Heterojunction solar cell printing pattern design and preparation method thereof

Abstract

The application discloses a printing pattern design of a heterojunction solar cell and a preparation method thereof, and belongs to the technical field of photovoltaic cells. The design comprises a light-receiving surface and a non-light-receiving surface, both of which are provided with a plurality of auxiliary grids, and the auxiliary grid density of the edge region of the light-receiving surface and the non-light-receiving surface is higher than that of the middle region, and the auxiliary grid density of the edge region is increased by 5% to 20% compared with that of the middle region. The application also provides a corresponding preparation method, which comprises providing a printing substrate, designing a main grid-free structure, sequentially printing auxiliary grids of the non-light-receiving surface and the light-receiving surface by using a screen printing technology, and sintering at 200 DEG C to 250 DEG C. The application optimizes the distribution of the auxiliary grid, improves the carrier collection efficiency, reduces the edge recombination loss, significantly improves the conversion efficiency and the fill factor of the cell, and has important application value and popularization prospect.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic cell technology, specifically relating to a printed pattern design for heterojunction solar cells and its fabrication method. Background Technology

[0002] Heterojunction solar cells have become a research hotspot in the photovoltaic field due to their high conversion efficiency, low temperature coefficient, and bifacial power generation characteristics. However, traditional main grid and sub-grid designs suffer from problems such as shading loss, resistivity loss, and high silver paste cost. Especially in the edge region, insufficient carrier collection capacity leads to edge recombination loss, affecting the overall performance of the cell. Summary of the Invention

[0003] This invention provides a printed pattern design for heterojunction solar cells and a method for fabricating the same, in order to address the problems mentioned in the background art.

[0004] To address the existing problems, this invention provides a printed pattern design for heterojunction solar cells, including:

[0005] Multiple sub-gates are provided on both the light-receiving and non-light-receiving surfaces, among which:

[0006] The sub-gate density in the edge region of the light-receiving surface and the non-light-receiving surface is higher than the sub-gate density in the middle region;

[0007] The subgate density in the edge region is increased by 5% to 60% compared to the middle region.

[0008] Furthermore, the number of light-receiving surface sub-gates is 50, of which 34 are set in the middle area and 16 are set in the edge area. The spacing between the sub-gates in the middle area is 2.20mm and the spacing between the sub-gates in the edge area is 1.95mm.

[0009] Furthermore, the number of non-light-receiving sub-gates is 130, of which 90 are set in the middle area and 40 are set in the edge area. The spacing between the sub-gates in the middle area is 0.9mm and the spacing between the sub-gates in the edge area is 0.5825mm.

[0010] Furthermore, the sub-gate linewidth is 18μm, and both the light-receiving and non-light-receiving sub-gates adopt the same linewidth design.

[0011] Furthermore, the non-light-receiving sub-gate uses a low-silver silver-coated copper low-temperature paste with a silver content of 20% to 30%.

[0012] This invention also provides a method for fabricating printed patterns for heterojunction solar cells, comprising the following steps:

[0013] a. Provide a heterojunction solar cell substrate with dimensions of 210mm × 105mm;

[0014] b. Design a gridless (OBB) graphic structure;

[0015] c. Sub-gates are set on the light-receiving surface and the non-light-receiving surface respectively, with the sub-gate density in the edge region being higher than that in the middle region;

[0016] d. Using screen printing technology, first print the non-light-receiving sub-gate, then print the light-receiving sub-gate;

[0017] e. Sintering is carried out at a temperature of 200°C to 250°C.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. This invention effectively enhances the carrier collection efficiency in the edge region and reduces edge recombination losses by setting a higher density of sub-gates in the edge region of the light-receiving surface and the non-light-receiving surface, thereby improving the overall performance of the battery.

[0020] 2. The non-light-receiving sub-gate of this invention uses a low-silver-content silver-coated copper low-temperature paste (silver content 20%~30%), which effectively reduces the amount of silver paste used while ensuring conductivity, and significantly saves manufacturing costs.

[0021] 3. The present invention adopts a gridless (OBB) structure design, which reduces the light-blocking area, improves the utilization rate of the light-receiving surface, and further enhances the photoelectric conversion capability of the battery. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the distribution of the sub-gratings on the light-receiving surface of the present invention;

[0023] Figure 2 For the present invention Figure 1 A partial schematic diagram;

[0024] Figure 3 This is a schematic diagram of the distribution of the non-light-receiving surface sub-gratings in this invention;

[0025] Figure 4 For the present invention Figure 3 A partial schematic diagram; Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Please see Figures 1-4 A printed graphic design for a heterojunction solar cell, comprising:

[0028] Multiple sub-gates are provided on both the light-receiving and non-light-receiving surfaces, among which:

[0029] The sub-gate density in the edge region of the light-receiving surface and the non-light-receiving surface is higher than the sub-gate density in the middle region;

[0030] The subgate density in the edge region is increased by 5% to 60% compared to the middle region.

[0031] The light-receiving surface has 50 sub-gates, with 34 in the middle area and 16 in the edge area. The spacing between the sub-gates in the middle area is 2.20 mm, and the spacing between the sub-gates in the edge area is 1.95 mm.

[0032] The number of non-light-receiving sub-gates is 130, with 90 in the middle area and 40 in the edge area. The spacing between the sub-gates in the middle area is 0.9 mm, and the spacing between the sub-gates in the edge area is 0.5825 mm.

[0033] The sub-gate linewidth is 18μm, and both the light-receiving and non-light-receiving sub-gates adopt the same linewidth design.

[0034] The non-light-receiving sub-gate uses a low-silver silver-coated copper low-temperature paste with a silver content of 20% to 30%.

[0035] This invention also provides a method for fabricating printed patterns for heterojunction solar cells, comprising the following steps:

[0036] a. Provide a heterojunction solar cell substrate with dimensions of 210mm × 105mm;

[0037] b. Design a gridless (OBB) graphic structure;

[0038] c. Sub-gates are set on the light-receiving surface and the non-light-receiving surface respectively, with the sub-gate density in the edge region being higher than that in the middle region;

[0039] d. Using screen printing technology, first print the non-light-receiving sub-gate, then print the light-receiving sub-gate;

[0040] e. Sintering is carried out at a temperature of 200°C to 250°C.

[0041] Example 1: This example provides a printed pattern design for a heterojunction solar cell. The substrate size is 210mm×105mm. It adopts a gridless design. There are 50 sub-grids on the light-receiving side, with 34 in the middle area and a spacing of 2.20mm, and 16 at the edge area with a spacing of 1.95mm. There are 130 sub-grids on the non-light-receiving side, with 90 in the middle area and a spacing of 0.9mm, and 40 at the edge area with a spacing of 0.5825mm. The linewidth of the sub-grids is 18μm.

[0042] During the preparation process, screen printing technology is used to first print the non-light-receiving sub-grid (using silver-coated copper low-temperature paste with a silver content of 20% to 30%), and then print the light-receiving sub-grid. The sintering temperature is 230℃.

[0043] Effect verification

[0044] Tests showed that the battery conversion efficiency of this invention reached 25.7%, an improvement of 0.3% compared to the control group; the short-circuit current was increased by 10mA to 20mA; and the fill factor was increased by 0.8% to 1.5%, verifying the technical effect of this invention.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Those skilled in the art can readily implement the present invention based on the accompanying drawings and the above description. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the present invention, utilizing the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A printed pattern design for a heterojunction solar cell, characterized in that, include: Multiple sub-gates are provided on both the light-receiving and non-light-receiving surfaces, among which: The sub-gate density in the edge region of the light-receiving surface and the non-light-receiving surface is higher than the sub-gate density in the middle region; The subgate density in the edge region is increased by 5% to 60% compared to the middle region.

2. The printed pattern design for a heterojunction solar cell according to claim 1, characterized in that, The number of light-receiving surface sub-grates is 50, of which 34 are set in the middle area and 16 are set in the edge area. The spacing between the sub-grates in the middle area is 2.20mm and the spacing between the sub-grates in the edge area is 1.95mm.

3. The printed pattern design for a heterojunction solar cell according to claim 1, characterized in that, The number of non-light-receiving surface sub-gates is 130, of which 90 are set in the middle area and 40 are set in the edge area. The spacing between the sub-gates in the middle area is 0.9mm and the spacing between the sub-gates in the edge area is 0.5825mm.

4. The printed pattern design for a heterojunction solar cell according to claim 1, characterized in that, The sub-gate linewidth is 18μm, and both the light-receiving and non-light-receiving sub-gates adopt the same linewidth design.

5. The printed pattern design for a heterojunction solar cell according to claim 1, characterized in that, The non-light-receiving sub-grid uses a low-silver silver-coated copper low-temperature paste with a silver content of 20% to 30%.

6. A method for fabricating a printed pattern design for a heterojunction solar cell, characterized in that, Includes the following steps: a. Provide a heterojunction solar cell substrate with dimensions of 210mm × 105mm; b. Design a gridless (OBB) graphic structure; c. Sub-gates are set on the light-receiving surface and the non-light-receiving surface respectively, with the sub-gate density in the edge region being higher than that in the middle region; d. Using screen printing technology, first print the non-light-receiving sub-gate, then print the light-receiving sub-gate; e. Sintering is carried out at a temperature of 200°C to 250°C.

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