Methods, equipment, and storage media for determining minority carrier lifetime of solar cells

Abstract

This application relates to the technical field of solar cells, and provides a method, device, and storage medium for determining the minority carrier lifetime of a solar cell. The method includes: determining the open-circuit voltage decay data of the solar cell according to the grayscale value image of the solar cell; the open-circuit voltage decay data refers to the difference between the first open-circuit voltage and the second open-circuit voltage; the first open-circuit voltage is the open-circuit voltage when the solar cell is irradiated with a light source; the second open-circuit voltage is the open-circuit voltage after the photogenerated carriers excited by the light source neutralize the charges on the surface of the solar cell; determining the minority carrier lifetime of the solar cell according to the open-circuit voltage decay data. Thus, it is possible to test the minority carrier lifetime on the surface of the solar cell when there are charges on the surface of the solar cell.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and in particular to a method, apparatus and storage medium for determining the minority carrier lifetime of a solar cell. Background Technology

[0002] Surface passivation of solar cells is a technique that generates a built-in electric field at the interface and uses the repulsion effect of like charges to prevent carriers of similar polarity from approaching, thereby reducing recombination and improving the performance of solar cells. In existing solutions, when there is a charge on the surface of the solar cell, it is difficult to test the minority carrier lifetime of the solar cell surface. Summary of the Invention

[0003] This application provides a method, apparatus, and storage medium for determining the minority carrier lifetime of a solar cell, which can test the surface minority carrier lifetime of the solar cell when there is a charge on the surface of the solar cell.

[0004] To achieve the above objectives, this application adopts the following technical solution: In a first aspect, a method for determining the minority carrier lifetime of a solar cell is provided, comprising: determining open-circuit voltage decay data of the solar cell based on a grayscale image of the solar cell; the open-circuit voltage decay data refers to the difference between a first open-circuit voltage and a second open-circuit voltage; the first open-circuit voltage is the open-circuit voltage when the solar cell is irradiated with a light source; the second open-circuit voltage is the open-circuit voltage after the photogenerated carriers excited by the light source neutralize the charge on the surface of the solar cell; and determining the minority carrier lifetime of the solar cell based on the open-circuit voltage decay data.

[0005] Based on this scheme, the open-circuit voltage decay data of the solar cell is determined according to the grayscale image of the solar cell. Then, based on this open-circuit voltage decay data, on the one hand, determining the open-circuit voltage decay data of the cell under test based on the grayscale image eliminates the need for a probe to contact the solar cell, enabling contactless determination of the open-circuit voltage decay data and thus determining the minority carrier lifetime of the solar cell. On the other hand, since the first open-circuit voltage is the open-circuit voltage when the solar cell is irradiated by a light source, and the second open-circuit voltage is the open-circuit voltage after the photogenerated carriers excited by the light source neutralize the charge on the surface of the solar cell, the minority carrier lifetime on the surface of the solar cell can be efficiently determined when there is a charge on the surface. In summary, this improves the measurement efficiency of the minority carrier lifetime when there is a charge on the surface of the solar cell.

[0006] In conjunction with the first aspect, in some embodiments of the first aspect, determining the minority carrier lifetime of a solar cell based on open-circuit voltage decay data includes: determining third open-circuit voltage data of the solar cell; the third open-circuit voltage data being the open-circuit voltage under conditions of no light source and no charge on the surface of the solar cell; determining a light neutralization time constant based on the open-circuit voltage decay data and the third open-circuit voltage data, and determining the light neutralization time constant as the minority carrier lifetime of the solar cell.

[0007] In conjunction with the first aspect, in some embodiments of the first aspect, the light neutralization time constant satisfies the following relationship: in, The time constant for light neutralization. This is open-circuit voltage attenuation data. This is the third open-circuit voltage data.

[0008] In conjunction with the first aspect, in some embodiments of the first aspect, the method further includes: acquiring a first grayscale image and a second grayscale image based on a graphics acquisition device; the first grayscale image refers to a grayscale image captured at the initial moment when the light source illuminates the solar cell; the second grayscale image refers to a grayscale image captured after the charge on the surface of the solar cell is neutralized by the photogenerated carriers excited by the light source; determining a first open-circuit voltage based on the first grayscale image and a preset relationship, and determining a second open-circuit voltage based on the second grayscale image and the preset relationship.

[0009] In conjunction with the first aspect, in some embodiments of the first aspect, the preset relationship includes: iVoc= ln( ) Where iVoc is the open-circuit voltage, k is the Boltzmann constant, T is the temperature of the solar cell, Ai is the range factor, and B is the photopolymerization coefficient. Intrinsic carrier concentration, is the average gray value of the grayscale image, and q is the intrinsic carrier concentration.

[0010] In conjunction with the first aspect, in some embodiments of the first aspect, acquiring a first grayscale image includes: depositing charge on the surface of a solar cell; and acquiring the first grayscale image under illumination by a light source.

[0011] In conjunction with the first aspect, in some embodiments of the first aspect, acquiring a second grayscale image includes: after acquiring a first grayscale image, taking multiple grayscale images of the solar cell according to a preset period to obtain multiple grayscale images; and determining the grayscale image as the second grayscale image when the average grayscale value of two adjacent grayscale images no longer changes.

[0012] In conjunction with the first aspect, in some embodiments of the first aspect, the image acquisition device is a line scan camera or an area scan camera.

[0013] Secondly, this application also provides a silicon wafer and an electronic device for implementing the testing method of the first aspect described above. The electronic device includes: an acquisition module and a determination module; the acquisition module is used to determine open-circuit voltage decay data of a solar cell; the open-circuit voltage decay data refers to the difference between a first open-circuit voltage and a second open-circuit voltage; the first open-circuit voltage is the open-circuit voltage when the solar cell is irradiated with a light source; the second open-circuit voltage is the open-circuit voltage after the photogenerated carriers excited by the light source neutralize the charge on the surface of the solar cell; the determination module is used to determine the minority carrier lifetime of the solar cell based on the open-circuit voltage decay data.

[0014] In conjunction with the second aspect, in some embodiments of the second aspect, the determining module is specifically used to: determine the third open-circuit voltage data of the solar cell; the third open-circuit voltage data is the open-circuit voltage under the condition of no light source and no charge on the surface of the solar cell; determine the light neutralization time constant based on the open-circuit voltage decay data and the third open-circuit voltage data, and determine the light neutralization time constant as the minority carrier lifetime of the solar cell.

[0015] In conjunction with the second aspect, in some embodiments of the second aspect, the light neutralization time constant satisfies the following relationship: in, The time constant for light neutralization. This is open-circuit voltage attenuation data. This is the third open-circuit voltage data.

[0016] In conjunction with the second aspect, in some embodiments of the second aspect, the determining module is specifically used to: acquire a first grayscale image and a second grayscale image based on a graphics acquisition device; the first grayscale image refers to a grayscale image captured at the initial moment when the light source illuminates the solar cell; the second grayscale image refers to a grayscale image captured after the charge on the surface of the solar cell is neutralized in the photogenerated carriers excited by the light source; determine a first open-circuit voltage based on the first grayscale image and a preset relationship, and determine a second open-circuit voltage based on the second grayscale image and the preset relationship.

[0017] In conjunction with the second aspect, in some embodiments of the second aspect, the preset relationships include: iVoc= ln( ) Where iVoc is the open-circuit voltage, k is the Boltzmann constant, T is the temperature of the solar cell, Ai is the range factor, and B is the photopolymerization coefficient. Intrinsic carrier concentration, is the average gray value of the grayscale image, and q is the intrinsic carrier concentration.

[0018] In conjunction with the second aspect, in some embodiments of the second aspect, the acquisition module is further configured to: deposit charge on the surface of a solar cell; and acquire a first grayscale image under illumination by a light source.

[0019] In conjunction with the second aspect, in some embodiments of the second aspect, the acquisition module is further configured to: after acquiring the first grayscale image, take multiple grayscale images of the solar cell according to a preset period to obtain multiple grayscale images; and determine the grayscale image as the second grayscale image when the average grayscale value of two adjacent grayscale images no longer changes.

[0020] In conjunction with the second aspect, in some embodiments of the second aspect, the image acquisition device is a line scan camera or an area scan camera.

[0021] Thirdly, an electronic device is provided, comprising: at least one processor and a memory for storing processor-executable instructions; wherein the processor is configured to execute the instructions to implement the methods provided by the first aspect and any possible implementation thereof.

[0022] Fourthly, a computer-readable storage medium is provided, wherein when instructions in the computer-readable storage medium are executed by a processor of an electronic device, the electronic device is enabled to perform the methods provided in the first aspect and any possible embodiments thereof.

[0023] Fifthly, a computer program product containing instructions is provided that, when run on a computer, enables the computer to perform the methods provided in the first aspect and any possible implementation thereof.

[0024] The technical effects of any one of the second to fifth aspects can be found in the technical effects of the different embodiments of the first aspect described above, and will not be repeated here. Attached Figure Description

[0025] Figure 1 A schematic diagram of the structure of a minority carrier lifetime determination system for a solar cell provided in this application; Figure 2 A schematic diagram of the structure of another minority carrier lifetime determination system for solar cells provided in this application; Figure 3 A flowchart illustrating a method for determining the minority carrier lifetime of a solar cell provided in this application; Figure 4A flowchart illustrating another method for determining the minority carrier lifetime of a solar cell provided in this application; Figure 5 A flowchart illustrating another method for determining the minority carrier lifetime of a solar cell provided in this application; Figure 6 A flowchart illustrating another method for determining the minority carrier lifetime of a solar cell provided in this application; Figure 7 A flowchart illustrating another method for determining the minority carrier lifetime of a solar cell provided in this application; Figure 8 A schematic diagram of the structure of an electronic device provided in this application; Figure 9 A schematic diagram of the structure of another electronic device provided in this application. Detailed Implementation

[0026] In the description of this application, unless otherwise stated, "multiple" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0027] Furthermore, to facilitate a clear description of the technical solutions in the embodiments of this application, the terms "first" and "second" are used in the embodiments of this application to distinguish identical or similar items with substantially the same function and effect. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and the terms "first" and "second" are not necessarily different.

[0028] In this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being better or more advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner to facilitate understanding.

[0029] It is understood that the term "embodiment" used throughout the specification means that a specific feature, structure, or characteristic related to an embodiment is included in at least one embodiment of this application. Therefore, various embodiments throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It is understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0030] It is understood that in this application, "when," "if," and "if" all refer to the corresponding processing that will be carried out under certain objective circumstances, and are not limited to a specific time, nor do they require that there must be a judgment action when implemented, nor do they imply any other limitations.

[0031] It is understood that some optional features in the embodiments of this application can be implemented independently in certain scenarios without relying on other features, such as the current solution on which they are based, to solve the corresponding technical problems and achieve the corresponding effects. Alternatively, they can be combined with other features as needed in certain scenarios. Correspondingly, the electronic devices given in the embodiments of this application can also implement these features or functions, which will not be elaborated here.

[0032] In this application, unless otherwise specified, the same or similar parts between the various embodiments can be referred to each other. In the various embodiments and implementation methods of the various embodiments in this application, unless otherwise specified or logically conflicting, the terminology and / or descriptions between different embodiments and between the implementation methods of the various embodiments are consistent and can be mutually referenced. The technical features in different embodiments and between the implementation methods of the various embodiments can be combined according to their inherent logical relationships to form new embodiments, implementation methods, implementation methods, or implementation approaches. The following embodiments of this application do not constitute a limitation on the scope of protection of this application.

[0033] In some solar cells, the grid lines in different polarity regions overlap, causing electrical conduction between the grid lines in different polarity regions.

[0034] To better understand the technical solution proposed in this application, some key terms involved will be explained first: Minority carrier lifetime: Minority carrier lifetime refers to the average survival time of minority carriers. It represents the time it takes for the minority carrier concentration to decrease to 1 / e of its original value. For solar cells, the shorter the minority carrier lifetime, the lower the cell efficiency.

[0035] Minority carriers: a concept in semiconductor physics, referring to the minority of charge carriers. It is the opposite of majority carriers.

[0036] Semiconductor materials contain two types of charge carriers: electrons and holes. If a certain type of charge carrier is in the minority and plays a minor role in conductivity, it is called a minority carrier. For example, in an N-type semiconductor, holes are minority carriers and electrons are majority carriers; in a P-type semiconductor, holes are majority carriers and electrons are minority carriers.

[0037] Surface passivation of solar cells is a technique that generates a built-in electric field at the interface and uses the repulsion effect of like charges to prevent carriers of similar polarity from approaching, thereby reducing recombination and improving the performance of solar cells. In existing solutions, when there is a charge on the surface of the solar cell, it is difficult to test the minority carrier lifetime of the solar cell surface.

[0038] To address the aforementioned problems, this application provides a method for determining the minority carrier lifetime of a solar cell. Figure 1 This application provides a schematic diagram of the structure of a detection system, and the method can be applied to... Figure 1 The detection system shown. (As shown) Figure 1 As shown, the detection system includes an electronic device 101, an image acquisition device 102, a first light source 103, a second light source 104, and a corona gun 105.

[0039] Electronic device 101 is communicatively connected to image acquisition device 102, for example, it can be a wired connection or a wireless connection, and there is no limitation on this.

[0040] Image acquisition device 102 is used to acquire grayscale images of solar cells under the action of first light source 103 and second light source 104, and send the grayscale images to electronic device 101.

[0041] Light sources 103 and 104 are used to emit light onto the solar cell to make the solar cell emit light.

[0042] The corona gun 105 is used to deposit charge onto solar cells.

[0043] Optional, Figure 1 In the detection system shown, the first light source 103 can be a bias light source and the second light source 104 can be a frequency scan area array light source.

[0044] Optional, Figure 1 In the detection system shown, the image acquisition device 102 can be a PL camera.

[0045] Optional, Figure 1 In the detection system shown, the type of solar cell may include OBB, MBB IBC, ABC, HPBC, PERC, TBC, TOPcon, HJT or perovskite tandem cells, and this application does not impose any specific restrictions on this.

[0046] Optional, Figure 1 In the detection system shown, the image acquisition device 102 can be a silicon-based CCD, InGaAs, InSb, HgCdTd, or other image acquisition device capable of detecting the luminescence characteristics of Si-based photovoltaic cells. Alternatively, the image acquisition device 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 any specific limitations on this.

[0047] In some embodiments, Figure 1 In the detection system shown, electronic device 101 and image acquisition device 102 can be integrated into the same device, or electronic device 101 and image acquisition device 102 can be independent devices. This application does not impose any specific restrictions on this.

[0048] Figure 2 This application provides a schematic diagram of the structure of a detection system, and the method can be applied to... Figure 2 The detection system shown. (As shown) Figure 2 As shown, the detection system includes an electronic device 101, an image acquisition device 102, a first light source 103, and a corona gun 104.

[0049] Optional, Figure 2 In the detection system shown, the first light source 103 can be a line scan light source. Other specific descriptions can be found in the above sections and will not be repeated here.

[0050] Figure 3 This application provides a flowchart illustrating a method for determining the minority carrier lifetime of a solar cell, as shown below. Figure 3 As shown, the method includes the following steps: S301. Determine the open-circuit voltage attenuation data of the solar cell based on the grayscale image of the solar cell.

[0051] The open-circuit voltage decay data refers to the difference between the first open-circuit voltage and the second open-circuit voltage; the first open-circuit voltage is the open-circuit voltage when the solar cell is irradiated by a light source; the second open-circuit voltage is the open-circuit voltage after the photogenerated carriers excited by the light source neutralize the charge on the surface of the solar cell.

[0052] One possible implementation is to pre-deposit charge on the surface of the solar cell using a corona gun. After depositing the charge, the solar cell is irradiated with a light source, and the open-circuit voltage of the solar cell is measured at the moment of irradiation, which is taken as the first open-circuit voltage. After the photogenerated carriers excited by the light source neutralize the charge on the surface of the solar cell, the open-circuit voltage of the solar cell is measured as the second open-circuit voltage, and the difference between the first open-circuit voltage and the second open-circuit voltage is taken as the open-circuit voltage decay data of the solar cell.

[0053] In some embodiments, the open-circuit voltage of a solar cell can also be measured using a metal probe, and this is not a limitation.

[0054] It should be noted that the specific details of determining the open-circuit voltage attenuation data of solar cells based on the grayscale image of the solar cells can be found in the following sections, and will not be repeated here.

[0055] S302. Determine the minority carrier lifetime of the solar cell based on the open-circuit voltage decay data.

[0056] Among them, since charges are pre-deposited on the surface of the solar cell, the minority carrier lifetime of the solar cell refers to the minority carrier lifetime on the surface of the solar cell when there are charges on the surface of the solar cell.

[0057] As one possible approach, the open-circuit voltage of a solar cell can be tested under conditions of no light source and no charge on the surface of the solar cell. This test is then used as the third open-circuit voltage data. Based on the open-circuit voltage decay data and the third open-circuit voltage data, the light neutralization time constant can be determined, and this light neutralization time constant can be defined as the minority carrier lifetime of the solar cell.

[0058] It should be noted that the light neutralization time constant satisfies the following relationship: in, The time constant for light neutralization. This is open-circuit voltage attenuation data. This is the third open-circuit voltage data.

[0059] In some embodiments, the open-circuit voltage of the solar cell can be tested under conditions of darkness and steady state, and used as a third open-circuit voltage data. The light neutralization time constant can be determined based on the open-circuit voltage decay data and the third open-circuit voltage data, and the light neutralization time constant can be determined as the minority carrier lifetime of the solar cell.

[0060] Understandably, the open-circuit voltage decay data of a solar cell can be determined based on its grayscale image. Furthermore, this open-circuit voltage decay data allows for contactless determination of the open-circuit voltage decay data and minority carrier lifetime. On the other hand, since the first open-circuit voltage is the voltage when the solar cell is irradiated by a light source, and the second open-circuit voltage is the voltage after the photogenerated carriers excited by the light source neutralize the charge on the surface of the solar cell, the minority carrier lifetime on the solar cell surface can be efficiently determined when a charge exists on the surface. In summary, this improves the measurement efficiency of minority carrier lifetime when a charge exists on the surface of the solar cell.

[0061] The above is a general description of the method for determining the minority carrier lifetime of the solar cell provided in this application. The following will provide a further explanation of the method for determining the minority carrier lifetime of the solar cell provided in this application in conjunction with the accompanying drawings.

[0062] In one possible embodiment, Figure 4 A flowchart illustrating yet another method for determining the minority carrier lifetime of a solar cell is shown, such as... Figure 4 As shown, in order to determine the minority carrier lifetime of a solar cell based on open-circuit voltage decay data, the above-mentioned S302 in this application may specifically include the following steps: S401. Determine the third open-circuit voltage data of the solar cell.

[0063] The third open-circuit voltage data is the open-circuit voltage under the condition of no light source and no charge on the surface of the solar cell.

[0064] One possible approach is to place the solar cell in darkness before depositing charge on its surface, and then capture a grayscale image of the solar cell while it is in a steady state. The open-circuit voltage of the solar cell can then be determined based on the grayscale image as a third open-circuit voltage data.

[0065] It should be noted that the getter chamber can be a high-temperature diffusion furnace.

[0066] As another possible implementation, the solar cell can be placed in darkness before the charge is deposited on its surface, and the open-circuit voltage of the solar cell can be measured using a metal probe while the solar cell is in a steady state, as a third open-circuit voltage data.

[0067] S402. Based on the open-circuit voltage decay data and the third open-circuit voltage data, determine the light neutralization time constant and define the light neutralization time constant as the minority carrier lifetime of the solar cell.

[0068] It should be noted that the specific details of the light neutralization time constant can be found in the explanations above, and are not limited here.

[0069] In this way, the dynamic process of photogenerated carrier recombination can be accurately captured, and combined with the third open-circuit voltage data, external interference can be eliminated, improving the measurement accuracy of minority carrier lifetime of solar cells. At the same time, grayscale images can achieve non-contact, non-destructive testing, avoiding sample damage; and providing a reliable basis for process optimization and material performance evaluation.

[0070] In one possible embodiment, Figure 5 A flowchart illustrating another method for determining the minority carrier lifetime of a solar cell provided in this application is shown below. Figure 5 As shown in the specific embodiments of this application, in order to determine the first open-circuit voltage and the second open-circuit voltage, this application may further include the following steps: S501. Acquire a first grayscale image and a second grayscale image based on a graphics acquisition device.

[0071] The first grayscale image refers to the grayscale image taken at the initial moment when the light source illuminates the solar cell; the second grayscale image refers to the grayscale image taken after the photogenerated carriers excited by the light source neutralize the charge on the surface of the solar cell.

[0072] The image acquisition equipment is either a line scan camera or an area scan camera.

[0073] Grayscale images can also be called photoluminescence (PL) images. Photoluminescence refers to the process by which a material (e.g., the battery cell under test in this embodiment) absorbs photon energy and is excited when irradiated by light. Subsequently, the excited electrons transition to lower energy levels and release energy, which is emitted in the form of photons, forming a light emission phenomenon. A grayscale image is an image obtained by an image acquisition device capturing this light emission phenomenon.

[0074] As one possible implementation, the electronic device can receive a message from an image acquisition device, the message including a first grayscale image and a second grayscale image, and the electronic device can obtain the first grayscale image and the second grayscale image from the message.

[0075] S502. Determine the first open-circuit voltage based on the first grayscale image and the preset relationship, and determine the second open-circuit voltage based on the second grayscale image and the preset relationship.

[0076] The phosphorus source is one of phosphorus oxychloride, trimethylphosphorus, triethylphosphorus, phosphorus pentoxide, or diethylphosphorus hydroxide.

[0077] It should be noted that the preset relationships include: iVoc= ln( ) Where iVoc is the open-circuit voltage, k is the Boltzmann constant, T is the temperature of the solar cell, Ai is the range factor, and B is the photopolymerization coefficient. Intrinsic carrier concentration, is the average gray value of the grayscale image, and q is the intrinsic carrier concentration.

[0078] As an example, for a first grayscale image, the electronic device determines the average grayscale value of the first grayscale image. The electronic device substitutes each parameter in the above preset relationship into the preset relationship to obtain iVoc1.

[0079] For example, an electronic device can determine the gray value of each pixel in a first grayscale image, and determine the average gray value of the first grayscale image as the ratio of the sum of the gray values ​​of each pixel to the number of pixels. .

[0080] For example, an electronic device can determine the gray values ​​of a subset of pixels in a first grayscale image, and determine the average gray value of the first grayscale image as the ratio of the sum of the gray values ​​of the subset of pixels to the number of the subset of pixels. .

[0081] For the second grayscale image, the electronic device determines the average grayscale value of the second grayscale image. The electronic device substitutes each parameter in the above preset relationship into the preset relationship to obtain iVoc2.

[0082] For example, an electronic device can determine the gray value of each pixel in a second grayscale image, and determine the average gray value of the second grayscale image as the ratio of the sum of the gray values ​​of each pixel to the number of pixels. .

[0083] For example, an electronic device can determine the grayscale values ​​of a subset of pixels in a second grayscale image, and determine the average grayscale value of the second grayscale image as the ratio of the sum of the grayscale values ​​of the subset of pixels to the number of the subset of pixels. .

[0084] Thus, by determining the open-circuit voltage decay data of the solar cell under test based on grayscale images, it is possible to determine the open-circuit voltage decay data of the solar cell without the probe contacting the solar cell, thereby determining the minority carrier lifetime of the solar cell. In one possible embodiment, Figure 6 A flowchart illustrating another method for determining the minority carrier lifetime of a solar cell provided in this application is shown below. Figure 6As shown in the specific embodiments of this application, in order to obtain the first grayscale image, this application may further include the following steps: S601, Deposit charge on the surface of solar cell.

[0085] One possible approach is to use a corona gun to deposit charges on the surface of a solar cell.

[0086] It should be noted that a corona gun is a charge emitter that uses gas ionization to generate charged particles and forces them to exit through a small hole under the focusing effect of an electric field. The corona gun generates a strong electric field through high-voltage electrodes (such as thin metal wires), which ionizes the surrounding gas molecules into charged particles. The corona gun is designed with an electric field focusing structure, such as a small hole or lens, to focus the charged particles and guide them to the exit port. Under the focusing effect of the electric field, the charged particles are emitted from the small hole, forming a charge beam. The charge beam is guided to the surface of the solar cell, where the charged particles are deposited on the surface of the solar cell to deposit charge.

[0087] S602. Under illumination by a light source, acquire the first grayscale image.

[0088] In this way, the first grayscale image of the solar cell with surface charge can be obtained.

[0089] In one possible embodiment, Figure 7 A flowchart illustrating another method for determining the minority carrier lifetime of a solar cell provided in this application is shown below. Figure 7 As shown in the specific embodiments of this application, in order to obtain the second grayscale image, this application may further include the following steps: S701. After acquiring the first grayscale image, the grayscale images of the solar cell are captured multiple times according to a preset cycle to obtain multiple grayscale images.

[0090] The preset period can be set as needed and is not restricted here.

[0091] Understandably, by continuously capturing multiple grayscale images, we can analyze the average grayscale value corresponding to different grayscale images, so as to determine the charge in the photogenerated carriers excited by the light source and the charge on the surface of the solar cell in a timely manner.

[0092] S702. When the average gray value of two adjacent gray value images no longer changes, determine the gray value image as the second gray value image.

[0093] In some embodiments, a grayscale image can be identified as the second grayscale image if the average rate of change of grayscale values ​​between two adjacent grayscale images is less than a rate of change threshold. The rate of change threshold can be set as needed and is not limited here.

[0094] In some other embodiments, a grayscale image can be determined as the second grayscale image if the average grayscale value of three adjacent grayscale images no longer changes.

[0095] It should be noted that after determining the second grayscale image, the capture of the grayscale values ​​of the solar cell can be stopped.

[0096] In this way, the grayscale images corresponding to the charges in the photogenerated carriers excited by the light source and the charges on the surface of the solar cell can be determined in a timely manner, thereby improving the efficiency of determining the minority carrier lifetime of the solar cell.

[0097] The foregoing mainly describes the solutions provided by the embodiments of this application from the perspective of electronic devices performing test methods. To achieve the above functions, the electronic device includes hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily recognize that, in conjunction with the units and algorithm steps of the various examples described in the embodiments disclosed herein, the embodiments of this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0098] This application embodiment can divide the electronic device into functional modules according to the above method example. For example, each function can be divided into a separate functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. Optionally, the module division in this application embodiment is illustrative and only represents one logical functional division; other division methods may be used in actual implementation. Furthermore, "module" here can refer to an application-specific integrated circuit (ASIC), a circuit, a processor and memory that executes one or more software or firmware programs, integrated logic circuits, and / or other devices that can provide the above functions.

[0099] When using functional module division Figure 8 A schematic diagram of the structure of an electronic device is shown. Figure 8 As shown, the electronic device 80 includes an acquisition module 801 and a determination module 802.

[0100] In some embodiments, the electronic device 80 may further include a storage module ( Figure 8 (not shown in the image) is used to store program instructions and data.

[0101] The acquisition module 801 is used to determine the open-circuit voltage decay data of the solar cell; the open-circuit voltage decay data refers to the difference between the first open-circuit voltage and the second open-circuit voltage; the first open-circuit voltage is the open-circuit voltage when the solar cell is irradiated with a light source; the second open-circuit voltage is the open-circuit voltage after the photogenerated carriers excited by the light source neutralize the charge on the surface of the solar cell; the determination module 802 is used to determine the minority carrier lifetime of the solar cell based on the open-circuit voltage decay data.

[0102] Optionally, the determining module 802 is specifically used to: determine the third open-circuit voltage data of the solar cell; the third open-circuit voltage data is the open-circuit voltage under the condition of no light source and no charge on the surface of the solar cell; determine the light neutralization time constant based on the open-circuit voltage decay data and the third open-circuit voltage data, and determine the light neutralization time constant as the minority carrier lifetime of the solar cell.

[0103] Optionally, the light neutralization time constant satisfies the following relationship: in, The time constant for light neutralization. This is open-circuit voltage attenuation data. This is the third open-circuit voltage data.

[0104] Optionally, the determining module 802 is specifically used to: acquire a first grayscale image and a second grayscale image based on the image acquisition device; the first grayscale image refers to the grayscale image captured at the initial moment when the light source illuminates the solar cell; the second grayscale image refers to the grayscale image captured after the photogenerated carriers excited by the light source and the charge on the surface of the solar cell are neutralized; determine a first open-circuit voltage based on the first grayscale image and a preset relationship, and determine a second open-circuit voltage based on the second grayscale image and the preset relationship.

[0105] Optional, preset relationships include: iVoc= ln( ) Where iVoc is the open-circuit voltage, k is the Boltzmann constant, T is the temperature of the solar cell, Ai is the range factor, and B is the photopolymerization coefficient. Intrinsic carrier concentration, is the average gray value of the grayscale image, and q is the intrinsic carrier concentration.

[0106] Optionally, the acquisition module 801 is also used to: deposit charge on the surface of the solar cell; and acquire a first grayscale image under illumination by a light source.

[0107] Optionally, the acquisition module 801 is further configured to: after acquiring the first grayscale image, take multiple grayscale images of the solar cell according to a preset period to obtain multiple grayscale images; and determine the grayscale image as the second grayscale image when the average grayscale value of two adjacent grayscale images no longer changes.

[0108] Optionally, the image acquisition device can be a line scan camera or an area scan camera.

[0109] All relevant content of each step involved in the above method embodiments can be referenced from the functional description of the corresponding functional module, and will not be repeated here.

[0110] When the functions of the above modules are implemented in hardware... Figure 9 A schematic diagram of the structure of yet another electronic device is shown. For example... Figure 9 As shown, the electronic device 90 includes a processor 901, a memory 902, and a bus 903. The processor 901 and the memory 902 can be connected via the bus 903.

[0111] Processor 901 is the control center of electronic device 90. It can be a single processor or a collective term for multiple processing elements. For example, processor 901 can be a general-purpose central processing unit (CPU) or other general-purpose processors. Among them, the general-purpose processor can be a microprocessor or any conventional processor.

[0112] As one embodiment, processor 901 may include one or more CPUs, for example Figure 9 CPU 0 and CPU 1 are shown in the diagram.

[0113] The memory 902 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or electrically erasable programmable read-only memory (EEPROM), disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but is not limited thereto.

[0114] As one possible implementation, the memory 902 can exist independently of the processor 901. The memory 902 can be connected to the processor 901 via a bus 903 and is used to store instructions or program code. When the processor 901 calls and executes the instructions or program code stored in the memory 902, it can implement the testing method provided in the embodiments of this application.

[0115] In another possible implementation, the memory 902 can also be integrated with the processor 901.

[0116] Bus 903 can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. This bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 9 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0117] It should be pointed out that, Figure 9 The structure shown does not constitute a limitation on the electronic device 90. Except... Figure 9 In addition to the components shown, the electronic device 90 may include more or fewer components than illustrated, or combine certain components, or have different component arrangements.

[0118] As an example, combined Figure 8 The functions implemented by the acquisition module 501 and the determination module 502 in the electronic device 50 are the same as those of the acquisition module 501 and the determination module 502. Figure 9 The processor 901 in it has the same function.

[0119] Optional, such as Figure 9 As shown, the electronic device 90 provided in this application embodiment may further include a communication interface 904.

[0120] Communication interface 904 is used to connect with other devices via a communication network. This communication network can be Ethernet, a wireless access network, a wireless local area network (WLAN), etc. Communication interface 904 may include a receiving unit for receiving data and a transmitting unit for sending data.

[0121] In one possible implementation, the communication interface 904 in the electronic device 90 provided in this application embodiment can also be integrated into the processor 901, and this application embodiment does not specifically limit this.

[0122] As one possible product form, the electronic device of the present application embodiment can also be implemented using the following: one or more field programmable gate arrays (FPGAs), programmable logic devices (PLDs), controllers, state machines, gate logic, discrete hardware components, any other suitable circuits, or any combination of circuits capable of performing the various functions described throughout this application.

[0123] Through the above description of the embodiments, those skilled in the art will clearly understand that, for the sake of convenience and brevity, only the division of the above functional units is used as an example. In practical applications, the above functions can be assigned to different functional units as needed, that is, the internal structure of the device can be divided into different functional units to complete all or part of the functions described above. The specific working process of the system, device, and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0124] This application also provides a computer-readable storage medium storing a computer program or instructions thereon, which, when executed, causes a computer to perform the various steps in the method flow shown in the above method embodiments.

[0125] Embodiments of this application provide a computer program product containing instructions that, when executed on a computer, cause the computer to perform the various steps in the method flow shown in the above-described method embodiments.

[0126] This application provides a chip system, including: a processor and an interface circuit; the interface circuit is used to receive computer programs or instructions and transmit them to the processor; the processor is used to execute the computer programs or instructions so that the chip system performs each step in the method flow shown in the above method embodiments.

[0127] The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), registers, hard disks, optical fibers, compact disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing, or any other form of computer-readable storage medium in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium may also be a component of the processor. The processor and the storage medium may reside in a purpose-specific ASIC. In the embodiments of this application, the computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0128] Since the electronic device, computer-readable storage medium, and computer program product provided in this embodiment can be applied to the testing method provided in this embodiment, the technical effects they can achieve can also be referred to the above method embodiments. The embodiments of this application will not be repeated here.

[0129] Although this application has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the accompanying drawings, disclosure, and appended claims, will understand and implement other variations of the disclosed embodiments in carrying out the claimed application. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple instances. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0130] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of this application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from the spirit and scope of this application. Thus, if such modifications and modifications of this application fall within the scope of the claims of this application and their equivalents, this application is also intended to include such modifications and modifications.

Claims

1. A method for determining the minority carrier lifetime of a solar cell, characterized in that, The method includes: Based on the grayscale image of the solar cell, the open-circuit voltage decay data of the solar cell is determined; the open-circuit voltage decay data refers to the difference between the first open-circuit voltage and the second open-circuit voltage; the first open-circuit voltage is the open-circuit voltage when the solar cell is irradiated with a light source; the second open-circuit voltage is the open-circuit voltage after the photogenerated carriers excited by the light source neutralize the charge on the surface of the solar cell. The minority carrier lifetime of the solar cell is determined based on the open-circuit voltage decay data.

2. The method according to claim 1, characterized in that, Determining the minority carrier lifetime of the solar cell based on the open-circuit voltage decay data includes: Determine the third open-circuit voltage data of the solar cell; the third open-circuit voltage data is the open-circuit voltage under the condition of no light source and no charge on the surface of the solar cell; Based on the open-circuit voltage decay data and the third open-circuit voltage data, the light neutralization time constant is determined, and the light neutralization time constant is determined as the minority carrier lifetime of the solar cell.

3. The method according to claim 2, characterized in that, The light neutralization time constant satisfies the following relationship: in, The time constant for light neutralization is... For the open-circuit voltage attenuation data, This refers to the third open-circuit voltage data.

4. The method according to claim 1, characterized in that, The method further includes: A first grayscale image and a second grayscale image are acquired using an image acquisition device; the first grayscale image refers to the grayscale image captured at the initial moment when the light source illuminates the solar cell; the second grayscale image refers to the grayscale image captured after the photogenerated charge carriers excited by the light source and the charge on the surface of the solar cell are charged. The first open-circuit voltage is determined based on the first grayscale image and a preset relationship, and the second open-circuit voltage is determined based on the second grayscale image and the preset relationship.

5. The method according to claim 4, characterized in that, The preset relationships include: iVoc= ln( ) Where iVoc is the open-circuit voltage, k is the Boltzmann constant, T is the temperature of the solar cell, Ai is the range factor, and B is the photopolymerization coefficient. Intrinsic carrier concentration, is the average gray value of the grayscale image, and q is the intrinsic carrier concentration.

6. The method according to claim 4, characterized in that, The process of obtaining the first grayscale image includes: Charge is deposited on the surface of the solar cell; Under the illumination of the light source, the first grayscale image is acquired.

7. The method according to claim 4, characterized in that, The process of obtaining the second grayscale image includes: After acquiring the first grayscale image, the grayscale images of the solar cell are captured multiple times according to a preset period to obtain multiple grayscale images; If the average gray value of two adjacent gray value images no longer changes, the gray value image is determined to be the second gray value image.

8. The method according to claim 4, characterized in that, The image acquisition device is a line scan camera or an area scan camera.

9. An electronic device, characterized in that, include: Get the module and determine the module; The acquisition module is used to determine the open-circuit voltage decay data of the solar cell; the open-circuit voltage decay data refers to the difference between the first open-circuit voltage and the second open-circuit voltage; the first open-circuit voltage is the open-circuit voltage when the solar cell is irradiated with a light source; the second open-circuit voltage is the open-circuit voltage after the photogenerated carriers excited by the light source neutralize the charge on the surface of the solar cell. The determining module is used to determine the minority carrier lifetime of the solar cell based on the open-circuit voltage decay data.

10. An electronic device, characterized in that, The electronic device includes: a processor coupled to a memory for storing programs or instructions that, when executed by the processor, cause the electronic device to perform the method as described in any one of claims 1 to 8.

11. A computer-readable storage medium having a computer program or instructions stored thereon, characterized in that, When the computer program or instructions are executed, they cause the computer to perform the method as described in any one of claims 1 to 8.

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