating functions, which can promptly transport the next battery cell 104 to be tested into the test area after the previous battery cell 104 has been tested, thereby improving testing efficiency.

[0057] Based on the testing system described in the foregoing embodiments, the testing method proposed in this application is described below. This invention proposes a testing method... Figure 2 This is a flowchart illustrating a testing method proposed in an embodiment of the present invention. Based on the foregoing embodiments, refer to... Figure 2 Test methods include:

[0058] S201. Measure the local resistance of a preset area on the cell under test using photoluminescent resistor testing and / or electroluminescent resistor testing.

[0059] Specifically, the local resistance of the preset area refers to the thin-layer resistance of the preset area, also known as the series resistance of the preset area. Photoluminescent resistance (PL-Rs) testing is a method for measuring the local resistance of a solar cell under test using the photoluminescence effect. When the solar cell under test is irradiated by a laser or a light source of a specific wavelength, the silicon material of the cell absorbs photons, generating electron-hole pairs. When these charge carriers recombine, they release fluorescence of a specific wavelength. PL-Rs testing uses image analysis to determine the distribution and attenuation characteristics of fluorescence intensity during photoluminescence, thereby indirectly calculating the local resistance of the preset area on the solar cell under test. Local resistance affects the carrier transport efficiency; the higher the local resistance, the faster the carrier recombination, the weaker the fluorescence intensity, and the more significant the attenuation. By establishing a correlation model between the image and the local resistance, non-contact measurement of the local resistance can be achieved.

[0060] For example, Figure 3 This is a schematic diagram of the region division of a battery cell under test provided in an embodiment of the present invention, combined with... Figure 1 and Figure 3 The battery cell 105 under test includes a first sub-region 301 and a second sub-region 302. When measuring local resistance using the PL-Rs test method, a target light source illuminates a local illumination region 303 within the first sub-region 301. The photocurrent generated in the local illumination region 303 is transmitted to the second sub-region 302, causing it to emit light. Simultaneously, two image acquisition components acquire grayscale images of the local illumination region 303 and the second sub-region 302 on the battery cell under test. The first open-circuit voltage (also called the local potential of the local illumination region 303) can be determined based on the grayscale image of the local illumination region 303, and the second open-circuit voltage (also called the local potential of the second sub-region 302) can be determined based on the grayscale image of the second sub-region 302. The second open-circuit voltage is the open-circuit voltage without neglecting the series resistance, and the formula for calculating the open-circuit voltage is... , Here, is the open-circuit voltage, k is the Boltzmann constant, T is the temperature of the cell under test, and A is the open-circuit voltage. i Where B is the range factor, and n is the photogenerated recombination coefficient. i Intrinsic carrier concentration, The average grayscale value of the corresponding grayscale image is denoted by q, and the amount of electron charge is q. The series resistance of the preset region, calculated based on the ratio of the target difference to the preset current density value, is the local resistance. The target difference is the difference between the first open-circuit voltage value and the second open-circuit voltage value. In other embodiments, the photoluminescence resistance testing method can also utilize a target light source to provide different light intensities to the preset region, and then determine the series resistance (i.e., local resistance) of the preset region based on the grayscale value images of the preset region under different light intensities. This will not be elaborated further here.

[0061] Electroluminescent resistance (EPL) testing is a method for measuring local resistance based on the electroluminescence effect, also known as EPL or EL testing. When a forward bias voltage is applied to the solar cell under test, the injected charge carriers recombine during diffusion, generating electroluminescence. The intensity of the electroluminescence is correlated with the internal voltage of the solar cell. EPL testing uses image analysis to determine the distribution and attenuation characteristics of fluorescence intensity during electroluminescence, thereby indirectly calculating the local resistance of a predetermined area on the solar cell under test.

[0062] For example, continue to combine Figure 1 By applying a reference current to the solar cell under test using paired electrodes, a standard image of a predetermined area on the solar cell is acquired using a near-infrared camera. The injected current is then increased to the test current, and a test image of the predetermined area on the solar cell is acquired using an infrared camera. The test current can be 2 to 3 times the reference current, but lower than the maximum withstand current of the solar cell. By performing pixel-level mathematical operations and modeling on the two images acquired under different currents, the series resistance between any two areas within the predetermined area can be calculated, which is the local resistance of the predetermined area.

[0063] Building upon photoluminescence resistance (PRR) and electroluminescence resistance (EMR) testing methods, a further approach can be adopted to measure the local resistance of a solar cell under test. This method combines PRR and EMR testing. For example, on one hand, a forward bias is applied to the device to inject current into the solar cell under test, generating a large number of charge carriers. On the other hand, photoluminescence-assisted excitation supplements the charge carriers, reducing the impact threshold of local resistance on charge carrier transport. Simultaneously, the nonlinear distortion of the EMR sampling signal is calibrated using the photoluminescence sampling signal. The EMR sampling signal reflects the recombination characteristics of electrically injected charge carriers, while the photoluminescence sampling signal reflects the transport characteristics of photoexcited charge carriers. Through the ratio or coupling analysis of these two signals, the contributions of local resistance and defects to charge carrier transport characteristics can be separated, achieving high-precision measurement of local resistance. This testing method is implemented by combining the previous two methods, which will not be elaborated further here.

[0064] S202. Calculate the sheet resistance of the cell under test based on the local resistance and the lateral transport path of charge carriers during measurement.

[0065] Specifically, sheet resistance differs from local resistance. It is a key parameter characterizing the in-plane conductivity of a solar cell. Its core physical meaning is the in-plane resistance of a unit square thin film. It is important to note that sheet resistance is determined by the material's inherent properties and thickness, and is independent of the side length of the square. The sheet resistance of the solar cell under test is directly proportional to the local resistance determined in step S201 and the width of the lateral transport path for charge carriers generated in step S201, and inversely proportional to the length of the lateral transport path. The lateral transport path for charge carriers refers to the lateral transport path of charge carriers along the extension direction of the solar cell under test. For example, combining... Figure 3 When the coverage area of ​​the lateral transmission path 304 is rectangular, the relevant parameters of the lateral transmission path 304 may include the width W and length L of the rectangle. In other embodiments, depending on the different settings of the local illumination area and the image sampling area, the coverage area of ​​the lateral transmission path 304 may also be other shapes. For example, if the coverage area of ​​the lateral transmission path 304 is annular, with charge carriers diffusing from the inner circle to the outer circle of the annulus, then the relevant parameters of the lateral transmission path 304 may include the inner circle radius and the outer circle radius of the annulus. Based on this, combined with the local resistance and the relevant parameters of the lateral transmission path 304 for charge carriers, the sheet resistance of the battery cell under test can be calculated.

[0066] In the testing method proposed in this embodiment, the local resistance of a preset area on the solar cell under test is measured using photoluminescence resistance (PRR) and / or electroluminescence resistance (EMR). The local resistance is the thin-layer resistance of the preset area. Based on the local resistance and the lateral transport path of charge carriers during measurement, the sheet resistance of the solar cell under test is calculated, thus achieving sheet resistance measurement. This method, based on PRR and / or ERR measurement, measures the local resistance and calculates the sheet resistance by combining the local resistance and the lateral transport path of charge carriers. This testing method is simpler and easier to implement than the four-probe method, and less affected by surface charge than the surface photovoltage method, eliminating the need for periodic calibration of surface charge. It improves the reliability of the test results while reducing the complexity of the testing method.

[0067] Figure 4 This is a flowchart illustrating another testing method provided by an embodiment of the present invention. In this testing method, the local resistance of a preset area is determined based on the photoluminescence resistance test method. Based on the aforementioned embodiments, and referring to... Figure 4 Test methods include:

[0068] S401. When the battery cell under test is locally illuminated, the local potential of the first sub-region and the local potential of the second sub-region are determined according to the grayscale image of the preset area on the battery cell under test.

[0069] Specifically, in combination Figure 3 The preset region includes at least a first sub-region 301 and a second sub-region 302. The illumination area of ​​the localized illumination is a localized area within the preset region. In some embodiments, the illumination area of ​​the localized illumination can be an area other than the first sub-region 301 and the second sub-region 302 within the preset region. In this case, while providing localized illumination, the local potential between the first sub-region 301 and the second sub-region 302 can be obtained based on the grayscale image of the preset region. In other embodiments, the illumination area of ​​the localized illumination can be either the first sub-region 301 or the second sub-region 302. In this case, while providing localized illumination, the local potential of the first sub-region 302 can be determined based on the grayscale image of the first sub-region 301, and the local potential of the second sub-region can be determined based on the grayscale image of the second sub-region.

[0070] S402. Calculate the local resistance of the preset region by combining the difference between the local potential of the first sub-region and the local potential of the second sub-region with the photocurrent of the preset region.

[0071] Specifically, the photocurrent in the preset region refers to the maximum current that can be collected in the preset region after it is illuminated, assuming that there is no series resistance loss and that carrier recombination is only radiative recombination in the preset region of the battery under test. The photocurrent can be determined based on the basic operating parameters of the light-emitting component in the target light source and the basic operating parameters of the battery under test. For example, when the light-emitting component in the target light source is a laser, the photocurrent I generated by the laser in the battery under test is... L It can be represented as ,in, Where is the current conversion efficiency of the laser, I is the supply current of the laser, and h is the optical coefficient of the cell under test. When the cell under test is a doped cell, its optical coefficient is a fixed value between 0.3 and 0.9.

[0072] The difference between the local potential of the first sub-region and the local potential of the second sub-region is the potential difference between the first and second sub-regions in the preset region. By calculating the ratio of the potential difference to the photocurrent, the local resistance of the preset region can be determined.

[0073] S403. Obtain the dimensional parameters of the lateral transport path of charge carriers during measurement.

[0074] Specifically, by combining the relative positional relationship between the illuminated area, the first sub-region, and the second sub-region, the size parameters of the lateral transport path of charge carriers generated by photoluminescence between the first and second sub-regions can be determined. For example, the size parameters of the lateral transport path can be determined by analyzing and processing the image of the preset area acquired by the image acquisition component. As one implementation method, Figure 5 This is a schematic diagram of another region division of the battery cell under test provided in an embodiment of the present invention, referring to... Figure 5 In a photoluminescence resistor testing method, where the local illumination area is the central circular region 501 of the battery cell under test, the preset region is the concentric annular region 502 outside the central circular region 501, the first sub-region is the inner edge region 503 of the concentric annular region 502, and the second sub-region is the outer edge region 504 of the concentric annular region 502, the dimensional parameters of the lateral transmission path include the inner edge diameter d1 and the outer edge diameter d2 of the concentric annular region 502. As another embodiment, refer to... Figure 3 In another photoluminescence resistor testing method, where the first sub-region 301 and the second sub-region 302 are arranged adjacently and the irradiated area of ​​the local illumination in the photoluminescence resistor testing method is at least a part of the first sub-region, the size parameters of the lateral transmission path 304 include the width W and length L of the solar cell on the lateral transmission path.

[0075] S404. Based on the functional relationship between the sheet resistance of the cell under test and its size parameters and local resistance, and combined with the local resistance of a preset area, calculate the sheet resistance of the cell under test.

[0076] Specifically, the sheet resistance of the cell under test has a definite functional relationship with the size parameters and the local resistance. The sheet resistance of the cell under test is directly proportional to the local resistance, and the functional relationship between the sheet resistance of the cell under test and the size parameters needs to be determined according to the type of size parameters. Based on the size parameters and the local resistance, the sheet resistance of the cell under test can be calculated by combining the functional relationship.

[0077] As one implementation method, refer to Figure 5 The dimensional parameters of the lateral transmission path include the inner edge diameter d1 and the outer edge diameter d2 of the concentric annular region 502. The sheet resistance of the tested solar cell 105 is inversely proportional to the logarithm of the parameter correlation, where the logarithm of the parameter correlation is equal to the logarithm of the ratio between the outer edge diameter d2 and the inner edge diameter d1 of the concentric annular region 502. The sheet resistance of the tested solar cell 105 has a definite functional relationship with the dimensional parameters and the local resistance, which can be expressed as the first relational expression. ,in, Let R be the sheet resistance of the battery cell 105 under test, and R be the local resistance of the preset area; substitute the inner edge diameter d1, the outer edge diameter d2, and the local resistance R into the first relationship. Then the sheet resistance of the battery cell 105 under test can be calculated. .

[0078] As another implementation method, refer to Figure 3 The dimensional parameters of the lateral transmission path include the width W and length L of the solar cell on the lateral transmission path 304. The sheet resistance of the solar cell 105 under test is directly proportional to the width W of the solar cell on the lateral transmission path 304 and inversely proportional to the length L of the solar cell on the lateral transmission path 304. The sheet resistance of the solar cell 105 under test has a definite functional relationship with the dimensional parameters and the local resistance, which can be expressed as follows: ,in, Let R be the sheet resistance of the cell under test, W be the local resistance of the preset area, W be the width of the cell on the lateral transmission path 304, and L be the length of the cell on the lateral transmission path 304. Based on the functional relationship between the sheet resistance of the cell under test 105 and the local resistance, the width W and the length L of the cell on the lateral transmission path 304, the sheet resistance of the cell under test 105 can be calculated by combining the local resistance, the width W and the length L of the cell on the lateral transmission path 304.

[0079] In the testing method provided in this embodiment, under localized illumination of the battery cell under test, the local potentials of the first sub-region and the second sub-region are determined based on the grayscale image of a preset area on the battery cell. The difference between the local potentials of the first and second sub-regions is used, combined with the photocurrent of the preset area, to calculate the local resistance of the preset area. The size parameters of the lateral transport path of charge carriers during measurement are obtained. Based on the functional relationships between the sheet resistance of the battery cell under test and the size parameters and the local resistance, combined with the local resistance of the preset area, the sheet resistance of the battery cell under test is calculated. This testing method uses photoluminescence resistance testing to determine the local resistance of the preset area, realizing non-contact testing of the battery cell under test. The testing process can be carried out online without damaging the battery cell under test, improving the reliability and real-time performance of the test.

[0080] Figure 6 This is a flowchart illustrating another testing method provided in an embodiment of the present invention. Based on the foregoing embodiments, it combines... Figure 5 and Figure 6 The testing methods include:

[0081] S601. Under the condition of irradiating the central circular area of ​​the battery cell under test, acquire the gray value image of the concentric ring area.

[0082] Specifically, the central circular region 501 refers to the circular region on the battery cell 105 under test, centered on the center point of the battery cell. During the test, a light-blocking component can be used to partially block the light emitted by the light-emitting component, thereby achieving partial illumination of the central circular region 501 of the battery cell 105 under test. While the central circular region 501 of the battery cell 105 under test is illuminated, an image acquisition component is used to acquire an image of the battery cell 105 under test, obtaining a grayscale image of the battery cell 105. Then, in the image processing stage, the illuminated area, the central circular region 501, can be shielded, and the grayscale image of the concentric ring region 502 surrounding the central circular region 501 can be determined.

[0083] S602. Based on the grayscale parameters of the inner and outer edge regions in the grayscale image, determine the local potential of the inner edge region and the local potential of the outer edge region respectively.

[0084] Specifically, the inner edge region 503 refers to the inner circular edge of the concentric ring region 502; the outer edge region 504 refers to the outer circular edge of the concentric ring region 502. For example, both the inner edge region 503 and the outer edge region 504 can be circular edge regions formed by connecting single pixels. Based on the grayscale image of the concentric ring region 502 determined in step S601, the grayscale parameters of the inner edge region 503 and the outer edge region 504 can be determined, where the grayscale parameter can be the average grayscale value of the corresponding edge region. The grayscale parameters of the inner edge region 503 and the outer edge region 504 are then substituted into the calculation formula for the open-circuit voltage. The open-circuit voltage of the inner edge region 503 and the open-circuit voltage of the outer edge region 504 can be determined separately, which are the local potentials of the inner edge region 503 and the outer edge region 504.

[0085] S603. Calculate the local resistance of the preset region by combining the difference between the local potential of the inner edge region and the local potential of the outer edge region with the photocurrent of the preset region.

[0086] Specifically, the difference between the local potential of the inner edge region 503 and the local potential of the outer edge region 504 is the potential difference between the inner edge region 503 and the outer edge region 504 in the preset region. By calculating the ratio of the potential difference to the photogenerated current, the local resistance of the preset region can be determined.

[0087] S604. When the lateral transport path of charge carriers in the measurement is from the inner edge region to the outer edge region, the size parameters of the lateral transport path are determined, including the inner edge diameter and the outer edge diameter of the concentric ring region.

[0088] Specifically, when the central circular region 501 of the solar cell under test is illuminated, the sheet resistance is measured using the grayscale image of the concentric annular region 502, which is concentric with the central circular region 501. The charge carriers propagate circumferentially outward from the central circular region 501, and the lateral transport path of the charge carriers is from the inner edge region 503 to the outer edge region 504. In this case, the dimensional parameters of the lateral transport path involved in the sheet resistance calculation include the inner and outer edge diameters of the concentric annular region 502. By performing image analysis and processing on the original image sampling results or grayscale image of the solar cell under test, the specific data of the inner edge diameter d1 and outer edge diameter d2 of the concentric annular region 502 can be determined.

[0089] S605. Substitute the inner edge diameter, outer edge diameter, and local resistance into the first relational expression to calculate the sheet resistance of the cell under test.

[0090] Specifically, the local resistance R of the preset region determined in step S603 and the inner edge diameter d1 and outer edge diameter d2 of the concentric annular region 502 determined in step S604 are substituted into the first relational expression. Then the sheet resistance of the battery cell 105 under test can be calculated. This is the sheet resistance test result of the battery cell 105 under test. Furthermore, in some embodiments, steps S602, S603, S604, and S605 of this embodiment are repeated multiple times to calculate multiple sets of sheet resistance of the battery cell under test based on the local resistance, outer edge diameter, and inner edge diameter corresponding to different concentric annular regions 502. The average value of the multiple sheet resistance calculation results can be used as the sheet resistance calculation result of the battery cell under test.

[0091] In the testing method provided in this embodiment, grayscale images of concentric ring regions are acquired while the central circular region of the battery cell under test is illuminated. Based on the grayscale parameters of the inner and outer edge regions in the grayscale images, the local potentials of the inner and outer edge regions are determined respectively. The difference between the local potentials of the inner and outer edge regions is used, combined with the photocurrent of a preset region, to calculate the local resistance of the preset region. When the lateral transport path of charge carriers in the measurement is from the inner edge region to the outer edge region, the size parameters of the lateral transport path are determined, including the inner and outer edge diameters of the concentric ring regions. The inner and outer edge diameters and the local resistance are substituted into the first relational expression to calculate the sheet resistance of the battery cell under test, thus realizing the measurement of the sheet resistance of the battery cell under test. This method uses grayscale images of regions outside the illuminated area to determine the local potential, and a single image can determine the potential difference between two locations, avoiding multiple image acquisitions and reducing the implementation complexity of the testing method.

[0092] Figure 7This is a flowchart illustrating another testing method provided in an embodiment of the present invention. Based on the foregoing embodiments, it combines... Figure 3 and Figure 7 The testing methods include:

[0093] S701. When at least a portion of the first sub-region is illuminated, acquire grayscale images of the illuminated area in the first sub-region and grayscale images of the second sub-region.

[0094] Specifically, the first sub-region 301 and the second sub-region 302 are arranged adjacent to each other, and the illuminated area 303 is at least a portion of the first sub-region 301. For example, the first sub-region 301 and the second sub-region 302 can be two adjacent rectangular regions with a width equal to the width of the solar cell under test, while the illuminated area 303 is a segment of the first sub-region 301, and its width is also the same as the width of the solar cell under test. In other embodiments, the illuminated area 303 can be the entire first sub-region 301, and its width may differ from the width of the second sub-region 302; no limitations are imposed here.

[0095] During the test, a light-shielding component can be used to partially block the light emitted by the light-emitting component, thereby illuminating at least a portion of the first sub-region 301 on the battery cell under test. With at least a portion of the first sub-region 301 illuminated, an image acquisition component is used to acquire images of the battery cell under test, obtaining grayscale images of the illuminated area 303 and the second sub-region 302 within the first sub-region 301. For example, two sets of image acquisition components are used to acquire images of the illuminated area 303 and the second sub-region 302 of the first sub-region 301, respectively, thereby obtaining the grayscale images of the illuminated area 303 and the second sub-region 302 within the first sub-region 301.

[0096] S702. Based on the grayscale image of the illuminated area in the first sub-region and the grayscale image of the second sub-region, the local potential of the illuminated area in the first sub-region and the local potential of the second sub-region in the second sub-region are determined respectively.

[0097] Specifically, based on the grayscale image of the illuminated area 303 in the first sub-region 301 determined in step S701, the grayscale parameter of the first sub-region 301 can be determined. Similarly, based on the grayscale image of the second sub-region 302 determined in step S701, the grayscale parameter of the second sub-region 302 can be determined. The grayscale parameter can be the average grayscale value of the corresponding region. Substituting the grayscale parameters of the illuminated area 303 in the first sub-region 301 and the grayscale parameters of the second sub-region 302 into the calculation formula for the open-circuit voltage, respectively... The open-circuit voltage of the irradiated region 303 in the first sub-region 301 and the open-circuit voltage of the second sub-region 302 can be determined respectively, which are the local potentials of the irradiated region 303 in the first sub-region 301 and the second sub-region 302.

[0098] S703. Calculate the local resistance of the preset region by combining the difference between the local potential of the irradiated area in the first sub-region and the local potential of the second sub-region with the photocurrent of the preset region.

[0099] Specifically, the difference between the local potential of the irradiated area 303 in the first sub-region 301 and the local potential of the second sub-region 302 is the potential difference between the irradiated area 303 and the second sub-region 302 in the preset region. By calculating the ratio of the potential difference to the photocurrent, the local resistance of the preset region can be determined.

[0100] S704. When the lateral transport path of charge carriers in the measurement is from the first sub-region to the second sub-region, the size parameters of the lateral transport path are determined, including the width of the cell and the length of the cell on the lateral transport path.

[0101] Specifically, when at least a portion of the first sub-region 301 is illuminated, the sheet resistance is tested using the grayscale image of the illuminated area 303 and the grayscale image of the second sub-region 302 in the first sub-region 301. Then, charge carriers propagate from the illuminated area 303 to the second sub-region 302 in the first sub-region 301. In some embodiments, both the illuminated area 303 and the second sub-region 302 in the first sub-region 301 are rectangles, and the two adjacent sides of the two rectangles are parallel. If the other sides of the rectangles are shorter than the two adjacent sides (for example, both the illuminated area 303 and the second sub-region 302 in the first sub-region 301 are regions composed of multiple single pixels, and the length of the other sides is the length of a single pixel), then the length of the other sides of the rectangles can be ignored. The lateral transmission path 304 of the charge carriers is the area enclosed by the lines connecting the two adjacent sides and their endpoints in sequence. The width W of the solar cell on the lateral transmission path 304 is the average length of the two adjacent sides, and the length L of the solar cell on the lateral transmission path 304 is the distance between the two adjacent sides. In other embodiments, the irradiated area 303 and the second sub-region 302 in the first sub-region 301 are both rectangles, and the two sides of the two rectangles are parallel. If the lengths of the other sides of the rectangles are not ignored, the lateral transport path 304 of the charge carriers is the area enclosed by the lines connecting the central axis segments O1 and O2 of the two rectangles and their endpoints in sequence. The central axis segments O1 and O2 pass through the centroid of the corresponding rectangle, are parallel to the side of the other rectangle, and their endpoints are on the other two sides of the corresponding rectangle. The width W of the battery cell on the lateral transport path 304 is the average length of the two central axis segments, and the length L of the battery cell on the lateral transport path 304 is the distance between the two central axis segments. Figure 3 The dimensions of the lateral transmission path 304 are shown only as an example, ignoring the side lengths of the other sides of the rectangle.

[0102] S705. Calculate the sheet resistance of the cell under test based on the local resistance, the width of the cell in the lateral transmission path, and the length of the cell in the lateral transmission path.

[0103] Specifically, the sheet resistance of the cell under test is directly proportional to the local resistance and the width of the cell on the lateral transmission path 304, and inversely proportional to the length of the cell on the lateral transmission path 304. By substituting the local resistance determined in step S703 and the width and length of the cell on the lateral transmission path 304 determined in step S704 into the formula, the sheet resistance of the cell under test can be calculated. The formula represents the functional relationship between the sheet resistance and the local resistance, the width W of the cell on the lateral transmission path 304, and the length L of the cell on the lateral transmission path 304, respectively.

[0104] In the testing method provided in this embodiment, when at least a portion of the first sub-region is illuminated, grayscale images of the illuminated area and the second sub-region within the first sub-region are acquired. Based on the grayscale images of the illuminated area and the second sub-region, the local potentials of the illuminated area and the second sub-region within the first and second sub-regions are determined, respectively. The difference between the local potential of the illuminated area and the local potential of the second sub-region is used, combined with the photocurrent of the preset region, to calculate the local resistance of the preset region. When the lateral transport path of charge carriers in the measurement is from the first sub-region to the second sub-region, the size parameters of the lateral transport path are determined, including the width and length of the solar cell along the lateral transport path. Based on the local resistance, the width and length of the solar cell along the lateral transport path, the sheet resistance of the solar cell under test is calculated, thus realizing the measurement of the sheet resistance of the solar cell under test. This method uses grayscale images of the illuminated area and adjacent areas to determine the local potential. The large difference in grayscale between the two areas facilitates calculation, improving the accuracy of the test results.

[0105] This invention also provides a testing device. Figure 8 This is a schematic diagram of the composition of a speed measuring device provided in an embodiment of the present invention. Based on any of the foregoing embodiments, refer to... Figure 8 The testing device 103 includes a processor 801 and a memory 802. The processor 801 is coupled to the memory 802. The memory 802 is used to store programs or instructions. When the program or instructions are executed by the processor, the testing device 103 executes any testing method of the present invention.

[0106] The present invention also provides a computer-readable storage medium. The computer-readable storage medium stores computer instructions that, when executed by a processor, implement the test method described in any embodiment of the present invention.

[0107] The testing method, apparatus, system, and storage medium proposed in this invention utilize photoluminescence resistance (PRR) and / or electroluminescence resistance (EMR) methods to measure the local resistance of a preset region on a solar cell under test. The local resistance is the thin-layer resistance of the preset region. Based on the local resistance and the lateral transport path of charge carriers during measurement, the sheet resistance of the solar cell under test is calculated, thus achieving sheet resistance measurement. This method, based on PRR and / or EMR, measures the local resistance and calculates the sheet resistance by combining the local resistance and the lateral transport path of charge carriers. This testing method is simpler and easier to implement than the four-probe method, and compared to the surface photovoltage method, it is less affected by surface charge and does not require periodic calibration of the surface charge. It improves the reliability of the test results while reducing the complexity of the testing method.

[0108] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0109] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A testing method, characterized in that, include: The local resistance of a preset area on the battery cell under test is measured using photoluminescence resistance testing and / or electroluminescence resistance testing, wherein the local resistance is the thin-layer resistance of the preset area; The sheet resistance of the cell under test is calculated based on the local resistance and the lateral transport path of charge carriers during measurement.

2. The method according to claim 1, characterized in that, The preset region includes a first sub-region and a second sub-region; The method of measuring the local resistance of a preset area on the battery cell under test using photoluminescence resistance testing and / or electroluminescence resistance testing includes: When the battery cell under test is locally illuminated, the local potential of the first sub-region and the local potential of the second sub-region are determined according to the grayscale image of the preset area on the battery cell under test. The difference between the local potential of the first sub-region and the local potential of the second sub-region is used to calculate the local resistance of the preset region by combining the photocurrent of the preset region.

3. The method according to claim 2, characterized in that, The localized illumination area is the central circular area of ​​the battery cell under test; the preset area is the concentric annular area outside the central circular area; the first sub-area is the inner edge area of ​​the concentric annular area, and the second sub-area is the outer edge area of ​​the concentric annular area; The step of determining the local potential of the first sub-region and the local potential of the second sub-region based on the grayscale image of the preset area on the battery cell under local illumination includes: When the central circular region of the battery cell under test is illuminated, a grayscale image of the concentric ring region is acquired. Based on the grayscale parameters of the inner edge region and the outer edge region in the grayscale image, the local potential of the inner edge region and the local potential of the outer edge region are determined respectively.

4. The method according to claim 2, characterized in that, The first sub-region and the second sub-region are arranged adjacent to each other, and the area illuminated by the local light is at least a portion of the first sub-region; The step of determining the local potential of the first sub-region and the local potential of the second sub-region based on the grayscale image of the preset area on the battery cell under local illumination includes: When at least a portion of the first sub-region is illuminated, a grayscale image of the illuminated area in the first sub-region and a grayscale image of the second sub-region are acquired. Based on the grayscale images of the illuminated area in the first sub-region and the grayscale images of the second sub-region, the local potentials of the illuminated area in the first sub-region and the second sub-region are determined respectively.

5. The method according to claim 1, characterized in that, The step of calculating the sheet resistance of the cell under test based on the local resistance and the lateral transport path of charge carriers during measurement includes: Obtain the dimensional parameters of the lateral transport path of charge carriers during measurement; Based on the functional relationship between the sheet resistance of the battery cell under test and the size parameters and the local resistance, and in conjunction with the local resistance of the preset region, the sheet resistance of the battery cell under test is calculated.

6. The method according to claim 5, characterized in that, The preset area includes a first sub-region and a second sub-region; the irradiated area of ​​the local illumination in the photoluminescence resistance test method is the central circular area of ​​the battery cell under test; the preset area is the concentric ring area outside the central circular area; the first sub-region is the inner edge area of ​​the concentric ring area, and the second sub-region is the outer edge area of ​​the concentric ring area. The step of obtaining the size parameters of the lateral transport path of charge carriers in the measurement includes: when the lateral transport path of charge carriers in the measurement is from the inner edge region to the outer edge region, determining that the size parameters of the lateral transport path include the inner edge diameter and the outer edge diameter of the concentric annular region; The calculation of the sheet resistance of the battery cell under test, based on the functional relationship between the sheet resistance and the size parameters and the local resistance, combined with the local resistance of the preset region, includes: substituting the inner edge diameter, the outer edge diameter, and the local resistance into the first relational expression. Calculate the sheet resistance of the battery cell under test; wherein, R is the sheet resistance, d1 is the inner edge diameter, and d2 is the outer edge diameter.

7. The method according to claim 5, characterized in that, The preset area includes a first sub-region and a second sub-region; the first sub-region and the second sub-region are arranged adjacent to each other, and the irradiated area of ​​the local illumination in the photoluminescence resistance test method is at least a part of the first sub-region; The step of obtaining the size parameters of the lateral transport path of charge carriers in the measurement includes: when the lateral transport path of charge carriers in the measurement is from the first sub-region to the second sub-region, determining that the size parameters of the lateral transport path include the width of the solar cell on the lateral transport path and the length of the solar cell on the lateral transport path. The step of calculating the sheet resistance of the battery cell under test based on the functional relationship between the sheet resistance of the cell under test and the size parameters and the local resistance, combined with the local resistance of the preset region, includes: calculating the sheet resistance of the battery cell under test based on the local resistance, the width of the battery cell on the lateral transmission path, and the length of the battery cell on the lateral transmission path; wherein the sheet resistance of the battery cell under test is directly proportional to the local resistance and the width of the battery cell on the lateral transmission path, and inversely proportional to the length of the battery cell on the lateral transmission path.

8. A testing device, characterized in that, include: A processor coupled to a memory for storing programs or instructions that, when executed by the processor, cause the test apparatus to perform the test method as described in any one of claims 1 to 7.

9. A testing system, characterized in that, The device includes a testing apparatus, an image acquisition component, and a light source. The light source is used to emit light to a local area of ​​the battery cell under test. The image acquisition component is used to acquire a grayscale image of the battery cell under test. The testing apparatus is used to perform the testing method as described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program or instructions stored thereon, characterized in that, When the computer program or instructions are executed, the computer performs the test method as described in any one of claims 1-7.

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