Method for testing IV of three-terminal laminated cell

Abstract

The invention discloses a test method for a three-terminal laminated cell IV, and belongs to the technical field of solar cell testing, and the method comprises the steps: moving a three-terminal laminated cell to an IV test bearing platform, stabilizing the cell through an index plate, starting an upper end positioning camera, recognizing a mark point of the cell, and obtaining position information; the dividing plate rotates according to a set program and conveys the positioned battery piece to a test probe by means of high-precision mechanical transmission; probe pressing and position correction: after the battery piece is in place, upper and lower probes are accurately pressed into the front and back surfaces of the battery piece, and a test connection circuit is constructed; the IV test of the three-terminal laminated solar cell is realized through one-time probe pressing and two-time flash test. The brand-new three-terminal laminated cell IV test method provided by the invention ensures accurate measurement, avoids the risk of cell piece breakage caused by secondary pressing, realizes one-time pressing of the three-terminal cell, improves the test efficiency, and simplifies the operation links.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cell testing, and particularly relates to a method for testing the IV of a three-terminal stacked cell. Background Art

[0002] In the current field of solar cell testing, conventional crystalline silicon solar cell wafers are mostly double-sided cells, relying on two rows of probe rows above and below to complete the measurement. For high-efficiency solar cell wafers using technologies such as XBC and MWT, their positive and negative electrodes are both placed on the back of the cell wafer, and the electrical performance signals are collected through the back, and the cell efficiency test can be completed with only one flash operation.

[0003] However, the front of the new three-terminal stacked solar cell wafer has one electrode, and the back contains two electrodes. This unique structure makes the electrical performance test face new challenges.

[0004] The three-terminal stacked solar cell is a new type of solar cell structure, and there is no mature and mass-producible test scheme. There are many drawbacks in the measurement of existing three-terminal solar cell wafers: Complicated operation process: In the whole test process, it is necessary to first manually press the probe row of the bottom cell, irradiate the light source to measure the efficiency of the bottom layer, then manually align the upper and lower probe rows again to press the positive and negative electrodes of the three-terminal cell, and replace the filter after flashing again to measure the efficiency of the top layer, and finally calculate the final efficiency manually. The steps are long and complex.

[0005] Many times of alignment and downward pressing: It is necessary to go through two alignments and two probe downward pressing operations, which not only takes time, but also easily introduces human errors due to multiple operations, reducing the test accuracy; and the two probe downward pressings are also likely to increase the breakage of the cell wafer.

[0006] Manually operate two flashes and manually replace the filter: In order to achieve different light source wavelengths to test the top and bottom cells, it is necessary to manually replace the filter, which is inconvenient to operate, further slows down the test process, makes the overall test process lack coherence, and is difficult to meet the mass production requirements.

[0007] In addition, the current IV test of three-terminal stacked solar cells mainly focuses on scientific research institutions such as universities. Limited by conditions, manual test means are mostly used, which are difficult to meet the requirements of industrial mass production for precise control and selection of spectra. The structure of the three-terminal stacked solar cell is special, and there are significant differences in materials, functions, and light absorption and conversion characteristics between the top cell and the bottom cell. When performing electrical performance tests, two flashes are required for separate measurements, and the flash spectra should be adapted to the characteristics of the corresponding cells.

[0008] However, in the exploration of traditional testing methods, many researchers have not paid attention to the problem of unreasonable spectral design. If the flash spectrum of the top cell does not match its light absorption range, such as improper wavelength distribution, exceeding or not covering the sensitive interval, the response light efficiency of the top cell will decrease, and parameters such as short-circuit current density and open-circuit voltage will deviate, unable to reflect the true performance. Similarly, when the bottom cell receives an inappropriate spectrum, with uneven energy distribution and inconsistent with the bandgap structure, the electrical performance parameters tested by the IV test curve will be inaccurate and the conversion efficiency calculation will be distorted, leading to misjudgment by R & D personnel and hindering the optimization and improvement of the battery. Summary of the Invention

[0009] The purpose of this section is to outline some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section, as well as in the abstract and title of the specification of this application, to avoid obscuring the purpose of this section, the abstract, and the title. However, such simplifications or omissions shall not be used to limit the scope of the present invention.

[0010] In view of the above and / or problems existing in the prior art, the present invention is proposed.

[0011] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for testing the IV of a three-terminal stacked cell.

[0012] To solve the above technical problems, the present invention provides the following technical solution: A method for testing the IV of a three-terminal stacked cell, including, Feeding and positioning of the cell: Move the three-terminal stacked cell to the IV test carrier stage. The index plate stabilizes the cell (the index plate is equipped with a vacuum adsorption device). The upper positioning camera is activated to identify the mark point of the cell (or the positions of the four sides of the cell), and the position information of the cell is obtained through fitting. Handling of the cell: The index plate rotates according to the set program and, relying on high-precision mechanical transmission, sends the positioned cell to the test probe. Probe pressing and position correction: After the cell is in place, the upper and lower probes are accurately pressed into its front and back sides to construct a test connection circuit. Among them, when the probes are pressed, the probe stage fine-tunes the probe pressing position according to the data fed back by the positioning camera to compensate for potential position errors and avoid deviations in the contact positions between the probes and the test points. Test results: The IV test of the three-terminal stacked solar cell is achieved through one-time probe pressing and two-time flash tests. Among them, the wavelength of the test light source for the bottom cell is 800 nm to 1200 nm, and the wavelength of the test light source for the top cell is 200 nm to 800 nm. Different cell designs may make fine-tuning in the selection of wavelengths. For example, when the bandgap of the top cell is relatively wide, the wavelength range of the test light source for the top cell may be adjusted towards the short-wave direction, and the lower limit of the wavelength of the test light source for the bottom cell may also be adjusted towards the short-wave direction, not limited to the above wavelength range. After the test is completed, the indexing plate rotates, and the blanking suction cup sends the battery cells to the conveyor belt. The loading suction cup simultaneously sucks new battery cells to repeat the test.

[0013] As a preferred embodiment of the test method described in the present invention, wherein: the three-terminal stacked battery cells are applicable to various three-terminal stacked battery structures, including the top battery with a positive or negative electrode on the front side, and the bottom battery having a BC structure (a structure with interdigitated positive and negative electrodes on the back side).

[0014] As a preferred embodiment of the test method described in the present invention, wherein: the three-terminal stacked battery structure further includes whole-piece, half-piece, three-piece, four-piece, and multi-piece battery structures, as well as front battery grid line design structures such as 0BB, MBB, multi-main grid, and front-side stacked grid.

[0015] As a preferred embodiment of the test method described in the present invention, wherein: the probes include short probes and long probes.

[0016] As a preferred embodiment of the test method described in the present invention, wherein: for the two flash tests, wherein, The first flash test includes disconnecting the button connected to the top battery electrode, turning on the buttons for the positive and negative electrodes of the bottom battery, and synchronously starting the light source of the test mechanism, so that the bottom battery of the three-terminal battery cells generates photovoltaic power, and measuring the IV performance of the bottom battery of the three-terminal battery cells. Here, the battery is a three-terminal stacked battery structure, and the top battery and the bottom battery are in a parallel structure; for other BC batteries with a series structure, this test method can also be used, that is, the efficiency test and fitting of the top and bottom batteries are realized through circuit control + two flashes.

[0017] As a preferred embodiment of the test method described in the present invention, wherein: during the first flash test, the test light intensity is 998 w / ㎡, and the test temperature is 24.5 °C.

[0018] As a preferred embodiment of the test method described in the present invention, wherein: for the two flash tests, wherein, The second flash test includes turning on the button connected to the top battery, disconnecting the buttons for the positive and negative electrodes of the bottom battery, and starting the light source again, and measuring the IV performance of the bottom battery of the three-terminal battery cells.

[0019] As a preferred embodiment of the test method described in the present invention, wherein: during the second flash test, the test light intensity is 1010 w / ㎡, and the test temperature is 24.6 °C.

[0020] As a preferred embodiment of the test method described in the present invention, wherein: the indexing plate has 4 rotating tables. One table is the test table, one table is the blanking table, one table is the waiting table, and the rotating motor in the middle of the table drives the table to rotate to realize the transmission and test of the battery cells.

[0021] Advantages of the present invention: The present invention presents a brand-new IV test method for three-terminal stacked cells, ensuring accurate measurement, avoiding the risk of cell breakage caused by secondary pressing, achieving one-time pressing of three-terminal cells, improving test efficiency, and streamlining the operation process; With the help of reasonable circuit control, one probe contact is combined with two flashes to measure the bottom and top cells respectively. The cell efficiency is obtained by fitting with software algorithms. This can not only avoid secondary pressing of the probe tooling fixture, reduce the cell fragmentation rate, and reduce resource waste, but also simplify the test process by automatically controlling the two flashes, making the test of three-terminal stacked cells mass-producible and meeting the requirements of industrial large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. Among them: Figure 1 It is a top view of the novel three-terminal stacked cell test device in the embodiment of the present invention.

[0023] Figure 2 It is a structural diagram of the novel three-terminal stacked cell in the embodiment of the present invention. Among them, the upper cell is a perovskite cell, and the lower cell is a crystalline silicon BC cell. The upper cell mainly absorbs short-wavelength light, and the lower cell absorbs long-wavelength light. The upper cell can be the positive or negative electrode, and the positive and negative electrodes of the lower cell are alternately distributed.

[0024] Figure 3 It is the test principle of the novel three-terminal stacked cell in the embodiment of the present invention. Among them, the upper part is the equivalent circuit diagram of the perovskite cell, and the lower part is the equivalent circuit diagram of the BC cell. The IV performance test of the upper and lower cells is realized by controlling the on-off of A1, A2, and A3.

[0025] Figure 4 It is the novel three-terminal stacked cell IV test mechanism in the embodiment of the present invention; among them, ① light source module, ② bias power supply module, ③ measurement unit (current measurement, voltage measurement), ④ temperature control module, ⑤ data acquisition and processing module.

[0026] Figure 5 It is a schematic diagram in the embodiment of the present invention, where (a) is a split probe row, (b) is an integrated probe row, and (c) is a probe.

[0027] Figure 6 It is a design schematic diagram of the light source simulator in the embodiment of the present invention.

[0028] Figure 7Schematic diagrams of positioning, indexing disk rotation, and probe pressing tests in the embodiments of the present invention; where a is the positioning camera test diagram, b is the indexing disk rotation test diagram, and c is the probe pressing test diagram.

[0029] Figure 8 IV curve graph of the test in the embodiments of the present invention.

[0030] Figure 9 Schematic diagram of the robot arm grasping the battery cell after the test in the embodiments of the present invention. Detailed implementation manners

[0031] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following will describe in detail the specific implementation manners of the present invention in conjunction with the embodiments of the specification.

[0032] The top view of the new three-terminal stacked battery test device is shown in Figure 1 , and from left to right, there are provided: 1. Loading conveyor belt, 2. Loading suction cup, 3. Positioning clamping device, 4. Indexing disk, 5. Indexing disk loading device, 6. Positioning camera, 7. Vacuum adsorption device, 8. Test station system, 9. Rotating motor, 10. Indexing disk unloading device, 11. Unloading suction cup, 12. Unloading conveyor belt; Specifically, the three-terminal stacked battery cell is moved to the indexing disk by the loading suction cup. There is a rotating motor in the middle. The indexing disk has four turntables, and the turntables are equipped with a vacuum adsorption device for adsorbing the battery cell (to prevent the position from changing during rotation, with a hollow in the middle, and the probe can just press on the battery cell). The indexing disk then turns on the vacuum adsorption to stabilize the battery cell. At the same time, the upper positioning camera is started to accurately identify the mark point of the battery cell (or the positions of the four sides of the battery cell), and the position information of the battery cell is obtained through fitting, laying a foundation for subsequent tests and ensuring the accuracy of the test position; The indexing disk rotates 90° according to the set program. With the high-precision mechanical transmission of the rotating motor, the positioned battery cell is smoothly and efficiently sent to the test station system; after the battery cell is in place, the upper and lower probes are accurately pressed into its front and back surfaces to build a test connection circuit; through the measurement system, various electrical performance data of the three-terminal battery are measured; After the test is completed, the indexing disk rotates, and the unloading suction cup adsorbs the battery cell to the unloading conveyor belt. The loading suction cup synchronously sucks a new battery cell to repeat the test, realizing the automation of the test process.

[0033] The IV test process of the new three-terminal stacked battery in the embodiments of the present invention is as follows: 1. Loading and positioning: Use a suction cup to move the triple-layer laminated solar cell to the IV test carrier, i.e., the indexing table. In the middle is a rotary motor, which drives four turntables. There are vacuum suction cups on the turntables for adsorbing the solar cell (to prevent position changes during rotation). The middle is hollow, and the probe can just press on the solar cell. Then the indexing table starts vacuum adsorption to stabilize the solar cell. At the same time, the upper positioning camera is activated to accurately identify the mark point of the solar cell (or the positions of the four sides of the solar cell), and the position information of the solar cell is obtained through fitting, laying a solid foundation for subsequent tests and ensuring the accuracy of the test position.

[0034] 2. Solar cell handling: The indexing table rotates 90° according to the set program and, relying on high-precision mechanical transmission, smoothly and efficiently delivers the positioned solar cell to the test probe. During this process, high-precision mechanical control can prevent the position of the solar cell from deviating during rotation, ensuring the continuity and efficiency of the test process. In addition, the indexing table has 4 rotating platforms. When one platform transports the solar cell to the measurement position, another platform can receive new solar cells to be tested.

[0035] 3. Probe pressing and position correction: After the solar cell is in place, the upper and lower probes are accurately pressed into its front and back sides to build a test connection circuit; When the probe is pressed, the probe table fine-tunes the probe pressing position according to the data fed back by the positioning camera. Among them, the correction method: (1) An automatic alignment mechanism can be adopted: the function of accurately aligning the target position determined by the probe table and the positioning camera; usually includes high-precision mechanical transmission components, sensors, and control systems. The mechanical transmission components are responsible for realizing the movement of the probe table in all directions. For example, the common lead screw and guide rail transmission system can ensure the movement accuracy of the probe table; the sensors are used to monitor the position information of the probe table in real time, such as photoelectric sensors, grating scales, etc., and feed the position data back to the control system; the control system calculates the amount that needs to be adjusted based on the target position information provided by the positioning camera and the current position information fed back by the sensors, and issues a control signal to drive the mechanical transmission components to act, thereby realizing the automatic alignment of the probe table; (2)Adopt an automatic positioning and adjustment mechanism: It focuses more on the function of automatically determining and adjusting the position of the probe station. In addition to the mechanical transmission and control parts similar to the automatic alignment mechanism, it also includes components for attitude adjustment, position compensation, etc. For example, when there is a certain angle or offset in the target position captured by the positioning camera, the automatic positioning and adjustment mechanism can not only achieve translational alignment, but also perform attitude adjustments such as rotation or tilting, enabling the probe station to accurately reach and adapt to the requirements of the target position. It usually requires more complex algorithms and control systems to process multi-dimensional position adjustment information to ensure that the probe station can quickly and accurately locate to the specified position), and after compensating for potential position errors, ensure that the probe makes close and good contact with the battery cell electrodes, ensuring accurate and reliable IV test data and providing a strong basis for battery performance evaluation; in addition, the probe row contains current needles and voltage needles (used to collect current and voltage respectively).

[0036] 4. Measurement system: (1)Light source configuration and control: The light source module includes a solar simulator energy storage / tuning unit, a solar simulator, and a light intensity sensing chip.

[0037] In view of the need for two flash tests for triple-junction stacked cells, the solar simulator above the test platform should be able to emit light with two different spectral distributions (two groups of light sources can be set, and LED light sources, gas discharge light sources, etc. can be selected according to the test requirements of the top and bottom cells). Combined with reasonable control of the circuit switch, rapid switching between the two light sources can be achieved. When irradiating with long-wavelength light, the bottom cell is measured, and when irradiating with short-wavelength light, the top cell is measured.

[0038] (2)Measurement control and result output: Refer to Figure 4 , which includes a②bias power supply module, a③measurement unit (current measurement, voltage measurement), a④temperature control module, and a⑤data acquisition and processing module.

[0039] First, the bottom cell test (the principle is referred to Figure 3 ): When measuring the bottom cell, first disconnect the A1 button connected to the top cell electrode, turn on the A2 button connected to the positive and negative electrodes of the bottom cell, start the light source, and promote the photovoltaic power generation of the bottom cell to accurately measure its electrical performance indicators (including EL); Secondly, the top cell test: After completing the bottom cell test, switch the light source, turn on the A1 button and disconnect the A2 button, and start the light source again to measure the electrical performance indicators of the top cell; The rapid switching between the A1 and A2 channels can be achieved by means of an analog switch or digital logic circuit (such as a NAND gate control interlock circuit, a programmable logic device, a field programmable gate array, etc.); Finally, through the operation of the test software (covering functions such as testing, calculation, correction, data fitting, etc.), the electrical performance test results of the triple-junction cell are output; calculation method: Among them, the short-circuit current, open-circuit voltage, and leakage value of the top cell and the bottom cell are actual measured values, while the fill factor, series resistance, and parallel resistance are software technology values (the calculation method is the same as that used in the current mass production of photovoltaic cells). The comprehensive electrical performance data is obtained by software fitting (in the patent, the top and bottom cells are in a parallel structure, and the calculation method refers to the calculation of two cells in parallel in the circuit. If the upper and lower stacked cells are in a series structure, the calculation method refers to the calculation of two cells in series in the circuit); The test results are fed back to the grading machine after testing, and the grading machine grades the wafers according to the test results; 5. Post-test processing after testing: After the test is completed, the indexing plate rotates, and the unloading suction cup sends the wafer to the conveyor belt. The loading suction cup simultaneously sucks a new wafer to repeat the test, realizing the automation of the test process.

[0040] Test structure-related characteristics: 1. Test structure: This test structure is highly flexible and applicable to various three-terminal stacked cell structures. The front side of the top cell can be either the positive or negative electrode, and the bottom cell has a BC structure (the positive and negative electrodes on the back are arranged in an interdigitated manner); it can also test the whole wafer, half wafer, third wafer, quarter wafer, and multi-segment wafer cell structures, as well as the front cell grid line designs of 0BB, MBB, multi-main grid, and stacked grid structures.

[0041] 2. Probe row structure: The probe row has two optional forms: split type and integrated type. For the split type, single-row probes need to be pre-assembled, and multiple assembled split probe rows are combined during use; for the integrated type, all probe rows are integrated into one body, and its production carrier is diverse and can be installed on a rack or made on a transparent glass plate or acrylic plate.

[0042] 3. Probe type: There are multiple choices for probes: distinguished by length, there are short probes and long probes. The short probes have a small compression amount during testing and a long service life; in terms of the contact form, gold-plated bumps can be used to replace the conventional probes to contact and test the wafer, reducing the contact resistance and test error.

[0043] 4. Light source simulator: The IV test of the stacked cell requires two flashes, and different requirements are imposed on the wavelength of the light source.

[0044] Based on this, the light source is designed into two groups of light sources with different wavelengths to simulate sunlight. This light source needs to meet the IEC 60904-9 standard in all aspects (including spectrum, light intensity, uniformity, stability, spot characteristics, irradiation angle, light source life, etc.), as shown in Figure 6 , where the left figure is a double xenon lamp design, and different spectral light outputs are achieved through the light source + filter; the right figure is an LED lamp design, and sunlight is simulated by mixing different color LED lamp beads. Two groups of LED lamp beads respectively output two different spectral lights; The dual-xenon lamp design and the two groups of LED lamp designs are both to meet the test spectral requirements of the top cell and the bottom cell; the selection of the spectrum (spectral range, uniformity, light intensity, etc.) has a huge impact on the accuracy of the test. It is necessary to accurately select the spectral range according to the absorption characteristics of the upper and lower cell wafers to obtain accurate electrical performance data of the cell wafers.

[0045] In the future, based on this test device, a light source with a suitable spectrum will be searched for, and the efficiency test of the tandem cell will be completed with one-time needle pressing and one-time flashing.

[0046] Example 1 IV test of perovskite stacked HTBC cell: (1) Loading and positioning of the cell wafer: Transport the three-terminal cell wafer to the indexing table, and the positioning camera positions the three-terminal cell wafer (such as Figure 7 a). At this time, the probe used in the test station has a length of 33.4 mm, an outer diameter of the needle tube of 1.37 mm, an outer diameter of the needle rod of 0.9 mm, and an outer diameter of the needle tip of 1.50 mm (such as Figure 5 -c), and there are 36 probes on a single probe row (which can be designed as 24 current needles and 12 voltage needles, such as Figure 5 -a).

[0047] (2) Handling of the cell wafer: After the cell wafer is placed on the indexing table, the vacuum chuck on the indexing table adsorbs the cell wafer on the turntable, and the indexing table rotates 90°, transporting the cell wafer to be tested to the test position (such as Figure 7 b), and the probe device (such as Figure 5 -b) automatically corrects the pressing position according to the camera positioning information. The original loading position is taken by the robotic arm chuck to pick up another cell wafer to be tested and place it in the test loading position.

[0048] (3) Probe pressing and position correction: Press the upper and lower probe rows of the cell wafer bearing platform (such as Figure 7 c), so that the upper and lower probes penetrate into the positive and negative electrode main grid lines on the back and the main grid on the front of the three-terminal stacked cell wafer (see the cell wafer principle Figure 2 ). The size of the test cell wafer is 182.35mm * 183.75mm for 16BB (a total of 32 groups of probe rows for a set of tests, 16 groups on the front and back respectively, and 8 groups of positive and negative electrodes for the 16 groups on the back), the probe row spacing is 10.8mm, the probe spacing is 15.18mm; the length is 230mm, the width is 40mm, the thickness is 2.5mm, and the center distance between adjacent probes is 5mm (probe rows see Figure 5 -a, Figure 5 -b); (4)Electrical performance test: Bottom cell test: Disconnect the A1 button connected to the top cell electrode, turn on the A2 button connecting the positive and negative electrodes of the bottom cell, and simultaneously start the light source 1 of the test mechanism (select a xenon lamp with a long-pass filter, spectral range: 800nm - 1200nm, non-uniformity < 2%, see the light source in Figure 6 ), so that the bottom cell of the triple-junction cell generates photovoltaic power, and measure the I - V performance of the bottom cell of the triple-junction cell; during this process, the test light intensity is 998w / ㎡, and the test temperature is 24.5℃.

[0049] Top cell test: Turn on the A1 button connected to the top cell, disconnect the A2 button connecting the positive and negative electrodes of the bottom cell, start the light source again (select a xenon lamp with a short-pass filter, spectral range: 200nm - 800nm, non-uniformity < 2%), and measure the I - V performance of the bottom cell of the triple-junction cell (see the test principle in Figure 3 , Figure 4 , where Figure 4 the left part in is the light source for IV test to ensure accurate output of test light intensity. The middle part is for data acquisition, including data such as temperature, light intensity, and electrical performance. The right part is for data fitting and correction. Together, they ensure the accuracy of the output of electrical performance data);

[0050] During this process, the test light intensity is 1010w / ㎡, and the test temperature is 24.6℃. Figure 8 Data correction and fitting: The test software corrects the measured ISC and VOC to the values at the standard test light intensity and temperature (1000w / ㎡, 25℃). The efficiency of the top perovskite cell is 20.5%; the conversion efficiency of the bottom hybrid HTBC cell is 12%, and the overall conversion efficiency is 32% (as shown in Figure 9 , the two curves in the figure are the IV test curves of the top cell and the bottom cell respectively. The short-circuit current and open-circuit voltage of the two cells can be seen on the curves. Data such as fill factor, series resistance, and parallel resistance are obtained through software fitting calculation; finally, the overall efficiency of the tandem cell is fitted);

[0051] Example 2 IV test of perovskite tandem TBC cell: (1)Loading and positioning: Transport the three-terminal cell to the indexing table, and the positioning camera positions the three-terminal cell. At this time, the tungsten carbide gold-plated probe used in the test station has a length of 25 mm, a diameter of 0.5 mm, and a tip diameter of 0.3 mm. There are 100 probes (96 current probes and 4 voltage probes) on a single probe row.

[0052] (2)Cell handling: After the cell is placed on the indexing table, the vacuum chuck on the indexing table adsorbs the cell on the turntable. The indexing table rotates 90°, transports the cell to be tested to the test position, and the probe device automatically corrects the pressing position according to the camera positioning information. The original loading position is taken by the robotic arm chuck to pick up another cell to be tested and place it in the test loading position.

[0053] (3)Probe pressing and position correction: Press the upper and lower probes of the cell carrier platform according to the corrected position, so that the upper and lower probes penetrate into the positive and negative electrode test positions on the front and back of the three-terminal stacked cell. The test cell size is 182.2mm * 210.2mm half cell + 0BB cell. The number of welding ribbons corresponding to the cell in the module is 20 (because the 0BB grid lines are denser and the distance between the positive and negative electrodes is short - the positive and negative fine grids are arranged in a cross pattern, so an integrated probe is used. There are 40 groups in total for a set of tests, 20 groups on the front and back respectively. Among the 20 groups on the back, 10 groups for the positive and negative electrodes respectively correspond to the welding positions of the module). The positive and negative electrodes are arranged in a finger-like pattern, and a single fine grid corresponds to a single test probe; (4)Electrical performance test: Bottom cell test: Disconnect the A1 button connected to the top cell electrode, turn on the A2 button connected to the positive and negative electrodes of the bottom cell, and synchronously start the light source 1 of the test mechanism (the light source selects a near-infrared LED light source, spectral range: ≥800nm, non-uniformity <2%), so that the bottom cell of the three-terminal cell generates photovoltaic power, and measure the I - V performance of the bottom cell of the three-terminal cell; During this process, the test light intensity is 999w / ㎡, and the test temperature is 24.7℃; Top cell test: Turn on the A1 button connected to the top cell, disconnect the A2 button connected to the positive and negative electrodes of the bottom cell, and start the light source again (the light source selects an ultraviolet-visible LED light source, spectral range: ≤800nm, non-uniformity <2%), and measure the I - V performance of the bottom cell of the three-terminal cell. During this process, the test light intensity is 1003w / ㎡, and the test temperature is 24.8℃.

[0054] Data correction and fitting: The test software corrects the measured ISC and VOC to the values at the standard test light intensity and temperature (1000w / ㎡, 25℃). The efficiency of the top perovskite cell is 20.3%; the conversion efficiency of the bottom hybrid BC cell is 11.5%, and the comprehensive conversion efficiency is 31.5%; Post - processing after testing: After the testing is completed, the indexing table rotates, and the blanking suction cup sends the solar cell to the conveyor belt. The loading suction cup synchronously sucks a new solar cell to repeat the testing, realizing the full automation of the testing process.

[0055] Comparative Example 1 IV testing of perovskite - stacked HPBC cells: (1) Loading and positioning: The standard solar cell (a solar cell whose efficiency has been certified by a certification agency) is transported from the AOI station in front of the IV testing to the station to be carried by the conveyor belt; There are fixed stoppers in front of the station to be carried, and clamping devices on both sides. The positioning of the solar cell is completed through mechanical limits; After the positioning is completed, the robotic arm transports the three - terminal solar cell to the indexing table (the indexing table is a device with a turntable electrode and 4 test platforms). At this time, the probe used in the testing station has a length of 33.4 mm, an outer diameter of the needle tube of 1.37 mm, an outer diameter of the needle rod of 0.9 mm, and an outer diameter of the needle tip of 1.50 mm (as Figure 5 - c), and there are 36 probes on a single probe row (which can be designed as 24 current needles and 12 voltage needles, as Figure 5 - a).

[0056] (2) Solar cell handling: After the solar cell is transported to the indexing table, the vacuum suction cup on the indexing table adsorbs the solar cell on the turntable. The indexing table rotates 90°, and transports the solar cell to be tested to the testing position (as Figure 7 b). After the turntable rotates in place, the probe automatically presses. At the original loading position, the robotic arm suction cup takes another solar cell to be tested and places it in the testing loading position.

[0057] (3) Probe pressing: Press the upper and lower probe rows of the solar cell bearing platform (as Figure 7 c), so that the upper and lower probes penetrate into the positive and negative electrode main grid lines on the back and the main grid on the front of the three - terminal stacked solar cell (see the principle of the solar cell Figure 2 ).

[0058] The size of the tested solar cell is 182.35mm * 183.75mm for 16BB (a total of 32 probe rows in a set of tests, 16 rows on the front and back respectively, with 8 rows of positive and negative electrodes on the back). The distance between probe rows is 10.8 mm, the distance between probes is 15.18 mm; the length is 230 mm, the width is 40 mm, the thickness is 2.5 mm, and the center distance between adjacent probes is 5 mm (the probe row is shown in Figure 5 - a, Figure 5 - b); (4) Electrical performance testing: A. Testing preparation: Select an IV tester for mass production of crystalline silicon cells, and connect the positive and negative electrodes corresponding to the upper and lower probe rows of the tester to the corresponding data acquisition modules respectively.

[0059] B. Light source configuration: A xenon lamp for photovoltaic use is adopted as the simulation light source, which complies with IEC 60904 - 9 "Performance Requirements for Solar Simulators". The goal is to complete the efficiency test of the laminated solar cell in one flash.

[0060] C. Software settings: Input the calibrated current temperature coefficient and voltage temperature coefficient of the standard cell into the software, and change the area of the cell in the software to the actual area of the three-terminal laminated cell.

[0061] D. First test: Start the test program. At this time, the current light intensity of 995 w / ㎡, the temperature of the cell of 23.2 °C, and the cell efficiency of 27% are shown on the display screen of the test equipment. (There is a relatively obvious deviation between this efficiency value and the pre-calibrated efficiency of 26% of this standard cell.)

[0062] E. Machine calibration operation and retest: Calibrate the efficiency of the standard cell to the calibrated 26% through the software; repeat the efficiency test of the standard cell again. F. Data analysis: However, it is found during this process that the fluctuation range of the measured efficiency value is relatively large, with a fluctuation of ±0.2%.

[0063] After investigation and analysis, it is determined that one of the reasons is that there are defects in the mechanical positioning method, which causes the accuracy of the probe to be unstable during the downward pressing process, and finally leads to the fluctuation of the test results.

[0064] G. Further expand the test scope, and use the calibrated test machine to conduct tests on other calibrated standard cells. Unfortunately, the test results still show inaccurate data with large deviations.

[0065] (5) Post-processing after the test: After the test is completed, the indexing plate rotates, and the blanking suction cup (such as Figure 9 ) sends the cell to the conveyor belt, and the loading suction cup synchronously sucks a new cell to repeat the test, realizing the automation of the test process.

[0066] Summary: Based on the test conditions of each of the above links, the current method of mechanical positioning plus single flash is still difficult to effectively meet the efficiency test requirements of laminated solar cells in terms of test accuracy and repeatability.

[0067] The IV test method proposed by the present invention focuses on mass production solutions while emphasizing spectral fine design and precise control. It deeply studies the optical properties of top and bottom cell materials, etc., and customizes spectral combinations suitable for two flashes. When measuring the top cell, the flash spectrum matches its light absorption peak and bandwidth to excite photocurrent; when measuring the bottom cell, the spectrum is optimized from multiple dimensions to reveal its electrical performance potential. The improved spectral design overcomes the drawbacks of inaccurate traditional test results, provides a reliable means for the performance evaluation, quality inspection, and scientific research and development of three-terminal tandem photovoltaic cells, and strongly promotes the technological progress in this field.

[0068] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the present invention.

Claims

1. A test method for a three-terminal stacked battery IV, characterized in that: Including, Wafer loading and positioning for triple-junction stacked wafers: Move the triple-junction stacked wafers to the IV test carrier stage. The indexing table secures the wafers, and the upper positioning camera is activated to identify the mark points on the wafers and obtain the position information. Wafer handling: The indexing table rotates according to the set program, and by virtue of high-precision mechanical transmission, the positioned wafers are sent to the test probes. Probe pressing and position correction: After the wafers are in place, the upper and lower probes are precisely pressed into the front and back sides of the wafers to form a test connection circuit. Among them, when the probes are pressed, the probe stage fine-tunes the probe pressing position based on the data fed back by the positioning camera to compensate for potential position errors. Test results: The IV test of the triple-junction stacked solar cell is achieved through one-time probe pressing and two flash tests. Among them, the wavelength of the test light source for the bottom cell is 800nm - 1200nm, and the wavelength of the test light source for the top cell is 200nm - 800nm. For different cell designs, fine-tuning may be done in the selection of the wavelength. When the bandgap of the top cell is relatively wide, the wavelength range of the test light source for the top cell can be adjusted towards the short-wave direction, and the lower limit of the wavelength of the test light source for the bottom cell can be adjusted towards the short-wave direction. After the test is completed, the indexing table rotates, and the unloading suction cup sends the wafers to the conveyor belt, while the loading suction cup simultaneously sucks new wafers to repeat the test.

2. The test method according to claim 1, wherein: The triple-junction stacked wafers are applicable to various triple-junction stacked cell structures, including cases where the front side of the top cell is the positive or negative electrode, and the bottom cell has a BC structure (a structure where the positive and negative electrodes on the back side are arranged in a finger-crossed pattern).

3. The test method according to claim 2, characterized in that: The triple-junction stacked cell structure also includes whole-piece, half-piece, three-piece, four-piece, and multi-piece cell structures, as well as front cell grid line design structures such as 0BB, MBB, multi-main grid, and front-side stacked grid.

4. The test method according to claim 1, wherein: The probes include short probes and long probes.

5. The testing method according to any one of claims 1, 2 or 4, characterized in that: Regarding the two flash tests, among them, The first flash test includes disconnecting the button connected to the top cell electrode, turning on the buttons connected to the positive and negative electrodes of the bottom cell, and simultaneously starting the light source of the test mechanism to enable the bottom cell of the triple-junction wafer to generate photovoltaic power, and measuring the IV performance of the bottom cell of the triple-junction wafer.

6. The test method according to claim 5, wherein: During the first flash test, The test light intensity is 998w / ㎡, and the test temperature is 24.5℃.

7. The testing method according to claim 5, characterized in that: Regarding the two flash tests, among them, The second flash test includes turning on the button connected to the top cell, disconnecting the buttons connected to the positive and negative electrodes of the bottom cell, and starting the light source again to measure the IV performance of the bottom cell of the triple-junction wafer.

8. The test method according to claim 5, characterized in that: During the second flash test, the test light intensity is 1010w / ㎡, and the test temperature is 24.6℃.

9. The testing method according to claim 1, characterized in that: The indexing table has 4 rotating platforms. One platform receives new wafers to be tested, one platform is the test platform, one platform is the unloading platform, and one platform is the waiting platform. The rotating motor in the middle of the platform drives the platform to rotate to achieve the transmission and testing of the wafers.

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