High-wettability glass powder, preparation method thereof and BC battery conductive silver paste

Abstract

The invention provides high-wettability glass powder, a preparation method of the high-wettability glass powder and BC battery conductive silver paste, and belongs to the technical field of photovoltaic battery paste. The glass powder comprises the following components in parts by mass: 50-60 parts of a first component, wherein the first component is PbO and Bi2O3; 30 to 40 parts by mass of a second component, wherein the second component is TeO2 and SiO2; the third component is prepared from the following components in parts by mass: Li2CO3, Na2CO3 and K2CO3; and 0.1 to 5 parts by mass of a fourth component, wherein the fourth component is at least one of MoO3, In2O3, SeO2, WO3, Al2O3 and ZnO. The glass powder disclosed by the invention has good wettability, and the problems of high interface resistance and low filling factor caused by non-uniform thickness of a glass layer in the prior art are solved.

Description

Technical Field

[0001] This disclosure belongs to the field of photovoltaic cell paste technology, specifically relating to a highly wettable glass powder and its preparation method, and a conductive silver paste for BC cells. Background Technology

[0002] As the photovoltaic industry transitions from P-type to N-type cells, BC (back contact) technology, with its structural advantages, has become the core development direction for high-efficiency cells. BC cells place both positive and negative electrodes on the back, eliminating the 3%-5% shading from the metal grid lines on the front, thus increasing the utilization rate of incident photons to 97.3%. Currently, the average conversion efficiency of mass-produced BC cells has reached 27%, and the efficiency of mass-produced modules exceeds 24%. Mainstream bifacial double-glass modules can achieve a power output of 665W, 30W higher than traditional TOPCon modules. In the BC cell paste system, glass powder plays a crucial role, profoundly impacting cell performance. As a key component of the paste, glass powder plays multiple critical roles in the production and application of BC cells.

[0003] The wettability of glass powder is crucial to the electrode performance of BC batteries, directly determining the spreading effect of the liquid glass layer and the quality of the silver-silicon interface during sintering. However, current research mainly focuses on three aspects: First, composition control, such as adjusting the B2O3 to Ga2O3 ratio to 6:1 to ensure the passivation layer etching effect, stabilize the glass network, enhance acid resistance, and reduce corrosion cracks in the electroplating solution. Second, process parameter control, such as adjusting the sintering temperature and glass powder particle size, combined with polymeric dispersants to optimize rheology and prevent agglomeration. However, most current technologies in this area focus on the inherent flowability of the glass powder, with limited research on the uniformity and thickness of the glass layer at the silver-silicon interface after silver powder sintering. Summary of the Invention

[0004] This disclosure aims to at least solve one of the technical problems existing in the prior art, and to provide a glass powder with high wettability and its preparation method, as well as a conductive silver paste for BC batteries.

[0005] In one aspect, this disclosure provides a highly wettable glass powder, the glass powder comprising:

[0006] 50-60 parts by mass of the first component, wherein the first component is PbO and Bi2O3;

[0007] 30-40 parts by mass of the second component, wherein the second component is TeO2 and SiO2;

[0008] 0.1 to 15 parts by weight of a third component, wherein the third component is Li2CO3, Na2CO3 and K2CO3;

[0009] 0.1 to 5 parts by mass of a fourth component, wherein the fourth component is at least one of MoO3, In2O3, SeO2, WO3, Al2O3 and ZnO.

[0010] Optionally, the fourth component is at least one of MoO3, In2O3, WO3 and Al2O3.

[0011] Optionally, in the first component, the content ratio of PbO to Bi2O3 is (1-4):(1-4).

[0012] Optionally, in the second component, the content ratio of TeO2 to SiO2 is 30:(5-6).

[0013] Optionally, in the third component, the content ratio of Li2CO3, Na2CO3 and K2CO3 is (1-2):(1-2):(1-2).

[0014] In another aspect of this disclosure, a method for preparing the highly wettable glass powder described above is provided, the method comprising:

[0015] The first, second, third, and fourth components are mixed and stirred evenly in a certain proportion, and then smelted and quenched. The cooled material is then crushed and ground to obtain semi-finished glass powder with different particle sizes.

[0016] The semi-finished glass powder is crushed and ground to obtain finished glass powder.

[0017] Optionally, the melting process is carried out at a temperature of 950–1100°C for 25–35 minutes.

[0018] The D50 of the semi-finished glass powder is 20-45 μm, and the D50 of the finished glass powder is 0.8-1.4 μm.

[0019] In another aspect of this disclosure, a conductive silver paste for BC batteries is provided, the conductive silver paste for BC batteries comprising:

[0020] 80-92 parts by weight of silver powder;

[0021] 7.5 to 14 parts by weight of organic adhesive;

[0022] 1.5 to 4.5 parts by weight of glass powder, wherein the glass powder is the glass powder described above.

[0023] Optionally, the BC battery conductive silver paste further includes 0.5 to 5 parts by weight of nano-silver powder; and / or,

[0024] The conductive silver paste for the BC battery also includes 0.1 to 5 parts by weight of metal oxide.

[0025] Optionally, the metal oxide is selected from at least one of molybdenum oxide, indium oxide, tungsten oxide, lead oxide, antimony oxide, and selenium oxide;

[0026] The D50 of the metal oxide is 0.5–1.5 μm.

[0027] This disclosure presents a highly wettable glass powder and its preparation method, as well as a conductive silver paste for BC batteries. The glass powder comprises: 50-60 parts by mass of a first component, wherein the first component is PbO and Bi₂O₃; 30-40 parts by mass of a second component, wherein the second component is TeO₂ and SiO₂; 0.1-15 parts by mass of a third component, wherein the third component is Li₂CO₃, Na₂CO₃, and K₂CO₃; and 0.1-5 parts by mass of a fourth component, wherein the fourth component is at least one of MoO₃, In₂O₃, SeO₂, WO₃, Al₂O₃, and ZnO. This disclosure provides a technical solution that can intuitively and effectively demonstrate the influence of glass powder wettability on the silver-silicon interface quality, enabling a more accurate understanding of the impact of glass wettability on the paste, thereby improving the paste's flux response (FF) and overall efficiency. Attached Figure Description

[0028] Figure 1 A flowchart illustrating a method for preparing highly wettable glass powder according to a specific embodiment of this disclosure;

[0029] Figure 2 This is a schematic diagram of the morphology of the glass layer at the silver-silicon interface in Embodiment 1 of this disclosure;

[0030] Figure 3 This is a schematic diagram of the morphology of the glass layer at the silver-silicon interface in Embodiment 2 of this disclosure;

[0031] Figure 4 This is a schematic diagram of the morphology of the glass layer at the silver-silicon interface in Embodiment 3 of this disclosure;

[0032] Figure 5 This is a schematic diagram of the morphology of the glass layer at the silver-silicon interface in Embodiment 4 of this disclosure;

[0033] Figure 6 This is a schematic diagram of the morphology of the glass layer at the silver-silicon interface in Embodiment 5 of this disclosure;

[0034] Figure 7 This is a schematic diagram of the morphology of the glass layer at the silver-silicon interface in Embodiment 6 of this disclosure;

[0035] Figure 8 This is a schematic diagram of the morphology of the glass layer at the silver-silicon interface in Embodiment 7 of this disclosure;

[0036] Figure 9This is a schematic diagram of the morphology of the glass layer at the silver-silicon interface in Embodiment 8 of this disclosure;

[0037] Figure 10 This is a schematic diagram of the morphology of the glass layer at the silver-silicon interface in Embodiment 9 of this disclosure;

[0038] Figure 11 This is a schematic diagram of the morphology of the glass layer at the silver-silicon interface in Embodiment 10 of this disclosure;

[0039] Figure 12 This is a schematic diagram of the morphology of the glass layer at the silver-silicon interface in Embodiment 11 of this disclosure;

[0040] Figure 13 This is a schematic diagram of the morphology of the glass layer at the silver-silicon interface in Embodiment 12 of this disclosure;

[0041] Figure 14 This is a schematic diagram of the morphology of the glass layer at the silver-silicon interface in Comparative Example 1 of this disclosure.

[0042] Figure 15 This is a schematic diagram of the morphology of the glass layer at the silver-silicon interface in Comparative Example 2 of this disclosure. Detailed Implementation

[0043] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this disclosure and represent a part of the embodiments of this disclosure, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the protection scope of this disclosure.

[0044] In one aspect of this disclosure, a highly wettable glass powder is provided, comprising: 50-60 parts by mass of a first component, wherein the first component is PbO and Bi2O3; 30-40 parts by mass of a second component, wherein the second component is TeO2 and SiO2; 0.1-15 parts by mass of a third component, wherein the third component is Li2CO3, Na2CO3 and K2CO3; and 0.1-5 parts by mass of a fourth component, wherein the fourth component is at least one of MoO3, In2O3, SeO2, WO3, Al2O3 and ZnO.

[0045] This embodiment innovatively proposes a highly wettable glass powder based on the influence of glass powder wettability on the quality of the silver-silicon interface. The glass powder comprises four components, which work synergistically to form a glass powder with good wettability, resulting in a thinner and more uniformly distributed glass layer at the silver-silicon interface after sintering, thereby improving electrical performance and battery efficiency.

[0046] In some preferred embodiments, the content ratio of PbO to Bi2O3 in the first component is (1-4):(1-4), for example, other ratios such as 1:4 or 4:1 are preferred.

[0047] It should be understood that when the PbO content in the first component is high, for example, when the ratio of PbO to Bi2O3 is 4:1, high-lead glass powder is formed; when the Bi2O3 content in the first component is high, for example, when the ratio of PbO to Bi2O3 is 1:4, high-bismuth lead glass powder is formed.

[0048] As a further preferred embodiment, the PbO in the first component can reduce the surface tension of the glass and enhance its interfacial contact area with the silver powder and silicon substrate, thereby improving the quality of the silver-silicon interface. This helps to reduce contact resistance and improve the fill factor (FF) and photoelectric conversion efficiency (Eta) of the cell.

[0049] As a further preferred option, in the first component, Bi2O3 can significantly reduce the surface tension of the glass melt, enhance its interfacial contact depth with silver powder and silicon substrate, further improve the wetting ability of glass powder on silver powder and silicon substrate, thereby optimizing the contact quality of the silver-silicon interface.

[0050] In some other preferred embodiments, the content ratio of TeO2 to SiO2 in the second component is 30:(5-6), for example, 30:5 or 30:6 is preferred.

[0051] As a further preferred option, in the second component, TeO2 differs from conventional low-melting-point oxides. While reducing the surface tension of the glass, it can form a chain-like flexible surface layer. This surface layer can adapt to the micro-undulations of the solid surface and avoid air trapping at the interface to form a "non-wetting zone", thus enhancing the wetting effect from the perspective of structural adaptability.

[0052] As a further preferred option, in the second component, SiO2 serves as a glass network forging body, providing structural stability, preventing glass phase separation, and ensuring interface uniformity after sintering.

[0053] In some other preferred embodiments, the content ratio of Li2CO3, Na2CO3 and K2CO3 in the third component is (1-2):(1-2):(1-2), for example, 1:1:1 or 1:1:2 is preferred.

[0054] As a further preferred embodiment, in the third component, the aforementioned component is able to provide Li + Na + K + Ions reduce melt viscosity, promote low-temperature flow, regulate the coefficient of thermal expansion, and reduce interfacial stress.

[0055] In other preferred embodiments, the fourth component may preferably be at least one of MoO3, In2O3, WO3 and Al2O3.

[0056] As a further preferred option, in the fourth component, MoO3, due to its low melting point, is incorporated into the glass. This not only reduces melt flow resistance by disrupting the dense Si-O network, but also replaces the highly polar Si-O bonds on the surface with weakly polar Mo=O bonds. This dual effect leads to a synergistic decrease in glass surface tension and viscosity, promoting efficient liquid spreading on the solid surface. Furthermore, MoO3 can reduce the high-temperature contact angle of the glass.

[0057] As a further preferred option, in the fourth component, In2O3 utilizes In... 3+ In₂O₃'s unique ionic radius and charge properties allow it to regulate ion distribution in glass systems to optimize melt structure. Simultaneously, by improving charge matching at the solid-liquid interface, it weakens interfacial repulsion, indirectly reducing interfacial tension and enhancing wettability. Furthermore, In₂O₃ can reduce the high-temperature contact angle of glass.

[0058] As a further preferred option, in the fourth component, WO3 significantly reduces the melting temperature by forming a eutectic with other oxides in the glass, thereby reducing the viscous resistance of the melt at high temperatures. At the same time, it utilizes the weak polarity of the W=O bond to dilute the surface polarity, thus promoting the spread and wetting of the glass liquid on the solid surface and improving the uniformity of the glass layer interface.

[0059] As a further preferred option, in the fourth component, Al2O3 flexibly switches its network role according to the alkali metal content in the glass, with the core being Al... 3+ The directional exchange of cations with the solid surface forms a stable "Al-O-solid" chemical bond, which reduces the solid-liquid interfacial tension and enhances the adsorption capacity of the glass surface for the solid, thereby improving wettability in both directions and improving the uniformity of the glass layer interface.

[0060] It should be noted that the glass powder in this embodiment can be either high-bismuth glass powder or high-lead glass powder, and the content of PbO and Bi2O3 can be adjusted according to actual needs. This yields the corresponding high-bismuth glass powder and high-lead glass powder.

[0061] like Figure 1 As shown, one aspect of this disclosure provides a method S100 for preparing the highly wettable glass powder described above, specifically including the following steps S110 to S120:

[0062] S110. The first component, the second component, the third component and the fourth component are mixed and stirred evenly in a certain proportion, and then smelted and quenched. The cooled material is then crushed and ground to obtain semi-finished glass powder with different particle sizes.

[0063] It should be noted that the specific components and contents of the first, second, third and fourth components in step S110 can be referred to the previous description and will not be repeated here.

[0064] In step S110, the melting temperature is 950–1100°C and the time is 25–35 min.

[0065] In step S110, the D50 of the semi-finished glass powder is 20-45 μm.

[0066] As a further preferred option, when the semi-finished glass powder is a high tellurium glass powder semi-finished product, its D50 is 20-40μm.

[0067] As a further preferred option, the semi-finished glass powder is a high-lead glass powder semi-finished product, and its D50 is 25-45μm.

[0068] S120. The semi-finished glass powder is crushed and ground to obtain the finished glass powder.

[0069] Specifically, the semi-finished glass powder is crushed and ground using an air jet mill until the powder reaches the target particle size. When the finished glass powder is high tellurium glass powder, its final glass powder D50 is 0.9-1.4μm, and when the finished glass powder is high lead glass powder, its final glass powder D50 is 0.8-1.2μm, thereby obtaining high bismuth glass powder and high lead glass powder respectively.

[0070] In another aspect of this disclosure, a conductive silver paste for BC batteries is provided, comprising: 80 to 92 parts by weight of silver powder; 7.5 to 14 parts by weight of organic binder; and 1.5 to 4.5 parts by weight of glass powder, wherein the glass powder is the glass powder described above, and the specific composition can be referred to the above description.

[0071] In some preferred embodiments, the silver powder is at least one of spherical silver powder and microcrystalline silver powder, with an average particle size of 0.6 to 2.5 μm.

[0072] In some other preferred embodiments, 0.5 to 5 parts by weight of nano-silver powder, with an average particle size of 200 to 700 nm, may be added to the conductive silver paste component.

[0073] In some other preferred embodiments, the conductive silver paste further includes 0.1 to 5 parts by weight of a metal oxide.

[0074] As a further preferred embodiment, the metal oxide is selected from at least one of molybdenum oxide, indium oxide, tungsten oxide, lead oxide, antimony oxide, and selenium oxide, and its D50 is 0.5 to 1.5 μm.

[0075] In some other preferred embodiments, the components of the organic adhesive include organic solvents, adhesive resins, and organic additives.

[0076] The peak sintering temperature range of the silver paste prepared in this embodiment is 800–820°C.

[0077] The following will further illustrate the highly wettable glass powder and its preparation method with specific embodiments:

[0078] Example 1

[0079] The glass powder formulation of this example is shown in Table 1, comprising 40 parts by mass of PbO, 10 parts by mass of Bi2O3, 30 parts by mass of TeO2, 6 parts by mass of SiO2, 2.5 parts by mass of Li2CO3, 2.5 parts by mass of Na2CO3, 5 parts by mass of K2CO3, and 4 parts by mass of MoO3.

[0080] Furthermore, the silver paste composition is as follows: 88.5 parts by weight of silver powder; 8 parts by weight of organic binder; and 3.5 parts by weight of the glass powder prepared above.

[0081] Furthermore, to prepare conductive silver paste for P-region BC cells, the glass powder addition was set at 3.5 wt% to control the silver paste performance. A screen printing process was used to precisely coat the prepared silver paste onto designated areas of the P-region BC cell, ensuring the integrity and consistency of the electrode pattern. The printed cells were then placed in a sintering furnace for high-temperature treatment, with the peak sintering temperature controlled at 820℃. A gradient heating and holding process was used to achieve good ohmic contact between the silver paste and the cell. After sintering, current-voltage (IV) characteristic tests were conducted on the cells, focusing on collecting and analyzing four core performance parameters: open-circuit voltage (Voc), series resistance (Rs), fill factor (FF), and photoelectric conversion efficiency (Eta). The test results are detailed below. Figure 2 As shown in Table 2.

[0082] Example 2

[0083] The glass powder formulation of this example is shown in Table 1, comprising 40 parts by mass of PbO, 10 parts by mass of Bi2O3, 30 parts by mass of TeO2, 6 parts by mass of SiO2, 2.5 parts by mass of Li2CO3, 2.5 parts by mass of Na2CO3, 5 parts by mass of K2CO3, and 4 parts by mass of SeO2.

[0084] The silver paste formulation in this example is the same as in Example 1. The specific test results for the solar cells are as follows: Figure 3 As shown in Table 2.

[0085] Example 3

[0086] The glass powder formulation in this example is shown in Table 1, comprising 40 parts by mass of PbO, 10 parts by mass of Bi2O3, 30 parts by mass of TeO2, 6 parts by mass of SiO2, 2.5 parts by mass of Li2CO3, 2.5 parts by mass of Na2CO3, 5 parts by mass of K2CO3, and 4 parts by mass of WO3.

[0087] The silver paste formulation in this example is the same as in Example 1. The specific test results for the solar cells are as follows: Figure 4 As shown in Table 2.

[0088] Example 4

[0089] The glass powder formulation of this example is shown in Table 1, comprising 40 parts by mass of PbO, 10 parts by mass of Bi2O3, 30 parts by mass of TeO2, 6 parts by mass of SiO2, 2.5 parts by mass of Li2CO3, 2.5 parts by mass of Na2CO3, 5 parts by mass of K2CO3, and 4 parts by mass of In2O3.

[0090] The silver paste formulation in this example is the same as in Example 1. The specific test results for the solar cells are as follows: Figure 5 As shown in Table 2.

[0091] Example 5

[0092] The glass powder formulation of this example is shown in Table 1, comprising 40 parts by mass of PbO, 10 parts by mass of Bi2O3, 30 parts by mass of TeO2, 6 parts by mass of SiO2, 2.5 parts by mass of Li2CO3, 2.5 parts by mass of Na2CO3, 5 parts by mass of K2CO3, and 4 parts by mass of Al2O3.

[0093] The silver paste formulation in this example is the same as in Example 1. The specific test results for the solar cells are as follows: Figure 6 As shown in Table 2.

[0094] Example 6

[0095] The glass powder formulation of this example is shown in Table 1, comprising 40 parts by mass of PbO, 10 parts by mass of Bi2O3, 30 parts by mass of TeO2, 6 parts by mass of SiO2, 2.5 parts by mass of Li2CO3, 2.5 parts by mass of Na2CO3, 5 parts by mass of K2CO3, 2 parts by mass of MoO3, and 2 parts by mass of WO3.

[0096] The silver paste formulation in this example is the same as in Example 1. The specific test results for the solar cells are as follows: Figure 7 As shown in Table 2.

[0097] Example 7

[0098] The glass powder formulation of this example is shown in Table 1, comprising 10 parts by mass of PbO, 40 parts by mass of Bi2O3, 30 parts by mass of TeO2, 5 parts by mass of SiO2, 5 parts by mass of Li2CO3, 5 parts by mass of Na2CO3 and 5 parts by mass of K2CO3, and 4 parts by mass of MoO3.

[0099] The silver paste formulation in this example is the same as in Example 1. The specific test results for the solar cells are as follows: Figure 8 As shown in Table 2.

[0100] Example 8

[0101] The glass powder formulation of this example is shown in Table 1, comprising 10 parts by mass of PbO, 40 parts by mass of Bi2O3, 30 parts by mass of TeO2, 5 parts by mass of SiO2, 5 parts by mass of Li2CO3, 5 parts by mass of Na2CO3 and 5 parts by mass of K2CO3, and 4 parts by mass of SeO2.

[0102] The silver paste formulation in this example is the same as in Example 1. The specific test results for the solar cells are as follows: Figure 9 As shown in Table 2.

[0103] Example 9

[0104] The glass powder formulation in this example is shown in Table 1, comprising 10 parts by mass of PbO, 40 parts by mass of Bi2O3, 30 parts by mass of TeO2, 5 parts by mass of SiO2, 5 parts by mass of Li2CO3, 5 parts by mass of Na2CO3 and 5 parts by mass of K2CO3, and 4 parts by mass of WO3.

[0105] The silver paste formulation in this example is the same as in Example 1. The specific test results for the solar cells are as follows: Figure 10 As shown in Table 2.

[0106] Example 10

[0107] The glass powder formulation of this example is shown in Table 1, comprising 10 parts by mass of PbO, 40 parts by mass of Bi2O3, 30 parts by mass of TeO2, 5 parts by mass of SiO2, 5 parts by mass of Li2CO3, 5 parts by mass of Na2CO3 and 5 parts by mass of K2CO3, and 4 parts by mass of In2O3.

[0108] The silver paste formulation in this example is the same as in Example 1. The specific test results for the solar cells are as follows: Figure 11 As shown in Table 2.

[0109] Example 11

[0110] The glass powder formulation of this example is shown in Table 1, comprising 10 parts by mass of PbO, 40 parts by mass of Bi2O3, 30 parts by mass of TeO2, 5 parts by mass of SiO2, 5 parts by mass of Li2CO3, 5 parts by mass of Na2CO3 and 5 parts by mass of K2CO3, and 4 parts by mass of Al2O3.

[0111] The silver paste formulation in this example is the same as in Example 1. The specific test results for the solar cells are as follows: Figure 12 As shown in Table 2.

[0112] Example 12

[0113] The glass powder formulation in this example is shown in Table 1, comprising 10 parts by mass of PbO, 40 parts by mass of Bi2O3, 30 parts by mass of TeO2, 5 parts by mass of SiO2, 5 parts by mass of Li2CO3, 5 parts by mass of Na2CO3 and 5 parts by mass of K2CO3, 2 parts by mass of MoO3 and 2 parts by mass of WO3.

[0114] The silver paste formulation in this example is the same as in Example 1. The specific test results for the solar cells are as follows: Figure 13 As shown in Table 2.

[0115] Comparative Example 1

[0116] The glass powder formulation of this example is shown in Table 1, comprising 10 parts by mass of PbO, 42 parts by mass of Bi2O3, 31 parts by mass of TeO2, 6 parts by mass of SiO2, 3 parts by mass of Li2CO3, 3 parts by mass of Na2CO3 and 5 parts by mass of K2CO3.

[0117] The silver paste formulation in this example is the same as in Example 1. The specific test results for the solar cells are as follows: Figure 14 As shown in Table 2.

[0118] Comparative Example 2

[0119] The glass powder formulation in this example is shown in Table 1, comprising 10 parts by mass of PbO, 40 parts by mass of Bi2O3, 30 parts by mass of TeO2, 5 parts by mass of SiO2, 5 parts by mass of Li2CO3, 5 parts by mass of Na2CO3 and 5 parts by mass of K2CO3.

[0120] The silver paste formulation in this example is the same as in Example 1. The specific test results for the solar cells are as follows: Figure 15 As shown in Table 2.

[0121] In summary, based on the various embodiments and comparative examples, it can be seen that the glass powder in Examples 1-6 is high-lead glass powder, and the glass powder in Examples 7-12 is high-bismuth glass powder. Regardless of whether it is high-bismuth or high-lead glass powder, the performance of each embodiment is improved. Specifically, the efficiency, on-state voltage, current, filling power, and resistance of Examples 6 and 12 are 25.23, 716.3, 16.211, 81.01, 1.04 and 25.2, 706.4, 16.15, 80.9, 1.05, respectively. It is particularly noteworthy that both high-bismuth and high-lead glass powders show a significant improvement in filling power compared to the comparative examples. Furthermore, scanning electron microscopy (SEM) reveals the uniformity and thickness of the glass layer at the silver-silicon interface after sintering the silver powder in each embodiment. The glass layer at the interface in Examples 6 and 12 is both thin and uniform, greatly improving the quality of the silver-silicon interface.

[0122] In summary, combining Figures 2-15 The morphology of the silver-silicon interface glass layer given shows that the glass layer thickness in Examples 1-12 is uniform, without pores or cracks, and the liquid glass completely covers the silver-silicon interface, forming a dense transition layer, reducing interface defects, and the thickness of the interface glass layer is small. In contrast, the glass layer thickness in Comparative Examples 1 and 2 is uneven, and the interface glass layer is thicker, with local agglomeration and pores, and incompletely spread areas at the interface, resulting in discontinuous charge transport paths.

[0123] Table 1 Glass powder formulations for each embodiment and comparative example.

[0124]

[0125] Table 2 Test results for each embodiment and comparative example

[0126]

[0127]

[0128] This disclosure proposes a high-wetting glass powder and its preparation method, as well as a conductive silver paste for BC batteries. Compared with the prior art, it has the following beneficial effects: By optimizing the composition of the glass powder and adding components such as MoO3, In2O3, and WO3, the contact angle of the glass melt at high temperature is significantly reduced, the liquid glass layer can be uniformly spread on the silver-silicon interface, reducing pores and defects, and reducing the thickness of the interface glass layer, thus forming a thinner and more uniform silver-silicon interface glass layer.

[0129] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A glass powder having high wettability, characterized by, The glass powder comprises: 50-60 parts by mass of a first component, the first component being PbO and Bi2O3; 30-40 parts by mass of a second component, the second component being TeO2 and SiO2; 0.1-15 parts by mass of a third component, the third component being Li2CO3, Na2CO3 and K2CO3; 0.1-5 parts by mass of a fourth component, the fourth component being at least one of MoO3, In2O3, SeO2, WO3, Al2O3 and ZnO.

2. The glass powder of high wettability according to claim 1, characterized in that, The fourth component is at least one of MoO3, In2O3, WO3 and Al2O3.

3. The glass powder of high wettability according to claim 1, characterized by In the first component, the content ratio of PbO and Bi2O3 is (1-4):(1-4).

4. The glass powder of claim 1, wherein, In the second component, the content ratio of TeO2 and SiO2 is 30:(5-6).

5. The highly wettable glass powder of claim 1, wherein, In the third component, the content ratio of Li2CO3, Na2CO3 and K2CO3 is (1-2):(1-2):(1-2).

6. A method of producing a glass powder with high wettability as claimed in any one of claims 1 to 5, characterized in that, The method comprises: mixing and stirring the first component, the second component, the third component and the fourth component in a certain ratio, then performing melting treatment and quenching cooling treatment, and performing crushing and grinding treatment on the obtained material after cooling to obtain semi-finished glass powder of different particle sizes; performing crushing and grinding treatment on the semi-finished glass powder to obtain finished glass powder.

7. The method of claim 6, wherein, The temperature of the melting treatment is 950-1100℃, and the time is 25-35 min; The D50 of the semi-finished glass powder is 20-45μm, and the D50 of the finished glass powder is 0.8-1.4μm.

8. A BC battery conductive silver paste, characterized by, The BC battery conductive silver paste comprises: 80-92 parts by mass of silver powder; 7.5-14 parts by mass of organic binder; 1.5-4.5 parts by mass of glass powder, the glass powder being the glass powder according to any one of claims 1-5.

9. The BC battery conductive silver paste of claim 8, wherein, The BC battery conductive silver paste further comprises 0.5-5 parts by mass of nano silver powder; and / or, The BC battery conductive silver paste further comprises 0.1-5 parts by mass of metal oxide.

10. The BC battery conductive silver paste of claim 9, wherein, The metal oxide is selected from at least one of molybdenum oxide, indium oxide, tungsten oxide, lead oxide, antimony oxide and selenium oxide; The D50 of the metal oxide is 0.5-1.5μm.

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