An aluminum paste and its preparation method, PERC cells, modules, and systems.

Abstract

This application relates to the field of solar cell technology, providing an aluminum paste and its manufacturing method, a PERC cell, a module, and a system. The manufacturing method of the aluminum paste for PERC cells includes: preparing a boron-aluminum-silicon composite oxide; adding the boron-aluminum-silicon composite oxide to a glass base material to form a glass raw material; and using the glass raw material to prepare the aluminum paste. Thus, because the glass raw material of the aluminum paste includes the boron-aluminum-silicon composite oxide, boron can be better retained in the laser-drilled grooves, increasing the doping of the back electric field, thereby improving the back passivation effect of the PERC cell and contributing to improved photoelectric conversion efficiency.

Description

Technical Field

[0001] This application belongs to the field of solar cell technology, and particularly relates to an aluminum paste and its preparation method, PERC cells, modules, and systems. Background Technology

[0002] Solar cell power generation is a sustainable and clean energy source that uses the photovoltaic effect of semiconductor pn junctions to convert sunlight into electrical energy.

[0003] In related technologies, aluminum paste is commonly used to fabricate the circuitry for PERC cells. In addition to transporting electrons, the back electric field formed at the aluminum-silicon interface of the aluminum paste also has a back passivation effect, which can effectively increase internal light reflection to improve long-wavelength response, and can also effectively reduce the back surface recombination rate and improve minority carrier lifetime.

[0004] Related technologies typically involve doping the back of PERC cells with P-type impurities to create a P-type electric field, thereby enhancing back-side passivation. Specifically, impurities such as SiO2 and B2O3 are added to the aluminum paste glass system to improve the adhesion of the aluminum paste and the photoelectric conversion efficiency after sintering. However, this is a mechanical mixing process, and the amount of boron brought into the back electric field by the glass system is limited.

[0005] Therefore, how to prepare aluminum paste to improve the doping of the back electric field has become an urgent problem to be solved. Summary of the Invention

[0006] This application provides an aluminum paste and its preparation method, a PERC cell, a module, and a system, aiming to solve the problem of how to prepare aluminum paste to improve the doping of the back electric field.

[0007] The method for preparing aluminum paste for PERC batteries provided in this application includes:

[0008] Fabrication of boron-aluminum-silicon composite oxides;

[0009] The boron-aluminum-silicon composite oxide is added to the glass base material to form a glass raw material;

[0010] Aluminum paste is prepared using the glass raw material.

[0011] Optionally, the content of the boron-aluminum-silicon composite oxide is 5%-30% of the glass raw material.

[0012] Optionally, the chemical formula of the boron-aluminum-silicon composite oxide is B2O3·xAl2SiO5, where x ranges from 10 to 60.

[0013] Optionally, a boron-aluminum-silicon composite oxide is fabricated, comprising:

[0014] A sol was prepared using sodium aluminate, silicic acid, anhydrous ethanol, boric acid solution, and concentrated ammonia.

[0015] The sol is subjected to constant temperature treatment;

[0016] The sol, after being treated at a constant temperature, is calcined under an oxygen and nitrogen atmosphere to obtain the boron-aluminum-silicon composite oxide.

[0017] Optionally, a sol is prepared using sodium aluminate, silica, anhydrous ethanol, boric acid solution, and concentrated ammonia, comprising:

[0018] The mixture of sodium aluminate and silicic acid was subjected to microwave treatment;

[0019] Add the anhydrous ethanol to the microwave-treated mixture and stir.

[0020] The boric acid solution was added to the stirred mixture and stirred.

[0021] Adjust the pH value of the mixture in which the boric acid solution has been added;

[0022] The pH-adjusted mixture is then aged to form a sol.

[0023] Concentrated ammonia solution is added to the sol.

[0024] Optionally, the glass base material includes lead oxide, silicon oxide, zinc oxide, barium oxide, titanium oxide, vanadium oxide, and antimony oxide.

[0025] The aluminum paste for PERC batteries provided in this application is manufactured using any of the above-mentioned methods for manufacturing aluminum paste for PERC batteries.

[0026] The PERC battery provided in this application has a back electric field made of the aforementioned aluminum paste used in PERC batteries.

[0027] The battery assembly provided in this application includes the aforementioned PERC battery.

[0028] The photovoltaic system provided in this application includes the aforementioned battery modules.

[0029] The aluminum paste and its manufacturing method, PERC cell, component, and system of the embodiments of this application, since the glass raw material of the aluminum paste includes boron aluminum silicon composite oxide, can better retain boron in the laser-opened groove, improve the doping of the back electric field, thereby improving the back passivation effect of the PERC cell and improving the photoelectric conversion efficiency of the PERC cell. Attached Figure Description

[0030] Figure 1 This is a schematic flowchart of a method for manufacturing aluminum paste for PERC batteries according to an embodiment of this application;

[0031] Figure 2This is a schematic flowchart of a method for manufacturing aluminum paste for PERC batteries according to an embodiment of this application;

[0032] Figure 3 This is a schematic flowchart of a method for manufacturing aluminum paste for PERC batteries according to an embodiment of this application. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0034] In this application, since the glass raw material of the aluminum paste includes boron aluminum silicon composite oxide, boron can be better retained in the laser-opened groove, which improves the doping of the back electric field, thereby improving the back passivation effect of the PERC cell and improving the photoelectric conversion efficiency of the PERC cell.

[0035] Example 1

[0036] Please see Figure 1 The method for preparing aluminum paste for PERC batteries according to embodiments of this application includes:

[0037] Step S11: Fabrication of boron-aluminum-silicon composite oxide;

[0038] Step S12: Add boron aluminum silicon composite oxide to the glass base material to form glass raw material;

[0039] Step S13: Use glass raw materials to make aluminum paste.

[0040] The method for manufacturing aluminum paste for PERC cells in this application embodiment includes boron-aluminum-silicon composite oxide in the glass raw material of the aluminum paste, which allows boron to remain better in the laser-drilled grooves, improves the doping of the back electric field, thereby improving the back passivation effect of the PERC cell and improving the photoelectric conversion efficiency of the PERC cell.

[0041] Specifically, in step S11, the chemical formula of the boron-aluminum-silicon composite oxide is B2O3·xAl2SiO5, where x is a positive integer, such as 1, 2, 10, 22, 40, 50, 60, or 70.

[0042] Specifically, in step S12, the boron-aluminum-silicon composite oxide can be mixed with the glass base material to form a mixed glass raw material. Alternatively, the boron-aluminum-silicon composite oxide can be used as one of the raw materials in the glass raw material without mixing it with the glass base material.

[0043] Specifically, in step S13, glass raw materials and non-glass raw materials can be mixed to obtain a mixture; the mixture of glass raw materials and non-glass raw materials is dispersed using a disperser; aluminum powder is added to the dispersed mixture; the mixture with added aluminum powder is dispersed using a disperser; the dispersed mixture is ground using a grinder; an organic solvent is added to the ground mixture; and the mixture with added organic solvent is dispersed using a disperser to obtain aluminum paste.

[0044] Furthermore, the non-glass raw materials include one or more of hydroxylated boron nitride, graphene, and organic binders. Thus, by using hydroxylated boron nitride and graphene as dopants, the thickness of the aluminum-silicon alloy and the doping concentration on the silicon surface can be improved, reducing the series resistance of the aluminum grid lines and thereby enhancing the photoelectric conversion efficiency of the solar cell.

[0045] Furthermore, the ratio of the mass of the glass raw material to the total mass of the aluminum paste ranges from 0.8% to 1.5%.

[0046] Furthermore, when using a disperser to disperse the mixture of glass and non-glass raw materials, the disperser speed ranges from 1000 rpm to 2000 rpm, and the dispersion time ranges from 20 min to 40 min. This ensures that the glass and non-glass raw materials are thoroughly mixed and uniformly dispersed.

[0047] Furthermore, the ratio of the mass of aluminum powder to the total mass of aluminum paste ranges from 75% to 85%.

[0048] Furthermore, when dispersing the mixture containing aluminum powder using a disperser, the disperser speed ranges from 1000 rpm to 2000 rpm, and the dispersion time ranges from 15 min to 30 min. This ensures that the aluminum powder and the mixture are thoroughly mixed and uniformly dispersed.

[0049] Furthermore, the grinding mill can be a three-roll mill. The number of grinding passes ranges from 8 to 12. Preferably, the number of grinding passes is 10.

[0050] Furthermore, the ratio of the mass of the organic solvent to the total mass of the aluminum paste ranges from 0.6% to 1.6%.

[0051] Furthermore, when dispersing the mixture containing the organic solvent using a disperser, the disperser speed ranges from 1000 rpm to 2000 rpm, and the dispersion time ranges from 10 min to 25 min. This ensures that the mixture and organic solvent are thoroughly mixed and uniformly dispersed.

[0052] Example 2

[0053] In some optional embodiments, the content of boron-aluminum-silicon composite oxide is 5%-30% of the glass raw material. For example, it is 5%, 8%, 10%, 12%, 15%, 18%, 20%, 25%, or 30%.

[0054] This ensures that the content of boron-aluminum-silicon composite oxide in the glass raw material is within a suitable range, avoiding insufficient doping due to too low a content and difficulty in producing aluminum paste due to too high a content, resulting in a better overall effect.

[0055] Preferably, the content of boron-aluminum-silicon composite oxide is 10%-15% of the glass raw material. For example, it is 10%, 11%, 12%, 13%, 14%, or 15%.

[0056] This allows the content of boron-aluminum-silicon composite oxide in glass raw materials to be within a more suitable range, resulting in a better overall effect of the aluminum paste.

[0057] Example 3

[0058] In some alternative embodiments, the boron-aluminum-silicon composite oxide has the chemical formula B2O3·xAl2SiO5, where x ranges from 10 to 60. For example, x can be 10, 12, 15, 22, 30, 35, 50, or 60.

[0059] This ensures that the ratio of aluminum, silicon, and boron in the boron-aluminum-silicon composite oxide is within a suitable range, which is beneficial for increasing the doping of the back electric field and thus improving the back passivation effect of the PERC cell.

[0060] Example 4

[0061] Please see Figure 2 In some optional embodiments, step S11 includes:

[0062] Step S111: Prepare a sol using sodium aluminate, silicic acid, anhydrous ethanol, boric acid solution, and concentrated ammonia.

[0063] Step S112: Perform constant temperature treatment on the sol;

[0064] Step S113: Under an oxygen and nitrogen atmosphere, the sol after constant temperature treatment is calcined to obtain boron-aluminum-silicon composite oxide.

[0065] In this way, boron-aluminum-silicon composite oxides can be produced with high efficiency and good quality.

[0066] Specifically, in step S112, the isothermal treatment temperature is 80℃-120℃. For example, it is 80℃, 90℃, 100℃, 110℃, or 120℃. Preferably, the isothermal treatment temperature is 110℃. This ensures that the isothermal treatment temperature is within a suitable range, avoiding poor quality of the boron-aluminum-silicon composite oxide or energy waste caused by excessively high or low temperatures.

[0067] Please note that the temperature for constant temperature treatment can be a fixed value within the range of 80℃-120℃, or it can fluctuate within the range of 80℃-120℃.

[0068] Specifically, in step S112, the isothermal treatment duration is 6-8 hours. For example, it can be 6 hours, 6.2 hours, 6.5 hours, 6.9 hours, 7 hours, 7.5 hours, 7.8 hours, or 8 hours. Preferably, the isothermal treatment duration is 6.5 hours. This ensures the isothermal treatment duration is within a suitable range, avoiding poor quality or energy waste caused by excessively long or short treatment times.

[0069] Please note that the duration of the constant temperature treatment can be a fixed value within 6 hours to 8 hours, or it can fluctuate within 6 hours to 8 hours.

[0070] Specifically, in step S113, the calcination temperature is 450℃-650℃. For example, it is 450℃, 480℃, 500℃, 550℃, or 650℃. Preferably, the calcination temperature is 600℃. This ensures that the calcination temperature is within a suitable range, avoiding poor quality of the boron-aluminum-silicon composite oxide or energy waste caused by excessively high or low temperatures.

[0071] Please note that the calcination temperature can be a fixed value within the range of 450℃-650℃, or it can fluctuate within the range of 450℃-650℃.

[0072] Specifically, in step S113, the calcination time is 3-6 hours. For example, it can be 3 hours, 3.2 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.8 hours, or 6 hours. Preferably, the calcination time is 4 hours. This ensures that the calcination time is within a suitable range, avoiding poor quality or energy waste caused by excessively long or short calcination times.

[0073] Please note that the roasting time can be a fixed value within 3h-6h, or it can fluctuate within 3h-6h.

[0074] Specifically, in step S113, the oxygen-nitrogen atmosphere can be an air atmosphere. This makes an air atmosphere readily available, ensuring the quality of the boron-aluminum-silicon composite oxide while improving efficiency and reducing costs.

[0075] Example 5

[0076] Please see Figure 3 In some optional embodiments, step S111 includes:

[0077] Step S1111: Microwave treatment of the mixture of sodium aluminate and silica;

[0078] Step S1112: Add anhydrous ethanol to the microwave-treated mixture and stir;

[0079] Step S1113: Add boric acid solution to the stirred mixture and stir;

[0080] Step S1114: Adjust the pH value of the mixture containing boric acid solution;

[0081] Step S1115: The pH-adjusted mixture is aged to form a sol;

[0082] Step S1116: Add concentrated ammonia to the sol.

[0083] In this way, sols can be made using sodium aluminate, silica, anhydrous ethanol, boric acid solution, and concentrated ammonia, with high production efficiency and good sol quality.

[0084] Specifically, in step S1111, the concentration of sodium aluminate is 0.05 mol / L to 0.15 mol / L. For example, it can be 0.05 mol / L, 0.07 mol / L, 0.1 mol / L, 0.13 mol / L, or 0.15 mol / L. Preferably, the concentration of sodium aluminate is 0.1 mol / L. This ensures that the concentration of sodium aluminate is within a suitable range, avoiding excessively high or low concentrations that could negatively impact the quality of the boron-aluminum-silicon composite oxide.

[0085] Specifically, in step S1111, the amount of sodium aluminate is 55mL-65mL. For example, 55mL, 58mL, 60mL, 62mL, or 65mL. Preferably, the amount of sodium aluminate is 60mL. This ensures that the amount of sodium aluminate is within a suitable range, avoiding excessive or insufficient amounts that could affect the quality of the boron-aluminum-silicon composite oxide.

[0086] Specifically, in step S1111, the concentration of silicic acid is 0.05 mol / L to 0.15 mol / L. For example, it can be 0.05 mol / L, 0.07 mol / L, 0.1 mol / L, 0.13 mol / L, or 0.15 mol / L. Preferably, the concentration of silicic acid is 0.1 mol / L. This ensures that the concentration of silicic acid is within a suitable range, avoiding excessively high or low concentrations that could negatively impact the quality of the boron-aluminum-silicon composite oxide.

[0087] Specifically, in step S1111, the amount of silicic acid is 55mL-65mL. For example, 55mL, 58mL, 60mL, 62mL, or 65mL. Preferably, the amount of silicic acid is 60mL. This ensures that the amount of silicic acid is within a suitable range, avoiding excessive or insufficient amounts that could affect the quality of the boron-aluminum-silicon composite oxide.

[0088] Specifically, in step S1111, the microwave treatment temperature is 85℃-95℃. For example, it can be 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, 91℃, 92℃, 93℃, 94℃, or 95℃. Preferably, the microwave treatment temperature is 90℃. This ensures that the microwave treatment temperature is within a suitable range, avoiding excessively high or low temperatures that could negatively impact the quality of the boron-aluminum-silicon composite oxide.

[0089] Specifically, in step S1111, the microwave treatment duration is 2-4 hours. For example, it can be 2 hours, 2.3 hours, 2.5 hours, 2.8 hours, 3 hours, 3.5 hours, or 4 hours. Preferably, the microwave treatment duration is 2.5 hours. This ensures the microwave treatment duration is within a suitable range, avoiding any negative impact on the quality of the boron-aluminum-silicon composite oxide due to excessively long or short treatment times.

[0090] Specifically, after step S1111 and before step S1112, the microwave-treated mixture is added to a 1L hydrothermal reactor. The anhydrous ethanol in step S1112, the boric acid solution in step S1113, and the pH-adjusting solution in step S1114 can all be added to the hydrothermal reactor. After step S1115, a portion of the sol can be transferred from this hydrothermal reactor to another hydrothermal reactor, and then concentrated ammonia is added to the reactor containing that portion of the sol. In this embodiment, 100g of sol is transferred to another hydrothermal reactor, and then 40-60mL of concentrated ammonia is added to the reactor containing the 100g of sol. In this embodiment, the concentrated ammonia is 45mL.

[0091] Specifically, in step S1112, the amount of anhydrous ethanol is 350mL-450mL. For example, it is 350mL, 380mL, 400mL, 420mL, or 450mL. Preferably, the amount of anhydrous ethanol is 400mL. This ensures that the amount of anhydrous ethanol is within a suitable range, avoiding excessive or insufficient amounts that could affect the quality of the boron-aluminum-silicon composite oxide.

[0092] Specifically, in step S1112, the stirring temperature is room temperature. The stirring speed is 150 r / min to 250 r / min. For example, 150 r / min, 180 r / min, 200 r / min, 230 r / min, and 250 r / min. Preferably, the stirring speed is 200 r / min. This ensures that the stirring speed is within a suitable range, avoiding excessively high or low speeds that could affect the quality of the boron-aluminum-silicon composite oxide.

[0093] Specifically, in step S1112, the stirring time is 1-2 hours. For example, it can be 1 hour, 1.2 hours, 1.5 hours, 1.8 hours, or 2 hours. Preferably, the stirring time is 1.5 hours. This ensures that the stirring time is within a suitable range, avoiding excessively high or low stirring speeds that could affect the quality of the boron-aluminum-silicon composite oxide.

[0094] Specifically, in step S1113, the concentration of boric acid is 0.15 mol / L to 0.25 mol / L. For example, it can be 0.15 mol / L, 0.17 mol / L, 0.2 mol / L, 0.23 mol / L, or 0.25 mol / L. Preferably, the concentration of boric acid is 0.2 mol / L. This ensures that the concentration of boric acid is within a suitable range, avoiding excessively high or low concentrations that could negatively impact the quality of the boron-aluminum-silicon composite oxide.

[0095] Specifically, in step S1113, the amount of boric acid is 55 mL to 65 mL. For example, 55 mL, 58 mL, 60 mL, 62 mL, or 65 mL. Preferably, the amount of boric acid is 60 mL. This ensures that the amount of boric acid is within a suitable range, avoiding excessive or insufficient amounts that could affect the quality of the boron-aluminum-silicon composite oxide.

[0096] Specifically, in step S1113, the stirring is divided into two stages. In the first stage, the stirring speed is 1500 r / min to 4000 r / min. For example, 1500 r / min, 1800 r / min, 2000 r / min, 2500 r / min, 3000 r / min, and 4000 r / min. Preferably, the stirring speed is 2000 r / min. The stirring duration is 4 h to 6 h. For example, 4 h, 4.5 h, 5 h, 5.5 h, and 6 h. Preferably, the stirring duration is 5.5 h. In this way, the stirring speed and duration in the first stage are within a suitable range, avoiding excessively high or low speeds that could affect the quality of the boron-aluminum-silicon composite oxide.

[0097] Specifically, in step S1113, the stirring is divided into two stages. In the second stage, the stirring speed is less than 100 r / min. For example, 100 r / min, 80 r / min, 70 r / min, 50 r / min, 20 r / min, or 2 r / min. Preferably, the stirring speed is 100 r / min. The stirring time is 4-6 hours. For example, 4 hours, 4.5 hours, 5 hours, 5.5 hours, or 6 hours. Preferably, the stirring time is 5.5 hours. This ensures that the stirring speed and duration in the first stage are within a suitable range, avoiding excessively high or low speeds that could affect the quality of the boron-aluminum-silicon composite oxide.

[0098] Specifically, in step S1114, nitric acid is used to adjust the pH value. Further, nitric acid is added during the second stirring stage of step S1113 to adjust the pH value.

[0099] Specifically, in step S1114, the pH value is adjusted to 5.5-7. For example, 5.5, 5.8, 6, 6.5, 6.8, or 7. Preferably, the pH value is adjusted to 6-6.5. This ensures that the pH value is within a suitable range, avoiding the negative impact of excessively high or low pH values ​​on the quality of the boron-aluminum-silicon composite oxide.

[0100] Specifically, in step S1115, the aging treatment temperature is 75℃-85℃. For example, it can be 75℃, 76℃, 77℃, 78℃, 79℃, 80℃, 81℃, 82℃, 83℃, 84℃, or 85℃. Preferably, the microwave temperature is 80℃. This ensures the aging treatment temperature is within a suitable range, preventing excessively high or low temperatures from affecting the quality of the boron-aluminum-silicon composite oxide.

[0101] Specifically, in step S1111, the microwave duration is 10-15 hours. For example, it can be 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, or 15 hours. Preferably, the microwave duration is 12 hours. This ensures that the microwave temperature is within a suitable range, preventing excessively high or low temperatures from affecting the quality of the boron-aluminum-silicon composite oxide.

[0102] In this embodiment, 60 mL of a mixture of 0.1 mol / L sodium aluminate and 60 mL of freshly prepared 0.1 mol / L silicate was microwaved at 90°C for 2.5 hours and then added to a 1 L hydrothermal reactor. 400 mL of anhydrous ethanol was then added, and the mixture was stirred at 200 rpm for 1.5 hours at room temperature. 60 mL of 0.2 mol / L boric acid solution was then slowly added to the hydrothermal reactor, and the mixture was stirred vigorously at 2000 rpm for 5.5 hours. The stirring speed was then reduced to below 100 rpm, the pH was adjusted to 6-6.5 with nitric acid, and the mixture was aged at 80°C for 12 hours to form a sol. 100 g of the sol was then transferred to another hydrothermal reactor, 45 mL of concentrated ammonia was added, and the mixture was kept at 110°C for 6.5 hours. Finally, the mixture was calcined at 600°C in air for 4 hours to obtain B2O3·22Al2SiO5.

[0103] Example 6

[0104] In some alternative embodiments, the glass base materials include lead oxide (PbO), silicon oxide (SiO2), zinc oxide (ZnO), barium oxide (BaO), titanium oxide (TiO2), vanadium oxide (V2O5), and antimony oxide (Sb2O3).

[0105] This ensures that the aluminum paste can be produced normally, resulting in better stability of the glass powder, better wettability and adhesion of the aluminum paste, and can reduce the warping of PERC cells.

[0106] In summary, the aluminum paste manufacturing method for PERC cells described in this application can enhance the back passivation of PERC cells, improve the photoelectric conversion efficiency of PERC cells by more than 0.05%, and increase the opening voltage by 1-2mV.

[0107] Example 7

[0108] The aluminum paste for PERC batteries in this application is made using the method for making aluminum paste for PERC batteries according to any one of Examples 1 to 6.

[0109] The aluminum paste used in the PERC cell of this application embodiment includes boron-aluminum-silicon composite oxide in its glass raw material, which allows boron to remain better in the laser-drilled groove, improves the doping of the back electric field, thereby improving the back passivation effect of the PERC cell and improving the photoelectric conversion efficiency of the PERC cell.

[0110] Example 8

[0111] The PERC battery of this application embodiment uses aluminum paste for the PERC battery of Example 7 to form the back electric field.

[0112] In the PERC cell of this application embodiment, since the glass raw material of the aluminum paste includes boron aluminum silicon composite oxide, boron can be better retained in the laser-opened groove, improving the doping of the back electric field, thereby improving the back passivation effect of the PERC cell and improving the photoelectric conversion efficiency of the PERC cell.

[0113] Please note that in this embodiment, the PERC grid lines are made using the aluminum paste used in the PERC battery of Example 7. In other embodiments, the PERC grid lines may not be made using the aluminum paste used in the PERC battery of Example 7. The materials used for the PERC grid lines are not limited here.

[0114] Example 9

[0115] The battery assembly of this application includes the PERC battery of Embodiment 8.

[0116] In the battery module of this application embodiment, since the glass raw material of the aluminum paste includes boron aluminum silicon composite oxide, boron can be better retained in the laser-opened groove, improving the doping of the back electric field, thereby improving the back passivation effect of the PERC cell and improving the photoelectric conversion efficiency of the PERC cell.

[0117] In this embodiment, multiple PERC cells in the battery assembly can be connected in series to form a battery string, thereby achieving series current output. For example, the battery cells can be connected in series by setting solder strips (busbars, interconnecting strips), conductive backplates, etc.

[0118] It is understood that in such embodiments, the battery assembly may also include a metal frame, a backsheet, photovoltaic glass, and an encapsulating film. The encapsulating film may be filled between the front and back of the PERC battery, the photovoltaic glass, and adjacent battery cells. As a filler, it may be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulating film may be an EVA film or a POE film, and the specific choice can be made according to the actual situation, without limitation.

[0119] Photovoltaic glass can be applied to the encapsulating film on the front of PERC cells. This photovoltaic glass can be ultra-clear glass, possessing high light transmittance, high transparency, and superior physical, mechanical, and optical properties. For example, ultra-clear glass can achieve a light transmittance of over 92%, protecting the PERC cells while minimizing impact on their efficiency. Simultaneously, the encapsulating film bonds the photovoltaic glass and PERC cells together, providing sealing, insulation, and waterproofing / moisture protection for the PERC cells.

[0120] The backsheet can be attached to the film on the back of the PERC cell. The backsheet protects and supports the PERC cell, providing reliable insulation, water resistance, and aging resistance. Multiple backsheet options are available, typically including tempered glass, acrylic glass, and aluminum alloy TPT composite film, etc. The specific choice depends on the specific circumstances and is not limited here. The backsheet, PERC cell, film, and photovoltaic glass together can be mounted on a metal frame. The metal frame serves as the main external support structure for the entire battery module, providing stable support and installation. For example, the battery module can be installed at the desired location using the metal frame.

[0121] Example 10

[0122] The photovoltaic system of this application includes the battery module of Embodiment Nine.

[0123] In the photovoltaic system of this application embodiment, since the glass raw material of the aluminum paste includes boron aluminum silicon composite oxide, boron can be better retained in the laser-opened groove, improving the doping of the back electric field, thereby improving the back passivation effect of the PERC cell and improving the photoelectric conversion efficiency of the PERC cell.

[0124] In this embodiment, the photovoltaic system can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. It can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple battery modules; for example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0125] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application. Furthermore, the specific features, structures, materials, or characteristics described in the various embodiments or examples of this application can be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A method for preparing aluminum paste for PERC batteries, characterized in that, include: Prepare boron-aluminum-silicon composite oxide; the chemical formula of the boron-aluminum-silicon composite oxide is B2O3·xAl2SiO5, where x ranges from 10 to 60; The boron-aluminum-silicon composite oxide is added to the glass base material to form a glass raw material; Aluminum paste is prepared using the aforementioned glass raw material; Fabrication of boron-aluminum-silicon composite oxides includes: A sol is prepared using sodium aluminate, silicic acid, anhydrous ethanol, boric acid solution, and concentrated ammonia. Specifically, the mixture of sodium aluminate and silicic acid is microwave-treated; anhydrous ethanol is added to the microwave-treated mixture and stirred; boric acid solution is added to the stirred mixture and stirred; the pH value of the mixture with added boric acid solution is adjusted; the pH-adjusted mixture is aged to form a sol; and concentrated ammonia is added to the sol. The sol is subjected to constant temperature treatment; The sol, after being treated at a constant temperature, is calcined under an oxygen and nitrogen atmosphere to obtain the boron-aluminum-silicon composite oxide.

2. The method for preparing aluminum paste for PERC batteries according to claim 1, characterized in that, The content of the boron-aluminum-silicon composite oxide is 5%-30% of the glass raw material.

3. The method for preparing aluminum paste for PERC batteries according to claim 1, characterized in that, The glass base materials include lead oxide, silicon oxide, zinc oxide, barium oxide, titanium oxide, vanadium oxide, and antimony oxide.

4. An aluminum paste for PERC batteries, characterized in that, It is made using the method for producing aluminum paste for PERC batteries according to any one of claims 1-3.

5. A PERC battery, characterized in that, The back field of the PERC battery is made of aluminum paste for PERC batteries as described in claim 4.

6. A battery assembly, characterized in that, Includes the PERC battery as described in claim 5.

7. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 6.

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