Inorganic glass frit compositions, inorganic glass frits, conductive pastes, and solar cells and modules

Abstract

The present application provides inorganic glass powder compositions, inorganic glass powders, conductive pastes, and solar cells and modules. The elemental composition of the inorganic glass powder compositions includes Si a -Bi b -Zn c -W d -M e , M is other elements, the composition contains oxides corresponding to the above elements and / or compounds capable of forming the above element oxides; in terms of molar ratio, a, b, c, d, e satisfy: 40%≤a≤60% or 5%≤b≤20%; 52%≤(a+b)≤65%; 6%≤c≤15% or 1∶4≤c∶(a+b)≤1∶7; 1∶1≤(a+b)∶(d+e)≤3∶1; 6%≤d≤15% or 10%≤e≤30%; a+b+c+d+e=100%. The present application also provides inorganic glass powders, conductive pastes, and solar cells and modules made of the composition. The glass powder can improve the open-circuit voltage, fill factor, and conversion efficiency of the cell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, in particular to an inorganic glass powder composition, an inorganic glass powder, a conductive paste, a solar cell and a module. BACKGROUND

[0002] From the conventional aluminum back field cell to the current mainstream back passivation emitter (PERC) cell, and then to the higher conversion efficiency tunnel oxide passivation contact (TOPCon) and heterojunction (HJT) cell, the main progress in technology is the improvement of surface passivation technology, and the metallization of the crystalline silicon solar cell is generally realized by screen printing a conductive paste. The glass component in the conductive paste needs to first corrode the passivation layer to form a good contact with the silicon wafer, and after the glass corrodes the passivation layer, it will further corrode the silicon, causing the passivation performance at the printed paste to deteriorate. Thus affecting the open-circuit voltage and conversion efficiency of the solar cell.

[0003] The existing conductive paste generally mainly considers the contact performance of the conductive paste and the silicon and the morphology of the fine grid line after printing. The contact resistance and light shielding area are minimized to improve the short-circuit current and fill factor of the cell, but the influence of the glass on the passivation layer and the load caused by the conductive paste itself are not considered.

[0004] The existing technology does not consider the corrosion of the glass component in the conductive paste on the passivation layer and the further corrosion of the silicon wafer, thereby causing the open-circuit voltage and conversion efficiency of the solar cell to be low. SUMMARY

[0005] In order to solve the above problems, the purpose of the present application is to provide an inorganic glass powder composition, an inorganic glass powder, a conductive paste, a solar cell and a module. The inorganic glass powder with a specific composition provided by the present application reduces the corrosion of the glass on the passivation layer when preparing the solar cell and the module, and avoids further corrosion of the silicon after corroding the passivation layer, thereby improving the passivation effect on the surface of the cell.

[0006] In order to solve the above problems, the present application provides an inorganic glass powder composition, which comprises the following elements: a -Bi b -Zn c -W d -M e M includes a combination of two or more of alkali metal, alkaline earth metal, rare earth metal, Cu, B, Al, Ga, Te, Ge, Sn, P, Sb, Nb, Ta, V, Ti, Mo, Cr, Zr, Pb; the inorganic glass powder composition comprises oxides corresponding to the above elements (silicon, bismuth, zinc, tungsten, M) and / or compounds capable of forming the above element oxides;

[0007] a, b, c, d, e are the molar percentage of silicon, bismuth, zinc, tungsten, M in the total amount of silicon, bismuth, zinc, tungsten, M elements in the composition respectively; the values of a, b, c, d, e simultaneously satisfy formula 1 to formula 6:

[0008] Formula 1: 40%≤a≤60% or one of 5%≤b≤20%;

[0009] Formula 2: 52%≤(a+b)≤65%;

[0010] Formula 3: 6%≤c≤15% or one of 1∶4≤c∶(a+b)≤1∶7;

[0011] Formula 4: 1∶1≤(a+b)∶(d+e)≤3∶1;

[0012] Formula 5: 6%≤d≤15% or one of 10%≤e≤30%;

[0013] Formula 6: a+b+c+d+e=100%.

[0014] In some specific embodiments, silicon, bismuth, zinc, tungsten, M in the composition can specifically exist in the form of "oxides corresponding to the above-mentioned elements", "compounds capable of forming oxides of the above-mentioned elements". The compounds capable of forming oxides of the corresponding elements include carbonates of the corresponding elements and the like. Among them, "carbonate" not only includes salts formed by various elements and carbonate (CO3 2- ) but also includes bicarbonate (acidic carbonate), basic carbonate.

[0015] In some specific embodiments, Si a -Bi b -Zn c -W d -M e are the element compositions corresponding to the main cations in the above-mentioned composition system. a is the molar percentage of Si / (Si+Bi+Zn+W+M), b is the molar percentage of Bi / (Si+Bi+Zn+W+M), c is the molar percentage of Zn / (Si+Bi+Zn+W+M), d is the molar percentage of W / (Si+Bi+Zn+W+M), and e is the molar percentage of M / (Si+Bi+Zn+W+M).

[0016] In the above inorganic glass powder composition, the alkali metal includes lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr); the alkaline earth metal includes beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra); and the rare earth metal includes scandium (Sc) and yttrium (Y) in the group IIIB, lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu) in the lanthanide series.

[0017] In the above inorganic glass powder composition, silicon-bismuth is the network skeleton of the glass system; zinc is the network intermediate, which can reduce the softening point of the glass and reduce the thermal expansion coefficient; and tungsten is the surface active metal, which can reduce the surface tension of the glass.

[0018] In some specific embodiments, the molar ratio of silicon in the total amount of silicon, bismuth, zinc, tungsten, and M elements can be further controlled as: 45%≤a≤55%.

[0019] In some specific embodiments, the molar ratio of bismuth in the total amount of silicon, bismuth, zinc, tungsten, and M elements can be further controlled as: 8%≤b≤16%.

[0020] In some specific embodiments, formula 2 can be: 55%≤(a+b)≤65%.

[0021] In some specific embodiments, formula 4 can be: 1.5:1≤(a+b):(d+e)≤2.5:1.

[0022] In the above inorganic glass powder composition, the M element can improve the glass-forming ability of the inorganic system and reduce the softening point of the glass. In some specific embodiments, the molar ratio of M in the total amount of silicon, bismuth, zinc, tungsten, and M elements can be further controlled as: 15%≤e≤25%.

[0023] In some specific embodiments, the M can include a combination of two or more of Li, Na, Cu, Al, Pb, and Te; for example, the M can include a combination of Li, Na, Cu, Al, and Pb, a combination of Li, Cu, Al, Pb, and Te, a combination of Li, Cu, Al, and Pb, etc.

[0024] In some specific embodiments, the element composition of the above inorganic glass powder composition is, in terms of molar ratio, Si a -Bi b -Zn c -W d -M eThe values of a, b, c, d, and e can simultaneously satisfy the following relationships:

[0025] Formula 1: 45%≤a≤55% and / or 6%≤b≤15%,

[0026] Formula 2: 52%≤(a+b)≤65%;

[0027] Formula 3: 8%≤c≤13% and / or 1:4≤c:(a+b)≤1:7;

[0028] Formula 4: 1.4:1≤(a+b):(d+e)≤2.5:1;

[0029] Formula 5: 5%≤d≤12% and / or 16%≤e≤24%;

[0030] Formula 6: a+b+c+d+e=100%.

[0031] In some specific embodiments, the above inorganic glass powder composition comprises oxides of the above elements and / or compounds capable of forming the oxides of the above elements; wherein the element composition in the composition comprises: Si a -Bi b -Zn c -W d -M e , M comprises a combination of two or more of alkali metal, alkaline earth metal, rare earth metal, Cu, B, Al, Ga, Te, Ge, Sn, P, Sb, Nb, Ta, V, Ti, Mo, Cr, Zr, Pb; a, b, c, d, e are respectively the molar proportion of silicon, bismuth, zinc, tungsten, M in the total amount of silicon, bismuth, zinc, tungsten, M elements in the composition, wherein 45%≤a≤55%, 6%≤b≤15%, 8%≤c≤13%, 5%≤d≤12%, 16%≤e≤24%.

[0032] The present application also provides an inorganic glass powder prepared from the above inorganic glass powder composition.

[0033] According to specific embodiments of the present application, the inorganic glass powder is in the form of oxides corresponding to the inorganic glass powder composition. Specifically, the composition of the inorganic glass powder can be Si a -Bi b -Zn c -W d -M e -O fwherein M comprises a combination of two or more of alkali metals, alkaline earth metals, rare earth metals, Cu, B, Al, Ga, Te, Ge, Sn, P, Sb, Nb, Ta, V, Ti, Mo, Cr, Zr, Pb, a, b, c, d, e are respectively the mole percentage of silicon, bismuth, zinc, tungsten, M in the total amount of silicon, bismuth, zinc, tungsten, M elements in the glass powder, and f is a number for charge balance of oxygen element and other elements in the glass powder;

[0034] wherein the values of a, b, c, d, e satisfy formula 1 to formula 6 simultaneously:

[0035] Formula 1: one of 40%≤a≤60% or 5%≤b≤20%;

[0036] Formula 2: 52%≤(a+b)≤65%;

[0037] Formula 3: one of 6%≤c≤15% or 1:4≤c:(a+b)≤1:7;

[0038] Formula 4: 1:1≤(a+b):(d+e)≤3:1;

[0039] Formula 5: one of 6%≤d≤15% or 10%≤e≤30%;

[0040] Formula 6: a+b+c+d+e=100%.

[0041] In some specific embodiments, the mole percentage of silicon in the total amount of silicon, bismuth, zinc, tungsten, M elements can be further controlled as 45%≤a≤55%.

[0042] In some specific embodiments, the mole percentage of bismuth in the total amount of silicon, bismuth, zinc, tungsten, M elements can be further controlled as 8%≤b≤16%.

[0043] In some specific embodiments, the sum of the mole percentages of silicon and bismuth in the total amount of silicon, bismuth, zinc, tungsten, M elements can be further controlled as 55%≤(a+b)≤65%.

[0044] In some specific embodiments, the sum of the mole percentages of silicon and bismuth in the total amount of silicon, bismuth, zinc, tungsten, M elements can be further controlled as 1.5:1≤(a+b):(d+e)≤2.5:1.

[0045] In some specific embodiments, the mole percentage of M in the total amount of silicon, bismuth, zinc, tungsten, M elements can be further controlled as 15%≤e≤25%.

[0046] In some embodiments, M can include a combination of two or more of Li, Na, Cu, Al, Pb, Te; for example, M can include a combination of Li, Na, Cu, Al, Pb, a combination of Li, Cu, Al, Pb, Te, a combination of Li, Cu, Al, Pb, and the like.

[0047] In some embodiments, the inorganic glass powder composition Si a -Bi b -Zn c -W d -M e -O f The values of a, b, c, d, e can satisfy the following relationships simultaneously:

[0048] Formula 1: 45%≤a≤55% and / or 6%≤b≤15%,

[0049] Formula 2: 52%≤(a+b)≤65%;

[0050] Formula 3: 8%≤c≤13% and / or 1:4≤c:(a+b)≤1:7;

[0051] Formula 4: 1.4:1≤(a+b):(d+e)≤2.5:1;

[0052] Formula 5: 5%≤d≤12% and / or 16%≤e≤24%;

[0053] Formula 6: a+b+c+d+e=100%.

[0054] In some embodiments, the particle size distribution of the inorganic glass powder generally satisfies D50=0.1-5μm.

[0055] In some embodiments, the softening temperature of the inorganic glass powder is generally 250-550℃.

[0056] In some embodiments, the inorganic glass powder composition can be an amorphous glass powder, a crystalline glass powder, or a combination of amorphous and crystalline glass powders.

[0057] In some embodiments, the method for preparing the inorganic glass powder can include: melting the inorganic glass powder composition, cooling, grinding, and obtaining the inorganic glass powder.

[0058] In the above method, the melting temperature is generally controlled to be 750-1100℃ (for example, 900℃), and the melting time is generally controlled to be 30-120min.

[0059] The present application also provides a conductive paste, which comprises a conductive phase, an organic carrier and an inorganic adhesive phase, wherein the inorganic adhesive phase comprises the inorganic glass powder.

[0060] In some embodiments, the mass content of the conductive phase in the conductive paste is generally controlled to be 86-93%.

[0061] In some embodiments, the mass content of the inorganic adhesive phase in the conductive paste is generally controlled to be 1-10%, and the mass content of the organic carrier in the conductive paste is generally controlled to be 5%-20%.

[0062] In some embodiments, the elements of the conductive phase comprise one or more than two combinations of conductive metals such as gold, silver and copper.

[0063] In some embodiments, the conductive phase preferably adopts silver powder.

[0064] In some embodiments, the D50 of the silver powder is generally 1 μm-5 μm, and the tap density of the silver powder is generally 5 g / cm 3 -9 g / cm 3

[0065] In some embodiments, the silver powder preferably adopts modified silver powder. Modification can improve the dispersion stability of the silver powder in the conductive paste.

[0066] In some embodiments, the modified silver powder can be obtained by using conventional modification methods. The modifier used by the modified silver powder can be one or more than two combinations of oleic acid, linoleic acid, linolenic acid, silane coupling agent, stearic acid, fatty acid amine, polyvinyl pyrrolidone, fatty alcohol polyoxyethylene ether and block macromolecular surfactant. Among them, the block macromolecular surfactant can include polyamide block macromolecular surfactant and the like.

[0067] In some embodiments, the organic carrier generally comprises resin, organic solvent and auxiliary agent.

[0068] In some embodiments, the mass ratio of the resin, organic solvent and auxiliary agent can be controlled to be (65-85):(10-25):(1-5).

[0069] In some embodiments, the resin can comprise one or more than two combinations of cellulose (such as ethyl cellulose), epoxy resin and acrylic resin and the like.

[0070] In some embodiments, the organic solvent can comprise one or more than two combinations of terpineol, butyl carbitol acetate, dodecanol ester and the like.

[0071] In some embodiments, the auxiliary agent includes one or a combination of more than one of a dispersing agent, a thixotropic agent, a lubricant, a humectant, and a plasticizer.

[0072] In the above-mentioned auxiliary agent, the dispersing agent is generally a macromolecular dispersing agent, such as one or a combination of more than one of a polyether, a polyester, a polyamide, a polyorganosilicon, etc.

[0073] In the above-mentioned auxiliary agent, the thixotropic agent can include one or a combination of more than one of hydrogenated castor oil, a polyamide, fumed silica.

[0074] In the above-mentioned auxiliary agent, the lubricant can include a surfactant, a silicone oil, etc.

[0075] In the above-mentioned auxiliary agent, the humectant can include one or a combination of more than one of diethylene glycol, triethylene glycol, PEG400, glycerol, ethylene glycol, sorbitol, 1,2-propanediol, diethylene glycol, diethylene glycol butyl ether, ethylene glycol, polyethylene glycol, N-methyl-2-pyrrolidone, a condensate of a polyol and ethylene oxide, xylitol, etc.

[0076] In the above-mentioned auxiliary agent, the plasticizer can include one or a combination of more than one of an aliphatic dibasic acid ester, a phthalate ester, a terephthalate ester, a benzenepolyacid ester, a benzoate ester, a polyol ester type epoxy, a citrate ester, a polyester.

[0077] In some embodiments, the average doctor blade fineness of the conductive silver paste is generally controlled to be 10 μm or less, preferably 5 μm or less.

[0078] According to the embodiments of the present application, the preparation method of the above-mentioned conductive paste can include:

[0079] 1) mixing the resin and the organic solvent in proportion, stirring uniformly at room temperature or with heating, to obtain an intermediate of the organic carrier;

[0080] 2) then adding the conductive phase and the inorganic adhesive phase to the intermediate of the organic carrier, mixing, and grinding and dispersing by a three-roll mill to an average doctor blade fineness of 10 μm or less (preferably 5 μm or less), to obtain the conductive paste;

[0081] The above-mentioned preparation process further includes the operation of adding the auxiliary agent, and specifically, the auxiliary agent can be added in whole in step 1) (thus obtaining the organic carrier), or in whole in step 2) of preparing the paste, or partially in step 1) and the remaining part in step 2).

[0082] The present application further provides a solar cell, the raw material for preparing which includes the above-mentioned conductive paste.

[0083] In some specific embodiments, the above-mentioned solar cell can be prepared by the SE process, which can specifically include the following steps:

[0084] 1. A reduction of reflection and a rough surface are made on one side of the silicon substrate, for example, a pyramid (single crystal) or uneven (polycrystalline) reduction of reflection is formed by etching with an alkali solution or an acid solution;

[0085] 2. An N-type diffusion layer is formed on the other side of the P-type silicon substrate to form a PN junction, a gas phase thermal diffusion method is used to form the N-type diffusion layer (preferably, phosphorus oxychloride is used as a diffusion source), the diffusion sheet resistance is 120-160 Ω / sq, then a laser SE doping is performed, the sheet resistance of the heavily doped region after the laser is 60-100 Ω / sq, then the phosphorus on the edge is removed, for example, by wet etching or dry etching;

[0086] 3. A thermal diffusion is performed on the N face to form an SiO2 oxide layer, then a SiNx reduction layer (or other similar coating layers with good reduction of reflection and passivation effect) is plated, and an Al2O3 and SiNx passivation layer is plated on the P face;

[0087] 4. A laser slotting is performed on the P face aluminum back field printing, a conductive silver paste is used to form vertical and horizontal main grids and fine grids on the reduction film on one side of the N-type silicon substrate by a screen printing method, a back electrode and an aluminum back field are printed on the P-type side, and an electrode body is formed by co-sintering at a sintering temperature of 700-900 ℃.

[0088] The application further provides a solar cell module, which is prepared from the above-mentioned conductive paste and is generally obtained by interconnecting and packaging the cell pieces.

[0089] The above-mentioned solar cell and solar cell module can be prepared by other conventional methods in the art.

[0090] The application has the following beneficial effects:

[0091] The inorganic glass powder provided by the application has low corrosion, and has little corrosion to the passivation layer and the silicon body in the solar cell; the conductive paste containing the inorganic glass powder composition has large viscosity, small lateral flowability and small damage area to the passivation layer when printed on the solar cell piece during sintering, thereby significantly improving the open circuit voltage, the fill factor and the conversion efficiency of the solar cell. BRIEF DESCRIPTION OF DRAWINGS

[0092] Figure 1 SEM image of the surface of a solar cell piece prepared from the conductive paste corresponding to Comparative Example 1.

[0093] Figure 2 SEM image of the surface of a solar cell piece prepared from the conductive paste corresponding to Example 2 No. 1. DETAILED DESCRIPTION

[0094] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present application, the technical solutions of the present application are described in detail as follows, but it should not be understood as a limitation on the implementable scope of the present application.

[0095] Example 1, Comparative Example 1 and Comparative Example 2

[0096] Example 1 provides inorganic glass powders numbered 1 to 10, and Comparative Example 1 and Comparative Example 2 each provide an inorganic glass powder. The composition of each inorganic glass powder is Si a -Bi b -Zn c -W d -M e -O f wherein M is at least one of Li, Na, Cu, Al and Pb, a, b, c, d, e are respectively the molar proportion of silicon, bismuth, zinc, tungsten and M in the total amount of silicon, bismuth, zinc, tungsten and M elements in the composition, and f is a number for charge balance of oxygen element and other elements.

[0097] Table 1 is the main element composition in each of the above inorganic glass powders.

[0098] Table 1

[0099]

[0100] The preparation method of the inorganic glass powders of the above examples and comparative examples is as follows:

[0101] The oxides containing the above elements, or substances that can generate the oxides of the above elements by reaction (for example, carbonates of corresponding elements) are used as the inorganic glass powder composition. The inorganic glass powder composition is mixed in proportion, heated in a muffle furnace at 900-1100℃ for 45min-90min, and then obtained by water quenching and steel plate cooling. The glass fragments are further broken, and then ball milled by a planetary ball mill to obtain the inorganic reaction system glass product with a particle size distribution D50 of 0.1-5μm, i.e. the inorganic glass powder.

[0102] Example 2

[0103] This example provides a conductive paste prepared from the inorganic glass powders obtained from Example 1, Comparative Example 1 and Comparative Example 2, and the preparation method of the conductive paste is as follows:

[0104] 1. A mixture of terpineol, butyl carbitol acetate, and dodecanol ester in a mass ratio of 1:1:1 is selected as the organic solvent, a mixture of ethyl cellulose and acrylic resin in a mass ratio of 2:1 is selected as the resin, and a mixture of hydrogenated castor oil and silicone oil in a mass ratio of 2:3 is selected as the additive. The mass ratio of the organic solvent, the resin, and the additive is 78:20:2. The resin and the organic solvent are heated and stirred thoroughly at 70-100°C, and then the additive is added after the resin is completely dissolved to obtain the organic carrier.

[0105] 2. A D50 of 1-5 μm and a tap density of 5-9 g / cm 3 -9 g / cm 3 The modified silver powder obtained by modification with oleic acid is used as the conductive phase.

[0106] 3. According to the total weight of the conductive paste being 100 parts, 88.5 parts of the modified silver powder, 2.5 parts of the inorganic glass powder (prepared in Example 1 or Comparative Example 1 or Comparative Example 2), and 9 parts of the organic carrier are weighed and mixed and stirred uniformly, and are ground and dispersed by a three-roll mill. The average fineness of the selected scraper is less than 10 μm to obtain the conductive paste.

[0107] Example 3

[0108] The present example provides a solar cell prepared by using the SE process. The specific method comprises the following steps:

[0109] 1. The semiconductor substrate is a P-type silicon substrate doped with boron or gallium. The P-type silicon substrate is a silicon wafer with a thickness of 150-200 μm and a side length of 156-210 mm. An alkali solution or an acid solution is used to etch one side of the silicon substrate to form a pyramid-shaped (single crystal) or uneven (polycrystal) anti-reflective matte surface.

[0110] 2. An N-type diffusion layer is formed on the other side of the P-type silicon substrate to form a PN junction. The N-type diffusion layer can be prepared by a gas phase thermal diffusion method using phosphorus oxychloride as a diffusion source. The sheet resistance of the diffusion layer is 120-170 Ω / sq. Then, the N-type diffusion layer is doped by laser SE. The sheet resistance of the heavily doped region after laser doping is 70-110 Ω / sq. The phosphorus on the edge is removed by wet etching or dry etching.

[0111] 3. An oxide layer of SiO2 is formed on the N surface by thermal diffusion, and then a SiNx anti-reflective layer is plated thereon. An aluminum oxide and silicon nitride film is plated on the P surface. Other coatings with good anti-reflective and passivation effects can also be used.

[0112] 4. Laser grooving is performed on the printed aluminum back field on the P surface. The conductive paste prepared in Example 2 is applied on the anti-reflective film on the N-type silicon substrate by screen printing to form vertical and horizontal main grids and fine grids. The back electrode and the aluminum back field are printed on the P-type side. The electrode body, i.e., the solar cell wafer, is formed by co-firing at a sintering temperature of 700-900°C.

[0113] Test Example 1

[0114] The solar cell of Example 3 was tested for electrical performance, specifically: using a solar simulator, under standard conditions, AM 1.5, 1000 W / m2, 25 °C. 2

[0115] The method for testing the corrosion rate of the surface of the cell was as follows: the solar cell prepared according to the method of Example 3 was corroded with a 30% dilute nitric acid solution at room temperature for 1 hour, then washed with purified water to remove the silver paste on the surface of the cell. The surface of the cell was observed using a high-power scanning electron microscope. Five cell samples were taken for each experiment, and five positions were tested for each sample. The ratio of the observed corrosion area to the total area of the measured positions was taken as the surface corrosion rate, and the surface corrosion rates of the various positions were averaged to obtain the average surface corrosion rate. The fill factor was measured using a conventional method in the art. Table 2 shows the open circuit voltage, fill factor, conversion efficiency and surface corrosion rate of the solar cell of Example 3.

[0116] Table 2

[0117]

[0118] From the above results, it can be seen that the cell prepared using the inorganic glass system conductive paste with the specific composition provided by the present application has a high open circuit voltage and conversion efficiency and low corrosion, with an open circuit voltage of more than 686 mV, a fill factor of more than 80%, a conversion efficiency of more than 23.2%, and an average cell corrosion rate of less than 50%, significantly improving the competitiveness of solar cell products.

[0119] Solar cells were prepared using the conductive paste corresponding to Comparative Example 1 and the conductive paste corresponding to Example 2, No. 1, as samples, and the surface of the solar cell (including the passivation layer) was characterized by scanning electron microscopy, as shown in Figure 1 , Figure 2 By comparison, it can be seen that the corrosion of the cell in Figure 1 is more severe than that in Figure 2 , indicating that the inorganic glass system conductive paste provided by the present application can make the prepared cell morphology more complete, proving that the conductive paste of the present application has less corrosion effect on the cell. Although Comparative Example 2 has less corrosion, the contact performance of the conductive paste and silicon is poor, resulting in a low FF, which leads to a low conversion efficiency of the cell.

[0120] ​From the above results, it can be seen that the inorganic glass powder with the specific composition provided by the application can effectively improve the passivation effect of the surface of the battery and improve the electrochemical performance of the battery sheet when applied in the field of solar cell manufacturing.

Claims

1. An inorganic glass frit composition, the elemental composition of which comprises: Si a -Bi b -Zn c -W d -M e , the M including a combination of two or more of Li, Na, Cu, Al, Pb, Te; the inorganic glass powder composition containing oxides corresponding to the above elements and / or compounds capable of forming the oxides of the above elements; a, b, c, d, e are respectively silicon, bismuth, zinc, tungsten, M, and the molar ratio of a, b, c, d, e in the total amount of silicon, bismuth, zinc, tungsten, M in the composition; the values of a, b, c, d, e simultaneously satisfy formula 1 to formula 6: Formula 1: 40%≤a≤60% or 5%≤b≤20%; Formula 2: 52%≤(a+b)≤65%; Formula 3: 6%≤c≤15% or c:(a+b) is 1:4 to 1:7; Formula 4: 1:1≤(a+b):(d+e)≤3:1; Formula 5: 6%≤d≤15% or 10%≤e≤30%; Formula 6: a+b+c+d+e=100%.

2. The inorganic glass powder composition according to claim 1, wherein, 45%≤a≤55% and / or 8%≤b≤16%.

3. The inorganic glass powder composition according to claim 1, wherein, Formula 2 is 55%≤(a+b)≤65%.

4. The inorganic glass powder composition according to claim 1, wherein, 15%≤e≤25%。 5. The inorganic glass powder composition according to claim 1, wherein, Formula 4 is 1.5:1≤(a+b):(d+e)≤2.5:

1.

6. The inorganic glass powder composition according to claim 1, wherein, The M includes a combination of Li, Na, Cu, Al, Pb, or a combination of Li, Cu, Al, Pb, Te, or a combination of Li, Cu, Al, Pb.

7. An inorganic glass powder prepared from the inorganic glass powder composition of any one of claims 1-6.

8. The inorganic glass powder according to claim 7, wherein, The inorganic glass powder has a composition of Si a -Bi b -Zn c -W d -M e -O f wherein the M includes a combination of two or more of Li, Na, Cu, Al, Pb, and Te, a, b, c, d, and e are respectively the molar proportions of silicon, bismuth, zinc, tungsten, and M in the total amount of silicon, bismuth, zinc, tungsten, and M elements, and f is a number for charge balance of oxygen and other elements. wherein the values of a, b, c, d, e simultaneously satisfy formula 1 to formula 6: Formula 1: 40%≤a≤60% or 5%≤b≤20%; Formula 2: 52%≤(a+b)≤65%; Formula 3: 6%≤c≤15% or c:(a+b) is 1:4 to 1:7; Formula 4: 1:1≤(a+b):(d+e)≤3:1; Formula 5: 6%≤d≤15% or 10%≤e≤30%; Formula 6: a+b+c+d+e=100%.

9. The inorganic glass powder according to claim 7, wherein, The particle size distribution of the inorganic glass powder satisfies D50 of 0.1 μm-5 μm.

10. The inorganic glass powder according to claim 7, wherein, The softening temperature of the inorganic glass powder is 250℃-550℃.

11. The inorganic glass powder according to claim 7, wherein, The preparation method of the inorganic glass powder includes: melting the inorganic glass powder composition, cooling, grinding, to obtain the inorganic glass powder.

12. The inorganic glass powder according to claim 11, wherein, The melting temperature is 750℃-1100℃, and the melting time is 30min-120min.

13. A conductive paste, comprising a conductive phase, an organic vehicle, and an inorganic bonding phase, the inorganic bonding phase comprising the inorganic glass powder of any one of claims 7-12.

14. The conductive paste of claim 13, wherein, The average doctor blade fineness of the conductive paste is 10 μm or less.

15. The conductive paste of claim 13, wherein, The average doctor blade fineness of the conductive paste is 5 μm or less.

16. The conductive paste of claim 13, wherein, The mass content of the conductive phase in the conductive paste is 86%-93%.

17. The conductive paste of claim 16, wherein, The mass content of the inorganic bonding phase in the conductive paste is 1%-10%, and the mass content of the organic vehicle in the conductive paste is 5%-20%.

18. The conductive paste of claim 13, wherein, The elements of the conductive phase include one or a combination of two or more of gold, silver, and copper.

19. The conductive paste of claim 18, wherein, The conductive phase includes silver powder.

20. The conductive paste of claim 19, wherein, The D50 of the silver powder is 1-5 pm, the tap density of the silver powder is 5 g / cm 3 -9 g / cm 3 .

21. The conductive paste of claim 18, wherein, The conductive phase includes modified silver powder.

22. The electroconductive paste of claim 21, wherein, The modifier used by the modified silver powder includes one or a combination of two or more of oleic acid, linoleic acid, linolenic acid, silane coupling agent, stearic acid, fatty acid amine, polyvinyl pyrrolidone, fatty alcohol polyoxyethylene ether, and block macromolecular surfactant.

23. The conductive paste of claim 22, wherein, The block macromolecular surfactant includes a polyamide block macromolecular surfactant.

24. The electroconductive paste according to any one of claims 13 to 23, wherein, The organic carrier includes a resin, an organic solvent and an auxiliary agent.

25. The electroconductive paste of claim 24, wherein, The mass ratio of the organic solvent, the resin and the auxiliary agent is (65-85):(10-25):(1-5).

26. The electroconductive paste of claim 24, wherein, The resin includes one or more than two combinations of ethyl cellulose, epoxy resin and acrylic resin.

27. The conductive paste of claim 24, wherein, The organic solvent includes one or more than two combinations of terpineol, butyl carbitol acetate and dodecanol ester.

28. The conductive paste of claim 24, wherein, The auxiliary agent includes one or more than two combinations of a dispersant, a thixotropic agent, a lubricant, a humectant and a plasticizer.

29. The conductive paste of claim 28, wherein, The dispersant includes one or more than two combinations of polyether, polyester, polyamide and polyorganosilicon. The thixotropic agent includes one or more than two combinations of hydrogenated castor oil, polyamide and fumed silica. The lubricant includes a surfactant and / or silicone oil. The humectant includes one or more than two combinations of diethylene glycol, triethylene glycol, glycerol, ethylene glycol, sorbitol, 1,2-propanediol, diethylene glycol butyl ether, polyethylene glycol, N-methyl-2-pyrrolidone, a condensate of polyhydric alcohol and ethylene oxide and xylitol. The plasticizer includes one or more than two combinations of aliphatic dibasic acid ester, phthalate ester, terephthalate ester, benzenepolyacid ester, benzoate ester, polyhydric alcohol ester type epoxy, citrate ester and polyester.

30. The conductive paste of claim 29, wherein, The polyethylene glycol includes PEG400.

31. A solar cell, the raw material of which includes the conductive paste according to any one of claims 13-30.

32. The solar cell of claim 31, wherein, The solar cell includes a solar cell made by SE technology.

33. A solar cell module, the raw material of which includes the conductive paste according to any one of claims 13-30.

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