High-temperature-resistant and acetic acid-resistant conductive paste and photovoltaic module

Abstract

The application provides a high-temperature-resistant and acetic acid-resistant conductive paste and a photovoltaic module. The high-temperature-resistant and acetic acid-resistant conductive paste comprises a main glass powder and a secondary glass powder, the mass fraction of the main glass powder in the paste is 1.5-2.5%, the mass fraction of the secondary glass powder is 0.2-1%, the secondary glass powder is a Bi-Si-B-Al glass, and the secondary glass powder comprises Bi2O3 and TeO2 accounting for 10-50% of the total mole percentage, SiO2 and GeO2 accounting for 15-30% of the total mole percentage, B2O3 accounting for 18-30% of the total mole percentage, Al2O3 accounting for 0-20% of the total mole percentage, and a modified additive accounting for 1-20% of the total mole percentage. The paste further comprises silver powder and an organic carrier, the mass fraction of the silver powder in the paste is 83-90%, and the mass fraction of the organic carrier is 8-15%. The paste in the application adjusts the low solubility of the electrode grid line in acetic acid through the secondary glass, and solves the problem that the acetic acid generated by the decomposition of EVA under high-temperature conditions affects the battery efficiency of the double-sided EVA module packaged battery.

Description

TECHNICAL FIELD

[0001] The application relates to the field of photovoltaic technology, in particular to a high-temperature-resistant and acetic acid-resistant conductive paste and a photovoltaic module. BACKGROUND

[0002] EVA is a transparent adhesive with good flexibility and bonding performance, good light transmission performance and aging resistance. It encapsulates the crystalline silicon module with "upper cover and lower pad", and is bonded into one body with the upper protective material glass and the lower protective material TPT by vacuum laminating technology to form a crystalline silicon module. The single-glass photovoltaic module absorbs solar energy from one side of the module, and the double-glass photovoltaic module absorbs solar energy from both sides and is composed of two tempered glasses, POE or EVA adhesive film and battery pieces.

[0003] The formal name of EVA resin is ethylene-vinyl acetate copolymer, and the content of vinyl acetate in EVA used in photovoltaic modules is usually 28-33%. In a high-temperature and high-humidity environment, the hydrolysis of EVA to produce acetic acid is inevitable, and the acetic acid accumulated in the photovoltaic module becomes an important inducement for most of the quality problems of the photovoltaic module. In a high-temperature and high-humidity acetic acid environment, the solar energy minority life is affected, the metal electrode contact site and the Ag-Si ohmic contact are greatly reduced, and the power of the module is seriously attenuated with the increase of the wet heat time. Therefore, the acetic acid produced under high-temperature conditions leads to the reduction of battery performance, interacts with the electrode, causes the degradation of the metalization site and the battery piece interface, increases the contact resistance, and the EL imaging is a dark area, which seriously affects the battery efficiency.

[0004] In order to solve the problem that the acetic acid produced by the decomposition of EVA under high-temperature conditions affects the battery efficiency of the double-sided EVA module encapsulated battery, the application provides a high-temperature-resistant and acetic acid-resistant conductive paste and a photovoltaic module. SUMMARY

[0005] In order to solve the problem that the acetic acid produced by the decomposition of EVA under high-temperature conditions affects the battery efficiency of the double-sided EVA module encapsulated battery, the application provides a high-temperature-resistant and acetic acid-resistant conductive paste, which comprises a main glass powder and a secondary glass powder, the mass fraction of the main glass powder in the paste is 1.5%-2.5%, the mass fraction of the secondary glass powder is 0.2%-1%, the secondary glass powder is a Bi-Si-B-Al system glass, and the total mole percentage content of the secondary glass powder is 100%, the secondary glass powder comprises Bi2O3 and TeO2, the total content of which is 10%-50%, SiO2 and GeO2, the total content of which is 15%-30%, B2O318%-30%, Al2O30%-20%, and a modified additive 1%-20%.

[0006] Acetic acid is a decomposition product of ethylene-vinyl acetate (EVA), a common module encapsulant material, which interacts with metallization, often leading to interfacial degradation between the front metal contact and the underlying silicon (Si) substrate. This results in loss of cell performance and contact adhesion, increased contact resistance, and dark areas seen in electroluminescence (EL) imaging, so it is urgent to develop new metallization pastes that are more resistant to acetic acid. The introduction of Ti can improve the acetic acid performance of the glass, and the present application adjusts the low solubility of the electrode grid in acetic acid through the secondary glass (Pb-Ti-Si-B system glass), improves the good chemical stability of the electrode, resists acetic acid erosion, and aims to achieve high temperature and high humidity resistance of the electrode grid, and provides module reliability.

[0007] Optionally, the elements in the modification additive include one or more of W, Ca, Mg, Zn, Pb, Ba, Y, Li, Na, K and Zr, and the modification additive is a compound.

[0008] Optionally, the main glass powder is a Pb-Si-B system glass, and the main glass powder includes 15-40% of SiO2, 18-40% of B2O3, 0-20% of Al2O3, 15-45% of PbO and BaO in total, and 1-20% of the modification additive, based on the total mole percentage content of the main glass powder being 100%.

[0009] Optionally, in the secondary glass powder, Bi2O3 is 10-49.3%, TeO2 is 0-25%, SiO2 is 8-29.5%, and GeO2 is 0-7%, based on the total mole percentage content of the secondary glass powder being 100%; and in the main glass powder, PbO is 13-42% and BaO is 0-7%, based on the total mole percentage content of the main glass powder being 100%.

[0010] Optionally, the elements in the modification additive include one or more of W, Ca, Mg, Se, Ag, Zn, P, Ga, Li, Na, K and Fe, and the modification additive is a compound.

[0011] Optionally, the paste further includes silver powder and an organic carrier, and in the paste, the mass fraction of the silver powder is 83-90%, and the mass fraction of the organic carrier is 8-15%.

[0012] Optionally, the organic carrier includes an organic solvent, an organic resin and an additive, and in the organic carrier, the mass fraction of the organic solvent is 60-90%, the mass fraction of the organic resin is 5-20%, and the mass fraction of the additive is 5-20%.

[0013] Optionally, the glass powder includes a main glass powder and a secondary glass powder, and the preparation method of the glass powder includes:

[0014] The raw materials are uniformly mixed, heated to melt, and then cooled to obtain a glass frit;

[0015] The glass frit is ground to obtain a glass powder.

[0016] Optionally, the preparation method specifically comprises:

[0017] The raw materials are uniformly mixed, loaded into a platinum crucible, and then heated to melt at 900-1300°C for 30-90 min, and then cooled to obtain a glass frit;

[0018] The glass frit is ground to obtain a glass powder, and the D100 of the glass powder is less than or equal to 6 um.

[0019] Optionally, the paste is applied to an N-type solar cell treated by a laser enhanced contact optimization process.

[0020] The application also provides a photovoltaic module, which comprises a first cover plate, a first adhesive film, a cell string, a second adhesive film, and a second cover plate arranged in layers, the first adhesive film and the second adhesive film being EVA; the cell string comprises a plurality of solar cells electrically connected to each other, and the electrodes of the solar cells are formed by using the high-temperature-resistant and acetic acid-resistant conductive paste according to any one of the application.

[0021] The application provides a high-temperature-resistant and acetic acid-resistant conductive paste and a photovoltaic module. The paste comprises a main glass powder and a secondary glass powder, the mass fraction of the main glass powder in the paste is 1.5%-2.5%, the mass fraction of the secondary glass powder in the paste is 0.2%-1%, the secondary glass powder is a Bi-Si-B-Al glass, and the secondary glass powder comprises Bi2O3 and TeO2, which account for 10%-50% of the total mole percentage of the secondary glass powder, SiO2 and GeO2, which account for 15%-30% of the total mole percentage of the secondary glass powder, B2O3 18%-30%, Al2O3 0%-20%, and a modified additive 1%-20%. The paste further comprises silver powder and an organic carrier, the mass fraction of the silver powder in the paste is 83%-90%, and the mass fraction of the organic carrier in the paste is 8%-15%. The paste in the application adjusts the low solubility of the electrode grid in acetic acid by the secondary glass, thereby solving the problem that the acetic acid generated by the decomposition of EVA under high-temperature conditions affects the efficiency of the battery in the packaging of the double-sided EVA module. The application also provides a photovoltaic module using the above paste. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the application, the drawings required in the embodiments will be briefly introduced below. Obviously, other drawings can also be obtained by those skilled in the art without any creative effort.

[0023] Figure 1 EL image of B1 cell before acetic acid atmosphere;

[0024] Figure 2 EL image of B1 cell after acetic acid atmosphere;

[0025] Figure 3 EL image of A2 cell before acetic acid atmosphere;

[0026] Figure 4 EL image of A2 cell after acetic acid atmosphere. DETAILED DESCRIPTION

[0027] The embodiments will be described in detail below with reference to examples thereof as illustrated in the accompanying drawings. In the following description, same numbers refer to same elements in all figures unless otherwise described. The embodiments described in the following examples do not represent all the implementations consistent with the present application. They are merely examples of systems and methods consistent with some aspects of the present application as detailed in the claims.

[0028] In order to solve the problem that the acetic acid produced by decomposition of EVA under high temperature conditions affects the efficiency of the battery of the double-sided EVA assembly packaged battery, the application provides a high-temperature-resistant and acetic acid-resistant conductive paste and a photovoltaic module. The paste comprises a main glass powder and a secondary glass powder, the mass fraction of the main glass powder in the paste is 1.5% to 2.5%, the mass fraction of the secondary glass powder is 0.2% to 1%, the secondary glass powder is a Bi-Si-B-Al system glass, and the total molar percentage content of the secondary glass powder is 100%, the secondary glass powder comprises Bi2O3 and TeO2, the total content of which is 10% to 50%, SiO2 and GeO2, the total content of which is 15% to 30%, B2O3 18% to 30%, Al2O3 0% to 20%, and a modified additive 1% to 20%.

[0029] EVA plays a role of air and electrical insulation in the assembly, protects it from mechanical damage and prevents corrosion from the external environment. However, under the action of photosynthetic heat, acetic acid is the decomposition product of ethylene-vinyl acetate (EVA) as a module packaging material. Acetic acid solution does not basically corrode pure aluminum under normal temperature conditions, but as the temperature rises, the corrosion rate accelerates, and the corrosion rate of 1% dilute acetic acid solution on aluminum at boiling temperature is 100 times that at normal temperature; the corrosion rate of acetic acid on aluminum is also related to the purity of aluminum, and the aluminum with low purity, such as containing iron, silicon, aluminum salt and other impurities on the surface, forms a loose and non-dense oxidation protective film, and has low corrosion resistance.

[0030] The minority carrier lifetime of solar cells is also increasing, i.e. the diffusion length of the minority carriers is increasing, and when the diffusion length of the minority carriers is comparable to or exceeds the thickness of the silicon wafer, the recombination at the back surface becomes significant for the solar cell properties. The back surface field is formed by sintering a silicon-aluminum alloy, and the aluminum acts as a P-type dopant in silicon, which reduces the recombination of the minority carriers at the metal-silicon interface, thereby increasing the open circuit voltage and the short circuit current. The quality of the aluminum back surface field directly influences the output properties of the solar cell.

[0031] The solder strip is soaked in dilute acetic acid solution at 60℃ for one week, the front main grid lines of the cell become yellow, the back grid lines of the cell become black, and the aluminum back field of the cell back falls off. The acetic acid produced by EVA can cause electrochemical corrosion of the tin-coated copper solder strip, and at the same time, it can corrode and oxidize the silver grid lines on the surface of the cell, making them black, and it can also corrode the aluminum back field of the cell, reducing the adhesion of the aluminum back field to the silicon wafer, which seriously affects the electrical performance of the cell. Further reduce the electrical performance of the module. Therefore, in the future development of photovoltaic modules, new packaging materials, new EVA formulations or other measures to reduce the generation of acetic acid by EVA aging need to be studied to protect the cell from the harm of acetic acid and have a longer service life.

[0032] More importantly, acetic acid interacts with metallization, often leading to degradation of the interface between the front metallization contacts and the underlying silicon (Si) substrate. This results in loss of cell performance and contact adhesion, increased contact resistance, and dark areas seen in electroluminescence (EL) imaging, so it is urgent to develop new pastes that are more resistant to acetic acid.

[0033] The introduction of Ti can improve the acetic acid performance of the glass, and the application adjusts the low solubility of the electrode grid line in acetic acid through the secondary glass (Pb-Ti-Si-B system glass), improves the good chemical stability of the electrode, and resists the erosion of acetic acid.

[0034] In some embodiments, the elements in the modification additive include one or more of W, Ca, Mg, Zn, Pb, Ba, Y, Li, Na, K, and Zr, and the modification additive is a compound.

[0035] In some embodiments, the main glass powder is a Pb-Si-B system glass, and the main glass powder includes SiO215%-40%, B2O318%-40%, Al2O30%-20%, PbO and BaO accounting for 15%-45% in total, and a modification additive 1%-20%, based on the total mole percentage content of the main glass powder being 100%.

[0036] In some embodiments, in the sub-glass powder, Bi2O310% to 49.3%, TeO20% to 25%, SiO28% to 29.5%, GeO20% to 7%, based on the total mole percentage content of the sub-glass powder being 100%; in the main glass powder, PbO13% to 42%, BaO0% to 7%, based on the total mole percentage content of the main glass powder being 100%.

[0037] In some embodiments, the element in the modification additive includes one or more of W, Ca, Mg, Se, Ag, Zn, P, Ga, Li, Na, K and Fe, and the modification additive is a compound.

[0038] In some embodiments, the slurry further includes silver powder and an organic carrier, and in the slurry, the mass fraction of the silver powder is 83% to 90%, and the mass fraction of the organic carrier is 8% to 15%.

[0039] In some embodiments, the silver powder is spherical silver powder, and the D50 of the silver powder is 1.4 to 2.0 um. D50 refers to the particle size corresponding to the cumulative percentage of 50% of a sample. Its physical meaning is that the particles with a particle size greater than it account for 50%, and the particles with a particle size less than it also account for 50%, and D50 is also called median diameter or median particle size.

[0040] In some embodiments, the organic carrier includes an organic solvent, an organic resin and an additive, and in the organic carrier, the mass fraction of the organic solvent is 60% to 90%, the mass fraction of the organic resin is 5% to 20%, and the mass fraction of the additive is 5% to 20%.

[0041] In some embodiments, the glass powder includes a main glass powder and a sub-glass powder, and the preparation method of the glass powder includes:

[0042] The raw materials of the components are uniformly mixed, heated to melt, and then cooled to obtain a glass material;

[0043] The glass material is ground and sieved to obtain a glass powder.

[0044] In some embodiments, the preparation method specifically includes:

[0045] The raw materials of the components are uniformly mixed, loaded into a platinum crucible, and then heated to melt at 900 to 1300 ℃ for 30 to 90 min. After cooling, a glass material is obtained;

[0046] The glass material is ground and sieved to obtain a glass powder, and the D100 of the glass powder is less than or equal to 6 um.

[0047] In some embodiments, the slurry is applied to an N-type solar cell treated by a laser enhanced contact optimization process.

[0048] The application also provides a photovoltaic module, which comprises a first cover plate, a first adhesive film, a cell string, a second adhesive film and a second cover plate arranged in layers, the first adhesive film and the second adhesive film being EVA; the cell string comprises a plurality of solar cells connected in an electric manner, and the electrodes of the solar cells are formed by using the high-temperature-resistant and acetic acid-resistant conductive paste according to any one of the above.

[0049] In some embodiments, the solar cell includes but is not limited to one or any combination of a PERC (Passivated Emitter Rear Cell) cell, an IBC (Interdigitated Back Contact) cell, a TOPCon (Tunnel Oxide Passivated Contact) cell, a HIT / HJT (Heterojunction Technology) cell, a solar thin film cell, and a stacked cell. The solar thin film cell includes but is not limited to a perovskite solar thin film cell, a copper-indium-selenium solar thin film cell, a gallium arsenide solar thin film cell, and a cadmium sulfide solar thin film cell. The stacked cell includes but is not limited to a perovskite cell stacked with a crystalline silicon cell, a perovskite cell stacked with a perovskite cell, and a perovskite cell stacked with a thin film cell.

[0050] Embodiment:

[0051] The sub-glass GH001 to GH007 is prepared according to the material proportions in Table 1, and the main glass powder BL001 to BL005 is prepared according to the material proportions in Table 2. The material proportions in Tables 1 and 2 are in terms of mole percentage. For example, in the sub-glass powder GH001, Bi2O3 is 49.3 mol%, SiO2 is 28.5 mol%, B2O3 is 18 mol%, Al2O3 is 3 mol%, CaO is 1 mol%, and Y2O3 is 0.2 mol%.

[0052] The components are mixed in a mixer to obtain a mixture, and the mixture is melted in a platinum crucible at 900-1300°C for 30-90 min. After the glass is homogenized, the glass frit is obtained by a water quenching method or a cold rolling method. After the glass frit is ground and sieved, the sub-glass GH001 to GH007 and the main glass powder BL001 to BL005 are obtained, and the particle size of the glass powder is less than or equal to 6 um.

[0053] The GH001-GH004 and BL001-BL002 are melted at 1000°C for 60 minutes, GH005 and BL003 are melted at 900°C for 30 minutes, and GH006, GH007, BL004 and BL005 are melted at 1300°C for 90 minutes.

[0054] Table 1: Material ratio of the sub-glass powder

[0055] Raw materials GH001 GH002 GH003 GH004 GH005 GH006 GH007 TeO2 0 5 0 10 25 12 0 Bi2O3 49.3 15 33 30 10 38 10 SiO2 28.5 29.5 20 18 12 8 29.5 GeO2 0 0.5 0 2 3 7 0.5 B2O3 18 28 25 22 30 18 30 PbO 0 0 5 4.5 2 0.5 3 ZnO 0 0 2 1 3 0.5 2 Al2O3 3 18 13 10 0 16 20 Li2CO3 0 1 0 1 2 0 1 WO3 0 0 0 0.5 3 0 0.5 Na2CO3 0 0 0 0.2 0 0 2 K2CO3 0 0.5 0 0 2 0 0 BaO 0 2.5 0 0 8 0 1 MgO 0 0 0 0.6 0 0 0.5 CaO 1 0 2 0 0 0 0 ZrO2 0 0 0 0.2 0 0 0 [Y2O3] 0.2 0 0 0 0 0 0

[0056] Table 2: Material ratio of the main glass powder

[0057] Raw materials BL001 BL002 BL003 BL004 BL005 PbO 30.4 42 13 40 21 BaO 2 0 2 5 7 SiO2 24 20 40 15 17 B2O3 32 25 40 19 18 Al2O3 1.5 7 0 20 17 ZnO 3 4.5 1 0.5 1 P2O5 0 0.3 1 0 2 Fe2O3 3 0 0.5 0 0 Ga2O3 1 0 0 0.5 2 Li2CO3 1.2 0 0 0 1 Na2CO3 0.2 0 0 0 1 K2CO3 0 0.2 0.5 0 2.5 MgO 0 0.5 0 0 3 CaO 0 0.5 1 0 3 Ag2O 0.2 0 0 0 1.5 SeO2 1.5 0 1 0 3

[0058] Example 1:

[0059] The 88.5wt% silver powder, 9wt% organic carrier, 2.0wt% of the prepared glass powder BL001 and 0.5wt% of the prepared glass powder GH001 are weighed. The organic carrier includes 75wt% organic solvent, 15wt% organic resin and 10wt% additive. The silver powder and the organic carrier are premixed by a planetary mixer, the slurry is ground for 6 times by a ceramic three-roll grinder, the grinding fineness is tested by a doctor blade fineness tester, the slurry fineness is less than 10um, the slurry is filtered by a 250 mesh filter cloth, and the front electrode silver paste A1 is prepared.

[0060] Example 2:

[0061] The 85.7wt% silver powder, 12wt% organic carrier, 1.8wt% of the prepared glass powder BL002 and 0.8wt% of the prepared glass powder GH002 are weighed. The organic carrier includes 75wt% organic solvent, 15wt% organic resin and 10wt% additive. The silver powder and the organic carrier are premixed by a planetary mixer, the slurry is ground for 6 times by a ceramic three-roll grinder, the grinding fineness is tested by a doctor blade fineness tester, the slurry fineness is less than 10um, the slurry is filtered by a 250 mesh filter cloth, and the front electrode silver paste A2 is prepared.

[0062] Example 3:

[0063] The 87.4wt% silver powder, 10wt% organic carrier, 2.2wt% of the prepared glass powder BL002 and 0.4wt% of the prepared glass powder GH003 are weighed. The organic carrier includes 75wt% organic solvent, 15wt% organic resin and 10wt% additive. The silver powder and the organic carrier are premixed by a planetary mixer, the slurry is ground for 6 times by a ceramic three-roll grinder, the grinding fineness is tested by a doctor blade fineness tester, the slurry fineness is less than 10um, the slurry is filtered by a 250 mesh filter cloth, and the front electrode silver paste A3 is prepared.

[0064] Example Four:

[0065] The silver powder 88.8wt%, organic vehicle 9wt%, glass powder BL002 1.9wt%, glass powder GH004 0.3wt% were weighed. The organic vehicle includes 75wt% organic solvent, 15wt% organic resin, 10wt% additives. The silver powder and organic vehicle were premixed by a planetary mixer, the slurry was grinded for 6 times by a ceramic three-roll mill, the fineness of the slurry was tested by a blade fineness gauge, the fineness of the slurry was <10um, the slurry was filtered by a 250 mesh filter cloth, and the front electrode silver paste A4 was prepared.

[0066] Example Five:

[0067] The silver powder 90wt%, organic vehicle 8wt%, glass powder BL003 1.5wt%, glass powder GH005 0.5wt% were weighed. The organic vehicle includes 60wt% organic solvent, 20wt% organic resin, 20wt% additives. The D50 of the silver powder was 2.0μ. The silver powder and organic vehicle were premixed by a planetary mixer, the slurry was grinded for 6 times by a ceramic three-roll mill, the fineness of the slurry was tested by a blade fineness gauge, the fineness of the slurry was <10um, the slurry was filtered by a 250 mesh filter cloth, and the front electrode silver paste A5 was prepared.

[0068] Example Six:

[0069] The silver powder 87.3wt%, organic vehicle 10wt%, glass powder BL004 2.5wt%, glass powder GH006 0.2wt% were weighed. The organic vehicle includes 90wt% organic solvent, 5wt% organic resin, 5wt% additives. The D50 of the silver powder was 1.7μ. The silver powder and organic vehicle were premixed by a planetary mixer, the slurry was grinded for 6 times by a ceramic three-roll mill, the fineness of the slurry was tested by a blade fineness gauge, the fineness of the slurry was <10um, the slurry was filtered by a 250 mesh filter cloth, and the front electrode silver paste A6 was prepared.

[0070] Example Seven:

[0071] The silver powder 83wt%, organic vehicle 15wt%, glass powder BL005 1wt%, glass powder GH007 1wt% were weighed. The organic vehicle includes 90wt% organic solvent, 5wt% organic resin, 5wt% additives. The D50 of the silver powder was 1.4μ. The D50 of the silver powder was 1.7μ. The silver powder and organic vehicle were premixed by a planetary mixer, the slurry was grinded for 6 times by a ceramic three-roll mill, the fineness of the slurry was tested by a blade fineness gauge, the fineness of the slurry was <10um, the slurry was filtered by a 250 mesh filter cloth, and the front electrode silver paste A7 was prepared.

[0072] Comparative Example 1

[0073] 89wt% silver powder, 9wt% organic vehicle, 2.0wt% of the prepared glass powder BL001. The organic vehicle includes 75wt% organic solvent, 15wt% organic resin, 10wt% additives. First, the silver powder and organic are pre-mixed by a planetary mixer, and the slurry is ground for 6 times by a ceramic three-roll mill. The grinding fineness is tested by a doctor blade fineness tester, and the slurry fineness is <10um. The slurry is filtered by a 250 mesh filter cloth to prepare the front electrode silver paste B1.

[0074] Comparative Example 2

[0075] 89wt% silver powder, 9wt% organic vehicle, 2.0wt% of the prepared glass powder BL002. The organic vehicle includes 75wt% organic solvent, 15wt% organic resin, 10wt% additives. First, the silver powder and organic are pre-mixed by a planetary mixer, and the slurry is ground for 6 times by a ceramic three-roll mill. The grinding fineness is tested by a doctor blade fineness tester, and the slurry fineness is <10um. The slurry is filtered by a 250 mesh filter cloth to prepare the front electrode silver paste B2.

[0076] The slurry prepared in Examples 1-7 and Comparative Examples 1-2 is printed on N-type 182 silicon wafers using a Mayway automatic printing machine, 100 pieces of each slurry are printed, and then sintered using a sintering furnace, and then treated by laser-enhanced contact optimization (LECO), and the IV of the battery piece is tested, and the data is recorded.

[0077] Vinegar test conditions:

[0078] 1) The battery piece to be etched is placed in the corresponding size basket in a way that the pieces are separated by one piece; the basket box is placed at the edge of the box with 2 pieces of accompanying pieces;

[0079] 2) Prepare the vinegar solution as required, pour it into the PP preservation box; then place the basket in the center of the preservation box and cover it with the box cover and buckle, and seal it with a plastic sealing film;

[0080] 3) Place the prepared vinegar box in an 85°C oven, and after 8h of incubation, take out the battery piece for testing

[0081] Formula: Eta attenuation value = (1-Eta after vinegar / Eta before vinegar) x 100%.

[0082] The experimental temperature, test time and vinegar solution preparation method are shown in Table 3, and the measured data are shown in Table 4.

[0083] Table 3 Vinegar test experimental conditions

[0084]

[0085] "Fan" in Table 3 means that a fan is installed in the acetic acid box container to make the concentration of the atmosphere in the acetic acid box container uniform; "test time 8 hours" means that the battery piece is kept in the acetic acid box container for 8 hours.

[0086] Table 4 experimental measurement data

[0087]

[0088] As shown in Table 4, Uoc is the open circuit voltage, FF is the fill factor, and Eta is the photoelectric conversion efficiency. The battery piece prepared by the slurry provided in the present application has a smaller change in the open circuit voltage and fill factor before and after the acetic acid atmosphere, a smaller decay value of the photoelectric conversion efficiency, and a photoelectric conversion efficiency of more than 20% after the acetic acid atmosphere. It can be seen that the slurry provided in the present application is more resistant to acetic acid. Figure 1 As shown in Table 4, Uoc is the open circuit voltage, FF is the fill factor, and Eta is the photoelectric conversion efficiency. The battery piece prepared by the slurry provided in the present application has a smaller change in the open circuit voltage and fill factor before and after the acetic acid atmosphere, a smaller decay value of the photoelectric conversion efficiency, and a photoelectric conversion efficiency of more than 20% after the acetic acid atmosphere. It can be seen that the slurry provided in the present application is more resistant to acetic acid. Figure 2 As shown in Table 4, Uoc is the open circuit voltage, FF is the fill factor, and Eta is the photoelectric conversion efficiency. The battery piece prepared by the slurry provided in the present application has a smaller change in the open circuit voltage and fill factor before and after the acetic acid atmosphere, a smaller decay value of the photoelectric conversion efficiency, and a photoelectric conversion efficiency of more than 20% after the acetic acid atmosphere. It can be seen that the slurry provided in the present application is more resistant to acetic acid. Figure 3 As shown in Table 4, Uoc is the open circuit voltage, FF is the fill factor, and Eta is the photoelectric conversion efficiency. The battery piece prepared by the slurry provided in the present application has a smaller change in the open circuit voltage and fill factor before and after the acetic acid atmosphere, a smaller decay value of the photoelectric conversion efficiency, and a photoelectric conversion efficiency of more than 20% after the acetic acid atmosphere. It can be seen that the slurry provided in the present application is more resistant to acetic acid. Figure 4 As shown in Table 4, Uoc is the open circuit voltage, FF is the fill factor, and Eta is the photoelectric conversion efficiency. The battery piece prepared by the slurry provided in the present application has a smaller change in the open circuit voltage and fill factor before and after the acetic acid atmosphere, a smaller decay value of the photoelectric conversion efficiency, and a photoelectric conversion efficiency of more than 20% after the acetic acid atmosphere. It can be seen that the slurry provided in the present application is more resistant to acetic acid. Figures 1-4 As shown in Table 4, Uoc is the open circuit voltage, FF is the fill factor, and Eta is the photoelectric conversion efficiency. The battery piece prepared by the slurry provided in the present application has a smaller change in the open circuit voltage and fill factor before and after the acetic acid atmosphere, a smaller decay value of the photoelectric conversion efficiency, and a photoelectric conversion efficiency of more than 20% after the acetic acid atmosphere. It can be seen that the slurry provided in the present application is more resistant to acetic acid.

[0089] As shown in Table 4, Uoc is the open circuit voltage, FF is the fill factor, and Eta is the photoelectric conversion efficiency. The battery piece prepared by the slurry provided in the present application has a smaller change in the open circuit voltage and fill factor before and after the acetic acid atmosphere, a smaller decay value of the photoelectric conversion efficiency, and a photoelectric conversion efficiency of more than 20% after the acetic acid atmosphere. It can be seen that the slurry provided in the present application is more resistant to acetic acid.

[0090] The present application provides a high-temperature-resistant and acetic acid-resistant conductive slurry and a photovoltaic module. The slurry comprises a main glass powder and a secondary glass powder, the mass fraction of the main glass powder in the slurry is 1.5% to 2.5%, the mass fraction of the secondary glass powder in the slurry is 0.2% to 1%, the secondary glass powder is a Bi-Si-B-Al system glass, and the total molar percentage content of the secondary glass powder is 100%, the secondary glass powder comprises Bi2O3 and TeO2, which together account for 10% to 50%, SiO2 and GeO2, which together account for 15% to 30%, B2O3 18% to 30%, Al2O3 0% to 20%, and a modified additive 1% to 20%. The slurry further comprises silver powder and an organic carrier, the mass fraction of the silver powder in the slurry is 83% to 90%, and the mass fraction of the organic carrier in the slurry is 8% to 15%. The slurry in the present application adjusts the low solubility of the electrode grid in acetic acid by the secondary glass, solving the problem that the acetic acid generated by the decomposition of EVA under high-temperature conditions affects the efficiency of the battery in the double-sided EVA module packaging battery. The present application also provides a photovoltaic module using the above-mentioned slurry.

[0091] The similar parts among the embodiments provided in the application can be referred to each other, the specific embodiments provided above are only several examples under the general concept of the application, and do not constitute the limitation of the protection scope of the application. Any other embodiments extended according to the application scheme without creative labor for those skilled in the art shall fall within the protection scope of the application.

Claims

1. A high temperature and acetic acid resistant conductive paste, characterized in that, The slurry includes a main glass powder and a secondary glass powder, the mass fraction of the main glass powder in the slurry is 1.5% to 2.5%, the mass fraction of the secondary glass powder is 0.2% to 1%, the secondary glass powder is a Bi-Si-B-Al system glass, the total molar percentage content of the secondary glass powder is 100%, the secondary glass powder includes Bi2O3 and TeO2, the total content of Bi2O3 and TeO2 is 10% to 50%, SiO2 and GeO2, the total content of SiO2 and GeO2 is 15% to 30%, B2O3 is 18% to 30%, Al2O3 is 0% to 20%, and a modified additive is 1% to 20%, in the secondary glass powder, Bi2O3 is 10% to 49.3%, TeO2 is 0% to 25%, SiO2 is 8% to 29.5%, and GeO2 is 0% to 7%, the main glass powder is a Pb-Si-B system glass, the total molar percentage content of the main glass powder is 100%, the main glass powder includes SiO2 15% to 40%, B2O3 18% to 40%, Al2O3 0% to 20%, PbO and BaO, the total content of PbO and BaO is 15% to 45%, and a modified additive is 1% to 20%, the slurry further includes silver powder and an organic carrier, in the slurry, the mass fraction of the silver powder is 83% to 90%, and the mass fraction of the organic carrier is 8% to 15%.

2. The high temperature and acetic acid resistant conductive paste as claimed in claim 1, wherein, The element in the modified additive of the secondary glass powder includes one or more of W, Ca, Mg, Zn, Pb, Ba, Y, Li, Na, K and Zr, and the modified additive of the secondary glass powder is a compound. 3.The high-temperature and acetic acid resistant conductive paste according to claim 1, wherein, In the main glass powder, the total molar percentage content is 100%, PbO is 13% to 42%, and BaO is 0% to 7%.

4. The high temperature and acetic acid resistant conductive paste as claimed in claim 3, wherein, The element in the modified additive of the main glass powder includes one or more of W, Ca, Mg, Se, Ag, Zn, P, Ga, Li, Na, K and Fe, and the modified additive of the main glass powder is a compound.

5. The high temperature and ac resistant conductive paste as claimed in claim 1, wherein, The organic carrier includes an organic solvent, an organic resin and an additive, in the organic carrier, the mass fraction of the organic solvent is 60% to 90%, the mass fraction of the organic resin is 5% to 20%, and the mass fraction of the additive is 5% to 20%.

6. The high temperature and ac resistant conductive paste as claimed in claim 1, wherein, The glass powder includes a main glass powder and a secondary glass powder, and the preparation method of the glass powder includes: The raw materials are uniformly mixed, heated to melt, and then cooled to obtain a glass material; The glass material is ground and sieved to obtain a glass powder.

7. The high temperature and acetic acid resistant conductive paste as claimed in claim 6, wherein, The preparation method specifically includes: The raw materials are uniformly mixed, loaded into a platinum crucible, and then heated to melt at 900-1300℃ for 30-90min, and then cooled to obtain a glass material; The glass material is ground and sieved to obtain a glass powder, and the D100 of the glass powder is less than or equal to 6μm.

8. A photovoltaic module, characterized by, The photovoltaic module includes a first cover plate, a first adhesive film, a cell string, a second adhesive film and a second cover plate which are stacked, the first adhesive film and the second adhesive film are EVA; the cell string includes a plurality of solar cells connected in series, and the electrodes of the solar cells are formed by using the high-temperature-resistant and acetic acid-resistant conductive slurry according to any one of claims 1 to 7.

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