Battery piece load testing method

Abstract

The invention relates to the technical field of photovoltaic cells, in particular to a battery piece load testing method. The battery piece load test method comprises the steps that a test battery piece is taken, and the test device applies a load to the test battery piece so that the test battery piece can deform by 5-15 mm in the thickness direction of the test battery piece. Appearance detection is carried out on the tested battery piece, the tested battery piece is an unqualified battery piece when the appearance detection is unqualified, power detection is carried out on the tested battery piece when the appearance detection is qualified, the tested battery piece is a qualified battery piece when the power is qualified, and the tested battery piece is an unqualified battery piece when the power is unqualified. The battery piece is directly tested, so that the test result is more visual, the acquisition difficulty of the test result is reduced, the deformation degree of the test battery piece is enabled to be the same as or similar to the actual deformation degree of the battery piece in the photovoltaic module by controlling the deformation degree of the test battery piece, and the accuracy and reliability of the test result can be improved.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic cell technology, and in particular to a cell load testing method. Background Art

[0002] PV panels contain multiple cells that convert sunlight into electricity to meet daily production needs. During installation and operation, these panels are subject to upward or downward forces along their thickness. For example, accumulated snow or rain on the panel's surface can exert a downward force, causing the cells within the panel to bend downward. In windy conditions, upward forces can also cause the cells within the panel to bend upward.

[0003] When the cell deforms upward or downward, there is a risk that the cell is damaged, resulting in a reduction in the output power of the photovoltaic module. Therefore, the load capacity of the cell needs to be tested to determine whether the load capacity of the cell is qualified.

[0004] Therefore, how to test the load capacity of battery cells is an important issue that needs to be solved in this field. Summary of the Invention

[0005] The present application provides a battery cell load testing method that can intuitively and effectively determine whether the load capacity of a battery cell is qualified.

[0006] The present application provides a battery cell load testing method, comprising: taking a test battery cell, and applying a load to the test battery cell by a testing device so that the test battery cell is deformed in its own thickness direction, and the deformation height of the test battery cell in its own thickness direction is 5mm to 15mm. Performing an appearance inspection on the test battery cell, if the appearance inspection of the test battery cell fails, the test battery cell is an unqualified battery cell, and if the appearance inspection of the test battery cell passes, performing a power inspection on the test battery cell. If the power of the test battery cell passes, the test battery cell is a qualified battery cell, and if the power of the test battery cell fails, the test battery cell is an unqualified battery cell.

[0007] In this application, the battery cells are directly tested, making the test results more intuitive. During the test process, the qualification of the battery cells can be directly judged based on the appearance of the test battery cells, which reduces the difficulty of obtaining the test results and can improve the accuracy and reliability of the test results.

[0008] By controlling the deformation degree of the test cell so that the deformation degree of the test cell is the same or similar to the actual deformation degree of the cell in the photovoltaic module, the accuracy and reliability of the test results can be improved.

[0009] In some possible designs, the step of applying a load to the test cell includes: a test device performing a dynamic load test on the test cell, the dynamic load test including at least one dynamic load cycle, the dynamic load cycle including: the test device pressing the test cell at a first preset pressure to cause the test cell to bend downward in its thickness direction; and the test device pulling up the test cell at a second preset pressure to cause the test cell to bend upward in its thickness direction.

[0010] In some possible designs, when the testing device presses down on the test cell at a first preset pressure, the test cell deforms to a height of 5 mm to 8 mm in its thickness direction. When the testing device pulls up on the test cell at a second preset pressure, the test cell deforms to a height of 5 mm to 8 mm in its thickness direction.

[0011] In some possible designs, the first preset pressure is 800 Pa to 1200 Pa. The second preset pressure is 800 Pa to 1200 Pa.

[0012] In some possible designs, the dynamic load test includes multiple dynamic load cycles with a frequency of 3 to 7 cycles per minute.

[0013] In some possible designs, the number of dynamic load cycles is not less than 1000 times.

[0014] In some possible designs, the step of applying a load to the test cell includes: a test device performing a static load test on the test cell, the static load test including at least one static load cycle, the static load cycle including: the test device pressing down the test cell at a third preset pressure to cause the test cell to bend downward in its thickness direction, and maintaining the pressure for a first preset time t1; and the test device pulling up the test cell at a fourth preset pressure to cause the test cell to bend upward in its thickness direction, and maintaining the pressure for a second preset time t2.

[0015] In some possible designs, when the testing device presses down on the test cell at three preset pressures, the test cell deforms to a height of 10 mm to 15 mm in its thickness direction. When the testing device pulls up on the test cell at a fourth preset pressure, the test cell deforms to a height of 6 mm to 10 mm in its thickness direction.

[0016] In some possible designs, the third preset pressure is 5200 Pa to 5600 Pa. The fourth preset pressure is 2200 Pa to 2600 Pa.

[0017] In some possible designs, 30 min ≤ t1 ≤ 90 min, and 30 min ≤ t2 ≤ 90 min.

[0018] In some possible designs, the number of static load cycles is not less than three.

[0019] In some possible designs, the steps of performing appearance inspection on the test cell include: observing the grid lines of the test cell; when the grid lines of the test cell are broken, the test cell is an unqualified cell; when the grid lines of the test cell are not broken, the appearance inspection of the test cell passes.

[0020] In some possible designs, before the test device applies a load to the test cell, the cell load testing method includes: taking a control cell and measuring the control cell's power P1. The power testing step for the test cell includes: measuring the test cell's power P2. Comparing P1 and P2, if (P1-P2) / P1 is less than 0.05, the test cell's power meets the requirements; if (P1-P2) / P1 is greater than or equal to 0.05, the test cell's power fails the requirements.

[0021] In some possible designs, the testing device includes a suction cup for adsorbing the test battery sheet.

[0022] It should be understood that the foregoing general description and the following detailed description are merely illustrative and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0024] Figure 1 A cross-sectional view of the structure of a photovoltaic module provided in this application in some embodiments; Figure 2 A schematic diagram of the connection structure of battery strings in some embodiments; Figure 3 Schematic diagram of the connection structure of battery strings in other embodiments; Figure 4 A comparison diagram of photovoltaic modules before and after stress in some embodiments; Figure 5 for Figure 4 Comparison of deformation amounts at various positions of the photovoltaic module during downward deformation; Figure 6 Comparison diagrams of photovoltaic modules before and after force in other embodiments; Figure 7 for Figure 6 Comparison of deformation amounts at various positions of the photovoltaic module during upward deformation; Figure 8 A test flow chart of a cell load test method provided in this application in one embodiment; Figure 9 for Figure 8 Flowchart of step S100 in a dynamic load test in some embodiments; Figure 10 for Figure 8 Flowchart of step S100 of the dynamic load test in other embodiments; Figure 11 for Figure 8 Flowchart of step S100 in a static load test in some embodiments; Figure 12 for Figure 8 Flowchart of step S100 of the static load test in other embodiments; Figure 13 for Figure 8 Step S200 in the test flow chart in some embodiments; Figure 14 A test flow chart for partial testing of a battery cell in some embodiments; Figure 15 This is a test flow chart of another embodiment of the battery cell load testing method provided in this application.

[0025] Reference numerals: 100-PV module; 110-cover plate; 120-encapsulation layer; 130-cell string; 131-battery cell; 131A1-first battery cell; 131B1-second battery cell; 131A2-first battery cell; 131B2-second battery cell; 132-welding strip; Z-thickness direction. DETAILED DESCRIPTION

[0026] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0027] It should be clear that the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0028] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0029] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. Furthermore, the character " / " in this document generally indicates an "or" relationship between the associated objects.

[0030] In the field of solar power generation technology, photovoltaic modules are the main components used to achieve photoelectric conversion. Figure 1 FIG is a cross-sectional view of the structure of a photovoltaic module in some embodiments. Figure 1 As shown, the photovoltaic module 100 includes a cover plate 110 , an encapsulation layer 120 and a cell string 130 .

[0031] The cover plate 110 may be made of a rigid material such as tempered glass, PET (Polyethylene Terephthalate), or PC (Polycarbonate).

[0032] Alternatively, the cover plate 110 may be made of a flexible material such as PVF (Polyvinyl Fluoride), ETFE (Ethylene-Tetra-Fluoro-Ethylene), or PVDF (Polyvinylidene Fluoride).

[0033] The encapsulation layer 120 is located between the cover plate 110 and the battery string 130. The encapsulation layer 120 is used to achieve encapsulation and fixation of the battery string 130 and the cover plate 110. The material of the encapsulation layer 120 is one of polyolefins such as EVA (Ethylene-Vinyl Acetate Copolymer), POE (Polyolefin Elastomer), PVB (Polyvinyl Butyral), etc. The above materials have high light transmittance, which is beneficial to improving the photoelectric conversion efficiency of photovoltaic modules.

[0034] The encapsulation layer 120 may also be an EPE film (EVA-POE-EVA co-extruded structure) or an EP film (EVA-POE co-extruded structure).

[0035] Figure 2 FIG. 1 is a schematic diagram of the connection structure of battery strings in some embodiments. Figure 2As shown, the battery string 130 is formed by connecting multiple battery cells 131 and welding strips 132. The battery cells are used to convert light energy into electrical energy to meet the electricity needs of daily production. Adjacent battery strings 130 are connected in series, and / or adjacent battery strings 130 are connected in parallel to increase the output power of the photovoltaic module.

[0036] The types of cell 131 include but are not limited to Passivated Emitter Rear Cell (PERC), Tunnel Oxide Passivated Contact (TOPCon), Heterojunction with Intrinsic Thin-film (HJT), Interdigitated Back Contact (IBC), perovskite cell, etc.

[0037] A PERC cell, along its thickness, consists of a front surface silver electrode, a front surface silicon nitride passivation layer, a phosphorus emitter layer, a P-type silicon substrate layer, a local aluminum back field, a metal aluminum back electrode, and a back passivation layer (Al2O3 / SiNx). PERC cells use a passivation film to passivate the back surface, replacing the all-aluminum back field. This enhances internal back reflection of light from the silicon substrate, reduces the back recombination rate, and increases cell efficiency by 0.5%-1%.

[0038] A TOPCon cell, along its thickness, consists of a silver electrode, a front silicon nitride passivation layer, a boron-doped emitter, an N-type base silicon layer, a diffused doped layer, an ultrathin silicon oxide layer, doped polysilicon, silicon nitride, and a silver electrode. The back of the cell consists of an ultrathin silicon oxide layer (1nm to 2nm) and a phosphorus-doped microcrystalline amorphous hybrid silicon thin film, which together form a passivated contact structure. This structure blocks minority carrier-hole recombination, improving the cell's open-circuit voltage and short-circuit current. The ultrathin oxide layer allows majority electrons to tunnel into the polysilicon layer while blocking minority carrier-hole recombination. The excellent passivation effect of the ultrathin silicon oxide and heavily doped silicon film causes surface band bending of the silicon wafer, creating a field passivation effect. This significantly increases the probability of electron tunneling and reduces contact resistance, thereby increasing the cell's open-circuit voltage and short-circuit current, and thus improving the cell's conversion efficiency.

[0039] For HJT cells, along their thickness direction, the HJT cells include a front low-temperature silver electrode, a front conductive film, an N-type amorphous silicon film, an intrinsic amorphous silicon film, an N-type base silicon layer, an intrinsic amorphous silicon film, a P-type amorphous silicon film, a back conductive film, and a back low-temperature silver electrode.

[0040] An IBC cell, along its thickness, consists of a silicon nitride inversion layer, an N+ front surface field, an N-type base silicon layer, a P+ emitter, an N+ back field, an aluminum oxide passivation layer, a silicon nitride anti-reflection layer, and a metallic silver electrode. IBC cells utilize ion implantation technology to achieve P and N regions with excellent uniformity and precisely controllable junction depth. The front of the cell is free of grid lines, eliminating current losses from metal electrode shading and maximizing the utilization of incident photons. This improves short-circuit current by approximately 7% compared to conventional solar cells. Due to the back-contact structure, grid line shading is not a concern, allowing for a wider grid line ratio, reducing series resistance and achieving a high fill factor. Surface passivation and surface light trapping structures can be optimized, resulting in a lower front-surface recombination rate and surface reflection.

[0041] A perovskite cell, along its thickness, consists of a substrate material, a conductive film, an electron transport layer (titanium dioxide), a perovskite absorption layer (hole transport layer), and a metal cathode. Perovskite materials have a high light absorption coefficient and a long carrier diffusion distance. Photons absorbed by the perovskite material are converted into electrons, which are easily collected by the electrode with minimal loss. This results in high photogenerated voltage and current, leading to high photoelectric conversion efficiency.

[0042] The embodiments of the present application do not impose any special restrictions on the specific type of battery cells.

[0043] Figure 2 The example of battery cell 131 is TOPCon battery. Figure 2 As shown, the battery cell 131 includes at least a first battery cell 131A1 and a second battery cell 131B1 adjacent to each other, one end of the soldering ribbon 132 is connected to the backlight surface of the first battery cell 131A1, and the other end of the soldering ribbon 132 is connected to the light-facing surface of the second battery cell 131B1, so that the first battery cell 131A1 and the second battery cell 131B1 are connected in series through the soldering ribbon 132.

[0044] Figure 3 is a schematic diagram of the connection structure of battery strings in other embodiments, Figure 3 The example of the battery cell 131 is an IBC battery. On this basis, Figure 3 As shown, the battery cell 131 includes at least a first battery cell 131A2 and a second battery cell 131B2 adjacent to each other, one end of the soldering ribbon 132 is connected to the backlight surface of the first battery cell 131A2, and the other end of the soldering ribbon 132 is connected to the light-facing surface of the second battery cell 131B2, so that the first battery cell 131A2 and the second battery cell 131B2 are connected in series through the soldering ribbon 132.

[0045] Based on the above-mentioned photovoltaic assembly 100 , when the photovoltaic assembly 100 is installed and in operation, the photovoltaic assembly 100 will be subjected to an upward or downward force along the thickness direction Z of the photovoltaic assembly 100 .

[0046] Figure 4 The following is a comparison diagram of photovoltaic modules before and after being subjected to force in some embodiments. Figure 4 In FIG, a solid-line frame is used to indicate the state of the photovoltaic assembly 100 when no force is applied, and a dotted-line frame is used to indicate the state of the photovoltaic assembly 100 when force is applied. Figure 4 As shown, when there are objects such as snow and rain on the surface of the photovoltaic component 100, the objects above the photovoltaic component 100 will apply a downward force in the thickness direction Z to the photovoltaic component 100, causing the photovoltaic component 100 to bend and deform downward, and then causing the battery cell 131 inside the photovoltaic component 100 to bend and deform downward.

[0047] Figure 5 This is a comparison diagram of the deformation amounts at various positions when the photovoltaic module 100 deforms downward. Figure 5 The red part in the figure represents the area where the photovoltaic module 100 has the largest deformation, such as Figure 5 As shown, when the photovoltaic component 100 is bent and deformed downward, the deformation amounts of the middle region and the center region of the edge of the photovoltaic component 100 are the largest.

[0048] Figure 6 The following are comparison diagrams of photovoltaic modules before and after force in other embodiments. Figure 6 In FIG, a solid-line frame is used to indicate the state of the photovoltaic assembly 100 when no force is applied, and a dotted-line frame is used to indicate the state of the photovoltaic assembly 100 when force is applied. Figure 6 As shown, in windy weather, the photovoltaic module 100 will be subjected to an upward force in the thickness direction Z, causing the photovoltaic module 100 to bend and deform upward, thereby causing the solar cells 131 inside the photovoltaic module 100 to bend and deform upward.

[0049] Figure 7 This is a comparison diagram of the deformation amounts at various positions when the photovoltaic module 100 deforms upward. Figure 7 The red part in the figure represents the area where the photovoltaic module 100 has the largest deformation, such as Figure 7 As shown, when the photovoltaic module 100 bends and deforms upward, the deformation amount of the central area of ​​the photovoltaic module 100 is the largest.

[0050] When the photovoltaic module 100 deforms upward or downward, the battery cell 131 inside the photovoltaic module 100 will also bend accordingly. There is a risk that the battery cell 131 is damaged, resulting in a reduction in the output power of the photovoltaic module 100. Therefore, it is necessary to test the load capacity of the battery cell 131 to determine whether the load capacity of the battery cell 131 is qualified.

[0051] In some embodiments, in order to test whether the load capacity of the cell 131 is qualified, a downward pressure in the thickness direction Z is applied to the entire photovoltaic module 100, and an upward tension in the thickness direction Z is applied to the entire photovoltaic module 100 to promote the deformation of the photovoltaic module 100. The tested photovoltaic module 100 is then subjected to a power test to determine whether the power of the tested photovoltaic module 100 still meets the requirements, thereby determining whether the load capacity of the cell 131 inside the photovoltaic module 100 is qualified.

[0052] This testing method cannot intuitively determine whether the solar cells 131 inside the photovoltaic module 100 are damaged. During the use of the photovoltaic module, the damaged solar cells 131 will act as a load to consume electricity and generate heat, causing local overheating of the photovoltaic module.

[0053] In view of this, an embodiment of the present application provides a battery cell load testing method, which can more intuitively determine whether the battery cell 131 is damaged after being subjected to force.

[0054] The following is a detailed discussion of the battery cell load testing method provided in the embodiments of the present application.

[0055] Figure 8 FIG. 1 is a flow chart of a load test for a battery cell in some embodiments. Figure 8 As shown, the battery cell load test method includes: S100: Take a test cell, which is the cell 131 mentioned above. The test device applies a load to the test cell to cause the test cell to deform in its thickness direction. The deformation height of the test cell in its thickness direction is 5 mm to 15 mm.

[0056] S200: Perform an appearance inspection on the test cell. If the appearance inspection of the test cell fails, the test cell is deemed an unqualified cell. If the appearance inspection of the test cell passes, proceed to step S300.

[0057] S300: Perform power testing on the test cell. If the power of the cell is qualified, the cell is qualified. If the power of the cell is unqualified, the cell is unqualified.

[0058] In this embodiment, the load is directly applied to the test cell so that the deformation of the test cell can simulate the Figure 5 and Figure 7 The maximum deformation in the test cell is determined, and then the appearance of the test cell after deformation is used to determine whether the test cell is damaged. At the same time, the power of the test cell is used to comprehensively determine whether the load capacity of the test cell meets the requirements.

[0059] In this embodiment, the battery cell is directly tested, making the test results more intuitive. During the test, the qualification of the battery cell can be directly judged based on the appearance of the test battery cell, which reduces the difficulty of obtaining the test results and can improve the accuracy and reliability of the test results.

[0060] By controlling the deformation degree of the test cell so that the deformation degree of the test cell is the same or similar to the actual deformation degree of the cell in the photovoltaic module, the accuracy and reliability of the test results can be improved.

[0061] Among them, the deformation height of the test cell in the thickness direction Z can be 5mm to 15mm. For example, the deformation height of the test cell can be 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, etc.

[0062] If the deformation height of the test cell is too small or too large, the deformation of the test cell will differ significantly from the actual deformation of the cells in the photovoltaic module, affecting the reliability of the test results. Therefore, the deformation height of the test cell in the thickness direction Z is 5mm to 15mm, which reduces the error in the test results and improves the reliability of the cell load capacity test results.

[0063] Exemplarily, the deformation height of the test cell in the thickness direction Z can be 5mm to 10mm, and the deformation height of the test cell can be 5.0mm, 5.2mm, 5.4mm, 5.6mm, 5.8mm, 6.0mm, 6.2mm, 6.4mm, 6.6mm, 6.8mm, 7.0mm, 7.2mm, 7.4mm, 7.6mm, 7.8mm, 8.0mm, 8.2mm, 8.4mm, 8.6mm, 8.8mm, 9.0mm, 9.2mm, 9.4mm, 9.6mm, 9.8mm, 10mm, etc.

[0064] Exemplarily, the deformation height of the test cell in the thickness direction Z can be 10 mm to 15 mm, and the deformation height of the test cell can be 10.0 mm, 10.2 mm, 10.4 mm, 10.6 mm, 10.8 mm, 11.0 mm, 11.2 mm, 11.4 mm, 11.6 mm, 11.8 mm, 12.0 mm, 12.2 mm, 12.4 mm, 12.6 mm, 12.8 mm, 13.0 mm, 13.2 mm, 13.4 mm, 13.6 mm, 13.8 mm, 14.0 mm, 14.2 mm, 14.4 mm, 14.6 mm, 14.8 mm, 15 mm, etc.

[0065] In the above step S100 , the test cell may be subjected to a dynamic load test or a static load test.

[0066] Figure 9 FIG. 1 is a flow chart of a dynamic load test in step S100 in some embodiments. Figure 9 As shown, the above step S100 includes: S110: The test device performs a dynamic load test on the test cell. The dynamic load test includes at least one dynamic load cycle. The dynamic load cycle includes: S111: The testing device presses down the test cell with a first preset pressure, so that the test cell bends and deforms downward in its thickness direction Z and reaches the above-mentioned deformation height.

[0067] S112: The testing device pulls up the test cell sheet at a second preset pressure, so that the test cell sheet bends and deforms upward in its thickness direction and reaches the above-mentioned deformation height.

[0068] In this embodiment, dynamic load testing is performed on the test cells to simulate the process of stepping on the photovoltaic module during the installation process, and to simulate the deformation of the photovoltaic module under strong winds. This is to determine whether the cells in the photovoltaic module are damaged under the rapid upward and downward alternating forces, and whether the output power of the photovoltaic module still meets the requirements, so as to judge the load capacity of the cells and photovoltaic modules, and to improve the stability of the cells and photovoltaic modules.

[0069] The embodiment of the present application does not specifically limit the order of step S111 and step S112. Step S111 may be performed first and then step S112, or step S112 may be performed first and then step S111.

[0070] like Figure 8 As shown, when performing step S111, the deformation height of the test cell in the thickness direction Z is 5mm to 8mm. Exemplarily, the deformation height of the cell can be 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, etc.

[0071] If the deformation height of the test cell is too small or too large, the deformation of the test cell will differ significantly from the actual deformation of the cells in the photovoltaic module, affecting the reliability of the test results. Therefore, the deformation height of the test cell is 5mm to 8mm, which reduces the error in the test results and improves the reliability of the cell load capacity test results.

[0072] Illustratively, when performing step S111, the deformation height of the test cell in the thickness direction Z can be 5mm to 6.5mm, and the deformation height of the cell can be 5mm, 5.1mm, 5.3mm, 5.5mm, 5.7mm, 5.9mm, 6.0mm, 6.1mm, 6.3mm, 6.5mm, etc.

[0073] Illustratively, when performing step S111, the deformation height of the test cell in the thickness direction Z can be 6.5mm to 8mm, and the deformation height of the cell can be 6.5mm, 6.7mm, 6.9mm, 7.0mm, 7.1mm, 7.3mm, 7.5mm, 7.7mm, 7.9mm, 8.0mm, etc.

[0074] When performing step S111, the first preset pressure is 800Pa to 1200Pa. Exemplarily, the first preset pressure can be 800Pa, 850Pa, 900Pa, 950Pa, 1000Pa, 1050Pa, 1100Pa, 1150Pa, 1200Pa, etc.

[0075] If the first preset pressure is too high or too low, the deformation of the test cell will differ significantly from the actual deformation of the cells in the photovoltaic module, affecting the reliability of the test results. Therefore, the first preset pressure is 800Pa to 1200Pa, which reduces the error in the test results and improves the reliability of the cell load capacity test results.

[0076] Exemplarily, the first preset pressure is 800Pa to 1000Pa. The first preset pressure may be 800Pa, 810Pa, 820Pa, 830Pa, 840Pa, 850Pa, 860Pa, 870Pa, 880Pa, 890Pa, 900Pa, 910Pa, 920Pa, 930Pa, 940Pa, 950Pa, 960Pa, 970Pa, 980Pa, 990Pa, 1000Pa, etc.

[0077] Exemplarily, the first preset pressure is 1000Pa to 1200Pa. The first preset pressure may be 1000Pa, 1010Pa, 1020Pa, 1030Pa, 1040Pa, 1050Pa, 1060Pa, 1070Pa, 1080Pa, 1090Pa, 1100Pa, 1110Pa, 1120Pa, 1130Pa, 1140Pa, 1150Pa, 1160Pa, 1170Pa, 1180Pa, 1190Pa, 1200Pa, etc.

[0078] like Figure 8As shown, when performing step S112, the deformation height of the test cell in the thickness direction Z is 5mm to 8mm. Exemplarily, the deformation height of the cell can be 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, etc.

[0079] If the deformation height of the test cell is too small or too large, the deformation of the test cell will differ significantly from the actual deformation of the cells in the photovoltaic module, affecting the reliability of the test results. Therefore, the deformation height of the test cell is 5mm to 8mm, which reduces the error in the test results and improves the reliability of the cell load capacity test results.

[0080] Illustratively, when performing step S112, the deformation height of the test cell in the thickness direction Z can be 5mm to 6.5mm, and the deformation height of the cell can be 5mm, 5.1mm, 5.3mm, 5.5mm, 5.7mm, 5.9mm, 6.0mm, 6.1mm, 6.3mm, 6.5mm, etc.

[0081] Exemplarily, when performing step S112, the deformation height of the test cell in the thickness direction Z can be 6.5mm to 8mm, and the deformation height of the cell can be 6.5mm, 6.7mm, 6.9mm, 7.0mm, 7.1mm, 7.3mm, 7.5mm, 7.7mm, 7.9mm, 8.0mm, etc.

[0082] When performing step S112, the second preset pressure is 800Pa to 1200Pa. Exemplarily, the second preset pressure can be 800Pa, 850Pa, 900Pa, 950Pa, 1000Pa, 1050Pa, 1100Pa, 1150Pa, 1200Pa, etc.

[0083] If the second preset pressure is too high or too low, the deformation of the test cell will differ significantly from the actual deformation of the cells in the photovoltaic module, affecting the reliability of the test results. Therefore, the second preset pressure is 800Pa to 1200Pa, which reduces the error in the test results and improves the reliability of the cell load capacity test results.

[0084] Exemplarily, the second preset pressure is 800Pa to 1000Pa. The second preset pressure may be 800Pa, 810Pa, 820Pa, 830Pa, 840Pa, 850Pa, 860Pa, 870Pa, 880Pa, 890Pa, 900Pa, 910Pa, 920Pa, 930Pa, 940Pa, 950Pa, 960Pa, 970Pa, 980Pa, 990Pa, 1000Pa, etc.

[0085] Exemplarily, the second preset pressure is 1000Pa to 1200Pa. The second preset pressure may be 1000Pa, 1010Pa, 1020Pa, 1030Pa, 1040Pa, 1050Pa, 1060Pa, 1070Pa, 1080Pa, 1090Pa, 1100Pa, 1110Pa, 1120Pa, 1130Pa, 1140Pa, 1150Pa, 1160Pa, 1170Pa, 1180Pa, 1190Pa, 1200Pa, etc.

[0086] One step S111 and one step S112 constitute one dynamic load cycle. Figure 10 A flow chart for dynamic load testing in some embodiments, such as Figure 10 As shown, the dynamic load test of the test cell includes multiple dynamic load cycles, that is, step S111 and step S112 are performed alternately multiple times.

[0087] The frequency of the dynamic load cycle is 3 times per minute to 7 times per minute. For example, the frequency of the dynamic load cycle is 3 times per minute, 4 times per minute, 5 times per minute, 6 times per minute or 7 times per minute.

[0088] If the frequency of dynamic load cycles is too high or too low, it will affect the reliability of the test results. Therefore, the frequency of dynamic load cycles is 3 to 7 times per minute, which reduces the error in the test results and improves the reliability of the battery cell load capacity test results.

[0089] In addition, the number of dynamic load cycles is not less than 1000. Exemplarily, the number of dynamic load cycles is 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000 or even more times.

[0090] If the number of dynamic load cycles is too small, the reliability of the test results will be affected. Therefore, the number of dynamic load cycles is not less than 1000, which reduces the error of the test results and improves the reliability of the battery cell load capacity test results.

[0091] Figure 11 FIG. 1 is a flow chart of a static load test in step S100 in some embodiments. Figure 11 As shown, the above step S100 includes: S120: The test device performs a static load test on the test cell. The static load test includes at least one static load cycle. The static load cycle includes: S121: The testing device presses the test cell with a third preset pressure to bend the test cell downward in its thickness direction, so that the test cell reaches a preset deformation height and maintains it for a first preset time t1.

[0092] S122: The testing device pulls up the test cell sheet at a fourth preset pressure to bend and deform the test cell sheet upward in its thickness direction, so that the test cell sheet reaches a preset deformation height and maintains the height for a second preset time t2.

[0093] In this embodiment, a static load test is performed on the test cell to simulate the accumulation of objects such as rain and snow on the photovoltaic module, and to simulate the deformation of the photovoltaic module under strong winds. This is to determine whether the cell in the photovoltaic module is damaged and whether the output power of the photovoltaic module still meets the requirements under the upward and downward forces that last for a long time, so as to facilitate the load capacity of the cell and photovoltaic module, and to improve the operation stability of the cell and photovoltaic module.

[0094] The embodiment of the present application does not specifically limit the order of step S121 and step S122. Step S121 can be performed first and then step S122, or step S122 can be performed first and then step S121.

[0095] like Figure 11 As shown, when performing step S121, the deformation height of the test cell in its thickness direction is 10 mm to 15 mm. For example, the deformation height of the test cell can be 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, etc.

[0096] If the deformation height of the test cell is too small or too large, the deformation of the test cell will differ significantly from the actual deformation of the cells in the photovoltaic module, thus affecting the reliability of the test results. Therefore, the deformation height of the test cell in the thickness direction Z is 10mm to 15mm, which reduces the error in the test results and improves the reliability of the cell load capacity test results.

[0097] Exemplarily, the deformation height of the test cell in the thickness direction Z can be 10 mm to 12.5 mm, and the deformation height of the test cell can be 10.0 mm, 10.1 mm, 10.3 mm, 10.5 mm, 10.7 mm, 10.9 mm, 11.0 mm, 11.1 mm, 11.3 mm, 11.5 mm, 11.7 mm, 11.9 mm, 12.0 mm, 12.1 mm, 12.3 mm, or 12.5 mm.

[0098] Exemplarily, the deformation height of the test cell in the thickness direction Z can be 12.5mm to 15mm, and the deformation height of the test cell can be 12.5mm, 12.7mm, 12.9mm, 13.0mm, 13.1mm, 13.3mm, 13.5mm, 13.7mm, 13.9mm, 14.0mm, 14.1mm, 14.3mm, 14.5mm, 14.7mm, 14.9mm, 15.0mm, etc.

[0099] When performing step S121, the third preset pressure is 5200Pa to 5600Pa. Exemplarily, the third preset pressure can be 5200Pa, 5250Pa, 5300Pa, 5350Pa, 5400Pa, 5450Pa, 5500Pa, 5550Pa, 5600Pa, etc.

[0100] If the third preset pressure is too high or too low, the deformation of the test cell will differ significantly from the actual deformation of the cells in the photovoltaic module, affecting the reliability of the test results. Therefore, the third preset pressure is 5200Pa to 5600Pa, which reduces the error in the test results and improves the reliability of the cell load capacity test results.

[0101] Exemplarily, the third preset pressure may be 5200Pa to 5400Pa, and the third preset pressure may be 5200Pa, 5210Pa, 5220Pa, 5230Pa, 5240Pa, 5250Pa, 5260Pa, 5270Pa, 5280Pa, 5290Pa, 5300Pa, 5310Pa, 5320Pa, 5330Pa, 5340Pa, 5350Pa, 5360Pa, 5370Pa, 5380Pa, 5390Pa, 5400Pa, etc.

[0102] Exemplarily, the third preset pressure may be 5400Pa to 5600Pa, and the third preset pressure may be 5400Pa, 5410Pa, 5420Pa, 5430Pa, 5440Pa, 5450Pa, 5460Pa, 5470Pa, 5480Pa, 5490Pa, 5500Pa, 5510Pa, 5520Pa, 5530Pa, 5540Pa, 5550Pa, 5560Pa, 5570Pa, 5580Pa, 5590Pa, 5600Pa, etc.

[0103] When performing step S121, the first preset time t1 satisfies: 30 min≤t1≤90 min. Exemplarily, the first preset time can be 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, etc.

[0104] If the first preset time is short, the reliability of the test result is poor.

[0105] If the first preset time is longer, the static load test cycle of the test cell is longer.

[0106] Therefore, 30min≤t1≤90min, which reduces the error of the test result, improves the reliability of the battery cell load capacity test result, and shortens the static load test cycle.

[0107] Exemplarily, 30min≤t1≤60min, the first preset time can be 30min, 32min, 34min, 36min, 38min, 40min, 42min, 44min, 46min, 48min, 50min, 52min, 54min, 56min, 58min, 60min, etc.

[0108] Exemplarily, 60min≤t1≤90min, the first preset time can be 60min, 62min, 64min, 66min, 68min, 70min, 72min, 74min, 76min, 78min, 80min, 82min, 84min, 86min, 88min, 90min, etc.

[0109] like Figure 11 As shown, when performing step S122, the deformation height of the test cell in its own thickness direction is 6mm to 10mm. Exemplarily, the deformation height of the test cell can be 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm, etc.

[0110] If the deformation height of the test cell is too small or too large, the deformation of the test cell will differ significantly from the actual deformation of the cells in the photovoltaic module, affecting the reliability of the test results. Therefore, the deformation height of the test cell in the thickness direction Z is 6mm to 10mm, which reduces the error in the test results and improves the reliability of the cell load capacity test results.

[0111] Exemplarily, the deformation height of the test cell in the thickness direction Z can be 6mm to 8mm, and the deformation height of the test cell can be 6.0mm, 6.1mm, 6.2mm, 6.3mm, 6.4mm, 6.5mm, 6.6mm, 6.7mm, 6.8mm, 6.9mm, 7.0mm, 7.1mm, 7.2mm, 7.3mm, 7.4mm, 7.5mm, 7.6mm, 7.7mm, 7.8mm, 7.9mm, 8.0mm, etc.

[0112] Exemplarily, the deformation height of the test cell in the thickness direction Z can be 8mm to 10mm, and the deformation height of the test cell can be 8.0mm, 8.1mm, 8.2mm, 8.3mm, 8.4mm, 8.5mm, 8.6mm, 8.7mm, 8.8mm, 8.9mm, 9.0mm, 9.1mm, 9.2mm, 9.3mm, 9.4mm, 9.5mm, 9.6mm, 9.7mm, 9.8mm, 9.9mm, 10.0mm, etc.

[0113] When performing step S121, the fourth preset pressure is 2200Pa to 2600Pa. Exemplarily, the fourth preset pressure can be 2200Pa, 2250Pa, 2300Pa, 2350Pa, 2400Pa, 2450Pa, 2500Pa, 2550Pa, 2600Pa, etc.

[0114] If the fourth preset pressure is too high or too low, the deformation of the test cell will differ significantly from the actual deformation of the cells in the photovoltaic module, thus affecting the reliability of the test results. Therefore, the fourth preset pressure is 2200Pa to 2600Pa, which reduces the error in the test results and improves the reliability of the cell load capacity test results.

[0115] Exemplarily, the fourth preset pressure may be 2200Pa to 2400Pa, and the fourth preset pressure may be 2200Pa, 2210Pa, 2220Pa, 2230Pa, 2240Pa, 2250Pa, 2260Pa, 2270Pa, 2280Pa, 2290Pa, 2300Pa, 2310Pa, 2320Pa, 2330Pa, 2340Pa, 2350Pa, 2360Pa, 2370Pa, 2380Pa, 2390Pa, 2400Pa, etc.

[0116] Exemplarily, the fourth preset pressure may be 2400Pa to 2600Pa, and the fourth preset pressure may be 2400Pa, 2410Pa, 2420Pa, 2430Pa, 2440Pa, 2450Pa, 2460Pa, 2470Pa, 2480Pa, 2490Pa, 2500Pa, 2510Pa, 2520Pa, 2530Pa, 2540Pa, 2550Pa, 2560Pa, 2570Pa, 2580Pa, 2590Pa, 2600Pa, etc.

[0117] When performing step S122, the second preset time t2 satisfies: 30min≤t2≤90min. Exemplarily, the second preset time can be 30min, 40min, 50min, 60min, 70min, 80min, 90min, etc.

[0118] If the second preset time is short, the reliability of the test result will be poor.

[0119] If the second preset time is longer, the static load test cycle of the test cell is longer.

[0120] Therefore, 30min≤t2≤90min, which reduces the error of the test results, improves the reliability of the battery cell load capacity test results, and shortens the static load test cycle.

[0121] Exemplarily, 30min≤t2≤60min, and the second preset time can be 30min, 32min, 34min, 36min, 38min, 40min, 42min, 44min, 46min, 48min, 50min, 52min, 54min, 56min, 58min, 60min, etc.

[0122] Exemplarily, 60min≤t2≤90min, the second preset time can be 60min, 62min, 64min, 66min, 68min, 70min, 72min, 74min, 76min, 78min, 80min, 82min, 84min, 86min, 88min, 90min, etc.

[0123] One step S121 and one step S122 constitute one static load cycle. Figure 12 A flow chart for static load testing in some embodiments, such as Figure 12 As shown, the dynamic load test of the test cell includes multiple static load cycles, that is, step S121 and step S122 are performed alternately multiple times.

[0124] The number of static load cycles is no less than three times. For example, the number of static load cycles is 3, 4, 5, 6, 7, 8, 9, 10 or even more times.

[0125] If the number of static load cycles is reduced, the reliability of the test results will be affected. Therefore, the number of static load cycles is not less than 3 times, which reduces the error of the test results and improves the reliability of the battery cell load capacity test results.

[0126] Figure 13 FIG. 1 is a test flow chart of step S200 in some embodiments. As shown in the figure, step S200 may include at least one of step S210 and step S220.

[0127] S210: Observe the gate lines of the test cell. If the gate lines of the test cell are broken, the appearance of the test cell is unqualified, and the test cell is considered an unqualified cell.

[0128] S220: Observe the surface cracks of the test cell. If there are obvious cracks on the surface of the test cell, the appearance of the test cell is unqualified and the test cell is an unqualified cell.

[0129] When performing the above step S200, only step S210 may be performed, only step S220 may be performed, or both step S210 and step S220 may be performed simultaneously.

[0130] In this embodiment, step S210 can determine whether the gate line of the test cell is broken, thereby determining whether the test cell can output current normally, and can also determine whether the output power of the test cell can meet the demand.

[0131] Step S210 can determine the degree of structural damage of the test cell, thereby determining the impact of the load on the life of the test cell.

[0132] In some embodiments, after performing the above step S300, the power of the test cell can be compared with the target power to determine whether the power of the test cell is lower than the target power, thereby determining whether the power of the test cell is qualified, and then determining whether the load capacity of the test cell is qualified.

[0133] In other embodiments, the power of the test cell before and after the load is applied can be compared to determine the degree of change in power before and after the load is applied, thereby determining whether the power of the test cell is qualified and further determining whether the load capacity of the test cell is qualified.

[0134] Figure 14 FIG. 1 is a test flow chart for partial testing of a battery cell in some embodiments. Figure 14 As shown, the battery cell load test method also includes: S400: Take a control cell, which is identical to the test cell, and test the power P1 of the control cell.

[0135] The above step S300 includes: S310: Testing the power P2 of the test cell.

[0136] S320: Compare P1 and P2. When (P1-P2) / P1 < 0.05, the power of the test cell passes. When (P1-P2) / P1 ≥ 0.05, the power of the test cell fails.

[0137] In this embodiment, by comparing the power before and after the load is applied to the test cell, it is possible to more intuitively judge the impact of the load on the output power of the test cell, thereby more intuitively judging whether the load capacity of the test cell is qualified, reducing the difficulty of judging whether the load capacity of the test cell is qualified.

[0138] Among them, step S400 can be before step S100, or between step S100 and step S200, or between step S200 and step S310, or between step S310 and step S320. The embodiment of the present application does not specifically limit the specific order of step S400.

[0139] The above-mentioned testing device can be a counterweight block, a push rod driven by a motor, or a suction cup.

[0140] In this embodiment, the above-mentioned testing device is a suction cup, which can vacuum absorb the test battery cell. By pulling the test battery cell upward or pushing the battery cell downward through the suction cup, the structure of the testing device can be simplified, and the testing difficulty and testing cost can be reduced.

[0141] In summary, Figure 15 This is a test flow chart of the battery cell load test method provided in this application in one embodiment. Figure 15 As shown, illustratively, the battery cell load testing method provided in the embodiment of the present application includes: S400: Take a control cell and test the power P1 of the control cell.

[0142] S110: The test device performs a dynamic load test on the test cell. The dynamic load test includes 1000 dynamic load cycles, and the frequency of the dynamic load cycles is three times per minute.

[0143] The dynamic load cycle includes: S111: The testing device presses the test cell at a first preset pressure of 1000 Pa, so that the test cell bends downward by 5 mm to 8 mm in its thickness direction Z.

[0144] S112: The testing device pulls up the test cell sheet at a second preset pressure of 1000 Pa, so that the test cell sheet bends upward by 5 mm to 8 mm in its thickness direction Z.

[0145] S120: The test device performs a static load test on the test cell, and the static load test includes 3 static load cycles.

[0146] The static load cycle includes: S121: The testing device presses the test cell at a third preset pressure of 5400 Pa, so that the test cell bends downward by 10 mm to 15 mm in its thickness direction Z, and maintains this pressure for 60 minutes.

[0147] S122: The testing device pulls up the test cell sheet at a fourth preset pressure of 2400 Pa, so that the test cell sheet is bent upward by 6 mm to 10 mm in its thickness direction Z, and maintained for 60 minutes.

[0148] S210: Observe the grid lines of the test cell. If the grid lines of the test cell are broken, the appearance of the test cell is unqualified and the test cell is deemed an unqualified cell.

[0149] When the grid lines of the test cell are not broken, the appearance of the test cell is qualified, and step S310 is performed.

[0150] S310: Testing the power P2 of the test cell.

[0151] S320: Compare P1 and P2. When (P1-P2) / P1 < 0.05, the power of the test cell passes. When (P1-P2) / P1 ≥ 0.05, the power of the test cell fails.

[0152] In this embodiment, the battery cell is directly tested, making the test results more intuitive. During the test, the qualification of the test battery cell can be directly judged based on the appearance of the test battery cell, which reduces the difficulty of obtaining the test results and can improve the accuracy and reliability of the test results.

[0153] By controlling the deformation degree of the test cell so that the deformation degree of the test cell is the same or similar to the actual deformation degree of the cell in the photovoltaic module, the accuracy and reliability of the test results can be improved.

[0154] Comparing the power before and after the load is applied to the test cell can more intuitively determine the impact of the load on the output power of the test cell, thereby more intuitively determining whether the load capacity of the test cell is qualified, reducing the difficulty of determining whether the load capacity of the test cell is qualified.

[0155] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A battery cell load testing method, characterized in that: The battery cell load testing method includes: A test cell is taken, and a test device applies a load to the test cell so that the test cell is deformed in its thickness direction, and the deformation height of the test cell in its thickness direction is 5 mm to 15 mm; Observing the grid lines of the test cell; When the gate line of the test cell is broken, the test cell is an unqualified cell; When the gate line of the test cell is not broken, the appearance inspection of the test cell is qualified, and the power test of the test cell is performed; When the power of the test cell is qualified, the test cell is a qualified cell; When the power of the test cell is unqualified, the test cell is an unqualified cell.

2. The battery cell load testing method according to claim 1, characterized in that: The step of applying a load to the test cell comprises: The testing device performs a dynamic load test on the test cell, wherein the dynamic load test includes at least one dynamic load cycle, and the dynamic load cycle includes: The testing device presses the test cell sheet with a first preset pressure to cause the test cell sheet to bend downward in its thickness direction; The testing device pulls up the testing cell sheet at a second preset pressure, so that the testing cell sheet is bent and deformed upward in its thickness direction.

3. The battery cell load testing method according to claim 2, characterized in that: When the testing device presses the test cell sheet at the first preset pressure, the deformation height of the test cell sheet in its thickness direction is 5 mm to 8 mm; When the testing device pulls up the testing battery sheet at the second preset pressure, the deformation height of the testing battery sheet in its thickness direction is 5 mm to 8 mm.

4. The battery cell load testing method according to claim 2, characterized in that: The first preset pressure is 800Pa to 1200Pa; The second preset pressure is 800Pa to 1200Pa.

5. The battery cell load testing method according to claim 2, characterized in that: The dynamic load test includes multiple dynamic load cycles, and the frequency of the dynamic load cycles is 3 times per minute to 7 times per minute.

6. The battery cell load testing method according to claim 5, characterized in that: The number of dynamic load cycles is not less than 1000 times.

7. The battery cell load testing method according to claim 1, characterized in that: The step of applying a load to the test cell comprises: The testing device performs a static load test on the test cell, wherein the static load test includes at least one static load cycle, and the static load cycle includes: The testing device presses the test cell sheet with a third preset pressure to cause the test cell sheet to bend downward in its thickness direction and maintain the pressure for a first preset time t1; The testing device pulls up the testing cell sheet at a fourth preset pressure, so that the testing cell sheet bends and deforms upward in its thickness direction, and maintains this state for a second preset time t2.

8. The battery cell load testing method according to claim 7, characterized in that: When the testing device presses the test cell sheet at the third preset pressure, the deformation height of the test cell sheet in its thickness direction is 10 mm to 15 mm; When the testing device pulls up the testing battery sheet at the fourth preset pressure, the deformation height of the testing battery sheet in its thickness direction is 6 mm to 10 mm.

9. The battery cell load testing method according to claim 7, characterized in that: The third preset pressure is 5200Pa to 5600Pa; The fourth preset pressure is 2200Pa to 2600Pa.

10. The battery cell load testing method according to claim 7, characterized in that: 30min≤t1≤90min; 30min≤t2≤90min.

11. The battery cell load testing method according to claim 7, characterized in that: The number of static load cycles is no less than three.

12. The battery cell load testing method according to any one of claims 1 to 11, characterized in that: Before the step of applying a load to the test cell by a testing device, the cell load testing method includes: Take a control cell and test the power P1 of the control cell; The step of performing power detection on the test cell comprises: Testing the power P2 of the test cell; Compare P1 and P2; When (P1-P2) / P1<0.05, the power of the test cell is qualified; When (P1-P2) / P1≥0.05, the power of the test cell is unqualified.

13. The battery cell load testing method according to any one of claims 1 to 11, characterized in that: The testing device includes a suction cup, and the suction cup is used to absorb the testing battery sheet.

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