Monocrystalline perc cell and electro-injection method, solar cell

Abstract

The present application relates to a kind of single crystal PERC cell piece and electric injection method, solar cell, the electric injection method includes the following steps: cell piece is sequentially carried out first electric injection, second electric injection and third electric injection, the injection current of second electric injection is greater than the injection current of first electric injection, the injection current of first electric injection is greater than the injection current of third electric injection;The injection time of third electric injection is respectively longer than the injection time of first electric injection and the injection time of second electric injection.The electric injection method of the present application makes the injection current of second electric injection greater than the injection current of first electric injection, the injection current of first electric injection is greater than the injection current of third electric injection, while controlling the time conditions such as electric injection, the light-electric conversion efficiency of the cell piece obtained after electric injection is significantly improved, and the light decay resistance is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, specifically to a monocrystalline PERC cell and an electrical injection method, and a solar cell. Background Technology

[0002] Energy is a vital foundation for human survival, and solar energy, as an inexhaustible energy source, has attracted widespread attention. A solar cell is a semiconductor device that converts light energy into electrical energy using the photovoltaic effect or photochemical effect. Solar cell wafers are the core component of a solar power generation system, and researchers have conducted extensive research on how to improve their photoelectric conversion efficiency. Among these methods, electrical injection, as the final step in solar cell production, has a significant impact. Electrical injection involves passing a specific current through the cell under certain temperature conditions, thereby passivating internal defects and improving its anti-degradation performance. Currently, this technology is widely used in the production of PERC cells.

[0003] In existing technologies, when performing electro-injection on solar cells, applying different currents to segments of the stacked structure can improve the uniformity of the injection, thereby enhancing the conversion efficiency and reducing the degradation rate of the solar cells. However, existing electro-injection methods do not significantly improve the resistance to light-induced degradation and the photoelectric conversion efficiency of monocrystalline PERC cells. Therefore, how to significantly improve the resistance to light-induced degradation and the photoelectric conversion efficiency of monocrystalline PERC cells during electro-injection is a pressing technical problem that needs to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a monocrystalline PERC solar cell and an electro-injection method, as well as a solar cell. The electro-injection method of this invention can significantly improve the solar cell's resistance to light decay and its photoelectric conversion efficiency.

[0005] In a first aspect, the present invention relates to an electro-injection method for a monocrystalline PERC solar cell, the electro-injection method comprising the following steps: sequentially performing a first electro-injection, a second electro-injection, and a third electro-injection on the solar cell, wherein the injection current of the second electro-injection is greater than the injection current of the first electro-injection, and the injection current of the first electro-injection is greater than the injection current of the third electro-injection; and the injection time of the third electro-injection is longer than the injection time of the first electro-injection and the injection time of the second electro-injection.

[0006] Optionally, the injection currents of the first electrical injection, the second electrical injection, and the third electrical injection are 9-14A, 12-15A, and 7-13A, respectively; the injection times of the first electrical injection and the second electrical injection are each 400-500s, and the injection time of the third electrical injection is 2400-3000s.

[0007] The injection temperatures of the first, second, and third electrical injections are each independently 170–180°C.

[0008] Optionally, the electro-injection method includes: stacking battery cells into an electro-injection hopper; and sequentially placing the electro-injection hopper containing the battery cells into different stations of the electro-injection device to perform the first electro-injection, the second electro-injection, and the third electro-injection, respectively.

[0009] Optionally, the first electrical injection is performed at station 2 of the electrical injection device, the second electrical injection is performed at station 3 of the electrical injection device, and the third electrical injection is performed sequentially at stations 4 to 9 of the electrical injection device, with the electrical injection time at each station from station 4 to station 9 being 400 to 500 seconds independently.

[0010] Optionally, the first electrical injection current is 9A, the second electrical injection current is 12A, and the third electrical injection current is 8A; the injection temperature of the first electrical injection, the second electrical injection, and the third electrical injection is 170℃, the injection time of the first electrical injection and the second electrical injection is 450s, and the electrical injection time at each of the stations 4 to 9 is 450s.

[0011] Optionally, the first electrical injection current is 10A, the second electrical injection current is 13A, and the third electrical injection current is 7A; the injection temperature of the first electrical injection, the second electrical injection, and the third electrical injection is 180℃, the injection time of the first electrical injection and the second electrical injection is 450s, and the electrical injection time at each of the stations 4 to 9 is 450s.

[0012] Optionally, the electro-injection box is provided with an upper electrode and a lower electrode, the upper electrode and the lower electrode being metal cover plates with a thickness of 2-3 mm.

[0013] Optionally, the solar cell is a monocrystalline PERC solar cell, which is obtained by the following steps in sequence: texturing, phosphorus diffusion, alkaline polishing, post-oxidation, back film, front film and screen printing.

[0014] In a second aspect, the present invention relates to a monocrystalline PERC solar cell, which is obtained by electro-injection using the electro-injection method described in the first aspect of the present invention.

[0015] Thirdly, the present invention relates to a solar cell having a monocrystalline PERC cell as described in the second aspect of the present invention.

[0016] Beneficial effects:

[0017] The electro-injection method of the present invention makes the injection current of the second electro-injection larger than that of the first electro-injection, and the injection current of the first electro-injection larger than that of the third electro-injection, while controlling the electro-injection time and other conditions, resulting in a significant improvement in the photoelectric conversion efficiency of the obtained electro-injected solar cell and a significant improvement in its resistance to light decay. Attached Figure Description

[0018] Figure 1 This is a schematic flowchart of an electro-injection method for a monocrystalline PERC solar cell according to the present invention. Detailed Implementation

[0019] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present application will become clearer and more apparent.

[0020] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0021] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0022] In a first aspect, the present invention relates to an electro-injection method for monocrystalline PERC solar cells, such as... Figure 1 As shown, the electro-injection method includes the following steps: sequentially performing a first electro-injection, a second electro-injection, and a third electro-injection on the solar cell, wherein the injection current of the second electro-injection is greater than the injection current of the first electro-injection, and the injection current of the first electro-injection is greater than the injection current of the third electro-injection; and the injection time of the third electro-injection is longer than the injection time of the first electro-injection and the injection time of the second electro-injection.

[0023] It should be noted that in the electro-injection method of this invention, the magnitudes of the currents for the first, second, and third electro-injections are controlled. The second electro-injection current is the largest, followed by the first electro-injection current, and then the third electro-injection current is the smallest. Simultaneously, the duration of each of the three electro-injections is controlled, with the third electro-injection time being longer than both the first and second electro-injections. This electro-injection method of the present invention performs three electro-injections, controlling the magnitude and duration of the currents for each injection, thereby significantly improving the anti-light-decay capability and photoelectric conversion efficiency of the electro-injected solar cell.

[0024] According to one embodiment of the electro-injection method of the first aspect of the present invention, the injection currents of the first electro-injection, the second electro-injection, and the third electro-injection are 9-14A, 12-15A, and 7-13A, respectively.

[0025] It should be noted that the injection currents of the first, second, and third electrical injections are all within the above-mentioned numerical ranges, and the injection current of the second electrical injection is greater than that of the first electrical injection, and the injection current of the first electrical injection is greater than that of the third electrical injection, which can further significantly improve the solar cell's resistance to light decay and its photoelectric conversion efficiency.

[0026] According to one embodiment of the electro-injection method of the first aspect of the present invention, the injection time of the first electro-injection and the second electro-injection are each independently 400-500s, and the injection time of the third electro-injection is 2400-3000s.

[0027] It should be noted that in this embodiment, the injection times of the first and second electrical injections can be the same, such as t, and the time of the third electrical injection can be 6t. In addition to controlling the magnitude of the current of the three electrical injections as described above, controlling the duration of the three electrical injections simultaneously is necessary to significantly improve the solar cell's resistance to light decay and its photoelectric conversion efficiency.

[0028] According to one embodiment of the electro-injection method of the first aspect of the present invention, the injection temperatures of the first electro-injection, the second electro-injection, and the third electro-injection are each independently 170-180°C.

[0029] It should be noted that the injection temperature can refer to the temperature of the station during electrical injection; in the electrical injection method of the present invention, electrical injection within the above temperature range can significantly improve the anti-light decay capability and photoelectric conversion efficiency of the solar cell.

[0030] According to one embodiment of the electro-injection method of the first aspect of the present invention, the electro-injection method includes:

[0031] The battery cells are stacked and placed into the electro-injection box; the electro-injection box containing the battery cells is then placed into different stations of the electro-injection device to perform the first electro-injection, the second electro-injection, and the third electro-injection respectively.

[0032] It should be noted that in the electro-injection method of the present invention, the electro-injection device used to electro-inject the solar cells in the electro-injection box can be a crystalline silicon solar cell defect passivation device, etc., and the number of solar cells stacked in the electro-injection box can be 400 to 450.

[0033] According to one embodiment of the electro-injection method of the first aspect of the present invention, the first electro-injection is performed at station 2 of the electro-injection device, the second electro-injection is performed at station 3 of the electro-injection device, and the third electro-injection is performed sequentially at stations 4 to 9 of the electro-injection device, and the electro-injection time at each station from station 4 to station 9 is independently 400 to 500 seconds.

[0034] According to one embodiment of the electro-injection method of the first aspect of the present invention, the current of the first electro-injection is 9A, the current of the second electro-injection is 12A, and the current of the third electro-injection is 8A; the injection temperature of the first electro-injection, the second electro-injection, and the third electro-injection is 170°C, the injection time of the first electro-injection and the second electro-injection is 450s, and the electro-injection time at each of the stations 4 to 9 is 450s.

[0035] It should be noted that this embodiment is a preferred embodiment of the electro-injection method of the present invention. The first electro-injection, the second electro-injection, and the third electro-injection are performed under the current, temperature, and time conditions of this embodiment, which can further improve the anti-light decay capability and photoelectric conversion efficiency of the electro-injected solar cell.

[0036] According to another embodiment of the first aspect of the electro-injection method of the present invention, the first electro-injection current is 10A, the second electro-injection current is 13A, and the third electro-injection current is 7A.

[0037] The injection temperature of the first, second, and third electrical injections is 180°C, the injection time of the first and second electrical injections is 450s, and the electrical injection time at each of the stations 4 to 9 is 450s.

[0038] It should be noted that this embodiment is another preferred embodiment of the electro-injection method of the present invention. Performing the first electro-injection, the second electro-injection, and the third electro-injection under the current, temperature, and time conditions of this embodiment can further improve the anti-light decay capability and photoelectric conversion efficiency of the electro-injected solar cell.

[0039] According to one embodiment of the electro-injection method of the first aspect of the present invention, the electro-injection box is provided with an upper electrode and a lower electrode, wherein the upper electrode and the lower electrode are metal cover plates with a thickness of 2 to 3 mm.

[0040] It should be noted that the electro-injection box and its structure can adopt conventional settings in the art.

[0041] According to one embodiment of the electro-injection method of the first aspect of the present invention, the solar cell is a monocrystalline PERC solar cell, which is obtained by the following steps in sequence: texturing, phosphorus diffusion, alkaline polishing, post-oxidation, back film, front film and screen printing.

[0042] It should be noted that conventional processes in the field can be used to prepare monocrystalline PERC solar cells, or commercially available monocrystalline PERC solar cells can also be electro-injected using the electro-injection method of this invention, both of which can significantly improve the light decay resistance and photoelectric conversion efficiency of monocrystalline PERC solar cells.

[0043] In a second aspect, the present invention relates to a monocrystalline PERC solar cell, which is obtained by electro-injection using the electro-injection method described in the first aspect of the present invention.

[0044] Thirdly, the present invention relates to a solar cell having a monocrystalline PERC cell as described in the second aspect of the present invention.

[0045] It should be noted that in the solar cells of the present invention, the monocrystalline PERC cells are obtained by electro-injection using the electro-injection method of the present invention, thus significantly improving the resistance to light decay and the photoelectric conversion efficiency.

[0046] The present invention will be further described in detail below through examples, but these examples are not intended to limit the invention.

[0047] The electro-injection device used in the following examples is a defect passivation device for crystalline silicon solar cells manufactured by Changzhou Shichuang. The PERC cells used in the following examples are PERC cells produced in-house using conventional processes.

[0048] Example 1

[0049] The PERC cells are prepared using the conventional process for PERC cells, and then subjected to texturing, phosphorus diffusion, alkaline polishing, post-oxidation, back film, front film, and screen printing to obtain PERC cells that have not undergone electrical injection.

[0050] 430 PERC solar cells from the production line are stacked into the electrode injection box. Both the upper and lower electrodes of the electrode injection box are covered with 2mm thick metal plates. The electrode injection box is placed in the preparation tank before the electrode injection device and then sequentially passes through each station (stations 2-9) for electrode injection processing. The electrode injection process parameters for each station are shown in Table 1.

[0051] Table 1

[0052] Workstation 2 Workstation 3 Workstation 4 Workstation 5 Workstation 6 Workstation 7 Workstation 8 Workstation 9 Current 9A 12A 8A 8A 8A 8A 8A 8A Duration of stay 450s 450s 450s 450s 450s 450s 450s 450s temperature 170℃ 170℃ 170℃ 170℃ 170℃ 170℃ 170℃ 170℃

[0053] Note: The residence time in Table 1 represents the electrical injection time.

[0054] Example 2

[0055] The PERC cells are prepared using the conventional process for PERC cells, and then subjected to texturing, phosphorus diffusion, alkaline polishing, post-oxidation, back film, front film, and screen printing to obtain PERC cells that have not undergone electrical injection.

[0056] 430 PERC solar cells were stacked into an electro-injection box. Both the upper and lower electrodes of the electro-injection box were covered with 2mm thick metal plates. The electro-injection box was placed in the preparation tank before the electro-injection device and then sequentially passed through each station (stations 2-9) for electro-injection processing. The electro-injection process parameters for each station are shown in Table 2.

[0057] Table 2

[0058]

[0059]

[0060] Note: The dwell time in Table 2 represents the electrical injection time.

[0061] Comparative Example 1

[0062] The PERC cells are prepared using the conventional process for PERC cells, and then subjected to texturing, phosphorus diffusion, alkaline polishing, post-oxidation, back film, front film, and screen printing to obtain PERC cells that have not undergone electrical injection.

[0063] 430 PERC solar cells from the production line are stacked into the electro-injection box. Both the upper and lower electrodes of the electro-injection box are covered with 2mm thick metal plates. The electro-injection box is placed in the preparation tank before the electro-injection device and then sequentially passes through each station (stations 2-9) for electro-injection processing. The electro-injection process parameters for each station are shown in Table 3.

[0064] Table 3

[0065] Workstation 2 Workstation 3 Workstation 4 Workstation 5 Workstation 6 Workstation 7 Workstation 8 Workstation 9 Current 8A 13A 9A 9A 9A 9A 9A 9A Duration of stay 430s 430s 430s 430s 430s 430s 430s 430s temperature 165℃ 165℃ 165℃ 165℃ 165℃ 165℃ 165℃ 165℃

[0066] Test Example 1

[0067] The electrical performance data of the solar cells before and after the electro-injection treatment in Examples 1, 2, and 1 (Comparative Example 1) were obtained by testing with a Halm tester. The mean values ​​of the test results are shown in Table 4. Wherein, Voc is the open-circuit voltage, Isc is the short-circuit current, Rs is the series resistance, Rsh is the parallel resistance, FF is the fill factor, and the area of ​​the solar cells in the examples and comparative examples is 0.0441 square meters, and the illuminance is 1000 W / m². 2 Eta is the photoelectric conversion efficiency. The photoelectric conversion efficiency Eta of the solar cell before or after electrical injection is calculated by the following formula (1):

[0068]

[0069] Table 4

[0070]

[0071]

[0072] As can be seen from the data in Table 4, the above embodiments use the improved process scheme of the present invention for electro-injection, which significantly improves the photoelectric conversion efficiency of the solar cell, mainly by improving the fill factor.

[0073] Furthermore, the light decay rate was measured after assembling the electro-injected solar cells from the above embodiments and comparative examples into batteries. The light decay rate of the batteries assembled from the electro-injected solar cells in the embodiments of the present invention was significantly lower than that of the comparative example under the same conditions and time, indicating that electro-injection of solar cells according to the electro-injection method of the present invention can significantly improve the solar cells' resistance to light decay.

[0074] In the description of this application, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship in the working state of this application. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0075] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0076] The present application has been described above with reference to preferred embodiments; however, these embodiments are merely exemplary and illustrative. Various substitutions and modifications can be made to the present application based on these embodiments, all of which fall within the protection scope of the present application.

Claims

1. A method for electrical injection into a monocrystalline PERC solar cell, characterized in that, The electro-injection method includes the following steps: The battery cell is subjected to a first electrical injection, a second electrical injection, and a third electrical injection in sequence. The injection current of the second electrical injection is greater than that of the first electrical injection, and the injection current of the first electrical injection is greater than that of the third electrical injection. The injection time of the third electrical injection is longer than the injection time of the first electrical injection and the injection time of the second electrical injection, respectively. The injection currents of the first electrical injection, the second electrical injection, and the third electrical injection are 9~14A, 12~15A, and 7~13A, respectively.

2. The electro-injection method according to claim 1, characterized in that, The injection times for the first and second electrical injections are each 400-500 s, and the injection time for the third electrical injection is 2400-3000 s. The injection temperatures of the first, second, and third electrical injections are each independently 170~180°C.

3. The electro-injection method according to claim 2, characterized in that, The electro-injection method includes: Stack the solar cells and place them into the electro-injection box; The electro-injection hopper containing the battery cells is sequentially placed into different stations of the electro-injection device to perform the first electro-injection, the second electro-injection, and the third electro-injection, respectively.

4. The electro-injection method according to claim 3, characterized in that, The first electrical injection is performed at station 2 of the electrical injection device, the second electrical injection is performed at station 3 of the electrical injection device, and the third electrical injection is performed sequentially at stations 4 to 9 of the electrical injection device. The electrical injection time at each station from station 4 to station 9 is independently 400 to 500 seconds.

5. The electro-injection method according to claim 4, characterized in that, The first electrical injection current is 9A, the second electrical injection current is 12A, and the third electrical injection current is 8A. The injection temperature of the first, second, and third electrical injections is 170°C, the injection time of the first and second electrical injections is 450s, and the electrical injection time at each of the stations 4 to 9 is 450s.

6. The electro-injection method according to claim 4, characterized in that, The first electrical injection current is 10A, the second electrical injection current is 13A, and the third electrical injection current is 7A. The injection temperature of the first, second, and third electrical injections is 180°C, the injection time of the first and second electrical injections is 450s, and the electrical injection time at each of the stations 4 to 9 is 450s.

7. The electro-injection method according to claim 3, characterized in that, The electro-injection box is provided with an upper electrode and a lower electrode, and the upper electrode and the lower electrode are metal cover plates with a thickness of 2~3mm.

8. The electro-injection method according to any one of claims 1 to 7, characterized in that, The solar cell is a monocrystalline PERC solar cell, which is prepared by the following steps: Texturing, phosphate spreading, alkali polishing, post-oxidation, back lamination, front lamination, and screen printing.

9. A monocrystalline PERC solar cell, characterized in that, The monocrystalline PERC solar cell is obtained by electro-injection using the electro-injection method described in any one of claims 1 to 8.

10. A solar cell, characterized in that, The solar cell is provided with the monocrystalline PERC cell as described in claim 9.

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