PERC bifacial cells

Abstract

The present invention provides a PERC bifacial cell, which has a passivation film and a plurality of aluminum grid lines on its back, and a plurality of through grooves are provided on the passivation film; the aluminum grid lines correspond to the through grooves one by one, and some of the aluminum grid lines have calibration windows that expose the through grooves outwardly. The PERC bifacial cell of the present invention is provided with calibration windows that expose the through grooves outwardly on the aluminum grid lines, and after the aluminum grid lines are printed, it can be judged by naked eyes at the calibration windows whether the aluminum grid lines are aligned with the through grooves.

Description

Technical Field

[0001] The present invention relates to the photovoltaic field, and in particular to a PERC double-sided solar cell which is convenient for checking whether a back aluminum grid line is aligned with a groove. Background Art

[0002] The back of the PERC cell (Passivated Emitter and Rear Cell) is first coated with aluminum oxide (AlOx) by atomic layer deposition (ALD), then coated with silicon nitride (SiNx), and then printed with aluminum paste on the back. The laser grooving is to enable the aluminum paste on the back to form ohmic contact with the silicon wafer through laser grooving to achieve the purpose of collecting electrons.

[0003] PERC bifacial cells replace the aluminum paste printed on the back of PERC monofacial cells with aluminum grid lines printed on the back, and the aluminum grid lines must overlap with the laser grooves on the back to form a good ohmic contact; if the two do not overlap, the electrons will not be collected at this place, which means the photovoltaic cell fails. Therefore, in the preparation process, it is necessary to check whether the aluminum grid lines and laser grooves overlap, but in the current process, it is difficult to observe whether there is a deviation between the two with the naked eye.

[0004] For example Figure 1 In the conventional PERC bifacial battery back electrode pattern design shown, the aluminum grid lines extend along the laser grooves during printing, and the aluminum grid lines and the laser grooves are the same length. The laser grooves will be completely covered by the entire aluminum grid lines, making it difficult to observe with the naked eye whether the two completely overlap or deviate in position.

[0005] The width of the laser groove is very small, basically 30μm to 40μm, and the color of the laser groove is silicon color, and the aluminum grid line paste is gray. Therefore, for existing products, if the aluminum grid line is slightly offset from the laser groove, the aluminum grid line cannot completely cover the laser groove, and it is difficult to identify it with the naked eye.

[0006] In view of this, it is necessary to provide an improved PERC bifacial cell to solve the above technical problems. Summary of the invention

[0007] The object of the present invention is to provide a PERC bifacial cell sheet which is convenient for checking whether the back aluminum grid lines are aligned with the grooves.

[0008] In order to achieve the above-mentioned purpose of the invention, the present invention provides a PERC double-sided solar cell, the back of which has a passivation film and a plurality of aluminum grid lines, and a plurality of through grooves are opened on the passivation film; the aluminum grid lines correspond to the through grooves one by one, and some of the aluminum grid lines have calibration windows that expose the through grooves outwardly.

[0009] As a further improvement of the present invention, at least two adjacently arranged aluminum grid lines each have a calibration window.

[0010] As a further improvement of the present invention, the calibration windows of at least two adjacently arranged aluminum grid lines together constitute a calibration area.

[0011] As a further improvement of the present invention, the projections of the calibration windows of at least two adjacently arranged aluminum grid lines in a direction perpendicular to the aluminum grid lines are adjacent, or intersecting, or overlapping.

[0012] As a further improvement of the present invention, the PERC bifacial cell has a plurality of calibration areas.

[0013] As a further improvement of the present invention, the calibration window is located at one end of the aluminum grid line along the length direction.

[0014] As a further improvement of the present invention, along a direction perpendicular to the aluminum grid lines, the calibration windows are provided on the eighth and ninth aluminum grid lines from the edge inward.

[0015] As a further improvement of the present invention, along a direction perpendicular to the aluminum grid lines, the eighth and ninth aluminum grid lines from the edge inwards have the calibration windows at both ends along the length direction of the aluminum grid lines.

[0016] As a further improvement of the present invention, the width of the calibration window is consistent with the width of the aluminum grid line, and the length of the calibration window is not less than 2.5 mm.

[0017] As a further improvement of the present invention, the through groove extends from the edge of one side of the PERC bifacial cell to the edge of the other side, and is a continuous straight through groove or a plurality of intermittently arranged through groove holes.

[0018] The beneficial effect of the present invention is that the PERC bifacial cell of the present invention has a calibration window on the aluminum grid line that exposes the through groove outwardly. After the aluminum grid line is printed, it can be judged by naked eyes at the calibration window whether the aluminum grid line is aligned with the through groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is the back electrode pattern design of PERC bifacial cell in the prior art;

[0020] Figure 2 It is a schematic diagram of the back electrode pattern design of a PERC bifacial cell in a preferred embodiment of the present invention;

[0021] Figure 3 yes Figure 2 Magnified view of wireframe area;

[0022] Figure 4This is a schematic diagram of another preferred embodiment of the present invention, in which the aluminum grid lines of the PERC bifacial cell are not printed to the through grooves, and the main grid is not shown. DETAILED DESCRIPTION

[0023] The present invention will be described in detail below in conjunction with the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional changes made by a person skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0024] See also Figure 2 to Figure 4 As shown, a PERC bifacial cell of a preferred embodiment of the present invention, the back side of the silicon substrate includes a passivation layer, a plurality of aluminum grid lines 1, and a plurality of main grids 3. The passivation layer is provided with a plurality of through grooves 2, and at least a portion of the structure of the plurality of aluminum grid lines 1 passes through the through grooves 2 to form an ohmic contact with the silicon substrate to realize carrier transmission on the back side of the PERC bifacial cell 100.

[0025] The passivation layer is an aluminum oxide film or a silicon oxide film. The PERC bifacial cell 100 also includes a silicon nitride film located on the side of the aluminum oxide film away from the silicon substrate, and the silicon nitride film plays a role in protecting the passivation layer and reducing reflection; the through groove 2 penetrates the silicon nitride film and the passivation layer. The other structures of the PERC bifacial cell 100 are structures in the prior art, and the through groove 2 can be formed by laser grooving 2, etching process, etc. in the prior art, which will not be repeated here.

[0026] A plurality of the aluminum grid lines 1 correspond to a plurality of the through grooves 2 one by one; some of the aluminum grid lines 1 have calibration windows (not numbered) that expose the through grooves 2. Therefore, after printing the aluminum grid lines 1, it is possible to visually determine whether the aluminum grid lines 1 and the through grooves 2 are aligned at the calibration windows.

[0027] The calibration window can be opened at any position on the aluminum grid line 1 , and its size and shape are not limited, as long as it can expose the through groove 2 to the outside, so as to determine whether the aluminum grid line 1 and the groove 2 are aligned.

[0028] At least two adjacent aluminum grid lines 1 each have a calibration window. After printing the aluminum grid lines 1, it can be determined in a nearby area whether the at least two adjacent aluminum grid lines 1 are aligned with the laser grooves 2 to avoid judgment errors.

[0029] Preferably, the projections of the calibration windows of at least two adjacently arranged aluminum grid lines 1 in the direction perpendicular to the aluminum grid lines 1 are adjacent, or partially overlapped, or completely overlapped, so that the distances between the multiple calibration windows are relatively close, which facilitates simultaneous observation and judgment of whether the multiple aluminum grid lines 1 are aligned with the through grooves 2. Among them, when the projections of several calibration windows partially overlap or completely overlap, the several calibration windows form a continuous area, which can be compared and observed without significantly moving the line of sight, thereby improving the accuracy of judgment.

[0030] The calibration windows of at least two adjacent aluminum grid lines 1 together constitute a continuous calibration area 12. In one calibration area 12, it is possible to simultaneously determine whether a plurality of adjacent aluminum grid lines 1 are aligned with the through grooves 2, which is more convenient. Furthermore, the PERC bifacial cell 100 has a plurality of calibration areas 12 arranged at intervals. By observing the plurality of calibration areas 12 in different regions, the accuracy of the determination can be improved and errors can be avoided.

[0031] In the above-mentioned embodiments, please refer to Figure 2 to Figure 4 As shown, the calibration window is preferably located at one end of the aluminum grid line 1 along the length direction; it can also be understood that: the through groove 2 maintains the length in the prior art, and the end of the aluminum grid line 1 with the calibration window retracts inward to expose the edge portion of the through groove 2; or it can be understood that the length of the aluminum grid line 1 is shorter than the length of the through groove 2, and the edge portion of the through groove 2 is exposed outward, so as to facilitate observation of whether the aluminum grid line 1 is aligned with the through groove 2. When the calibration window is set at the end of the aluminum grid line 1, the entire aluminum grid line 1 is continuous and will not affect the collection and transmission of electrons, and the calibration window is located at the edge of the PERC bifacial cell 100, so as to facilitate observation.

[0032] Yu Ru Figure 2-Figure 3 In the specific embodiment shown, along the direction perpendicular to the aluminum grid lines 1 , the eighth and ninth aluminum grid lines 1 from the edge inward are provided with the calibration windows, so the PERC bifacial cell 100 can be observed at its edge.

[0033] Furthermore, the eighth and ninth aluminum grid lines 1 have calibration windows at both ends along the length direction of the aluminum grid lines 1, so that the four corners of the PERC bifacial cell 100 have calibration areas 12 formed by calibration windows, which facilitates multi-angle observation and judgment, and symmetrical calibration can avoid observation errors. Of course, the calibration windows are set as follows Figure 4 The other aluminum grid lines 1 shown can also facilitate calibration.

[0034] In the present invention, the through groove 2 extends from the edge of one side of the PERC bifacial cell 100 to the edge of the other side, and is a continuous straight through groove or a plurality of intermittently arranged through groove holes. The width of the calibration window is consistent with the width of the aluminum grid line 1, and the length of the calibration window is not less than 2.5 mm, or when the through groove 2 is a plurality of intermittently arranged through groove holes, the length of the calibration window is designed to expose at least two or more through groove holes to the outside. The through groove 2 located at the bottom of the calibration window is obviously exposed, and it can be judged by naked eyes whether the aluminum grid line 1 and the through groove 2 are aligned.

[0035] In summary, the PERC bifacial cell 100 of the present invention has a calibration window on the aluminum grid line 1 that exposes the through groove 2 to the outside. After the aluminum grid line 1 is printed, it can be judged by naked eyes at the calibration window whether the aluminum grid line 1 is aligned with the through groove 2.

[0036] It should be understood that although this specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation mode may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0037] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present invention. They are not intended to limit the scope of protection of the present invention. All equivalent implementation methods or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A PERC bifacial cell, characterized in that: The back has: A passivation film, wherein a plurality of through grooves are formed on the passivation film; A plurality of aluminum grid lines, each of which corresponds to the through grooves one by one, and some of the aluminum grid lines have calibration windows that expose the through grooves outward; at least two adjacent aluminum grid lines both have calibration windows.

2. The PERC bifacial cell according to claim 1, characterized in that: The calibration windows of at least two adjacently arranged aluminum grid lines together form a calibration area.

3. The PERC bifacial cell according to claim 2, characterized in that: The projections of the calibration windows of at least two adjacently arranged aluminum grid lines in a direction perpendicular to the aluminum grid lines are adjacent, or intersecting, or overlapping.

4. The PERC bifacial cell according to claim 2, characterized in that: The PERC bifacial cell according to claim 1, characterized in that: the PERC bifacial cell has a plurality of calibration areas.

5. The PERC bifacial cell according to any one of claims 1 to 4, characterized in that: The calibration window is located at one end of the aluminum grid line along the length direction.

6. The PERC bifacial cell according to any one of claims 1 to 4, characterized in that: Along the direction perpendicular to the aluminum grid lines, the calibration windows are provided on the eighth and ninth aluminum grid lines inward from the edge.

7. The PERC bifacial cell according to any one of claims 1 to 4, characterized in that: Along the direction perpendicular to the aluminum grid lines, the eighth and ninth aluminum grid lines from the edge inwards have the calibration windows at both ends along the length direction of the aluminum grid lines.

8. The PERC bifacial cell according to claim 1, characterized in that: The width of the calibration window is consistent with the width of the aluminum grid line, and the length of the calibration window is not less than 2.5 mm.

9. The PERC bifacial cell according to claim 1, characterized in that: The through slot is a continuous straight through slot or a plurality of intermittently arranged through slot holes.

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