Solder paste, preparation method of solar cell module and solar cell module

Abstract

The present invention provides a solder paste, which comprises solder powder and a flux. The solder powder includes tin powder, lead powder and silver powder. In the solder powder, the mass fraction of the tin powder is 61.5% - 62.5%, the mass fraction of the lead powder is 35.5% - 36.5%, and the mass fraction of the silver powder is 1% - 3%. Among them, the solder paste is used for interconnecting solar cells. The solder paste in the present invention can improve the welding effect. The present invention also provides a preparation method of a solar cell module and a solar cell module.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and particularly to a solder paste, a preparation method of a solar cell module, and a solar cell module. Background Art

[0002] In the preparation process of a solar cell module, it is usually necessary to connect multiple solar cells with solder ribbons. However, for some types of solar cells, such as back-contact solar cells, since the positive and negative electrodes of the back-contact solar cells are made by screen printing and sintering, there is usually a height difference of 50 μm to 150 μm between the formed positive and negative fine grid lines and the portion to be connected. The conventional solder ribbon interconnection method is to connect multiple solar cells by welding the solder ribbon to the portion to be connected. However, due to the existence of the height difference between the fine grid line and the portion to be connected, it is difficult for the solder ribbon to fully contact the portion to be connected, which is not conducive to the welding between the solder ribbon and the portion to be connected, resulting in welding failure or an increase in contact resistance, affecting the power output of the solar cell.

[0003] To solve the problem of the height difference between the portion to be connected and the fine grid line, solder paste is usually printed on the portion to be connected at present. However, since the main component of the portion to be connected is silver, silver will dissolve in the solder paste at high temperatures, and the dissolution rate is faster at higher temperatures. The temperature used in the welding process is usually greater than 150 °C, and even reaches 350 °C. At such a high temperature, silver will quickly dissolve in the solder paste. At the same time, since the thickness of silver in the portion to be connected is usually only about 10 μm, silver will quickly dissolve completely in the solder paste, causing the portion to be connected to fall off, and further resulting in welding failure. Summary of the Invention

[0004] Based on this, it is necessary to provide a solder paste that can improve the welding effect.

[0005] In addition, it is also necessary to provide a preparation method of a solar cell module.

[0006] In addition, it is also necessary to provide a solar cell module including the above solder paste.

[0007] In addition, it is also necessary to provide a solar cell module prepared by the above preparation method.

[0008] At least one embodiment of the present invention provides a solder paste, which includes:

[0009] Solder powder, the solder powder includes tin powder, lead powder, and silver powder. In the solder powder, the mass fraction of tin powder is 61.5% - 62.5%, the mass fraction of lead powder is 35.5% - 36.5%, and the mass fraction of silver powder is 1% - 3%; and

[0010] Flux;

[0011] Among them, the solder paste is used for interconnecting solar cells.

[0012] In some embodiments, the flux includes an organic-inorganic combined activator, and the organic-inorganic combined activator includes an organic acid and an inorganic activator.

[0013] In some embodiments, the solder paste includes at least one of the following (1) to (2):

[0014] (1) The organic acid includes at least one of phthalic acid, sebacic acid, glutamic acid, lactic acid, and malonic acid;

[0015] (2) The inorganic activator includes ZnCl 2 and NH 4 Cl.

[0016] In some embodiments, the solder paste includes at least one of the following (3) to (4):

[0017] (3) The flux further includes a solvent, and the solvent includes at least one of ethylene glycol carbonate, diethylene glycol, and succinonitrile;

[0018] (4) The flux further includes a film-forming agent, and the film-forming agent includes at least one of rosin, (C 3 H 4 O 2 )n, and C 7 H 6 O 2 .

[0019] At least one embodiment of the present invention provides a method for manufacturing a solar cell module, including the following steps:

[0020] Providing a plurality of solar cells, one surface of the solar cell has a connection portion to be connected, and the material of the connection portion includes silver; and

[0021] Welding at least two of the solar cells using a solder strip and the above-mentioned solder paste.

[0022] In some embodiments, welding at least two of the solar cells using a solder strip and the above-mentioned solder paste includes the following steps:

[0023] Reflow soldering the solder paste on the connection portions to be connected of at least two of the solar cells to obtain at least two solar cell complexes; and

[0024] Connecting the solder paste of at least two of the solar cell complexes using the solder strip by means of thermal welding.

[0025] In some of these embodiments, the preparation method includes at least one of the following (5) to (7):

[0026] (5) The temperature of the reflow soldering is 120°C to 220°C;

[0027] (6) The temperature of the thermal soldering is 300°C to 350°C;

[0028] (7) The time of the thermal soldering is less than 10 s.

[0029] In some of these embodiments, the thermal soldering includes the following steps:

[0030] Laying at least two of the solar cell complexes; and

[0031] Pressing the solder tape onto the solder paste of at least two of the solar cell complexes for thermal soldering, so that at least two of the solar cell complexes are connected by the solder tape.

[0032] At least one embodiment of the present invention provides a solar cell module, which includes a plurality of solar cells, solder tapes, and the above-mentioned solder paste after curing, and at least two of the solar cells are interconnected by the solder tapes and the solder paste.

[0033] In some of these embodiments, both the positive electrode and the negative electrode of the solar cell are located on the same surface of the solar cell. One surface of the solar cell has grid lines and a connection part electrically connected to the grid lines, and the height of the connection part on the surface of the solar cell is less than the height of the grid lines on the surface of the solar cell, and the grid lines are distributed in a finger-like shape on the solar cell.

[0034] In some of these embodiments, one surface of the solar cell has grid lines and a connection part electrically connected to the grid lines, and the height of the connection part on the surface of the solar cell is less than the height of the grid lines on the surface of the solar cell, and the height of the solder paste located on the connection part is greater than the height difference between the connection part and the grid lines.

[0035] In some of these embodiments, the connection part includes at least one of a solder pad and a solder disc.

[0036] At least one embodiment of the present invention provides a solar cell module, which is prepared by using the above-mentioned preparation method.

[0037] The present invention provides a novel solder paste, and the solder paste is used for interconnecting solar cells. The solder paste in the present invention not only contains tin powder and lead powder, but also contains silver powder. Since the solder paste in the present invention contains silver powder, silver reaches a saturated concentration in the solder paste, thereby preventing silver in the to-be-connected part from dissolving into the solder paste during the soldering process, thus improving the soldering effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a flowchart for preparing a solar cell module provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0041] At least one embodiment of the present invention provides a solder paste, and the solder paste includes solder powder and a flux. Among them, the solder paste is used for interconnecting solar cells.

[0042] In one embodiment, the solder powder includes tin powder, lead powder, and silver powder. In one embodiment, in the solder powder, the mass fraction of tin powder is 61.5% - 62.5%, the mass fraction of lead powder is 35.5% - 36.5%, and the mass fraction of silver powder is 1% - 3%.

[0043] In one embodiment, the flux includes an activator, a solvent, and a film-forming agent.

[0044] In one embodiment, the activator includes an organic-inorganic combined activator. In one embodiment, the organic-inorganic combined activator includes an organic acid and an inorganic activator. In one embodiment, the organic acid includes at least one of phthalic acid, sebacic acid, glutamic acid, lactic acid, and malonic acid. In one embodiment, the inorganic activator includes ZnCl 2 and NH 4At least one of Cl. Wherein, the organic-inorganic combined activator can increase the activation time of the activator, and solve the problem of short activation time of the activator in the existing solder paste.

[0045] In one embodiment, the solvent includes at least one of ethylene glycol carbonate, diethylene glycol, and succinonitrile. Among them, the solvents in the present invention, such as ethylene glycol carbonate, diethylene glycol, and succinonitrile, have a higher boiling point than the conventional solvent system and a slower evaporation rate.

[0046] In one embodiment, the film-forming agent includes at least one of rosin, (C 3 H 4 O2)n, and C 7 H 6 O 2 Among them, n in (C 3 H 4 O2)n is a positive integer.

[0047] Please refer to Figure 1 , at least one embodiment of the present invention provides a method for manufacturing a solar cell module, including the following steps:

[0048] Step S11, providing a plurality of solar cells.

[0049] In one embodiment, one surface of the solar cell has grid lines and a connection part to be connected electrically connected to the grid lines. Among them, the height of the connection part on the surface of the solar cell is less than the height of the grid lines on the surface of the solar cell. That is, there is a height difference between the connection part and the grid lines. In one embodiment, the height difference between the connection part and the grid lines is 50μm to 150μm.

[0050] In one embodiment, the material of the connection part includes silver. In one embodiment, the connection part includes at least one of a solder pad and a solder disk.

[0051] In one embodiment, the solar cell can be a back-contact solar cell. Among them, the back-contact solar cell means that the positive electrode and the negative electrode of the solar cell are both distributed on one surface of the solar cell, that is, distributed on the back surface of the solar cell. In addition, the grid lines are distributed in a finger-like shape on the back-contact solar cell. Among them, the front surface of the back-contact solar cell has no obstruction, so the photoelectric conversion efficiency of the back-contact solar cell can be greatly improved.

[0052] Among them, the positive electrode of the back-contact solar cell includes the grid line of the positive electrode and the connection part to be connected, and the negative electrode of the back-contact solar cell includes the grid line of the negative electrode and the connection part to be connected. Among them, the positive electrode and the negative electrode of the back-contact solar cell are made by screen printing and sintering, so there is a height difference between the connection part to be connected and the grid line.

[0053] Step S12: Reflow solder the solder paste on the connection parts to be connected of at least two of the solar cells respectively to obtain at least two solar cell complexes.

[0054] Specifically, use a printing machine to print the above-mentioned solder paste on the connection parts to be connected of at least two of the solar cells respectively by means of stencil printing, and reflow solder the solder paste on the connection parts to be connected of at least two of the solar cells, so that the solder paste located on the connection part to be connected is fixedly connected to the connection part to be connected, and at least two of the solar cell complexes are obtained.

[0055] In one embodiment, the solar cell printed with the solder paste can be placed in a reflow oven for reflow soldering, so that the solder paste on the connection part to be connected sequentially undergoes the processes of preheating, activation, reflow and cooling, so that the solder paste is fixedly connected to the connection part to be connected, that is, tightly connected, and the solar cell complex is obtained.

[0056] Among them, the reflow soldering is to pre-form a certain bond between the solder paste located on the connection part to be connected and the connection part to be connected, so that the solder paste will not move and fall off during the movement in the subsequent processes, and the welding accuracy is improved.

[0057] In one embodiment, the temperature of the reflow soldering is 120°C to 220°C. That is, the temperature of the reflow oven is 120°C to 220°C. Specifically, the temperature of the reflow soldering can be 120°C, 140°C, 160°C, 180°C, 200°C or 220°C. Among them, since high temperature can promote the dissolution of silver, and the temperature of the reflow soldering in the present invention is relatively low, the dissolution and migration of silver in the connection part to be connected into the solder paste can be reduced.

[0058] Among them, printing the above-mentioned solder paste on the connection part to be connected can solve the problem of the height difference between the connection part to be connected and the grid line, so that the subsequent solder tape is in full contact with the connection point, which is beneficial to the welding between the solder tape and the connection point, prevents welding failure or an increase in contact resistance, and further is beneficial to the power output of the solar cell.

[0059] Among them, the height of the solder paste located on the to-be-connected part should be greater than the height difference between the to-be-connected part and the grid line, so that the subsequent solder ribbon can be in full contact with the solder paste to achieve a good welding effect.

[0060] Step S13: Connect the solder paste of at least two of the solar cell complexes with the solder ribbon by means of thermal welding.

[0061] Specifically, lay at least two of the solar cell complexes on the same plane, then use a pick-and-place machine to accurately place the solder ribbon on the solder paste of at least two of the solar cell complexes, and then press the solder ribbon onto the solder paste of at least two of the solar cell complexes through a screen pressing mechanism for thermal welding, so that the solder paste of at least two of the solar cell complexes is connected by the solder ribbon, thereby realizing the interconnection between at least two of the solar cells.

[0062] Compared with the prior art which usually uses a single welding method, that is, directly mounting the solder ribbon on the solder paste for reflow soldering after printing the solder paste on the solar cell, the solder ribbon often shifts during the welding process, making it difficult to ensure the welding accuracy. While the present invention uses a two-step welding method, that is, the first welding is reflow soldering and the second welding is thermal welding. Since the solder ribbon and the solar cell complex do not move during the welding process, the welding accuracy of the solder ribbon can be improved.

[0063] In one embodiment, the temperature of the thermal welding can be 300°C to 350°C. Specifically, the temperature of the thermal welding can be 300°C, 310°C, 320°C, 330°C, 340°C or 350°C.

[0064] In one embodiment, the time of the thermal welding is less than 10 s. Among them, compared with the reflow soldering in step S12, the thermal welding in step S13 has a higher temperature, but since the time of the thermal welding is short and is completed within a few seconds, it can minimize the dissolution and migration of silver in the to-be-connected part into the solder paste. In addition, since the time of the thermal welding is short, it can also prevent the heat-sensitive materials in the solar cell complex from failing due to heat, thereby improving the yield of the subsequent prepared solar cell module.

[0065] Among them, the flux in the solder paste can reduce the temperature of the thermal welding, thereby reducing the dissolution and migration of silver in the to-be-connected part into the solder paste, preventing welding failure, and thus improving the welding effect.

[0066] It should be noted that the present invention is not limited to connecting two solar cells, and multiple solar cells can also be connected to form a solar cell module. That is, the number of solar cells in the solar cell module can be not only two, but also multiple, such as three, four, etc.

[0067] At least one embodiment of the present invention provides a solar cell module, which includes a plurality of solar cells, solder ribbons, and the above-mentioned cured solder paste.

[0068] In one embodiment, one surface of the solar cell has grid lines and a connection part to be connected electrically connected to the grid lines. Among them, the height of the connection part to be connected on the surface of the solar cell is less than the height of the grid lines on the surface of the solar cell. That is, there is a height difference between the connection part to be connected and the grid lines. In one embodiment, the height difference between the connection part to be connected and the grid lines is 50 μm to 150 μm.

[0069] In one embodiment, the material of the connection part to be connected includes silver. In one embodiment, the connection part to be connected includes at least one of solder pads and solder discs.

[0070] In one embodiment, the solar cell can be a back-contact solar cell. Among them, the back-contact solar cell means that the positive electrode and the negative electrode of the solar cell are both distributed on one surface of the solar cell, that is, on the back surface of the solar cell. In addition, the grid lines are distributed in an interdigitated shape on the back-contact solar cell. Among them, the front surface of the back-contact solar cell is unobstructed, so the photoelectric conversion efficiency of the back-contact solar cell can be greatly improved.

[0071] Among them, the positive electrode of the back-contact solar cell includes the grid lines and the connection part to be connected of the positive electrode, and the negative electrode of the back-contact solar cell includes the grid lines and the connection part to be connected of the negative electrode. Among them, the positive electrode and the negative electrode of the back-contact solar cell are made by screen printing and sintering, so there is a height difference between the connection part to be connected and the grid lines.

[0072] Among them, the above-mentioned cured solder paste is on the connection part to be connected, and the height of the solder paste on the connection part to be connected is greater than the height difference between the connection part to be connected and the grid lines, so as to facilitate the connection between the solder paste on the connection part to be connected and the solder ribbon.

[0073] In one embodiment, the solder ribbon connects the solder paste on the connection part to be connected of at least two solar cells at the same time, so as to realize the interconnection of at least two solar cells.

[0074] To solve the problem of poor soldering between the solder tape and the part to be connected, the present invention adds a layer of solder paste as an intermediate conversion layer on the part to be connected, realizes the connection between the solder tape and the part to be connected through the solder paste, and makes the height of the solder paste located on the part to be connected greater than the height difference between the part to be connected and the grid line, so that the solder tape can fully contact the solder paste located on the part to be connected, achieving a good soldering effect.

[0075] At least one embodiment of the present invention provides a solar cell module, which is prepared by the above preparation method.

[0076] In one embodiment, the solar cell module can be a back-contact solar cell module.

[0077] The present invention provides a new type of solder paste and uses the solder paste for solar cell interconnection. The solder paste in the present invention not only contains tin powder and lead powder, but also contains silver powder. Since the solder paste in the present invention contains silver powder, silver reaches a saturated concentration in the solder paste, thereby preventing silver in the part to be connected from dissolving into the solder paste during the soldering process, thus improving the soldering effect.

[0078] In addition, organic acids or organic amines are usually used as activators in the existing solder paste. The characteristics of these activators are that the active time is short and the reaction ability is limited. And the solvent in the flux of the existing solder paste usually uses compounds of ethylene glycol type. This type of solvent has a low boiling point, which also shortens the action time of the flux. Therefore, the characteristics of the existing flux are suitable for soldering in a short time and are not suitable for soldering with a long duration, such as applications that require multiple soldering. Therefore, the present invention provides a new type of solder paste, that is, the above solder paste, which has a long action time, thereby improving the soldering effect.

[0079] The present invention is further described below through specific examples and comparative examples.

[0080] Example 1

[0081] (1) Provide two back-contact solar cells. Among them, one surface of the back-contact solar cell has grid lines and solder pads electrically connected to the grid lines. The height of the solder pads on the surface of the back-contact solar cell is less than the height of the grid lines on the surface of the back-contact solar cell, and the height difference between the solder pads and the grid lines is 50 μm. The material of the solder pads includes silver.

[0082] (2) Use a printing press to print solder paste on the pads of two back-contact solar cells respectively by means of stencil printing, and then place the two back-contact solar cells printed with solder paste in a reflow oven for reflow soldering, so that the solder paste located on the pads is fixedly connected to the pads, obtaining two solar cell complexes. Among them, the solder paste includes solder powder and flux. The solder powder includes tin powder, lead powder and silver powder. And in the solder powder, the mass fraction of tin powder is 62%, the mass fraction of lead powder is 36%, and the mass fraction of silver powder is 2%; the flux includes activator, solvent and film-forming agent, and the activator is phthalic acid and ZnCl 2 , the solvent is ethylene glycol carbonate, and the film-forming agent is rosin. Among them, the temperature of reflow soldering is 220°C.

[0083] (3) Lay the two back-contact solar cell complexes on the same plane, then use a pick-and-place machine to accurately install the solder tape on the solder paste of the two back-contact solar cell complexes, and then press the solder tape on the solder paste of the two back-contact solar cell complexes through a mesh pressing mechanism for soldering, so that the solder paste of the two back-contact solar cell complexes is connected through the solder tape, thereby realizing the interconnection of the two back-contact solar cells, obtaining a back-contact solar cell module. Among them, the temperature of thermal soldering is 300°C.

[0084] Comparative Example 1

[0085] (1) Provide two back-contact solar cells. Among them, one surface of the back-contact solar cell has grid lines and pads electrically connected to the grid lines. The height of the pads on the surface of the back-contact solar cell is less than the height of the grid lines on the surface of the back-contact solar cell, and the height difference between the pads and the grid lines is 50 μm. The material of the pads includes silver.

[0086] (2) Use a printing press to print solder paste on the pads of two back-contact solar cells respectively by means of stencil printing, obtaining two back-contact solar cell complexes. Among them, the solder paste includes solder powder and flux. The solder powder includes tin powder and lead powder. And in the solder powder, the mass fraction of tin powder is 63%, and the mass fraction of lead powder is 37%; the flux includes activator, solvent and film-forming agent, and the activator is phthalic acid, the solvent is ethylene glycol, and the film-forming agent is rosin.

[0087] (3) Lay the two back-contact solar cell complexes on the same plane, then use a pick-and-place machine to accurately install the pads on the solder paste in the two back-contact solar cell complexes, and perform reflow soldering on the two back-contact solar cell complexes and the solder tape, so that the solder paste of the two back-contact solar cell complexes is connected through the solder tape, thereby realizing the interconnection of the two back-contact solar cells, obtaining a back-contact solar cell module. Among them, the temperature of reflow soldering is 220°C.

[0088] Comparative Example 2

[0089] The steps of Comparative Example 2 are basically the same as those of Comparative Example 1, except that:

[0090] In step (3), the temperature of the reflow soldering is 350 °C.

[0091] Comparative Example 3

[0092] The steps of Comparative Example 3 are basically the same as those of Comparative Example 1, except that:

[0093] In step (2), the solder powder includes tin powder, lead powder and silver powder. In the solder powder, the mass fraction of the tin powder is 62%, the mass fraction of the lead powder is 36%, and the mass fraction of the silver powder is 2%; the activator is phthalic acid and ZnCl2, and the solvent is ethylene glycol carbonate;

[0094] In step (3), the temperature of the reflow soldering is 350 °C.

[0095] Comparative Example 4

[0096] The steps of Comparative Example 4 are basically the same as those of Example 1, except that:

[0097] In step (2), the solder powder only includes tin powder and lead powder. In the solder powder, the mass fraction of the tin powder is 63%, the mass fraction of the lead powder is 37%, and the activator is phthalic acid, and the solvent is ethylene glycol.

[0098] Comparative Example 5

[0099] The steps of Comparative Example 5 are basically the same as those of Example 1, except that:

[0100] In step (2), the solder powder only includes tin powder and lead powder. In the solder powder, the mass fraction of the tin powder is 63%, the mass fraction of the lead powder is 37%, and the activator is phthalic acid, and the solvent is ethylene glycol;

[0101] In step (3), the temperature of the thermal soldering is 350 °C.

[0102] The welding tensile force and the yield rate of the back-contact solar cell modules obtained in Example 1 and Comparative Examples 1 to 5 were respectively tested, and the test results are shown in Table 1 below.

[0103] Table 1 Preparation processes, welding tensile forces and yield rate test results of the back-contact solar cell modules in Example 1 and Comparative Examples 1 to 5

[0104]

[0105]

[0106] Among them, 62Sn36Pb2Ag in Example 1 of Table 1 above means that in the solder powder, the mass fraction of tin powder is 62%, the mass fraction of lead powder is 36%, and the mass fraction of silver powder is 2%. The specific meanings of 63Sn37Pb, 63Sn37Pb, 62Sn36Pb2Ag, 63Sn37Pb, and 63Sn37Pb in Comparative Examples 1 to 5 in Table 1 above can be referred to Example 1 and will not be elaborated here.

[0107] As can be seen from Table 1 above, the solder tapes in the back-contact solar cell modules prepared in Example 1 did not shift, while the solder tapes in the back-contact solar cell modules prepared in Comparative Examples 1 to 5 shifted. This indicates that compared with the back-contact solar cell modules prepared in Comparative Examples 1 to 5, the back-contact solar cell modules prepared in Example 1 have better welding accuracy. At the same time, as can also be seen from Table 1 above, the welding tensile force of the back-contact solar cell modules prepared in Example 1 is the largest, up to 1.3 N / mm, while the welding tensile forces of the back-contact solar cell modules prepared in Comparative Examples 1 to 5 are all smaller. In addition, as can also be seen from Table 1 above, the back-contact solar cell modules prepared in Example 1 are qualified, so the yield is relatively high, while the back-contact solar cell modules prepared in Comparative Examples 1 to 5 are all unqualified, so the yield is relatively low.

[0108] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0109] The above-described embodiments only express several implementation manners of the present invention, and the description is relatively specific and detailed, but it cannot be understood as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A solder paste, characterized in that, the solder paste comprises: solder powder, the solder powder comprises tin powder, lead powder and silver powder, in the solder powder, the mass fraction of tin powder is 61.5% - 62.5%, the mass fraction of lead powder is 35.5% - 36.5%, and the mass fraction of silver powder is 1% - 3%; and Flux; the flux includes an organic-inorganic combined activator, and the organic-inorganic combined activator includes an organic acid and an inorganic activator; the organic acid includes at least one of phthalic acid, sebacic acid, glutamic acid, lactic acid, and malonic acid; the inorganic activator includes at least one of ZnCl 2 and NH 4 Cl; the flux further includes a solvent, and the solvent includes at least one of ethylene glycol carbonate, diethylene glycol, and succinonitrile; wherein, the solder paste is used for interconnecting solar cells.

2. The solder paste according to any one of claims 1, characterized in that, The flux further includes a film-forming agent, and the film-forming agent includes at least one of rosin, (C 3 H 4 O 2 )n, and C 7 H 6 O 2 .

3. A method for manufacturing a solar cell module, characterized in that, comprises the following steps: providing a plurality of solar cells, one surface of the solar cell has a portion to be connected, and the material of the portion to be connected comprises silver; and using a solder strip and the solder paste according to any one of claims 1 to 2 to weld at least two of the solar cells.

4. The method for manufacturing a solar cell module according to claim 3, characterized in that, using a solder strip and the solder paste according to any one of claims 1 to 2 to weld at least two of the solar cells comprises the following steps: reflow soldering the solder paste on the portions to be connected of at least two of the solar cells respectively to obtain at least two solar cell complexes; and using the solder strip to connect the solder paste of at least two of the solar cell complexes by means of thermal welding.

5. The method for manufacturing a solar cell module according to claim 4, characterized in that, the manufacturing method comprises at least one of the following (1) to (3): (1) The temperature of the reflow soldering is 120°C - 220°C; (2) The temperature of the thermal welding is 300°C - 350°C; (3) The time of the thermal welding is less than 10 s.

6. The method for manufacturing a solar cell module according to claim 5, characterized in that, the thermal welding comprises the following steps: laying at least two of the solar cell complexes; and pressing the solder strip on the solder paste of at least two of the solar cell complexes for thermal welding so that at least two of the solar cell complexes are connected by the solder strip.

7. A solar cell module, characterized in that, the solar cell module comprises a plurality of solar cells, a solder strip and the solder paste according to any one of claims 1 to 2 after curing, and at least two of the solar cells are interconnected by the solder strip and the solder paste.

8. The solar cell module according to claim 7, characterized in that, the positive electrode and the negative electrode of the solar cell are both located on the same surface of the solar cell, one surface of the solar cell has grid lines and a portion to be connected electrically connected to the grid lines, and the height of the portion to be connected on the surface of the solar cell is less than the height of the grid lines on the surface of the solar cell, and the grid lines are distributed in a finger-like shape on the solar cell.

9. The solar cell module according to claim 7, characterized in that, One surface of the solar cell has grid lines and a connection part to be connected electrically to the grid lines, and the height of the connection part on the surface of the solar cell is less than the height of the grid lines on the surface of the solar cell, and the height of the solder paste located on the connection part is greater than the height difference between the connection part and the grid lines.

10. The solar cell module according to claim 8 or 9, characterized in that the connection part includes at least one of a solder pad and a pad.

11. A solar cell module, characterized in that the solar cell module is prepared by using the preparation method according to any one of claims 3 to 6.

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