Detection method for solar cell and related equipment

Abstract

The invention relates to a detection method and related equipment for a solar cell, and the method comprises the steps: obtaining a measurement point position of a surface film of a to-be-detected solar cell, and determining a detection light source based on the to-be-detected solar cell; irradiating the measuring point film at the measuring point position by using a detection light source to obtain the reflectivity of the measuring point film; obtaining the film thickness of the measuring point film based on the surface film, the detection light source and the reflectivity; and obtaining a detection result of the to-be-detected solar cell based on the reflectivity and the film thickness. By using the method of the invention, efficient and accurate automatic detection can be performed on the solar cell.

Description

Background Art

[0002] Improving the efficiency and reducing the cost of crystalline silicon cells is the key to the development of solar cell technology. Its conversion efficiency is affected by two factors: the cell itself and sunlight. Surface passivation and reducing surface reflection losses have always been the research topics of solar cells, so higher requirements are placed on the production process and quality of solar cells. These requirements make solar companies urgently need advanced testing equipment to automatically test solar cells in order to improve the accuracy and efficiency of testing. Therefore, there is an urgent need for a method that can automatically test solar cells efficiently and accurately. Summary of the invention

[0003] In order to solve the above problems, the present application provides a detection method and related equipment for solar cells.

[0004] In the first aspect, in order to solve the above technical problems, the present application provides a detection method for solar cells, comprising:

[0005] Obtaining the measurement point position of the surface film of the solar cell to be tested, and determining the detection light source based on the solar cell to be tested;

[0006] Using a detection light source to illuminate a measuring point film located at a measuring point position, and obtaining the reflectivity of the measuring point film;

[0007] Based on the surface film, detection light source and reflectivity, the film thickness of the film at the measuring point is obtained;

[0008] The test results of the solar cell to be tested are obtained based on the reflectivity and film thickness.

[0009] In a second aspect, the present application also provides a solar cell detection device, which uses a detection method for solar cells; the device includes a detection light source, a spectrum detection module and a probe; the detection light source and the spectrum detection module are connected to the probe through an optical fiber;

[0010] When testing the surface film of the solar cell to be tested, the light emitted by the detection light source is controlled to irradiate the measurement point film located at the measurement point position of the surface film through the probe, and the reflectivity of the measurement point film is obtained by using the spectral detection module, so as to obtain the film thickness of the measurement point film based on the surface film, the detection light source and the reflectivity.

[0011] In a third aspect, the present application also provides a detection system for solar cells, comprising:

[0012] An acquisition module is used to acquire the measurement point position of the surface film of the solar cell to be tested, and determine the detection light source based on the solar cell to be tested;

[0013] An irradiation module is used to irradiate a measuring point film located at a measuring point position with a detection light source to obtain a reflectivity of the measuring point film;

[0014] The first obtaining module is used to obtain the film thickness of the film at the measuring point based on the surface film, the detection light source and the reflectivity;

[0015] The second obtaining module is used to obtain the detection result of the solar cell to be tested based on the reflectivity and film thickness.

[0016] In a fourth aspect, the present application also provides a computing device, including a memory, a processor, and a program stored in the memory and running on the processor, and when the processor executes the program, the steps of a detection method for solar cells as described above are implemented.

[0017] In a fifth aspect, the present application also provides a computer-readable storage medium, in which instructions are stored. When the instructions are executed on a terminal device, the terminal device executes the steps of a detection method for solar cells.

[0018] The beneficial effects of the present application are as follows: since the measuring point positions of the surface film of the solar cell to be tested are uniformly arranged at multiple positions, the measuring point films located at each measuring point position are illuminated and tested one by one using the detection light source determined by the solar cell to be tested, and the reflectivity of each measuring point film is obtained, and the film thickness of each measuring point film is obtained based on the surface film, the detection light source and the reflectivity. Then, when determining the detection result of the solar cell to be tested, the film thickness and reflectivity of the film at each measuring point of the solar cell to be tested are taken into account, that is, the relatively comprehensive overall film situation of the solar cell to be tested is taken into account, thereby improving the accuracy of the detection result of the solar cell to be tested. At the same time, the automated detection method of the present application also realizes efficient detection of the solar cell to be tested. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic flow chart of a detection method for solar cells shown as an exemplary embodiment of the present application;

[0020] Figure 2 This is a schematic structural diagram of a solar cell detection device shown as an exemplary embodiment of the present application;

[0021] Figure 3 This is a schematic diagram of a mobile test of a solar cell to be tested in an exemplary embodiment of the present application;

[0022] Figure 4 The present invention is a schematic structural diagram of a detection system for solar cells according to an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0023] The following examples are provided to further explain and supplement the present application and do not constitute any limitation to the present application.

[0024] A detection method for solar cells and related equipment according to an embodiment of the present application are described below in conjunction with the accompanying drawings.

[0025] A detection method for solar cells in an embodiment of the present application is applied to a terminal device. In the present application scheme, the terminal device is used as the execution subject to illustrate the present application scheme. The terminal device is used to execute the steps of a detection method for solar cells.

[0026] See also Figure 1 , Figure 1 A detection method for solar cells is shown as an exemplary embodiment of the present application, such as Figure 1 As shown, the present application provides a detection method for solar cells, comprising:

[0027] Step S11, obtaining the measurement point position of the surface film of the solar cell to be tested, and determining the detection light source based on the solar cell to be tested;

[0028] Step S12, irradiating the measuring point film located at the measuring point position with a detection light source to obtain the reflectivity of the measuring point film;

[0029] Step S13, obtaining the film thickness of the film at the measuring point based on the surface film, the detection light source and the reflectivity;

[0030] Step S14, obtaining the detection result of the solar cell to be tested based on the reflectivity and the film thickness.

[0031] In the detection method for solar cells of the present embodiment, since the measuring point positions of the surface film of the solar cell to be tested are uniformly set at multiple positions, the detection light source determined by the solar cell to be tested is used to irradiate and detect the measuring point films located at each measuring point position one by one during the detection, so as to obtain the reflectivity of the film at each measuring point, and based on the surface film, the detection light source and the reflectivity, the film thickness of the film at each measuring point is obtained. Then, when determining the detection result of the solar cell to be tested, the film thickness and reflectivity of the film at each measuring point of the solar cell to be tested are taken into account, that is, the relatively comprehensive overall film condition of the solar cell to be tested is taken into account, thereby improving the accuracy of the detection result of the solar cell to be tested. At the same time, the automated detection method of the present embodiment also realizes efficient detection of the solar cell to be tested.

[0032] In this embodiment, the surface thin film may be a polysilicon film, a silicon nitride film, or an aluminum oxide film.

[0033] Optionally, determining a detection light source based on a solar cell to be tested includes:

[0034] Obtaining manufacturing parameters when manufacturing the solar cell to be tested;

[0035] Obtaining target wavelength light based on manufacturing parameters;

[0036] Obtain a light source that emits light of the target wavelength and use the light source as the detection light source.

[0037] In this embodiment, the manufacturing parameters when manufacturing the solar cell to be tested can reflect the manufacturing environment of the solar cell to be tested and the possible parameter conditions of the solar cell to be tested, then the target wavelength light is obtained based on the possible parameter conditions corresponding to the manufacturing parameters, and the light source emitting the target wavelength light is used as the detection light source for testing. In this way, under the manufacturing parameters, no matter how many possible parameter conditions the solar cell to be tested has, the detection light source capable of emitting the target wavelength light can be used to test the solar cell to be tested, and an effective reflectivity can be obtained. This facilitates the subsequent detection result of the solar cell to be tested based on the effective reflectivity, thereby further improving the accuracy of the detection result.

[0038] In this embodiment, the detection light source is an LED light source, a halogen light source or a xenon light source, etc. The LED light source can be combined with a suitable LED light according to the required spectral range. The available wavelength range of the halogen light source is 360-2500nm, and the available wavelength range of the xenon light source is 200-2500nm. The surface films of different solar cells respond differently to light of different wavelengths. For films of general thickness, an LED light source or a halogen light source can be selected, such as the thickness of a polycrystalline silicon film; for thinner films, short-wavelength ultraviolet light needs to be supplemented to observe interference phenomena. At this time, a xenon lamp or a deuterium lamp is required as a light source, such as an aluminum oxide film.

[0039] Optionally, the manufacturing parameters include a preset coating thickness, a film material type, and a film thickness manufacturing error;

[0040] Obtaining target wavelength light based on manufacturing parameters, including:

[0041] Based on the preset coating thickness and the film thickness manufacturing error, a reference film thickness range of the solar cell to be tested is obtained;

[0042] A battery membrane with a thickness within a reference film thickness range and a type of membrane material is used as a target membrane;

[0043] Find the target wavelength light corresponding to the light interference phenomenon with the target film from the preset table.

[0044] In this embodiment, based on the preset coating thickness and film thickness manufacturing error, the possible parameter conditions of the solar cell to be tested can be reflected, and the reference film thickness range of the solar cell to be tested is obtained by combining the possible parameter conditions, and the cell film with a thickness within the reference film thickness range and a film material type is used as the target film, and the target wavelength light corresponding to the light interference phenomenon with the target film is found from the preset table, so that the light source emitting the target wavelength light can have a light interference phenomenon with all target films with a thickness within the reference film thickness range and a film material type, thereby obtaining an effective reflectivity. It is convenient to obtain the test result of the solar cell to be tested based on the effective reflectivity in the subsequent process, and the accuracy of the test result can be further improved.

[0045] Optionally, irradiating a measuring point film located at a measuring point position with a detection light source to obtain a reflectivity of the measuring point film includes:

[0046] Using a detection light source to illuminate a measuring point film located at a measuring point position, and obtaining a reflected light intensity of reflected light reflected by the measuring point film;

[0047] Obtaining the incident light intensity of the target wavelength light emitted by the detection light source;

[0048] Based on the incident light intensity and the reflected light intensity, the reflectivity of the film at the measuring point is obtained.

[0049] In this embodiment, after the detection light source irradiates the measuring point film located at the measuring point position, the measuring point film will reflect the emitted light. Based on the emitted light and the reflected light intensity and the incident light intensity of the target wavelength light emitted by the detection light source, the reflectivity of the measuring point film is obtained, which is convenient for subsequently obtaining the film thickness of the measuring point film based on the reflectivity and obtaining the detection result of the solar cell to be tested.

[0050] In this embodiment, the incident light intensity corresponding to the target wavelength light emitted by the detection light source is first collected, and then the calibration reflected light intensity corresponding to the calibration reflected light reflected by the calibration film after being vertically irradiated by the detection light source is collected, and the calibration reflected light intensity / incident light intensity=C. Then, the reflected light intensity of the reflected light reflected by the measurement point film after being vertically irradiated by the detection light source is collected, and the reflectivity of the measurement point film at this time=C×(reflected light intensity / incident light intensity).

[0051] Optionally, based on the surface film, the detection light source and the reflectivity, the film thickness of the film at the measuring point is obtained, including:

[0052] Based on the surface film, the corresponding refractive index and extinction coefficient are obtained;

[0053] Obtaining the reflection wavelength of the reflected light reflected by the film at the measuring point after being irradiated by the detection light source;

[0054] Based on the refractive index, extinction coefficient, reflection wavelength and reflectivity, the film thickness of the film at the measuring point is obtained;

[0055] In this embodiment, the reflectivity of the film at the measuring point is mathematically inverted using the refractive index and extinction coefficient corresponding to the surface film, and the reflection wavelength of the film at the measuring point after being irradiated by the detection light source, to obtain the film thickness of the film at the measuring point, so as to facilitate the subsequent detection results of the solar cell to be tested based on the reflectivity and film thickness.

[0056] In this embodiment, taking vertical irradiation of a test point film of a solar cell to be tested coated with a double-layer film as an example, mathematical inversion is performed using the refractive index, extinction coefficient, reflection wavelength and reflectivity corresponding to the test point film to obtain the film thickness of the test point film of the solar cell to be tested as follows:

[0057] The characteristic matrix of the double-layer film can be written as:

[0058]

[0059] in, represents the characteristic matrix of the double-layer film, n i represents the refractive index of the i-th film layer, k i represents the extinction coefficient of the i-th film, d i represents the thickness of the i-th film, n g represents the substrate refractive index, λ represents the reflection wavelength of the reflected light;

[0060] Since the calculation formula of the reflectivity of the film is expressed as:

[0061]

[0062] Where R represents the reflectivity of the film, η 0 =n 0 =1,n 0 represents the refractive index of air;

[0063] Then the calculation formula of the reflectivity of the film can be simplified to:

[0064]

[0065] Then the film feature matrix Substituting into the calculation formula of reflectivity, we can get:

[0066]

[0067] in,

[0068] From the calculation formula (4), it can be seen that the reflectivity of the film at the measuring point is a function of the refractive index, extinction coefficient, film thickness and reflection wavelength, that is:

[0069] R~(λ,ni (λ),k i (λ),d i )(5)

[0070] Finally, by performing mathematical inversion using formula (4), the thickness of the double-layer film of the solar cell to be tested is obtained.

[0071] Optionally, the corresponding refractive index and extinction coefficient are obtained based on the surface film, including:

[0072] Get the material type of the surface film;

[0073] Based on the material type, the refractive index and extinction coefficient corresponding to the surface film are obtained.

[0074] In this embodiment, based on the material type of the surface film, the light reaction of the surface film can be understood, and the light reaction includes the refractive index and extinction coefficient of the film. The light reaction can be reflected by the dispersion model, so as to directly obtain the refractive index and extinction coefficient corresponding to the surface film, so as to facilitate the subsequent film thickness of the film at the measuring point based on the refractive index and extinction coefficient, so as to obtain the test results of the solar cell to be tested based on the reflectivity and film thickness. Among them, the dispersion model includes the Cauchy dispersion model or the Lorentz dispersion model.

[0075] Optionally, the reflectivity includes a plurality of rate values, and the film thickness includes a plurality of thickness values; and the test result of the solar cell to be tested is obtained based on the reflectivity and the film thickness, including:

[0076] For each value of the reflectivity, when the value is within a preset qualified reflectivity range, determining a first qualified situation corresponding to the value is qualified, otherwise determining the first qualified situation is unqualified;

[0077] For each thickness value of the film thickness, when the thickness value is within a preset qualified film thickness range, determining the second qualified condition corresponding to the thickness value as qualified, otherwise determining the second qualified condition as unqualified;

[0078] When the plurality of first qualified conditions are all qualified and the plurality of second qualified conditions are all qualified, the test result of the solar cell to be tested is determined to be qualified; otherwise, the test result is determined to be unqualified.

[0079] In this embodiment, the number of multiple rate values, the number of multiple thickness values ​​and the number of measuring point positions are equal. When the first qualified conditions corresponding to the multiple rate values ​​of reflectivity are all qualified, and the second qualified conditions corresponding to the multiple thickness values ​​of film thickness are all qualified, the test result of the solar cell to be tested is determined to be qualified, and when at least one of the first qualified conditions corresponding to the multiple rate values ​​of reflectivity is unqualified, and / or at least one of the second qualified conditions corresponding to the multiple thickness values ​​of film thickness is unqualified, the test result of the solar cell to be tested is determined to be unqualified. In this way, based on the screening conditions of this embodiment, solar cells with reflectivity defects and / or film thickness defects can be screened out, leaving only solar cells without reflectivity defects and film thickness defects, so as to improve the qualified rate of solar cells entering the market, thereby increasing the economic benefits brought by qualified solar cells.

[0080] See also Figure 2 , Figure 2 A solar cell detection device is shown as an exemplary embodiment of the present application. Figure 2 As shown, the present application provides a solar cell detection device, which applies the above-mentioned detection method for solar cells; the device includes a detection light source, a spectrum detection module and a probe arranged in a light source module; the detection light source and the spectrum detection module are connected to the probe through an optical fiber;

[0081] When testing the surface film of the solar cell to be tested, the light emitted by the detection light source is controlled to irradiate the measurement point film located at the measurement point position of the surface film through the probe, and the reflectivity of the measurement point film is obtained by using the spectral detection module, so as to obtain the film thickness of the measurement point film based on the surface film, the detection light source and the reflectivity.

[0082] In a solar cell detection device of this embodiment, the detection light source and the spectrum detection module are connected to the probe through optical fiber, and when the surface film of the solar cell to be tested is tested, the light emitted by the detection light source is controlled to be sent to the probe through the light source end and the first and second branch ends of the optical fiber, and the probe is controlled to irradiate the received light vertically to the measuring point film located at the measuring point position of the surface film, and the measuring point film will interfere with the incident light and reflect (or transmit). The probe is controlled to receive the reflected light intensity of the reflected light reflected (or transmitted) by the measuring point film, and the reflected light intensity is sent to the spectrum detection module through the second branch end and the first branch end for modulation and calculation, so as to filter the spectral data such as the reflected light intensity, eliminate the burrs or noise in the spectral data, reduce the interference information, and thus improve the detection accuracy of the solar cell. And in the spectrum detection module, based on the surface film, the detection light source and the reflectivity, the film thickness of the measuring point film is obtained, and in the terminal device, the detection result of the solar cell to be tested is obtained based on the reflectivity and the film thickness. Since the measuring points of the surface film of the solar cell to be tested are uniformly arranged at multiple positions, the film thickness and reflectivity of the film at each measuring point of the solar cell to be tested are taken into account when determining the test result of the solar cell to be tested, that is, the relatively comprehensive overall film situation of the solar cell to be tested is taken into account, thereby improving the accuracy of the test result of the solar cell to be tested. At the same time, the automated detection method of the present application also realizes efficient detection of the solar cell to be tested.

[0083] Among them, the optical fiber is a Y-type optical fiber, consisting of two branches, one end of which is merged together as the second branch end connected to the probe, one of the other two ends is connected to the detection light source as the light source end, and the other end is connected to the spectral detection module as the first branch end.

[0084] In an exemplary embodiment, the detection light source is connected to the light source end of the Y-type optical fiber through a multi-channel optical fiber, which is an optical fiber with one channel divided into multiple channels. The multi-channel optical fiber includes a main line and multiple branch lines. The branch lines are single-core optical fibers, and the number of inner cores of the main line is equal to the number of multiple branch lines. Among them, the detection light source is connected to one end of the main line of the multi-channel optical fiber, and the other end of the main line is coupled with one end of the multiple branch lines through an optical fiber coupler for single-core corresponding coupling, so that the optical signal generated by the detection light source is transmitted to the multiple branch lines through the main line, and the branch lines do not interfere with each other. The light source separated from each branch line is an independent full-spectrum light source. At the same time, the other end of each branch line is connected to the light source end of a Y-type optical fiber, so as to realize multi-point detection. In this embodiment, the number of multiple branch lines of the multi-channel optical fiber is equal to the number of optical fibers.

[0085] In an exemplary embodiment, the prior art in China mainly detects solar cells through single-point or multi-point online non-contact measurement technology. Single-point testing cannot evaluate the surface film condition of the entire cell sheet, and multi-point measurement generally adopts a single-point superposition method. On the one hand, considering the installation environment, the number of measurement points is relatively limited, and multi-point measurement requires multiple spectrometers to be matched, and the detection cost is high; on the other hand, whether single-point or multi-point detection requires each cell sheet to pause for about 0.5s when reaching the detection position, and the demand for automation is high. However, using the method and device of the present application, before testing, the measurement point position of each row on the solar cell to be tested is divided into rows as the rows to be tested to obtain multiple rows to be tested. And based on the solar cell to be tested, the detection light source for detection is determined, and the detection light source is selected from LED light source, halogen light source or xenon light source, etc. The optical fiber in the solar cell detection device can be selected from Y-type optical fiber or straight optical fiber based on the type of solar cell to be tested, and the probe in the device selects integrating sphere, direct probe or multi-angle incident probe according to the type of solar cell to be tested or the test environment. At the same time, the incident angle of the probe used to illuminate the measuring point position can be selected at any angle according to different test parameters. For example, the angle between the pyramid cone surface formed by the texturing of the silicon nitride surface and the base is 55°. The pyramid cone surface is used as the measured reflection surface, and the incident surface and the reflection surface are perpendicular to each other. Since the solar cell is parallel to the base when running on the belt, only by changing the direction of the incident surface can it be perpendicular to the pyramid cone surface. The oblique incident angle is mainly used to observe the intensity of polarized light P light and S light, so as to obtain more information about the thin film material.

[0086] Then, during the test, TCP / IP or IO communication is used between the components in the solar cell detection device, and the target wavelength light emitted by the test light source is transmitted to multiple probes through multiple optical fibers and multiple Y-type optical fibers, and the target wavelength light is received by the multiple probes to vertically irradiate the measuring point films at multiple measuring point positions on each row to be tested in turn, and the reflectivity and film thickness corresponding to the multiple measuring point films on each row to be tested are obtained, and then the test results of the solar cell to be tested are obtained based on the reflectivity and film thickness, so as to realize the automatic detection of solar cells. Figure 2As shown, multiple probes are used as a probe combination, and the solar cells (cells) to be tested on the conveyor belt are moved through the conveyor belt, and the probe combination is used in turn to vertically irradiate multiple test point films on each test row of the solar cells to be tested, so as to obtain the reflectivity and film thickness corresponding to the multiple test point films on each test row, and then the test results of the solar cells to be tested are obtained based on the reflectivity and film thickness. When the test result is unqualified, the solar cell to be tested is displayed as NG (No Good) on the test software interface of the display, and then the robot is controlled to grab the NG solar cells on the assembly line to screen out the unqualified solar cells on the assembly line. Among them, TCP / IP is generally the communication protocol selected by automation manufacturers. The internal proximity switch of IO is directly triggered, and no automation assistance is required.

[0087] Compared with the single-point detection or single-point superposition detection method in the prior art, the method of this embodiment takes a shorter time to complete the detection of all the measuring point positions of the solar cell to be tested, so that the speed of obtaining the detection result of the solar cell to be tested is faster, thereby improving the test efficiency of the solar cell to be tested. The method and device of this application also realize the efficient detection of the solar cell to be tested through an automated detection method. Among them, the number of multiple Y-type optical fibers, the number of multiple measuring point positions of the row to be tested, and the number of multiple probes are all equal, and the second branch ends of the multiple Y-type optical fibers are connected to the multiple probes one by one.

[0088] In the current experiment, when the detection method for solar cells of the present application is used to detect the solar cells to be tested, one row to be tested on the surface of the solar cells to be tested is detected each time, and the row to be tested includes 15 test point positions. Multiple rows can be selected for synchronous testing according to the detection requirements, and considering factors such as space size and production cycle, the solar cell detection device and the test time can also be integrated and optimized.

[0089] Figure 2In the invention, a solar cell detection device also includes a position sensor (proximity switch). When the conveyor belt moves the row to be tested of the solar cell (cell) to be tested to the detection range of the position sensor (e.g., the range where the rays are located), the control probe combination performs vertical line array irradiation on the multiple measuring point films on the row to be tested, and no automation assistance is required to make the cell pause for 0.5 seconds. The spectrum detection module detects the multiple rows to be tested in turn at a fixed interval of milliseconds based on the detection situation of the position sensor. The fixed interval of milliseconds and the number of detections are set according to the running speed of the solar cell to be tested (the transmission speed of the conveyor belt) to complete the line scan detection of the multiple measuring point films on the row to be tested. Therefore, the detection of the reflectivity of multiple measuring point positions on a row to be tested of the solar cell to be tested can be achieved with only one spectrometer. The spectrometer is arranged in the spectrum detection module. A solar cell detection device also includes an industrial computer and a display. The spectrum detection module is connected to the industrial computer via a USB cable, and the industrial computer is connected to the display. The industrial computer can be used as the terminal device of the present application, and the display is used to display the reflectivity and film thickness of the film at each measuring point, and to display the detection results of the solar cell to be tested based on the reflectivity and film thickness.

[0090] See also Figure 3 , Figure 3 This is a schematic diagram of a mobile test of a solar cell to be tested in an exemplary embodiment of the present application, such as Figure 3As shown, the conveyor belt is controlled to move with the solar cell to be tested, so that the spectrum detection module can detect multiple rows to be tested in turn at a fixed interval of milliseconds based on the detection situation of the position sensor, so as to realize the mobile test of the solar cell to be tested. Among them, the fixed interval of milliseconds and the number of detections are set according to the running speed of the solar cell to be tested (the transmission speed of the conveyor belt). In general, the conveyor belt moves at a uniform speed, and the speed is recorded as v. The time required to move the position of the measuring point closest to the position sensor in the first row of the solar cell to be tested to the detection range of the position sensor is recorded as t1, and the distance between the two is S1=v*t1. Since the distances between two adjacent measuring points in the row to be tested of the solar cell to be tested are equal and evenly arranged, when a probe is used to detect multiple measuring points in the row to be tested, the interval distances S2 to Sn of the adjacent measuring points except the measuring point closest to the position sensor are all equal, that is, S2 = S3 = ... = Sn, where S2 = v*t2, ..., Sn = v*tn, n is the number of detections of the probe, and is also the number of multiple measuring points in the row to be tested, so that the values ​​of t2, ..., tn can be obtained. The number of detections n can be set by the user in the test software in the display, and the time t can be viewed in the test software in the display, and it is only necessary to ensure that the distance of ΣSi (i = 1, 2, ..., n) does not exceed the distance of the battery itself. In special cases, if the conveyor belt is not running at a uniform speed, you can choose to install multiple probes and multiple proximity switches. At this time, the n measuring points in the first row to be tested are in the vertical downward position of the probe combination, and the n measuring points correspond to the n probes in the probe combination. It is only necessary to ensure that each probe is vertically irradiated on the corresponding measuring point position on the surface of the solar cell. When the belt is not running at a uniform speed, you can also choose an encoder to convert the angular velocity of the encoder into a linear velocity, and integrate the changing speed with the test time to obtain the transmission distance.

[0091] By using the device and method of the present application, various parameters of solar cells, such as reflectivity, film thickness, etc., can be monitored online, while retaining the big data in the production process of solar cells, helping to optimize the preparation process, improve the stability of the interface, the passivation effect, and reduce the reflection loss on the surface of the solar cell, laying the foundation for improving the photoelectric conversion efficiency and long-term stability of the solar cell. For example, through automated connection, each solar cell has an independent ID number, which can be traced back to the specific furnace tube number and the specific boat number. In addition, the reflectivity or film thickness of the solar cells at the tail and the mouth of the furnace are different, and the process can be directly observed in the statistical function of the software to evaluate the process level. In addition, TOPCon (photovoltaic) cells achieve field passivation by preparing a tunneling oxide layer and a polysilicon layer on the back, so the thickness, density and uniformity of the tunneling oxide layer and the polysilicon layer will affect the passivation quality. The device and method of the present application are also applicable to ellipsometry detection. The ellipsometry method is to obtain the optical constants and structural information of the material by changing the polarization state of light before and after reflection on the surface of the medium.

[0092] See also Figure 4 , Figure 4 A detection system for solar cells is shown as an exemplary embodiment of the present application, such as Figure 4 As shown, the present application provides a detection system for solar cells, comprising:

[0093] An acquisition module is used to acquire the measurement point position of the surface film of the solar cell to be tested, and determine the detection light source based on the solar cell to be tested;

[0094] An irradiation module is used to irradiate a measuring point film located at a measuring point position with a detection light source to obtain a reflectivity of the measuring point film;

[0095] The first obtaining module is used to obtain the film thickness of the film at the measuring point based on the surface film, the detection light source and the reflectivity;

[0096] The second obtaining module is used to obtain the detection result of the solar cell to be tested based on the reflectivity and film thickness.

[0097] In the detection system for solar cells of the present embodiment, since the measuring point positions of the surface film of the solar cell to be tested are multiple positions evenly set, the detection light source corresponding to the solar cell to be tested is determined by the acquisition module during detection, and the measuring point films located at each measuring point position are irradiated and detected one by one in the irradiation module to obtain the reflectivity of each measuring point film, and the film thickness of each measuring point film is obtained based on the surface film, the detection light source and the reflectivity in the first obtaining module. Then, when the second obtaining module determines the detection result of the solar cell to be tested, the film thickness and reflectivity of the film at each measuring point of the solar cell to be tested are taken into account, that is, the relatively comprehensive overall film situation of the solar cell to be tested is taken into account, thereby improving the accuracy of the detection result of the solar cell to be tested. At the same time, the detection system of the present embodiment also realizes efficient detection of the solar cell to be tested through an automated detection method.

[0098] Optionally, obtain a module, specifically for:

[0099] Obtaining manufacturing parameters when manufacturing the solar cell to be tested;

[0100] Obtaining target wavelength light based on manufacturing parameters;

[0101] Obtain a light source that emits light of the target wavelength and use the light source as the detection light source.

[0102] Optionally, the manufacturing parameters include a preset coating thickness, a film material type, and a film thickness manufacturing error;

[0103] Get the module, specifically for:

[0104] Based on the preset coating thickness and the film thickness manufacturing error, a reference film thickness range of the solar cell to be tested is obtained;

[0105] A battery membrane with a thickness within a reference film thickness range and a type of membrane material is used as a target membrane;

[0106] Find the target wavelength light corresponding to the light interference phenomenon with the target film from the preset table.

[0107] Optionally, the irradiation module is specifically used for:

[0108] Using a detection light source to illuminate a measuring point film located at a measuring point position, and obtaining a reflected light intensity of reflected light reflected by the measuring point film;

[0109] Obtaining the incident light intensity of the target wavelength light emitted by the detection light source;

[0110] Based on the incident light intensity and the reflected light intensity, the reflectivity of the film at the measuring point is obtained.

[0111] Optionally, the first module is specifically used to:

[0112] Based on the surface film, the corresponding refractive index and extinction coefficient are obtained;

[0113] Obtaining the reflection wavelength of the reflected light reflected by the film at the measuring point after being irradiated by the detection light source;

[0114] Based on the refractive index, extinction coefficient, reflection wavelength and reflectivity, the film thickness of the film at the measuring point is obtained.

[0115] Optionally, the first module is specifically used to:

[0116] Get the material type of the surface film;

[0117] Based on the material type, the refractive index and extinction coefficient corresponding to the surface film are obtained.

[0118] Optionally, the reflectivity includes a plurality of reflectivity values, and the film thickness includes a plurality of thickness values; the second obtaining module is specifically used for:

[0119] For each value of the reflectivity, when the value is within a preset qualified reflectivity range, determining a first qualified situation corresponding to the value is qualified, otherwise determining the first qualified situation is unqualified;

[0120] For each thickness value of the film thickness, when the thickness value is within a preset qualified film thickness range, determining the second qualified condition corresponding to the thickness value as qualified, otherwise determining the second qualified condition as unqualified;

[0121] When the plurality of first qualified conditions are all qualified and the plurality of second qualified conditions are all qualified, the test result of the solar cell to be tested is determined to be qualified; otherwise, the test result is determined to be unqualified.

[0122] It should be noted that the detection system for solar cells provided in the above embodiment and the detection method for solar cells provided in the above embodiment belong to the same concept, wherein the specific manner in which each module and unit performs the operation has been described in detail in the method embodiment, and will not be repeated here. In practical applications, the detection system for solar cells provided in the above embodiment can distribute the above functions to different functional modules as needed, that is, divide the internal structure of the system into different functional modules to complete all or part of the functions described above, and this is not limited here.

[0123] A computing device according to an embodiment of the present application includes a memory, a processor, and a program stored in the memory and running on the processor. When the processor executes the program, part or all of the steps of the above-mentioned detection method for solar cells are implemented.

[0124] Among them, the computing device can be a computer, and correspondingly, its program is computer software. The above-mentioned parameters and steps in a computing device of the present application can refer to the parameters and steps in an embodiment of a detection method for solar cells mentioned above, and will not be repeated here.

[0125] In an embodiment of the present application, a computer-readable storage medium is provided, in which instructions are stored. When the instructions are executed, the steps of the above-mentioned detection method for solar cells are executed.

[0126] The computer-readable storage medium may be a transient computer-readable storage medium or a non-transitory computer-readable storage medium.

[0127] The technical solution of the embodiment of the present disclosure can be embodied in the form of a software product, which is stored in a storage medium and includes one or more instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method of the embodiment of the present disclosure. The aforementioned computer-readable storage medium may be a non-transitory computer-readable storage medium, including: a USB flash drive, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a disk or an optical disk, and other media that can store program codes, or a transient computer-readable storage medium.

[0128] The flowchart and block diagram in the accompanying drawings illustrate the possible architecture, functions and operations of the system, method and computer program product according to various embodiments of the present application. Wherein, each box in the flowchart or block diagram can represent a module, a program segment, or a part of the code, and the above-mentioned module, program segment, or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0129] Those skilled in the art know that the present application can be implemented as a system, method or computer program product. Therefore, the present disclosure can be specifically implemented in the following forms, namely: it can be complete hardware, it can be complete software (including firmware, resident software, microcode, etc.), or it can be a combination of hardware and software, generally referred to as "module" or "system" herein. In addition, in some embodiments, the present application can also be implemented in the form of a computer program product in one or more computer-readable media, and the computer-readable medium contains computer-readable program code. Computer-readable storage media can be, for example, but not limited to - electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or devices, or any combination of the above.

[0130] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0131] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A detection method for solar cells, characterized in that: include: Acquire the measurement point position of the surface film of the solar cell to be tested, and determine the detection light source based on the solar cell to be tested; Using the detection light source to illuminate the measuring point film located at the measuring point position to obtain the reflectivity of the measuring point film; Based on the surface film, the detection light source and the reflectivity, the film thickness of the film at the measuring point is obtained; The detection result of the solar cell to be tested is obtained based on the reflectivity and the film thickness.

2. The method according to claim 1, characterized in that The step of determining a detection light source based on the solar cell to be tested comprises: Obtaining manufacturing parameters when manufacturing the solar cell to be tested; Obtaining target wavelength light based on the manufacturing parameters; A light source emitting light of the target wavelength is obtained, and the light source is used as a detection light source.

3. The method according to claim 2, characterized in that The manufacturing parameters include preset coating thickness, film material type and film thickness manufacturing error; The step of obtaining the target wavelength light based on the manufacturing parameters comprises: Based on the preset coating thickness and the film thickness manufacturing error, a reference film thickness range of the solar cell to be tested is obtained; Taking a battery membrane having a thickness within the reference film thickness range and of the type of the film material as a target membrane; The target wavelength light corresponding to the light interference phenomenon with the target film is found from the preset table.

4. The method according to claim 1, characterized in that: The step of irradiating the measuring point film located at the measuring point position with the detection light source to obtain the reflectivity of the measuring point film includes: Using the detection light source to illuminate the measuring point film located at the measuring point position, and obtaining the reflected light intensity of the reflected light reflected by the measuring point film; Acquiring the incident light intensity of the target wavelength light emitted by the detection light source; Based on the incident light intensity and the reflected light intensity, the reflectivity of the film at the measuring point is obtained.

5. The method according to any one of claims 1 to 4, characterized in that: The step of obtaining the film thickness of the film at the measuring point based on the surface film, the detection light source and the reflectivity includes: Obtaining a corresponding refractive index and extinction coefficient based on the surface film; Acquire the reflection wavelength of the reflected light reflected by the film at the measuring point after being irradiated by the detection light source; The film thickness of the thin film at the measuring point is obtained based on the refractive index, the extinction coefficient, the reflection wavelength and the reflectivity.

6. The method according to claim 5, characterized in that The obtaining of the corresponding refractive index and extinction coefficient based on the surface film comprises: Obtaining the material type of the surface film; Based on the material type, the refractive index and extinction coefficient corresponding to the surface film are obtained.

7. The method according to claim 1, characterized in that The reflectivity includes a plurality of rate values, and the film thickness includes a plurality of thickness values; and obtaining the detection result of the solar cell to be tested based on the reflectivity and the film thickness includes: For each of the reflectivity values, when the reflectivity value is within a preset qualified reflectivity range, determining a first qualified condition corresponding to the reflectivity value as qualified, otherwise determining the first qualified condition as unqualified; For each thickness value of the film thickness, when the thickness value is within a preset qualified film thickness range, determining that the second qualified condition corresponding to the thickness value is qualified, otherwise determining that the second qualified condition is unqualified; When the plurality of first qualified conditions are all qualified and the plurality of second qualified conditions are all qualified, the test result of the solar cell to be tested is determined to be qualified; otherwise, the test result is determined to be unqualified.

8. A solar cell detection device, characterized in that: A detection method for solar cells according to any one of claims 1 to 7 is used; the device comprises a detection light source, a spectrum detection module and a probe; the detection light source and the spectrum detection module are connected to the probe via an optical fiber; When testing the surface film of the solar cell to be tested, the light emitted by the detection light source is controlled to irradiate the measuring point film located at the measuring point position of the surface film through the probe, and the reflectivity of the measuring point film is obtained by using the spectral detection module, so as to obtain the film thickness of the measuring point film based on the surface film, the detection light source and the reflectivity.

9. A computing device comprising a memory, a processor, and a program stored in the memory and running on the processor, characterized in that: When the processor executes the program, the steps of a detection method for solar cells as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, and when the instructions are executed on a terminal device, the terminal device executes the steps of a detection method for solar cells as claimed in any one of claims 1 to 7.

Images