Preparation method of solar cell, solar cell and selective light processing equipment

Abstract

The invention provides a preparation method of a solar cell, the solar cell and selective light processing equipment, and relates to the technical field of solar cell preparation. According to the preparation method of the solar cell, a cell structure is provided, and the cell structure comprises a substrate and functional layers located on the two sides of the substrate; the battery structure comprises a first surface and a second surface; printing conductive paste on the first surface of the battery structure; performing selective light treatment on the conductive slurry on the first surface by using a light treatment unit; and carrying out curing treatment on the cell structure after selective light treatment. In the preparation method of the solar cell, the selective light treatment is firstly performed on the conductive slurry and then the curing treatment is performed, the selective light treatment can improve the line resistance of the conductive slurry, and the curing treatment can improve the contact resistance between the electrode and the functional layer; therefore, the performance of the solar cell can be improved by performing selective light treatment and then curing treatment on the conductive paste.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cell preparation, and particularly to a method for preparing a solar cell, a solar cell, and a selective light treatment device. Background Art

[0002] During the preparation of a solar cell, an electrode is obtained by printing a conductive paste above a transparent conductive layer. After the conductive paste is printed, it is necessary to perform a curing treatment on the conductive paste to form an electrode. In the prior art, thermal curing is mostly used. If the conductive paste of a cell is to be cured, a relatively high temperature is required, and the temperature has a great influence on the performance of the non-paste area. When the curing temperature is relatively low, the curing effect is poor, the line resistance of the cured paste is relatively large, and the paste and the transparent conductive layer cannot form good contact, resulting in poor cell performance. In addition, when the curing temperature is relatively high, the film layer in the non-paste area is damaged greatly. For low-temperature solar cells, such as heterojunction solar cells, too high a temperature will damage the performance of the passivation layer in the heterojunction solar cell, thereby affecting the overall passivation effect of the cell and resulting in a decrease in cell efficiency. Therefore, there is an urgent need for a method for preparing a solar cell that can cure the conductive paste, obtain a relatively low line resistance and good contact, and control the temperature in the non-paste area below a predetermined temperature. Summary of the Invention

[0003] An object of a first aspect of the present invention is to provide a method for preparing a solar cell, which solves the problem of poor performance of a cell caused by curing treatment in the prior art.

[0004] An object of a second aspect of the present invention is to provide a solar cell.

[0005] An object of a third aspect of the present invention is to provide a selective light treatment device.

[0006] In particular, the present invention provides a method for preparing a solar cell, including:

[0007] providing a cell structure, where the cell structure includes a substrate and functional layers on both sides of the substrate; the cell structure includes a first surface and a second surface;

[0008] printing a conductive paste on the first surface of the cell structure;

[0009] performing selective light treatment on the conductive paste on the first surface by using a light treatment unit;

[0010] performing a curing treatment on the cell structure after the selective light treatment.

[0011] Optionally, after performing selective light treatment on the conductive paste on the first surface by using a light treatment unit, it further includes:

[0012] Print a conductive paste on the second surface of the battery structure;

[0013] Use a light processing unit to perform selective light processing on the conductive paste on the second surface.

[0014] Optionally, when using the light processing unit to perform selective light processing on the conductive paste on the first surface and the second surface, the temperature of the paste area is higher than that of the non-paste area.

[0015] Optionally, using the light processing unit to perform selective light processing on the conductive paste on the first surface specifically includes: on the side where the second surface of the battery structure is located, using the light processing unit to perform selective light processing on the conductive paste on the first surface; and / or,

[0016] Using the light processing unit to perform selective light processing on the conductive paste on the second surface specifically includes: on the side where the first surface of the battery structure is located, using the light processing unit to perform selective light processing on the conductive paste on the second surface.

[0017] Optionally, the temperature difference between the paste area and the non-paste area is between 20 - 200 °C.

[0018] Optionally, during the selective light processing, the temperature of the non-paste area is less than 250 °C.

[0019] Optionally, after printing the conductive paste and before performing the selective light processing, it further includes;

[0020] Dry the conductive paste.

[0021] Optionally, print a conductive paste on the first surface of the battery structure; on the side where the second surface of the battery structure is located, using the light processing unit to perform selective light processing on the conductive paste on the first surface specifically includes:

[0022] Print a first conductive paste on the first surface of the battery structure and perform drying treatment;

[0023] Print a second conductive paste on the first surface of the battery structure and perform drying treatment,

[0024] On the side where the second surface of the battery structure is located, use the light processing unit to perform selective light processing on the first conductive paste and the second conductive paste on the first surface.

[0025] Optionally, the first conductive paste is the main grid line paste and the second conductive paste is the sub-grid line paste, or the first conductive paste is the sub-grid line paste and the second conductive paste is the main grid line paste.

[0026] Optionally, the main gate line paste and the sub-gate line paste have different conductivity.

[0027] Optionally, the functional layer includes a transparent conductive layer;

[0028] After forming the transparent conductive layer and before printing the conductive paste, it further includes:

[0029] Annealing the battery structure; wherein, the conditions for annealing are: the temperature is 50 - 250 °C, and the time is 5 - 25 min.

[0030] Optionally, the conductive paste is selected from one of copper paste, silver paste, and silver-coated copper paste, and when the conductive paste is silver-coated copper paste, the silver content in the silver-coated copper paste is less than 30%.

[0031] Optionally, the light source of the light treatment unit is at least one of a lamp light source or a laser light source.

[0032] Optionally, the lamp light source includes a halogen lamp and a filter; the filter is used to filter the light of the halogen lamp to form light with a predetermined wavelength, and the predetermined wavelength is 1000 nm - 2500 nm.

[0033] Optionally, the laser light source is selected from one or more of a deep ultraviolet laser light source, a visible light laser light source, a near-infrared laser light source, and a mid-infrared laser light source.

[0034] Optionally, the laser light source is a CO2 laser light source.

[0035] Optionally, the step of curing the battery structure after selective light treatment includes:

[0036] Placing the battery structure after selective light treatment in a curing furnace for curing and sintering, and irradiating the battery structure with an LED lamp;

[0037] Wherein, the conditions for curing and sintering are: the temperature is 30 °C - 230 °C, and the time is 0 - 30 min.

[0038] In particular, the present invention also provides a solar cell prepared by the above-mentioned preparation method of the solar cell; wherein, the cell includes at least one of an HJT cell, an xBC cell, and a perovskite / silicon heterojunction cell.

[0039] In particular, the present invention also provides a selective light treatment device applied to the above-mentioned preparation method of the solar cell, and the selective light treatment device includes:

[0040] A transport mechanism for transporting solar cells to be selectively light - processed;

[0041] A light - processing unit, which is arranged above the transport mechanism and is used to perform selective light - processing on the solar cells by means of the light - processing unit.

[0042] Optionally, the light - processing unit includes at least one of a lamp light source and a laser light source.

[0043] Optionally, when the light - processing unit is the lamp light source, the lamp light source includes:

[0044] A halogen lamp, arranged above the transport mechanism;

[0045] A filter element, arranged between the halogen lamp and the transport mechanism to filter the light of the halogen lamp to form light of a predetermined wavelength, and use the filtered light to perform selective light - processing on the solar cells, where the predetermined wavelength is 1000nm - 2500nm.

[0046] Optionally, the selective light - processing device further includes:

[0047] A first cooling system for cooling the light - processing unit; and / or,

[0048] A second cooling system located below the transport mechanism.

[0049] In this solution, after printing conductive paste on the first surface of the battery structure, selective light - processing is performed on the conductive paste on the first surface, and then curing treatment is carried out. Selective light - processing can improve the line resistance of the conductive paste, while curing treatment can improve the contact resistance between the electrode and the functional layer. Therefore, performing selective light - processing on the conductive paste first and then curing treatment can improve the performance of the solar cell.

[0050] When performing selective light - processing on the conductive paste on the first surface from the side where the second surface is located, since the light processes the first surface from the second surface, the conductive paste has a certain reflection for the light, and compared with front - side light - processing, the position where the conductive paste contacts the functional layer is more likely to absorb light. While performing light - processing on the conductive paste, it further improves the contact performance between the conductive paste and the functional layer, thereby improving the overall performance of the battery.

[0051] In this solution, after performing selective light - processing on the conductive paste, further curing treatment will be carried out. Selective light - processing can reduce the resistance of the electrode formed by the conductive paste, and the further curing treatment is mainly to make the conductive paste have good contact with the functional layer, which can also reduce the resistance, thereby improving the performance of the battery.

[0052] After forming the transparent conductive layer, an annealing treatment is performed. The absorption rate of the annealed transparent conductive layer for photons in a preset wavelength band is lower than that of the transparent conductive layer without annealing treatment for photons in the preset wavelength band. Therefore, after the annealing treatment in this solution, when selective light treatment is performed, the battery structure absorbs less photon energy, so the temperature is lower. Under the same light treatment conditions, the damage to the battery structure is ultimately smaller. Or, under the same temperature conditions, the conditions for selective light treatment are simpler.

[0053] From the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will more clearly understand the above and other objects, advantages, and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Some specific embodiments of the present invention will be described in detail hereinafter with reference to the accompanying drawings in an exemplary but not restrictive manner. The same reference numerals in the drawings denote the same or similar components or parts. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0055] Figure 1 is a schematic structural diagram of a solar cell according to a specific embodiment of the present invention;

[0056] Figure 2 is a schematic flowchart of a method for manufacturing a solar cell according to a specific embodiment of the present invention;

[0057] Figure 3 is a schematic flowchart of a method for manufacturing a solar cell according to another specific embodiment of the present invention;

[0058] Figure 4 is a schematic flowchart of a method for manufacturing a solar cell according to yet another specific embodiment of the present invention;

[0059] Figure 5 is a schematic flowchart of a method for manufacturing a solar cell according to yet another specific embodiment of the present invention;

[0060] Figure 6 is a schematic flowchart of a method for manufacturing a solar cell according to yet another specific embodiment of the present invention;

[0061] Figure 7 is a schematic flowchart of a method for manufacturing a solar cell according to yet another specific embodiment of the present invention;

[0062] Figure 8 is a schematic flowchart of a method for manufacturing a solar cell according to yet another specific embodiment of the present invention;

[0063] Figure 9 is a schematic flow chart of a method for manufacturing a solar cell according to another specific embodiment of the present invention;

[0064] Figure 10 is a schematic flow chart of a method for manufacturing a solar cell according to another specific embodiment of the present invention;

[0065] Figure 11 is a graph showing the relationship between wavelength and absorption rate before and after annealing of the transparent conductive layer of the battery structure;

[0066] Figure 12 is a schematic structural diagram of a selective light treatment device according to a specific embodiment of the present invention.

[0067] Description of reference numerals:

[0068] Solar cell - 100; Battery structure - 10; Substrate - 110; Functional layer - 120; Transparent conductive layer - 130; First surface - 150; Second surface - 160; Electrode - 140; Selective light treatment device - 200; Transmission mechanism - 210; Light treatment unit - 220; Halogen lamp - 221; Filter element - 222; First cooling system - 230; Second cooling system - 240. Detailed description of the specific embodiment

[0069] In the description of this embodiment, it should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "height", "upper", "lower", "left", "right", "vertical", "horizontal", "bottom", "inner", "outer", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0070] As a specific embodiment of the present invention, a method for manufacturing the solar cell 100 of this embodiment. More specifically, as Figure 1As shown in the figure, the structure of the existing solar cell 100 includes a substrate 110, functional layers 120 on both side surfaces of the substrate 110, and an electrode 140 above the functional layers 120. The functional layer 120 includes a transparent conductive layer 130, and the electrode 140 is located on the transparent conductive layer 130. Specifically, the solar cell 100 in this embodiment is a low-temperature solar cell. Among the functional layers 120 prepared on both sides of the substrate 110 of the solar cell 100, the functional layer 120 is sensitive to temperature, and too high temperature will affect its performance. In addition, the functional layers 120 of different cells are different. For example, the functional layer 120 of the heterojunction solar cell 100 includes a passivation layer and a doping layer between the substrate 110 and the transparent conductive layer 130. The functional layer 120 of the perovskite cell can include an electron transport layer, a perovskite light-absorbing layer, a hole transport layer, etc. The functionality of the BC cell can include a front surface field, a passivation layer, an antireflection layer, etc.

[0071] Specifically, as Figure 2 shown, the preparation method of the solar cell in this embodiment may include:

[0072] Step S100, providing a cell structure 10, the cell structure 10 includes a substrate 110 and functional layers 120 on both sides of the substrate 110; the cell structure 10 includes a first surface 150 and a second surface 160;

[0073] Step S200, printing conductive paste on the first surface 150 of the cell structure 10;

[0074] Step S300, performing selective light treatment on the conductive paste on the first surface 150 by using a light treatment unit 220;

[0075] Step S400, performing a curing treatment on the cell structure 10 after the selective light treatment.

[0076] Specifically, in this embodiment, after printing the conductive paste on the first surface 150 of the cell structure 10, performing selective light treatment on the conductive paste on the first surface 150, and then performing a curing treatment. The selective light treatment can reduce the line resistance of the conductive paste, and the curing treatment can improve the contact performance between the electrode and the functional layer 120. Therefore, performing selective light treatment on the conductive paste first and then performing a curing treatment in this embodiment can improve the overall performance of the solar cell.

[0077] Or, according to this embodiment, performing selective light treatment first and then performing a curing treatment. Even when the degree of resistance reduction is the same finally, due to the benefits brought by the light treatment, only a lower temperature is required during the curing treatment to meet the conditions, and the lower temperature can reduce the damage to the functional layer in the non-paste area, and can also improve the performance of the solar cell.

[0078] Preferably, for a heterojunction solar cell, the selective light treatment further ensures that the temperature in the non-paste area is below a predetermined temperature, thereby minimizing the damage caused by the passivation layer during the entire selective light treatment process, and ultimately improving the light conversion efficiency of the solar cell.

[0079] As a specific embodiment of the present invention, as Figure 3 shown, after the step S300 of this embodiment uses the light treatment unit 220 to perform selective light treatment on the conductive paste on the first surface 150, it may further include:

[0080] Step S500, printing a conductive paste on the second surface 160 of the battery structure 10;

[0081] Step S600, using the light treatment unit 220 to perform selective light treatment on the conductive paste on the second surface 160.

[0082] Specifically, in this embodiment, after the selective light treatment of the paste on the first surface 150 is completed, a conductive paste still needs to be printed on the second surface 160. Similarly, after the conductive paste is printed on the second surface 160, by performing selective light treatment on the conductive paste on the second surface 160 and then performing a curing treatment, the performance of the finally prepared battery can be improved.

[0083] As one of the embodiments, as Figure 3 shown, after printing the conductive paste on the first surface 150, performing selective light treatment on the conductive paste on the first surface 150, then printing the conductive paste on the second surface 160, performing selective light treatment on the conductive paste on the second surface 160, and then performing a curing treatment on the conductive paste on the first surface 150 and the second surface 160 simultaneously.

[0084] In another embodiment, as Figure 4 shown, after printing the conductive paste on the first surface 150, performing selective light treatment and curing treatment on the conductive paste on the first surface 150, then printing the conductive paste on the second surface 160, and performing selective light treatment and curing treatment on the conductive paste on the second surface 160. Comparing the two embodiments, one-time curing can reduce the operation steps and simplify the preparation process, while two-time curing, while curing the conductive paste on the second surface 160, cures the conductive paste on the first surface 150 again, further improving the contact resistance between the conductive paste on the first surface 150 and the functional layer 120.

[0085] As a specific embodiment of the present invention, as Figure 5 shown, the step S300 of this embodiment, the step of using the light treatment unit 220 to perform selective light treatment on the conductive paste on the first surface 150 may include:

[0086] Step S310: Use the optical processing unit 220 to perform selective optical processing on the conductive paste on the first surface 150 on the side where the first surface 150 is located.

[0087] Or as another embodiment, as Figure 6 shown, step S300: The step of using the optical processing unit 220 to perform selective optical processing on the conductive paste on the first surface 150 may include:

[0088] Step S320: Use the optical processing unit 220 to perform selective optical processing on the conductive paste on the first surface 150 on the side where the second surface 160 is located.

[0089] In the present invention, by using a suitable optical processing unit to perform selective optical processing on the conductive paste on the first surface 150 from the side where the first surface 150 is located, since the paste area and the non-paste area on the first surface 150 have different absorption and reflection of light, it can not only satisfy the processing of the paste area, but also prevent the temperature of the non-paste area from being too high to damage the functional layer of the non-paste area.

[0090] However, when performing selective optical processing on the conductive paste on the first surface 150 from the side where the first surface 150 is located, that is, front-side selective optical processing, it has been found through research that due to the presence of metal particles, organic solvents, binders, etc. in the conductive paste, it will have a certain reflection on light, resulting in low light utilization rate and the line resistance of the electrode after optical processing not reaching the expected value. In the prior art, usually, the power of the light source is increased and the processing time is prolonged to perform heat treatment on the conductive paste, so as to obtain a lower line resistance and a lower contact resistance. However, too high energy and processing time will damage the non-paste film layer during the curing and sintering process, especially seriously damaging the performance of the passivation layer of the heterojunction solar cell. Too high temperature will damage the passivation effect of the heterojunction solar cell. Therefore, for front-side selective optical processing, it is necessary to select a suitable wavelength to perform selective optical processing on the conductive paste. Considering factors such as the absorption of light by the conductive paste and the transparent conductive layer, and the light utilization rate, a wavelength in the band greater than 1000 nm (for example, 1000 nm to 2500 nm) or a laser light source in a suitable band is used for selective optical processing, so that the positive gain of the conductive paste is greater than the damage to the battery, thereby improving the overall performance of the battery.

[0091] In addition, in order to further improve the light utilization rate and reduce the damage to the film layer in the non-paste area during the selective light treatment, preferably, in the present invention, on the side where the second surface 160 is located (the non-printed conductive paste side), the conductive paste on the first surface 150 is selectively light-treated by a light treatment unit, that is, backside selective light treatment. Since the light selectively light-treats the conductive paste on the first surface 150 from the second surface 160, compared with the frontside selective light treatment, the position where the conductive paste contacts the functional layer is more likely to absorb photon energy. Therefore, the photon heat absorbed by the conductive paste per unit area is greater than that absorbed by the non-paste area, so that the temperature at the conductive paste is lower than that at the non-paste area, thereby reducing the damage to the functional layer in the non-paste area while performing the light treatment on the conductive paste. In addition, while performing the backside selective light treatment on the conductive paste, it further improves the contact performance between the conductive paste and the functional layer, thereby overall improving the performance of the battery.

[0092] It should be noted that during the backside selective light treatment, after the conductive paste is printed on the first surface 150, the light treatment unit 220 can be arranged below the battery structure 10, and then on the second surface 160 side of the battery structure 10, the conductive paste on the first surface 150 is selectively light-treated. Also, after the conductive paste is printed on the first surface 150, it can be dried and then flipped. After flipping, the second surface 160 of the battery structure 10 faces upward and the first surface 150 faces downward, and the light treatment unit 220 can be arranged above the battery structure 10, that is, on the second surface 160 side of the battery structure 10, the conductive paste on the first surface 150 is selectively light-treated, and no further description will be made here.

[0093] As another specific embodiment of the present invention, as Figure 7 shown, step S600, the selective light treatment of the conductive paste on the second surface 160 by the light treatment unit 220 may include:

[0094] Step S610, on the side where the second surface 160 of the battery structure 10 is located, the conductive paste on the second surface 160 is selectively light-treated by the light treatment unit 220.

[0095] Or, as Figure 8 shown, another embodiment is: step S620, on the side where the first surface 150 of the battery structure 10 is located, the conductive paste on the second surface 160 is selectively light-treated by the light treatment unit 220.

[0096] Just like the principle of the selective light treatment of the conductive paste on the first surface 150 above, the selective light treatment of the conductive paste on the second surface 160 from the first surface 150 can improve the performance of the battery, and no further description will be made here.

[0097] In yet another embodiment, as Figure 9 shown, when printing a conductive paste on the first surface 150 and performing selective light treatment on the conductive paste on the first surface 150 from the side where the second surface 160 is located, and then printing a conductive paste on the second surface 160 and performing selective light treatment on the conductive paste on the second surface 160 from the side where the first surface 150 is located, that is, both selective light treatments are performed from the non-paste printing side. It should be noted that although the non-paste area of the first surface 150 will still be damaged to some extent during the process of performing selective light treatment on the second surface 160 from the side where the first surface 150 is located, generally speaking, the treatment of the paste area on the second surface 160 by this light treatment method improves the battery performance more than the damage to the non-paste area on the first surface 150 reduces the battery performance. Therefore, generally speaking, the overall battery performance will still be improved.

[0098] Specifically, regardless of the embodiment, when using the light treatment unit 220 to perform selective light treatment on the conductive paste on the first surface 150, or on the second surface 160 side, using the light treatment unit 220 to perform selective light treatment on the conductive paste on the first surface 150, the temperature of the paste area is higher than that of the non-paste area.

[0099] Specifically, since the paste area and the non-paste area have different absorptions of photon energy, the temperature of the paste area and the non-paste area will be different during light treatment. When selecting light with an appropriate wavelength, the photon energy absorption per unit area in the paste area is greater than that in the non-paste area, that is, the temperature of the paste area will be higher than that of the non-paste area. Furthermore, while curing the conductive paste in the paste area, the temperature of the non-paste area will not be too high, thus avoiding damaging the performance of the functional layer in the non-paste area and having a greater impact on the battery performance. The main difference between the two is that when performing selective light treatment on the paste on the printing side from the non-printing paste side using the light treatment unit, the difference in light absorption between the paste area and the non-paste area is greater than that in the front-side selective light treatment. On the basis of the same improvement in electrode performance, for the functional damage to the non-paste area, the back-side selective light treatment is less than the front-side selective light treatment, and the overall battery efficiency is improved better.

[0100] Specifically, the temperature difference between the slurry area and the non-slurry area in this embodiment is between 20 and 200 °C. When performing selective light treatment on the conductive slurry, due to the different absorption of photon energy by the slurry area and the non-slurry area, the final heat generation situation is also different. Per unit area, the absorption of photon energy by the non-slurry area is lower than that of the slurry area, so the temperature of the slurry area is lower than that of the conductive slurry. Therefore, when performing selective light treatment on the battery structure 10, the temperatures of the slurry area and the non-slurry area are detected, and the temperature difference is between 20 and 200 °C. For example, the temperature difference can be 20 °C, 50 °C, 80 °C, 100 °C, 150 °C, 180 °C or 200 °C. Preferably, the temperature difference between the slurry area and the non-slurry area in this embodiment is 100 °C, 150 °C, 180 °C or 200 °C.

[0101] In some embodiments, when the battery structure is a heterojunction solar cell, the functional layer 120 includes a passivation layer and a doping layer located on the first surface and the second surface. When the temperature of the non-slurry area is greater than 250 °C, the performance of the passivation layer in the functional layer 120 is damaged greatly. Therefore, the temperature of the functional layer 120 in the non-slurry area must be controlled below 250 °C. In this embodiment, since the non-slurry area absorbs less photon energy during selective light treatment, its temperature can be ensured to be below 250 °C, thereby ensuring the performance of the battery.

[0102] Regardless of the above embodiments, after printing the conductive slurry on the battery structure 10, before performing selective light treatment, it may further include:

[0103] Drying the conductive slurry.

[0104] In this embodiment, drying the conductive slurry before performing selective light treatment is more conducive to light absorption, the contact between the conductive slurry and the transparent conductive layer 130 is better, and the line resistance of the electrode 140 formed by the conductive slurry is lower.

[0105] The following further illustrates by taking the example of performing selective light treatment on the conductive slurry on the side opposite to the side where the conductive slurry is disposed on the battery structure 10.

[0106] As a specific embodiment of the present invention, as Figure 10 shown, step S200 of this embodiment prints the conductive slurry on the first surface 150 of the battery structure 10, and step S320, on the side where the second surface 160 of the battery structure 10 is located, uses the light treatment unit 220 to perform selective light treatment on the conductive slurry on the first surface 150, specifically including:

[0107] Step S210, printing the first conductive slurry on the first surface 150 of the battery structure 10 and performing drying treatment;

[0108] Step S220, print a second conductive paste on the first surface 150 of the battery structure 10 and perform a drying process;

[0109] Step S321, on the side where the second surface 160 of the battery structure 10 is located, use the light treatment unit 220 to perform selective light treatment on the first conductive paste and the second conductive paste on the first surface 150.

[0110] The electrode 140 grid lines finally formed by the conductive paste on the functional layer 120 of the battery can be divided into main grid lines and sub-grid lines. In this embodiment, the first conductive paste and the second conductive paste are respectively one of the main grid line paste and the sub-grid line paste, that is, when the first conductive paste is the main grid line paste, the second conductive paste is the sub-grid line paste, or when the first conductive paste is the sub-grid line paste, the second conductive paste is the main grid line paste.

[0111] Specifically, the printing sequence of the main grid line paste and the sub-grid line paste is not limited. The main grid line paste can be printed on the first surface 150 of the battery structure 10 first, then the main grid line paste is dried, then the sub-grid line paste is printed, and the sub-grid line paste is dried, and then selective light treatment is performed on the main grid line paste and the sub-grid line paste on the first surface 150 from the second surface 160. Or vice versa, the sub-grid line paste can be printed on the first surface 150 of the battery structure 10 first, then the sub-grid line paste is dried, then the main grid line paste is printed, and the main grid line paste is dried, and then selective light treatment is performed on the main grid line paste and the sub-grid line paste on the first surface 150 from the second surface 160.

[0112] Similarly, the first conductive paste and the second conductive paste in this embodiment are respectively one of the main grid line paste and the sub-grid line paste, that is, when the first conductive paste is the main grid line paste, the second conductive paste is the sub-grid line paste, and when the first conductive paste is the sub-grid line paste, the second conductive paste is the main grid line paste. Specifically, the printing sequence of the main grid line paste and the sub-grid line paste is not limited.

[0113] Similarly, the conductive paste on the second surface 160 of the battery structure 10 can also be divided into a first conductive paste and a second conductive paste, and the preparation process is the same as that of the first surface 150, which will not be elaborated here.

[0114] Specifically, the temperature of the drying treatment in the above embodiments can all be 30°C to 250°C, and the time is 0 to 300 s. For example, the temperature of the drying treatment can be 30°C, 80°C, 120°C, 150°C, 180°C, 200°C, 220°C, 240°C, 250°C, etc. The time of the drying treatment can be 10 s, 50 s, 80 s, 120 s, 160 s, 200 s, 240 s, 280 s, or 300 s, etc. It should be noted that when the temperature of the drying treatment is selected to be high, the treatment time can be shortened, and it will not cause damage to the functional layer.

[0115] Specifically, during the drying process of this embodiment, the drying rate of the conductive paste is 90% to 99%. For example, the drying rate of the conductive paste can be 90%, 91%, 93%, 95%, 97%, or 99%, etc. If the specific drying rate is too small, the shaping effect cannot be achieved; if the drying rate is too high, the effect of the subsequent selective light treatment will be affected.

[0116] Specifically, performing a pre-drying treatment before the selective light treatment in this embodiment is more conducive to the absorption of light by the conductive paste, the contact between the conductive paste and the transparent conductive layer 130 is better, and the line resistance of the electrode 140 formed by the conductive paste is lower.

[0117] As a specific embodiment of the present invention, the functional layer 120 of this embodiment further includes a transparent conductive layer 130, and after forming the transparent conductive layer 130 and before printing the conductive paste, it may further include:

[0118] Annealing the battery structure 10; wherein, the conditions of the annealing treatment are: the temperature is 50 to 250°C, and the time is 5 to 25 min. It should be noted that when the temperature of the annealing treatment is selected to be high, the treatment time can be shortened, and it will not cause damage to the functional layer.

[0119] Specifically, the temperature for annealing the battery structure 10 in this embodiment can be 50°C, 80°C, 100°C, 150°C, 180°C, 200°C, 220°C, or 250°C. The time can be 5 min, 10 min, 15 min, 20 min, or 25 min.

[0120] Specifically, when the battery structure 10 is annealed, its absorption rate of photons in the preset wavelength band is lower than that of the battery structure 10 without annealing treatment for the photons of the preset wavelength. Therefore, in this embodiment, after annealing treatment and then performing selective light treatment, the non-paste area of the battery structure 10 absorbs less photon energy, so the temperature is lower. Under the same light treatment conditions, the damage to the functional layer in the battery structure 10 is smaller in the end. Or, under the condition of reaching the same temperature, the conditions for the selective light treatment are simpler.

[0121] Specifically, there are various combinations and deformations in this embodiment, which cannot be exhausted here. Any appropriate deformation within the scope of the inventive point of this application is within the protection scope of this application.

[0122] Specifically, the conductive pastes in this embodiment are copper paste, silver paste, and silver-coated copper paste, and the silver content in the silver paste or silver-coated copper paste is less than 30%. Preferably, the silver content in the silver paste or silver-coated copper paste in this embodiment is less than 25%. The higher the silver content in the silver paste or silver-coated copper paste, the greater the light reflection of the paste, and the less obvious the improvement in the performance of the solar cell by selective light treatment, or even no improvement can be obtained.

[0123] More specifically, the light source of the light treatment unit 220 in this embodiment may include at least one of a lamp light source and a laser light source. Specifically, the conductive paste can be selectively light-treated with a lamp light source alone, or with a laser light source alone, or with a combination of a lamp light source and a laser light source.

[0124] More specifically, the lamp light source in this embodiment is a halogen lamp combined with a filter, and the light emitted by the halogen lamp is filtered through the filter to obtain light of a predetermined wavelength.

[0125] Such as Figure 11 As shown, the transparent conductive layer after the crystalline silicon annealing treatment absorbs less light in the same wavelength band than the transparent conductive layer without annealing treatment, which can further reduce the problem of the non-paste area. In addition, for the light coefficient rate of the transparent conductive layer, when the wavelength is about 1000 nm, its light absorption rate becomes worse, and the transparent conductive layer (blue film) in the non-paste area absorbs less photon energy, further controlling the temperature of the non-paste area. For the above reasons, considering factors such as the light absorption of the conductive paste and the transparent conductive layer, the predetermined wavelength is greater than 1000 nm. Preferably, the predetermined wavelength is between 1100 - 2500 nm, or between 1100 - 1700 nm.

[0126] Specifically, when the light treatment unit 220 selects a laser light source, the laser light source can be selected from one or more of a deep ultraviolet laser light source, a visible light laser light source, a near-infrared laser light source, and a mid-infrared laser light source. The specific light treatment unit 220 can be selected according to actual needs.

[0127] Preferably, the laser light source in this embodiment is a carbon dioxide laser light source. The carbon dioxide laser light source can emit laser light with a wavelength of 1026 nm, and the light in this band is more easily absorbed by the organic solvents and binders in the conductive paste, thereby reducing the line resistance of the electrode.

[0128] As a specific embodiment of the present invention, the step S400 of curing the battery structure 10 after selective light treatment includes:

[0129] Placing the battery structure 10 after selective light treatment into a curing furnace for curing and sintering, and irradiating the battery structure 10 with an LED lamp;

[0130] Among them, the conditions for curing and sintering are: the temperature is 30°C to 230°C, and the time is 0 min to 30 min. It should be noted that in some embodiments, the transparent conductive layer is annealed, and the conductive paste is dried, and then selective light treatment is performed. After multiple heat treatments, it has obtained a lower sheet resistance and good contact, so the curing treatment may not be performed, and no further description is made here.

[0131] Specifically, in this embodiment, the battery structure 10 can also be only placed in a curing furnace for curing and sintering without LED lamp irradiation. The two sets of solutions can be selected according to the actual situation.

[0132] The specific curing and sintering temperature can be 30°C, 50°C, 80°C, 120°C, 180°C, 200°C, 230°C, etc. And the curing and sintering time can be 1 min, 5 min, 10 min, 15 min, 20 min, 25 min or 30 min, etc.

[0133] Specifically, after the battery structure 10 is subjected to selective light treatment and then cured and sintered, the curing and sintering temperature should not be too high at this time. This process is the same as the process of curing and sintering after printing the conductive paste on the transparent conductive layer 130 in the prior art. However, in this embodiment, after selective light treatment and then curing and sintering, it can shorten the curing time and curing temperature. Selective light treatment reduces the resistance after the conductive paste forms the electrode 140, and then curing and sintering can further improve the contact performance between the electrode 140 and the transparent conductive layer 130, thereby improving the overall battery performance.

[0134] As a specific embodiment of the present invention, this embodiment provides a solar cell, which can be prepared by the above preparation method of the solar cell. Among them, the solar cell can include at least one of an HJT cell, an xBC cell, and a perovskite / silicon heterojunction cell.

[0135] Specifically, during the preparation of the solar cell in this embodiment, the temperature of the non-paste area should not be too high during the selective light treatment of the conductive paste, which can reduce the damage to the functional layer of the low-temperature solar cell, thereby ensuring the performance of the low-temperature solar cell. Therefore, it is applicable to low-temperature solar cells.

[0136] As a specific embodiment of the present invention, this embodiment provides a selective light processing device 200, which can be applied to the above-mentioned method for preparing a solar cell. The selective light processing device 200 may include a transmission mechanism 210 and a light processing unit 220. Among them, the transmission mechanism 210 is used to transmit the solar cell 100 to be selectively light-processed. The light processing unit 220 is disposed above the transmission mechanism 210, and the solar cell 100 is selectively light-processed by using the light processing unit 220.

[0137] Specifically, the light processing unit 220 of this embodiment may include at least one of a lamp light source and a laser light source. When the light processing unit 220 is a lamp light source, as Figure 12 shown, the lamp light source may include a halogen lamp 221 and a filter member 222. Among them, the halogen lamp 221 is disposed above the transmission mechanism 210. The filter member 222 is disposed between the halogen lamp 221 and the transmission mechanism 210 to filter the light emitted by the halogen lamp 221 to form light of a predetermined wavelength, and the filtered light is used to selectively light-process the battery structure 10, where the predetermined wavelength is 1000 nm to 2500 nm.

[0138] Specifically, the halogen lamp 221 of this embodiment can emit light with a range of wavelengths. The filter member 222 may be a filter, and the filter can filter the light of the halogen lamp 221 to obtain light with a specific wavelength range, and then apply it to selective light processing. In this embodiment, the wavelength of the light filtered by the filter is also a range, and when the light with a certain wavelength range irradiates the conductive paste, the difference in photon absorption between the paste area and the non-paste area can be made larger.

[0139] Specifically, the selective light processing device 200 includes a first cooling system 230. Specifically, the first cooling system 230 of this embodiment may be disposed near the lamp light source to cool the lamp light source and prevent the system from being damaged due to the over-high temperature of the lamp light source.

[0140] For a heterojunction solar cell, since it is sensitive to temperature and its over-high temperature will affect the passivation effect, preferably, the selective light processing device 200 further includes a second cooling system 240. The second cooling system 240 is disposed below the transmission mechanism 210 and can cool the transmission mechanism 210 and the battery structure to prevent the transmission mechanism 210 from generating heat during transmission, thereby preventing the temperature of the transmitted solar cell 100 from being too high, resulting in a deterioration of the passivation effect, and further preventing the performance of the solar cell 100 from being affected.

[0141] Specifically, both the first cooling system 221 and the second cooling system 222 in this embodiment can be air-cooling systems. By continuously blowing cold air on the equipment to be cooled through the air-cooling system, the heat of the equipment can be taken away.

[0142] The following is a specific description with specific embodiments:

[0143] Embodiment 1

[0144] Provide a battery structure;

[0145] Print conductive paste on the first surface of the functional layer of the battery structure;

[0146] Dry the battery structure printed with conductive paste at 30°C to 250°C for 5 to 300 s;

[0147] The light processing unit uses a CO2 laser light source as the light source. The CO2 laser light source irradiates the battery structure from the side where the first surface of the battery structure is located, irradiating for 0.5 s, 0.75 s, and 1 s respectively, so as to perform selective light processing on the conductive paste on the first surface. After processing, the temperatures of the paste area and the non-paste area on the first surface of the battery structure are shown in Table 1:

[0148] Table 1

[0149] Irradiation duration (s) 0.5 0.75 1 Slurry area temperature (°C) 83.8 115.2 140.1 Non-slurry area temperature (°C) 63.4 87.1 109.3 Temperature difference (°C) 20.4 28.1 30.8

[0150] Place the battery structure after selective light processing in a curing furnace and sinter it at 30°C to 230°C for 0 min to 30 min.

[0151] As can be seen from Table 1, during the preparation of this embodiment, the temperatures of the paste area and the non-paste area are detected. The temperature of the paste area is higher than that of the non-paste area. When the irradiation duration is 0.5 s, the temperature difference is 20.4 degrees Celsius. When the irradiation duration is 0.75 s, the temperature difference is 28.1°C. When the irradiation duration is 1 s, the temperature difference is 30.8°C. That is, when using a CO2 laser light source as the light source for selective light processing, the temperature of the paste area is higher than that of the non-paste area, and as the irradiation duration increases, the temperature difference further increases, so that it can control the temperature of the non-paste area below a predetermined temperature while curing the conductive paste.

[0152] Embodiment 2

[0153] Provide a battery structure;

[0154] Print conductive paste on the first surface of the functional layer of the battery structure;

[0155] Dry the battery structure printed with conductive paste at 30°C to 250°C for 5 to 300 s;

[0156] The light processing unit uses a CO2 laser light source as the light source. The light processing unit irradiates the battery structure from the side where the second surface of the battery structure is located, irradiating for 0.5 s, 0.75 s, and 1 s respectively, and then performs selective light processing on the conductive paste on the first surface. The temperatures of the paste area and the non-paste area on the first surface of the battery structure are shown in Table 2:

[0157] Table 2

[0158] Irradiation duration (s) 0.5 0.75 1 Slurry area temperature (°C) 104.3 145.6 185.8 Non-slurry area temperature (°C) 60.4 85.4 106.6 Temperature difference (°C) 43.9 60.2 79.2

[0159] Place the battery structure after selective light processing in a curing furnace and sinter at 30°C to 230°C for 0 min to 30 min. The process parameters of this implementation are the same as those of Example 1, only the positions of the light processing unit and the battery structure are different.

[0160] As can be seen from Table 2, during the preparation of this embodiment, the temperatures of the paste area and the non-paste area are detected. The temperature of the paste area is higher than that of the non-paste area. And when the irradiation duration is 0.5 s, the temperature difference is 43.9°C; when the irradiation duration is 0.75 s, the temperature difference is 60.2°C; when the irradiation duration is 1 s, the temperature difference is 79.2°C. That is, when using a CO2 laser light source as the light source and performing backside selective light processing, the temperature of the paste area is higher than that of the non-paste area, and as the irradiation duration increases, the temperature difference further increases. It can cure the conductive paste while controlling the temperature of the non-paste area below a predetermined temperature.

[0161] In addition, combining Table 1 and Table 2, it can be seen that when performing backside selective light processing, the temperature of the paste area is higher than that of the paste area during frontside selective light processing, further indicating that during backside selective light processing, light is more easily absorbed by the paste area. In addition, when performing backside selective light processing, the temperature difference between the paste area and the non-paste area is also greater than that during frontside selective light processing. Thus, while facilitating the curing of the conductive paste, it can control the temperature of the non-paste area below a predetermined temperature, further reducing the damage to the functional layer and overall improving the performance of the solar cell.

[0162] Example 3

[0163] Provide a battery structure;

[0164] Print conductive paste on the first surface of the functional layer of the battery structure;

[0165] Dry the battery structure printed with conductive paste at 30°C to 250°C for 5 to 300 s;

[0166] The light processing unit uses a light source, which consists of a halogen lamp and a filter element. The wavelength band retains above 1000 nm, and the transmission speed is 28 m / min. The light source irradiates the battery structure from the side where the first surface of the battery structure is located, and performs selective light processing on the conductive paste on the first surface.

[0167] Place the battery structure after selective light processing in a curing furnace and sinter it at 30°C to 230°C for 0 min to 30 min.

[0168] During the preparation of this embodiment, the temperature of the paste area and the non-paste area is detected. The temperature of the paste area is 178.1°C, and the temperature of the non-paste area is 156°C. The temperature of the paste area is higher than that of the non-paste area, and the temperature difference between the paste area and the non-paste area is 22.1°C.

[0169] Example 4

[0170] Provide a battery structure;

[0171] Print conductive paste on the first surface of the functional layer of the battery structure;

[0172] Dry the battery structure printed with conductive paste at 30°C to 250°C for 5 to 300 s;

[0173] The light processing unit uses a light source, which consists of a halogen lamp and a filter element. The wavelength band retains above 1000 nm, and the transmission speed is 28 m / min. The light source irradiates the battery structure from the side where the second surface of the battery structure is located, and performs selective light processing on the conductive paste on the first surface.

[0174] Place the battery structure after selective light processing in a curing furnace and sinter it at 30°C to 230°C for 0 min to 30 min. This embodiment has the same process parameters as Example 3, only the positions of the light processing unit and the battery structure are different.

[0175] During the preparation of this embodiment, the temperature of the paste area and the non-paste area is detected. The temperature of the paste area is 185.9°C, and the temperature of the non-paste area is 153.7°C. The temperature difference is 32.2°C, and the temperature of the paste area is higher than that of the non-paste area. In addition, by comparing Example 3 and Example 4, it can be seen that when performing backside selective light processing, the temperature of the paste area is higher than that of the paste area during frontside selective light processing. Further, it shows that when using a light source as the light source for backside selective light processing, the light is more easily absorbed by the paste area. For the temperature difference, the temperature difference of backside selective light processing is greater than that of frontside selective light processing. Furthermore, while curing the conductive paste, the temperature of the non-paste area is controlled below a predetermined temperature, further reducing the damage to the functional layer and overall improving the performance of the solar cell.

[0176] At this point, those skilled in the art should recognize that although numerous exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived from the disclosed content of the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all such other variations or modifications.

Claims

1. A method for preparing a solar cell, characterized in that, Comprising: Providing a battery structure, the battery structure including a substrate and functional layers located on both sides of the substrate; the battery structure including a first surface and a second surface; Printing conductive paste on the first surface of the battery structure; Performing selective light treatment on the conductive paste on the first surface by using a light treatment unit; Performing a curing treatment on the battery structure after the selective light treatment.

2. The method for manufacturing a solar cell according to claim 1, wherein After performing selective light treatment on the conductive paste on the first surface by using a light treatment unit, it further includes: Printing conductive paste on the second surface of the battery structure; Performing selective light treatment on the conductive paste on the second surface by using a light treatment unit.

3. The method for manufacturing a solar cell according to claim 2, wherein Performing selective light treatment on the conductive paste on the first surface by using a light treatment unit specifically includes: on the side where the second surface of the battery structure is located, performing selective light treatment on the conductive paste on the first surface; and / or, Performing selective light treatment on the conductive paste on the second surface by using a light treatment unit specifically includes: on the side where the first surface of the battery structure is located, performing selective light treatment on the conductive paste on the second surface.

4. The method for manufacturing a solar cell according to any one of claims 1-3, wherein When performing selective light treatment on the conductive paste on the first surface and the second surface by using a light treatment unit, the temperature of the paste area is higher than the temperature of the non-paste area.

5. The method for manufacturing a solar cell according to claim 4, wherein The temperature difference between the paste area and the non-paste area is between 20-200°C.

6. The method for manufacturing a solar cell according to claim 4, wherein During the selective light treatment process, the temperature of the non-paste area is less than 250°C.

7. The method for manufacturing a solar cell according to any one of claims 1-3, wherein After printing the conductive paste and before performing selective light treatment, it further includes; Performing a drying treatment on the conductive paste.

8. The method for manufacturing a solar cell according to claim 7, wherein Printing conductive paste on the first surface of the battery structure; On the side where the second surface of the battery structure is located, performing selective light treatment on the conductive paste on the first surface specifically includes: Printing a first conductive paste on the first surface of the battery structure and performing a drying treatment; Printing a second conductive paste on the first surface of the battery structure and performing a drying treatment, On the side where the second surface of the battery structure is located, performing selective light treatment on the first conductive paste and the second conductive paste on the first surface by using a light treatment unit.

9. The method for manufacturing a solar cell according to claim 8, wherein The first conductive paste is the main grid line paste, and the second conductive paste is the auxiliary grid line paste; or, the first conductive paste is the auxiliary grid line paste, and the second conductive paste is the main grid line paste.

10. The method for manufacturing a solar cell according to claim 1, wherein the functional layer includes a transparent conductive layer; after forming the transparent conductive layer and before printing the conductive paste, it further includes: annealing the battery structure; wherein, the conditions for the annealing treatment are: the temperature is 50 - 250 °C, and the time is 5 - 25 min.

11. The method for manufacturing a solar cell according to claim 1, wherein the conductive paste is selected from one of copper paste, silver paste, and silver-coated copper paste, and when the conductive paste is silver-coated copper paste, the silver content in the silver-coated copper paste is less than 30%.

12. The method for manufacturing a solar cell according to claim 1, wherein the light source of the light treatment unit is at least one of a lamp light source and a laser light source.

13. The method for manufacturing a solar cell according to claim 12, wherein the lamp light source includes a halogen lamp and a filter; the filter is used to filter the light of the halogen lamp to form light with a predetermined wavelength, and the predetermined wavelength is 1000 nm - 2500 nm.

14. The method for manufacturing a solar cell according to claim 12, wherein the laser light source is selected from one or more of a deep ultraviolet laser light source, a visible light laser light source, a near-infrared laser light source, and a mid-infrared laser light source.

15. The method for manufacturing a solar cell according to claim 14, wherein the laser light source is a CO2 laser light source.

16. The method for manufacturing a solar cell according to claim 1, wherein the step of curing the battery structure after selective light treatment includes: placing the battery structure after selective light treatment in a curing furnace for curing and sintering, and irradiating the battery structure with an LED lamp; wherein, the conditions for the curing and sintering are: the temperature is 30 °C - 230 °C, and the time is 0 - 30 min.

17. A solar cell, characterized in that, Prepared by the method for manufacturing a solar cell according to any one of claims 1 - 16; wherein, the battery includes at least one of an HJT battery, an xBC battery, and a perovskite / silicon heterojunction tandem cell.

18. A selective light processing device, characterized in that, Applied to the method for manufacturing a solar cell according to any one of claims 1 - 16, the selective light treatment device includes: a transmission mechanism for transmitting the solar cell to be subjected to selective light treatment; a light treatment unit, the light treatment unit is arranged above the transmission mechanism, and the solar cell is subjected to selective light treatment by using the light treatment unit.

19. The selective light treatment device according to claim 18, wherein the light treatment unit includes at least one of a lamp light source and a laser light source.

20. The selective light treatment device according to claim 19, wherein when the light treatment unit is the lamp light source, the lamp light source includes: a halogen lamp arranged above the transmission mechanism; A light filter is disposed between the halogen lamp and the transmission mechanism to filter the light of the halogen lamp to form light of a predetermined wavelength, and use the filtered light to perform selective light treatment on the solar cell, wherein the predetermined wavelength is 1000 nm to 2500 nm.

21. The selective light treatment device according to claim 18, wherein the selective light treatment device further comprises: a first cooling system for cooling the light treatment unit; and / or, a second cooling system located below the transmission mechanism.

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