TOPCon front slurry organic carrier and application thereof

Abstract

The invention discloses a TOPCon front slurry organic carrier and application, and belongs to the technical field of solar cells, the TOPCon front slurry organic carrier comprises the following raw materials by mass: 2.5%-14% of resin, 75%-87% of a solvent, 1%-7% of a thixotropic agent, and 1%-5% of an auxiliary agent; the resin comprises ethyl cellulose, cellulose acetate butyrate and acrylic resin; the solvent comprises triethylene glycol monobutyl ether, dodecanol ester, diethylene glycol monobutyl ether acetate and benzyl benzoate; the thixotropic agent comprises polyamide wax, a modified polyurea compound and phenoxyethanol; the thixotropic agent comprises polyamide wax, a modified polyurea compound and phenoxyethanol; by adjusting and verifying the variety and proportion of the raw materials of the organic carrier, the printability, fluidity and plasticity of the TOPCon front paste are optimized, and the TOPCon front paste has the advantages of good conductivity, wettability, printability and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of solar cells and relates to a TOPCon front slurry organic carrier and application thereof, and is particularly suitable for a narrow line width printing process. Background Art

[0002] Solar cells primarily collect and conduct electrons through silver grid lines printed on silicon wafers. The quality of the front silver paste determines its conversion efficiency, so front silver paste plays a crucial role in the production of solar cells. Front silver paste is primarily based on an organic carrier, with silver powder, glass powder, and additives mixed in a specific ratio to form a suspension system.

[0003] As the photovoltaic industry's demand for high-efficiency solar cells continues to increase, TOPCon (Tunnel Oxide Passivated Contact) cells have become one of the core technologies of the new generation of high-efficiency crystalline silicon cells due to their excellent passivation effect and carrier transport performance.

[0004] At present, the industrialization process of TOPCon batteries has entered a bottleneck period, which has put forward more stringent requirements on cost control. Narrowing the width of the gate line has become a must for battery manufacturers.

[0005] Existing technology, such as patent number CN202311425901.0, titled "Conductive Paste, Organic Vehicle, and Application for Preparing Conductive Gridlines," discloses an organic vehicle for conductive pastes. However, its line width remains moderate (>25μm), and further narrowing the line width will lead to a decline in printing performance. Therefore, there is an urgent need to develop a specialized organic vehicle suitable for TOPCon front-side narrow line width printing. Summary of the Invention

[0006] The purpose of the present invention is to provide an organic carrier for TOPCon front slurry and its application, and to solve the above technical problems by adjusting and verifying the type and ratio of organic carrier raw materials and optimizing the printability, fluidity and plasticity of the slurry.

[0007] The present invention solves the above technical problems through the following technical solutions: The invention provides a TOPCon front organic carrier, which comprises the following raw materials in percentage by weight: 2.5% to 14% of resin, 75% to 87% of solvent, 1% to 7% of thixotropic agent, and 1% to 5% of auxiliary agent.

[0008] Furthermore, the resin includes the following components: ethyl cellulose, cellulose acetate butyrate, and acrylic resin.

[0009] Furthermore, based on the mass of the organic carrier, the mass proportion of the ethyl cellulose is 0.5% to 3.5%, the mass proportion of the cellulose acetate butyrate is 0.5% to 3.8%, and the mass proportion of the acrylic resin is 2.5% to 6.7%.

[0010] Preferably, based on the mass of the organic carrier, the mass proportion of the ethyl cellulose is 0.6% to 3%, the mass proportion of the cellulose acetate butyrate is 0.8% to 3.2%, and the mass proportion of the acrylic resin is 2.5% to 6%.

[0011] Specifically, based on the mass of the organic carrier, the mass proportion of the ethyl cellulose is 1%, the mass proportion of the cellulose acetate butyrate is 1%, and the mass proportion of the acrylic resin is 6%; Optionally, based on the mass of the organic carrier, the mass proportion of the ethyl cellulose is 1%, the mass proportion of the cellulose acetate butyrate is 1%, and the mass proportion of the acrylic resin is 6%; Alternatively, based on the mass of the organic carrier, the mass proportion of the ethyl cellulose is 2%, the mass proportion of the cellulose acetate butyrate is 2%, and the mass proportion of the acrylic resin is 4%; The present invention regulates the type of resin and first selects ethyl cellulose containing ethoxy, hydroxyl and ether bonds. On the one hand, the hydrophobicity of the ethoxy makes it easily soluble in commonly used organic solvents such as diethylene glycol dibutyl ether, butyl carbitol, etc., forming a uniform slurry, thereby promoting the dispersion of silver powder and preventing agglomeration. The cellulose skeleton composed of ether bonds has a stable structure, which is conducive to fixing the conductive silver powder and preventing particle displacement or shedding before sintering. Hydroxyl, as an important group in the organic carrier, exists simultaneously in ethyl cellulose and cellulose acetate butyrate. It forms weak crosslinks through the formation of hydrogen bonds, giving the slurry a shear-thinning property. On the one hand, it reduces the low viscosity during printing and improves the printability of the slurry. On the other hand, the viscosity rises after printing, so that the slurry has certain thixotropic properties.

[0012] In addition, the polarity of the acetyl group in cellulose acetate butyrate makes it more compatible with ester solvents, helping to dissolve the resin and making it have better wettability. The long-chain butyryl group has a steric hindrance effect that can adjust the thixotropy of the slurry, balancing the fluidity during printing and the anti-sedimentation ability when stationary. The acrylic resin has strong viscosity, which is conducive to achieving a better aspect ratio under narrow screen openings, and the carboxylic acid group allows the acrylic resin to have good performance in the dispersion and adhesion of the slurry. The acrylic resin has a network structure, which makes the slurry have better mesh passing properties under narrow opening screen conditions. The present invention compounds ethyl cellulose, cellulose acetate butyrate and acrylic resin, which can not only give full play to the performance of each resin itself, but also synergistically enhance the effect, optimize the fluidity, shaping and adhesion of the slurry, and show good printing ability on narrow opening screens.

[0013] The ethyl cellulose described in the present invention has a high molecular weight, a long molecular chain that is easy to entangle, and has a relatively good inward force, which is conducive to the shaping of the slurry. The inventors have proved through a large number of experiments that when the proportion of ethyl cellulose is less than 0.6%, the height of the grid line after printing is too low, the width is too large, and there are problems with shaping. When the proportion is higher than 4.2%, it is easy to block the screen under narrow opening screen printing, causing the grid to break on both sides of the battery cell. Similarly, the addition amount of the cellulose acetate butyrate and acrylic resin is also within the range specified by the present invention, and the viscosity of the slurry is wet weight, which is conducive to printing.

[0014] Furthermore, the solvent is triethylene glycol butyl ether, dodecyl alcohol ester, diethylene glycol butyl ether acetate, and benzyl benzoate.

[0015] Furthermore, based on the mass of the organic carrier, the mass proportion of the triethylene glycol butyl ether is 20% to 45%, the mass proportion of the dodecyl alcohol ester is 15% to 30%, the mass proportion of the diethylene glycol butyl ether acetate is 20% to 40%, and the mass proportion of the benzyl benzoate is 10% to 25%.

[0016] Preferably, based on the mass of the organic carrier, the mass proportion of the triethylene glycol butyl ether is 25% to 30%, the mass proportion of the dodecyl alcohol ester is 15% to 25%, the mass proportion of the diethylene glycol butyl ether acetate is 25% to 35%, and the mass proportion of the benzyl benzoate is 10% to 20%.

[0017] Specifically, based on the mass of the organic carrier, the mass ratio of triethylene glycol butyl ether is 26%, the mass ratio of lauryl ester is 18%, the mass ratio of diethylene glycol butyl ether acetate is 28%, and the mass ratio of benzyl benzoate diacetate is 12%. Alternatively, based on the mass of the organic carrier, the mass proportion of triethylene glycol butyl ether is 28%, the mass proportion of dodecyl alcohol ester is 15%, the mass proportion of diethylene glycol butyl ether acetate is 25%, and the mass proportion of benzyl benzoate is 15%.

[0018] By optimizing solvent types and regulating the ratio of each component, the present invention optimizes the fluidity and wettability of the TOPCon front slurry formulated with an organic vehicle for narrow-aperture screen printing. Triethylene glycol butyl ether contains hydroxyl groups and three ether bonds, resulting in good hydrophilicity. Its high surface tension, coupled with its weak affinity for the surface of silver powder coated with a hydrophobic layer, enhances its plasticity. Furthermore, compared with other solvents with lower polarity and surface tension, triethylene glycol butyl ether exhibits a larger contact angle after wetting silver powder, resulting in excellent screen passability. Both of these advantages of triethylene glycol butyl ether are well-suited to the characteristics of a slurry suitable for narrow-aperture printing. However, a triethylene glycol butyl ether content exceeding 45% can result in high slurry viscosity, making it unsuitable for printing. When the triethylene glycol butyl ether content is below 20%, the slurry's aspect ratio deviates significantly, resulting in low line height and wide line width. The lauryl alcohol ester contains both long-chain alkyl and ester groups, but the long-chain alkyl group plays a dominant role, resulting in a lower polarity and providing better fluidity for the silver powder. When the content of dodecyl ester is less than 15%, it cannot play the role of regulating viscosity; when the content of dodecyl ester is higher than 30%, the organic carrier evaporates too quickly, and the paste is prone to drying out after long-term printing, resulting in false printing and broken screens. Diethylene glycol butyl ether acetate contains ether bonds and ester groups, and has both polarity and hydrophobicity. It is highly versatile and is a good solvent choice for dissolving the resin and wetting silver powder. It helps the silver powder to be evenly dispersed in the organic carrier. Diethylene glycol butyl ether acetate is not easy to volatilize, which can ensure the long-term printability of the paste. However, when the content of diethylene glycol butyl ether acetate is lower than 20%, the stability of the silver paste is reduced, and the solvent will evaporate quickly at high temperatures, causing silver paste splashing. Benzyl benzoate has low surface tension and low polarity. Its performance is supported by two hydrophobic groups. It has a strong affinity with the hydrophobic surface of silver powder, which helps the silver powder to be evenly dispersed in the paste, reduces agglomeration, and thus improves conductivity and printing performance. When the benzyl benzoate content is higher than 25%, the slurry will spread excessively during printing, which is not conducive to maintaining the line shape. When the benzyl benzoate content is lower than 10%, the organic vehicle's dispersibility decreases and the leveling time after printing is insufficient, forming holes and cracks in the film layer, reducing the density of the electrode.

[0019] Furthermore, the thixotropic agent includes the following components: polyamide wax, modified polyurea compound, and phenoxyethanol.

[0020] Further, based on the mass of the organic carrier, the mass ratio of the polyamide wax is 0.1% to 1%, the mass ratio of the modified polyurea compound is 0.1% to 1%, and the mass ratio of phenoxyethanol is 0.1% to 1%. Preferably, based on the mass of the organic carrier, the mass proportion of the polyamide wax is 0.2% to 0.8%, the mass proportion of the modified polyurea compound is 0.3% to 0.9%, and the mass proportion of phenoxyethanol is 0.2% to 0.7%.

[0021] Specifically, based on the mass of the organic carrier, the mass proportion of the polyamide wax is 0.3%, the mass proportion of the modified polyurea compound is 0.4%, and the mass proportion of phenoxyethanol is 0.3%; Alternatively, based on the mass of the organic carrier, the mass proportion of the polyamide wax is 0.2%, the mass proportion of the modified polyurea compound is 0.3%, and the mass proportion of phenoxyethanol is 0.5%.

[0022] The present invention adjusts the ratio of three thixotropic agents: polyamide wax, modified polyurea compound, and phenoxyethanol to obtain a thixotropic agent suitable for narrow line width printing. The polar amide group oxygen atoms in the polyamide wax have strong electronegativity and form hydrogen bonds with hydrocarbon hydrogen to form a three-dimensional network structure, which gives the slurry shear thinning properties, that is, hydrogen bonds break under high shear rates, causing the slurry viscosity to decrease. After printing, the shear rate decreases, the hydrogen bonds are rebuilt, and a good aspect ratio is maintained. If the polyamide wax accounts for less than 0.1%, the silver paste has insufficient thixotropy and the grid line aspect ratio is small; if the polyamide wax accounts for more than 1%, the slurry has insufficient fluidity, resulting in false printing. The modified polyurea compound forms a dynamic and reversible physical cross-linked network through the urea group, which dissociates under shear force and recovers after standing, balancing high thixotropy and fluidity. The polarity of the urea bond is higher than that of the amide bond, the hydrogen bond density is higher, and the thixotropic response is faster. If the modified polyurea compound accounts for more than 1%, the residual nitrogen compounds after sintering will affect the conductivity of the grid line. The hydrophobic group of the phenoxyethanol reduces the affinity between the slurry and the surface of the battery cell, reducing lateral diffusion. If the proportion of phenoxyethanol is higher than 1%, the viscosity of the slurry will be reduced too much, which is not conducive to shaping.

[0023] Furthermore, the auxiliary agent includes the following components: 50 viscosity dimethyl silicone oil, 100 viscosity dimethyl silicone oil, and dodecylamine.

[0024] Furthermore, based on the mass of the organic carrier, the mass proportion of the 50 viscosity dimethyl silicone oil is 1% to 5%, the mass proportion of the 100 viscosity dimethyl silicone oil is 1% to 7%, and the mass proportion of dodecylamine is 0.8% to 3%.

[0025] Preferably, based on the mass of the organic carrier, the mass proportion of the 50 viscosity dimethyl silicone oil is 1% to 4%, the mass proportion of the 100 viscosity dimethyl silicone oil is 1% to 5%, and the mass proportion of dodecylamine is 1% to 3%.

[0026] Specifically, based on the mass of the organic carrier, the mass proportion of the 50 viscosity dimethyl silicone oil is 2%, the mass proportion of the 100 viscosity dimethyl silicone oil is 4%, and the mass proportion of dodecylamine is 1%; Alternatively, based on the mass of the organic vehicle, the mass proportion of the 50 viscosity dimethyl silicone oil is 3%, the mass proportion of the 100 viscosity dimethyl silicone oil is 3%, and the mass proportion of dodecylamine is 2%.

[0027] The present invention optimizes the thixotropic properties of the paste during narrow-aperture printing by compounding two silicone oils of different viscosities, maintaining a favorable aspect ratio. It also enhances the paste's wettability to the silicon nitride anti-reflection coating on the silicon wafer surface, reducing printed line widening. The surface of glass powder used in silver paste is generally hydrophilic, making it difficult to disperse evenly in the lipophilic silver powder and resin. Dodecylamine has both hydrophilic amino groups and lipophilic long-chain alkyl groups. By adjusting the ratio of dodecylamine, the present invention improves the dispersibility of glass powder in the silver paste, thereby preventing glass powder agglomeration.

[0028] The TOPCon organic carrier provided by the present invention is used in the technical field of solar cells.

[0029] The present invention also claims protection for the TOPCon battery front slurry, which is composed of the above-mentioned TOPCon organic carrier, silver powder and inorganic glass powder.

[0030] As a preferred embodiment of the present invention, in the TOPCon battery front slurry, the TOPCon battery organic vehicle accounts for 5% to 14% of the total mass of the front slurry, the silver powder accounts for 82% to 90% of the total mass of the front slurry, and the inorganic glass powder accounts for 1% to 10% of the total mass of the front slurry. Beneficial effects

[0031] (1) The present invention regulates the types of resins and selects ethyl cellulose, cellulose acetate butyrate and acrylic resin for compounding. Ethyl cellulose contains ethoxy, hydroxyl and ether bonds. The ethoxy group makes it soluble in organic solvents and promotes the dispersion of silver powder. The ether bond fixes the silver powder. The hydroxyl group imparts shear thinning properties to the slurry through weak cross-linking with hydrogen bonds. The acetyl group of cellulose acetate butyrate has good compatibility with ester solvents, and the butyryl group can adjust the thixotropy. Acrylic resin has strong viscosity and contains carboxylic acid groups. Its network structure is conducive to narrow screen passing. The three resins are compounded to give full play to their respective properties and synergistically enhance the slurry's fluidity, shaping and adhesion, and exhibit good printing ability under narrow line width screens.

[0032] (2) The present invention improves the fluidity and wettability of the TOPCon front slurry prepared with an organic carrier by optimizing the solvent type, making it suitable for narrow line width screen printing. Triethylene glycol butyl ether contains hydroxyl groups and ether bonds, has good hydrophilicity and high surface tension, can increase plasticity, has weak affinity with silver powder, has a large contact angle, and has good screen passing ability; dodecyl alcohol ester is dominated by long-chain alkyl groups and has low polarity, which gives the silver powder excellent fluidity; diethylene glycol butyl ether acetate has both polarity and hydrophobicity, can effectively dissolve the resin and evenly disperse the silver powder, and has low volatility, ensuring the long-term printability of the slurry; benzyl benzoate has low surface tension and polarity, and its double hydrophobic groups make it have a strong affinity with the hydrophobic surface of the silver powder, which is beneficial to the dispersion of the silver powder, reduces agglomeration, and thus improves the conductivity and printing performance of the slurry.

[0033] (3) The present invention improves the thixotropic properties and leveling of the slurry by regulating three different thixotropic agents, respectively using intermolecular hydrogen bond networks, reversible physical crosslinking, and surface tension regulation. These three different thixotropic agent action mechanisms improve the slurry's adaptability under narrow line width printing. The type and proportion of silicone oil and the proportion of dispersant are adjusted to uniformly mix the slurry and improve filling contact. Therefore, by regulating the type and proportion of each component of the organic carrier, the TOPCon battery front slurry prepared with the organic carrier has the advantages of moderate viscosity, good linear flatness, moderate aspect ratio, and good wettability under narrow line width printing. DETAILED DESCRIPTION

[0034] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below with reference to specific embodiments.

[0035] Resins: including Dow Chemical's ethyl cellulose, Eastman TM Cellulose acetate butyrate, acrylic resin; Dispersant: Maclean's dodecylamine; Thixotropic agents: polyamide wax from Nanben; modified polyurea compound from Wanhua Chemical; phenoxyethanol from BASF.

[0036] Additives: Sinopharm's 50 viscosity dimethyl silicone oil and 100 viscosity dimethyl silicone oil.

[0037] Testing process

[0038] Viscosity detection: 15-20 g of the slurry was sampled and the average viscosity of the slurry was measured using a Brookfield DV2 viscometer and a spindle SC-14 at 25°C / 50 rpm / 60 seconds.

[0039] Printability testing: The conductive pastes described in the examples and comparative examples were screen-printed onto the front surface of the silicon wafer. The printability test screen used was a knot-free, multi-opening 550-mesh screen with a line diameter of 5 μm, a total thickness of 12 μm, and openings of 7 μm. The cells were dried in an infrared oven. The pastes were then visually inspected for any smearing and electroluminescence (EL) to determine if there were any broken gates. Laser confocal microscopy was used to measure the paste's aspect ratio and smoothness. Example 1

[0040] The organic carrier for the TOPCon front slurry described in this embodiment includes the following raw materials in percentage by weight: 26 parts of triethylene glycol dibutyl ether, 12 parts of benzyl benzoate, 18 parts of lauryl ester, 28 parts of diethylene glycol butyl ether acetate, 1 part of ethyl cellulose, 1 part of cellulose acetate butyrate, 6 parts of acrylic resin, 0.3 parts of polyamide wax, 0.4 parts of modified polyurea compound, 0.3 parts of phenoxyethanol, 2 parts of 50 viscosity dimethyl silicone oil, 4 parts of 100 viscosity dimethyl silicone oil, and 1 part of dodecylamine.

[0041] The TOPCon front slurry described in this embodiment includes the following components in percentage by weight: 89.3% silver powder, 2.5% inorganic glass powder, and 8.2% organic vehicle. Example 2

[0042] The organic carrier for the TOPCon front slurry described in this embodiment includes the following raw materials in percentage by weight: 26 parts of triethylene glycol dibutyl ether, 12 parts of benzyl benzoate, 18 parts of lauryl ester, 28 parts of diethylene glycol butyl ether acetate, 1 part of ethyl cellulose, 2 parts of cellulose acetate butyrate, 5 parts of acrylic resin, 0.3 parts of polyamide wax, 0.4 parts of modified polyurea compound, 0.3 parts of phenoxyethanol, 2 parts of 50 viscosity dimethyl silicone oil, 4 parts of 100 viscosity dimethyl silicone oil, and 1 part of dodecylamine.

[0043] The TOPCon front paste described in this embodiment includes the following components in percentage by weight: 89.3% silver powder, 2.5% inorganic glass powder, and 8.2% organic vehicle. Example 3

[0044] The organic carrier for the TOPCon front slurry described in this embodiment includes the following raw materials in percentage by weight: 26 parts of triethylene glycol dibutyl ether, 12 parts of benzyl benzoate, 18 parts of lauryl ester, 28 parts of diethylene glycol butyl ether acetate, 2 parts of ethyl cellulose, 2 parts of cellulose acetate butyrate, 4 parts of acrylic resin, 0.3 parts of polyamide wax, 0.4 parts of modified polyurea compound, 0.3 parts of phenoxyethanol, 2 parts of 50 viscosity dimethyl silicone oil, 4 parts of 100 viscosity dimethyl silicone oil, and 1 part of dodecylamine.

[0045] The TOPCon front paste described in this embodiment includes the following components in percentage by weight: 89.3% silver powder, 2.5% inorganic glass powder, and 8.2% organic vehicle.

[0046] Comparative Example 1 The organic carrier for the TOPCon front slurry described in this embodiment includes the following raw materials in percentage by weight: 26 parts of triethylene glycol dibutyl ether, 12 parts of benzyl benzoate, 18 parts of lauryl ester, 28 parts of diethylene glycol butyl ether acetate, 0.6 parts of ethyl cellulose, 1.8 parts of cellulose acetate butyrate, 5.6 parts of acrylic resin, 0.3 parts of polyamide wax, 0.4 parts of modified polyurea compound, 0.3 parts of phenoxyethanol, 2 parts of 50 viscosity dimethyl silicone oil, 4 parts of 100 viscosity dimethyl silicone oil, and 1 part of dodecylamine.

[0047] The TOPCon front paste described in this embodiment includes the following components in percentage by weight: 89.3% silver powder, 2.5% inorganic glass powder, and 8.2% organic vehicle.

[0048] Comparative Example 2 The organic carrier for the TOPCon front slurry described in this embodiment includes the following raw materials in percentage by weight: 26 parts of triethylene glycol dibutyl ether, 12 parts of benzyl benzoate, 18 parts of lauryl ester, 28 parts of diethylene glycol butyl ether acetate, 1.2 parts of ethyl cellulose, 3.5 parts of cellulose acetate butyrate, 3.3 parts of acrylic resin, 0.3 part of polyamide wax, 0.4 part of modified polyurea compound, 0.3 part of phenoxyethanol, 2 parts of 50 viscosity dimethyl silicone oil, 4 parts of 100 viscosity dimethyl silicone oil, and 1 part of dodecylamine.

[0049] The TOPCon front paste described in this embodiment includes the following components in percentage by weight: 89.3% silver powder, 2.5% inorganic glass powder, and 8.2% organic vehicle.

[0050] Comparative Example 3 The organic carrier for the TOPCon front slurry described in this embodiment includes the following raw materials in percentage by weight: 26 parts of triethylene glycol dibutyl ether, 12 parts of benzyl benzoate, 18 parts of lauryl ester, 28 parts of diethylene glycol butyl ether acetate, 0.3 parts of ethyl cellulose, 2.3 parts of cellulose acetate butyrate, 5.4 parts of acrylic resin, 0.3 parts of polyamide wax, 0.4 parts of modified polyurea compound, 0.3 parts of phenoxyethanol, 2 parts of 50 viscosity dimethyl silicone oil, 4 parts of 100 viscosity dimethyl silicone oil, and 1 part of dodecylamine.

[0051] The TOPCon front paste described in this embodiment includes the following components in percentage by weight: 89.3% silver powder, 2.5% inorganic glass powder, and 8.2% organic vehicle.

[0052] Comparative Example 4 The organic carrier for the TOPCon front slurry described in this embodiment includes the following raw materials in percentage by weight: 26 parts of triethylene glycol dibutyl ether, 12 parts of benzyl benzoate, 18 parts of lauryl ester, 28 parts of diethylene glycol butyl ether acetate, 3.8 parts of ethyl cellulose, 0.2 parts of cellulose acetate butyrate, 4 parts of acrylic resin, 0.3 parts of polyamide wax, 0.4 parts of modified polyurea compound, 0.3 parts of phenoxyethanol, 2 parts of 50 viscosity dimethyl silicone oil, 4 parts of 100 viscosity dimethyl silicone oil, and 1 part of dodecylamine.

[0053] The TOPCon front paste described in this embodiment includes the following components in percentage by weight: 89.3% silver powder, 2.5% inorganic glass powder, and 8.2% organic vehicle.

[0054] Comparative Example 5 The organic carrier for the TOPCon front slurry described in this embodiment includes the following raw materials in percentage by weight: 26 parts of triethylene glycol dibutyl ether, 12 parts of benzyl benzoate, 18 parts of lauryl ester, 28 parts of diethylene glycol butyl ether acetate, 3 parts of ethyl cellulose, 3 parts of cellulose acetate butyrate, 2 parts of acrylic resin, 0.3 parts of polyamide wax, 0.4 parts of modified polyurea compound, 0.3 parts of phenoxyethanol, 2 parts of 50 viscosity dimethyl silicone oil, 4 parts of 100 viscosity dimethyl silicone oil, and 1 part of dodecylamine.

[0055] The TOPCon front paste described in this embodiment includes the following components in percentage by weight: 89.3% silver powder, 2.5% inorganic glass powder, and 8.2% organic vehicle. Example 4

[0056] The organic carrier for the TOPCon front slurry described in this embodiment includes the following raw materials in percentage by weight: 28 parts of triethylene glycol dibutyl ether, 15 parts of benzyl benzoate, 15 parts of lauryl ester, 25 parts of diethylene glycol butyl ether acetate, 2 parts of ethyl cellulose, 1.5 parts of cellulose acetate butyrate, 4.5 parts of acrylic resin, 0.2 parts of polyamide wax, 0.3 parts of modified polyurea compound, 0.5 parts of phenoxyethanol, 3 parts of 50 viscosity dimethyl silicone oil, 3 parts of 100 viscosity dimethyl silicone oil, and 2 parts of dodecylamine.

[0057] The TOPCon front paste described in this embodiment includes the following components in percentage by weight: 89.3% silver powder, 2.5% inorganic glass powder, and 8.2% organic vehicle. Example 5

[0058] The organic carrier for the TOPCon front slurry described in this embodiment includes the following raw materials in percentage by weight: 28 parts of triethylene glycol dibutyl ether, 15 parts of benzyl benzoate, 15 parts of lauryl ester, 25 parts of diethylene glycol butyl ether acetate, 2.2 parts of ethyl cellulose, 2.8 parts of cellulose acetate butyrate, 3 parts of acrylic resin, 0.2 parts of polyamide wax, 0.3 parts of modified polyurea compound, 0.5 parts of phenoxyethanol, 3 parts of 50 viscosity dimethyl silicone oil, 3 parts of 100 viscosity dimethyl silicone oil, and 2 parts of dodecylamine.

[0059] The TOPCon front paste described in this embodiment includes the following components in percentage by weight: 89.3% silver powder, 2.5% inorganic glass powder, and 8.2% organic vehicle. Example 6

[0060] The organic carrier for the TOPCon front slurry described in this embodiment includes the following raw materials in percentage by weight: 28 parts of triethylene glycol dibutyl ether, 15 parts of benzyl benzoate, 15 parts of lauryl ester, 25 parts of diethylene glycol butyl ether acetate, 2.3 parts of ethyl cellulose, 3.2 parts of cellulose acetate butyrate, 2.5 parts of acrylic resin, 0.2 parts of polyamide wax, 0.3 parts of modified polyurea compound, 0.5 parts of phenoxyethanol, 3 parts of 50 viscosity dimethyl silicone oil, 3 parts of 100 viscosity dimethyl silicone oil, and 2 parts of dodecylamine.

[0061] The TOPCon front paste described in this embodiment includes the following components in percentage by weight: 89.3% silver powder, 2.5% inorganic glass powder, and 8.2% organic vehicle.

[0062] Comparative Example 6 The organic carrier for the TOPCon front slurry described in this embodiment includes the following raw materials in percentage by weight: 28 parts of triethylene glycol dibutyl ether, 15 parts of benzyl benzoate, 15 parts of lauryl ester, 25 parts of diethylene glycol butyl ether acetate, 3 parts of ethyl cellulose, 2 parts of cellulose acetate butyrate, 3 parts of acrylic resin, 0.2 parts of polyamide wax, 0.3 parts of modified polyurea compound, 0.5 parts of phenoxyethanol, 3 parts of 50 viscosity dimethyl silicone oil, 3 parts of 100 viscosity dimethyl silicone oil, and 2 parts of dodecylamine.

[0063] The TOPCon front paste described in this embodiment includes the following components in percentage by weight: 89.3% silver powder, 2.5% inorganic glass powder, and 8.2% organic vehicle.

[0064] Comparative Example 7 The organic carrier for the TOPCon front slurry described in this embodiment includes the following raw materials in percentage by weight: 28 parts of triethylene glycol dibutyl ether, 15 parts of benzyl benzoate, 15 parts of lauryl ester, 25 parts of diethylene glycol butyl ether acetate, 1.9 parts of ethyl cellulose, 3.2 parts of cellulose acetate butyrate, 2.9 parts of acrylic resin, 0.2 parts of polyamide wax, 0.3 parts of modified polyurea compound, 0.5 parts of phenoxyethanol, 3 parts of 50 viscosity dimethyl silicone oil, 3 parts of 100 viscosity dimethyl silicone oil, and 2 parts of dodecylamine.

[0065] The TOPCon front paste described in this embodiment includes the following components in percentage by weight: 89.3% silver powder, 2.5% inorganic glass powder, and 8.2% organic vehicle.

[0066] Comparative Example 8 The organic carrier for the TOPCon front slurry described in this embodiment includes the following raw materials in percentage by weight: 28 parts of triethylene glycol dibutyl ether, 15 parts of benzyl benzoate, 15 parts of lauryl ester, 25 parts of diethylene glycol butyl ether acetate, 3.8 parts of ethyl cellulose, 1.7 parts of cellulose acetate butyrate, 2.5 parts of acrylic resin, 0.2 parts of polyamide wax, 0.3 parts of modified polyurea compound, 0.5 parts of phenoxyethanol, 3 parts of 50 viscosity dimethyl silicone oil, 3 parts of 100 viscosity dimethyl silicone oil, and 2 parts of dodecylamine.

[0067] The TOPCon front paste described in this embodiment includes the following components in percentage by weight: 89.3% silver powder, 2.5% inorganic glass powder, and 8.2% organic vehicle.

[0068] Comparative Example 9 The organic carrier for the TOPCon front slurry described in this embodiment includes the following raw materials in percentage by weight: 28 parts of triethylene glycol dibutyl ether, 15 parts of benzyl benzoate, 15 parts of lauryl ester, 25 parts of diethylene glycol butyl ether acetate, 0.7 parts of ethyl cellulose, 4 parts of cellulose acetate butyrate, 3.3 parts of acrylic resin, 0.2 parts of polyamide wax, 0.3 parts of modified polyurea compound, 0.5 parts of phenoxyethanol, 3 parts of 50 viscosity dimethyl silicone oil, 3 parts of 100 viscosity dimethyl silicone oil, and 2 parts of dodecylamine.

[0069] The TOPCon front paste described in this embodiment includes the following components in percentage by weight: 89.3% silver powder, 2.5% inorganic glass powder, and 8.2% organic vehicle.

[0070] Comparative Example 10 The organic carrier for the TOPCon front slurry described in this embodiment includes the following raw materials in percentage by weight: 28 parts of triethylene glycol dibutyl ether, 15 parts of benzyl benzoate, 15 parts of lauryl ester, 25 parts of diethylene glycol butyl ether acetate, 0.6 parts of ethyl cellulose, 0.5 parts of cellulose acetate butyrate, 6.9 parts of acrylic resin, 0.2 parts of polyamide wax, 0.3 parts of modified polyurea compound, 0.5 parts of phenoxyethanol, 3 parts of 50 viscosity dimethyl silicone oil, 3 parts of 100 viscosity dimethyl silicone oil, and 2 parts of dodecylamine.

[0071] The TOPCon front paste described in this embodiment includes the following components in percentage by weight: 89.3% silver powder, 2.5% inorganic glass powder, and 8.2% organic vehicle.

[0072] The raw material components of Examples 1 to 6 and Comparative Examples 1 to 10 are shown in Table 1 below.

[0073] Table 1 Raw material components of Examples 1 to 6 and Comparative Examples 1 to 10:

[0074] Table 1 Table 2 Performance results of TOPCon front slurries prepared in Examples 1-6 and Comparative Examples 1-10: Table 2

[0075] According to the performance data in Table 2, compared with Comparative Examples 1-2 and Comparative Examples 6-7, the addition amount of each component of the organic vehicle for the TOPCon front slurry in Examples 1-6 is within the specified range of the present invention. The prepared organic vehicle is used for the TOPCon front slurry, so that the TOPCon front slurry has the advantages of moderate viscosity, no false printing in appearance, no broken EL grid, and appropriate aspect ratio, thereby adapting to the printing of narrow line width screens.

[0076] Compared with Comparative Example 3, in Examples 1-6, the proportion of ethyl cellulose in the organic vehicle for the TOPCon front slurry is lower than the specified range, the printing performance of the TOPCon front slurry prepared with the obtained organic vehicle is reduced, and the problem of broken grids on both sides of the cell is prone to occur.

[0077] Compared with Comparative Example 4, in Examples 1-6, the proportion of cellulose acetate butyrate in the organic carrier for the TOPCon front slurry is lower than the specified range, and the printing performance of the TOPCon front slurry prepared with the obtained organic carrier is reduced, and the phenomenon of false printing occurs.

[0078] Compared with Comparative Example 5, in Examples 1-6, the proportion of acrylic resin in the organic carrier of the TOPCon front slurry is lower than the specified range, the printing performance of the TOPCon front slurry prepared from the obtained organic carrier is reduced, the slurry viscosity is too high, false printing occurs, and gourd knots are generated.

[0079] Compared with Comparative Example 8, in Examples 1-6, the ethyl cellulose in the organic carrier used in the TOPCon front slurry is higher than the specified range. The printing performance of the TOPCon front slurry prepared with the obtained organic carrier is reduced, the ink return is poor, the slurry is stringy, and the front side is broken. The line shape also has ups and downs, and the gourd knot is relatively serious.

[0080] Compared with Comparative Example 9, in Examples 1-6, the proportion of cellulose acetate butyrate in the organic carrier for the TOPCon front slurry is higher than the specified range, and the printing performance of the TOPCon front slurry prepared with the obtained organic carrier is reduced, the grid break problem is prone to occur, and the printing linearity is poor.

[0081] Compared with Comparative Example 10, the acrylic resin content of the TOPCon front slurry in Examples 1-6 exceeded the specified range. The TOPCon front slurry prepared with the resulting organic vehicle had average printing performance, wide line widths, poor aspect ratios, and thick lines. The linear grid lines were also uneven in thickness.

[0082] The embodiments provided above are not intended to limit the scope of the present invention, nor are the steps described to limit their execution order. Any obvious improvements to the present invention made by those skilled in the art in combination with existing common knowledge shall fall within the scope of protection defined by the claims of the present invention.

Claims

1. A TOPCon front slurry, characterized in that: The invention is composed of a TOPCon front paste organic carrier, silver powder and inorganic glass powder. In the TOPCon battery front paste, the TOPCon battery organic carrier accounts for 5% to 14% of the total mass of the front paste, the silver powder accounts for 82% to 90% of the total mass of the front paste, and the inorganic glass powder accounts for 1% to 10% of the total mass of the front paste. The TOPCon front paste organic carrier includes the following raw materials in percentage by mass: Resin: 2.5% to 14%, Solvent: 75% to 87%, Thixotropic agent: 1% to 7%, Additives: 1% to 5%, The resin includes ethyl cellulose, cellulose acetate butyrate and acrylic resin, wherein: Ethyl cellulose accounts for 0.5% to 3.5% of the mass of the organic carrier. Cellulose acetate butyrate accounts for 0.5% to 3.8% of the mass of the organic carrier. The acrylic resin accounts for 2.5% to 6.7% of the mass of the organic carrier.

2. The TOPCon front slurry organic carrier according to claim 1, characterized in that: The solvent includes triethylene glycol butyl ether, lauryl alcohol ester, diethylene glycol butyl ether acetate and benzyl benzoate, wherein: Triethylene glycol butyl ether accounts for 20% to 45% of the mass of the organic carrier, The lauryl alcohol ester accounts for 15% to 30% of the mass of the organic carrier. Diethylene glycol butyl ether acetate accounts for 20% to 40% of the mass of the organic carrier, Benzyl benzoate accounts for 10% to 25% of the mass of the organic carrier.

3. The TOPCon front slurry organic carrier according to claim 1, characterized in that: The thixotropic agent comprises polyamide wax, modified polyurea compound and phenoxyethanol, wherein: The polyamide wax accounts for 0.1% to 1% of the mass of the organic carrier. The modified polyurea compound accounts for 0.1% to 1% of the mass of the organic carrier. Phenoxyethanol accounts for 0.1% to 1% of the mass of the organic carrier.

4. The TOPCon front slurry organic carrier according to claim 1, characterized in that: The auxiliary agent includes 50 viscosity dimethyl silicone oil, 100 viscosity dimethyl silicone oil and dodecylamine, wherein: 50 viscosity dimethyl silicone oil accounts for 1% to 5% of the mass of the organic carrier, 100 viscosity dimethyl silicone oil accounts for 1% to 7% of the mass of the organic carrier, Dodecylamine accounts for 0.8% to 3% of the mass of the organic carrier.

5. The TOPCon front slurry organic carrier according to claim 1, characterized in that: The mass percentage of the resin is: Ethyl cellulose 0.6% to 3%, Cellulose acetate butyrate 0.8%~3.2%, Acrylic resin 2.5%~6%.

6. The TOPCon front slurry organic carrier according to claim 1, characterized in that: The thixotropic agent comprises polyamide wax, modified polyurea compound and phenoxyethanol, wherein: The mass percentage of the solvent is: Triethylene glycol butyl ether 25% to 30%, Dodecyl ester 15% to 25%, Diethylene glycol butyl ether acetate 25% to 35%, Benzyl benzoate 10%~20%.

7. The TOPCon front slurry organic carrier according to claim 3, characterized in that: The thixotropic agent comprises polyamide wax, modified polyurea compound and phenoxyethanol, wherein: The mass percentage of the thixotropic agent is: Polyamide wax 0.2%~0.8%, Modified polyurea compound 0.3% to 0.9%, Phenoxyethanol 0.2%~0.7%.

8. The TOPCon front slurry organic carrier according to claim 4, characterized in that: The auxiliary agent includes 50 viscosity dimethyl silicone oil, 100 viscosity dimethyl silicone oil and dodecylamine, wherein: The mass percentage of the auxiliary agent is: 50 viscosity dimethyl silicone oil 1% to 4%, 100 viscosity dimethyl silicone oil 1% to 5%, Dodecylamine 1%~3%.

9. The TOPCon front slurry according to claim 1, characterized in that: The addition amount of the organic carrier of the TOPCon front slurry is 8% to 12% of the total mass of the front slurry, and the purity of the silver powder is ≥99.9%.

10. The TOPCon front slurry organic carrier according to any one of claims 1 to 9, characterized in that: The application of the TOPCon front slurry organic carrier in the field of solar cell technology.

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