CN219419047U - Solar cell - Google Patents

Abstract

The application provides a solar cell, and relates to the technical field of photovoltaics. The solar cell comprises a cell, a main grid line and a plurality of auxiliary grid lines, wherein the main grid line and the auxiliary grid lines are positioned on at least one surface of the cell in the thickness direction. The battery sheet includes a diffusion layer and a passivation layer stacked in a thickness direction; the surface is provided with a plurality of first grooves, second grooves and third grooves which penetrate through the passivation layer along the thickness direction. The extending direction of the first groove is parallel to the auxiliary grid line and is positioned in the auxiliary grid region; the second grooves are positioned at the intersections of the main grid lines and the auxiliary grid lines and are positioned at two opposite sides of the first grooves; the third groove is positioned in the main gate region and connects two second grooves positioned between two adjacent first grooves. The auxiliary grid line is at least partially accommodated in the first groove and the second groove and is in ohmic contact with the diffusion layer; the main grid line is at least partially accommodated in the second groove and the third groove and is in ohmic contact with the diffusion layer. The solar cell has better current collection effect and photoelectric conversion efficiency.

Description

Solar cell

Technical Field

The application relates to the technical field of photovoltaics, in particular to a solar cell.

Background

SE-PERC solar cells incorporating PERC (Passivated Emitterand Rear Cell, emitter and back passivation cells) in combination with selective emitter technology (SE) are currently a common high efficiency cell in the industry.

The SE technology is one of methods for improving the cell efficiency in the production process of the crystalline silicon solar cell, and refers to high-concentration doping at the contact part of the metal gate line electrode and the silicon wafer and the vicinity thereof, and low-concentration doping at the silicon wafer area outside the metal gate line electrode, so that the recombination of a diffusion layer can be effectively reduced, the contact resistance of the metal gate line electrode on a light receiving surface and the silicon wafer is reduced, and the short-circuit current, the open-circuit voltage and the filling factor of the cell are improved, thereby improving the photoelectric conversion efficiency.

The current solar cell adopts SE laser to open grooves in the area of the cell surface for forming the electrode of the auxiliary grid line, so that the auxiliary grid line is in ohmic contact with the diffusion layer. However, the existing solar cell has poor contact between the grid line structure and the cell, and cannot meet the requirements of industry on higher current collection effect and photoelectric conversion efficiency.

Disclosure of Invention

The present application is directed to a solar cell, which is intended to improve the current collection effect and photoelectric conversion efficiency of the existing solar cell.

The present application provides a solar cell, comprising: the battery comprises a battery piece, a main grid line and a plurality of auxiliary grid lines, wherein the main grid line and the auxiliary grid lines are positioned on at least one surface of the battery piece in the thickness direction. The battery sheet includes a diffusion layer and a passivation layer stacked in a thickness direction.

The surface of the battery piece in the thickness direction is provided with a plurality of first grooves, second grooves and third grooves which penetrate through the passivation layer in the thickness direction.

The extending direction of the first groove is parallel to the auxiliary grid line and is positioned in the auxiliary grid region; the second grooves are positioned at the intersection of the main grid line and the auxiliary grid line and are positioned on two opposite sides of the first groove; the third groove is positioned in the main grid area and is connected with the two second grooves positioned between the two adjacent first grooves.

The auxiliary grid line is at least partially accommodated in the first groove and the second groove and is in ohmic contact with the diffusion layer; the main grid line is at least partially accommodated in the second groove and the third groove and is in ohmic contact with the diffusion layer.

The first groove, the second groove and the third groove which penetrate through the passivation layer along the thickness direction are formed in the surface of the battery piece in the thickness direction; the first groove is positioned in the auxiliary grid line area, the extending direction of the first groove is parallel to the auxiliary grid line, and the auxiliary grid line is at least partially accommodated in the first groove and in ohmic contact with the diffusion layer, so that the contact resistance between the auxiliary grid line and the battery piece can be effectively reduced; the third groove is located the main grid region, the second groove is located the intersection department of main grid line and vice grid line and is located the relative both sides of first groove, two second grooves between two adjacent first grooves pass through the second groove connection, set up main grid line at least partly hold in second groove and third groove and with diffusion layer ohmic contact, can effectively reduce the contact resistance of main grid line and battery piece, still be favorable to improving the contact nature of grid line structure and battery piece of main grid line and vice grid line overlap joint department (i.e. centipede angle department), be favorable to improving main grid line and vice grid line and to the collecting effect of carrier.

Therefore, the arrangement of the first groove, the second groove and the third groove effectively improves the current collection effect of the main grid line and the auxiliary grid line, improves the short-circuit current, the open-circuit voltage and the filling factor of the battery, and accordingly improves the photoelectric conversion efficiency of the solar battery.

In an alternative embodiment of the present application, the extending direction of the second groove is parallel to the auxiliary gate line.

The arrangement mode is beneficial to further reducing the contact resistance between the auxiliary grid line and the battery piece.

In an alternative embodiment of the present application, an extension direction of the third groove is parallel to the main gate line.

The arrangement mode is beneficial to further reducing the contact resistance between the main grid line and the battery piece.

In an alternative embodiment of the present application, the second groove is symmetrically disposed with respect to the main gate line.

The arrangement mode is beneficial to further improving the contact property between the grid line structure and the battery piece at the lap joint position (namely the centipede angle position) of the main grid line and the auxiliary grid line, and further beneficial to further improving the collecting effect of the main grid line and the auxiliary grid line on current carriers.

In an alternative embodiment of the present application, two second grooves located on two opposite sides of the first groove are symmetrically disposed with an extension direction of the first groove as an axis.

The arrangement mode is beneficial to further improving the contact property between the grid line structure and the battery piece at the lap joint position (namely the centipede angle position) of the main grid line and the auxiliary grid line, and further beneficial to further improving the collecting effect of the main grid line and the auxiliary grid line on current carriers.

In an alternative embodiment of the present application, opposite ends of the third groove connect two second grooves located between two adjacent first grooves.

In an alternative embodiment of the present application, the distance from the opposite ends of the third groove to the first groove is 10-30 μm.

The distance from the opposite ends of the third groove to the first groove is 10-30 mu m, so that the doping concentration can be effectively improved, and the suede structure of the battery piece is prevented from being damaged. If the distance from the opposite ends of the third groove to the first groove is too large, the doping concentration is not improved, and the photoelectric conversion efficiency is reduced; if the distance from the two opposite ends of the third groove to the first groove is too small, the suede of the battery piece is easily damaged, and adverse effects are caused on the solar battery.

In an optional embodiment of the present application, the number of the first grooves is equal to the number of the auxiliary gate lines, and the positions of the plurality of first grooves are in one-to-one correspondence with the positions of the plurality of auxiliary gate lines respectively.

By means of the arrangement mode, each auxiliary grid line can be electrically communicated with the corresponding diffusion layer through the corresponding first groove, contact resistance between the whole auxiliary grid line structure and the battery piece is reduced, and further photoelectric conversion efficiency of the solar cell is improved.

In an alternative embodiment of the present application, the lengths of the second grooves along the extending direction of the auxiliary gate lines are all 0.6-0.64mm.

The arrangement mode is beneficial to further improving the collecting effect of the main grid line and the auxiliary grid line on carriers.

In an alternative embodiment of the present application, the first groove, the second groove and the third groove together occupy 2.5-4.4% of the total surface area.

The arrangement mode is beneficial to effectively reducing the contact resistance between the grid line structure (comprising the main grid line and the auxiliary grid line) and the battery piece, and further improving the photoelectric conversion efficiency of the battery.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered limiting the scope, and that other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 shows a schematic structural diagram of a solar cell according to an embodiment of the present application.

Fig. 2 shows an enlarged view at a in fig. 1.

Fig. 3 shows a cross-sectional view of fig. 2 in the direction B-B.

Fig. 4 shows a schematic structural diagram of a battery sheet according to an embodiment of the present application.

Fig. 5 shows an enlarged view at C in fig. 4.

Fig. 6 shows an enlarged view at D in fig. 5.

Icon: 10-a solar cell; 100-cell pieces; 101-a sub-gate region; 102-a main gate region; 110-a passivation layer; 120-a diffusion layer; 130-silicon matrix; 140-a first groove; 150-a second groove; 160-a third groove; 200-main grid lines; 300-sub-gate line.

Detailed Description

Embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical solutions of the present application, and thus are only examples, and are not intended to limit the scope of protection of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description of the present application and in the description of the drawings above are intended to cover non-exclusive inclusions.

In the description of the embodiments of the present application, the technical terms "first," "second," etc. are used merely to distinguish between different objects and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, a particular order or a primary or secondary relationship. In the description of the embodiments of the present application, the meaning of "plurality" is two or more unless explicitly defined otherwise.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

In the description of the embodiments of the present application, the term "plurality" refers to two or more (including two), and the same applies.

In the description of the embodiments of the present application, the orientation or positional relationship indicated by the technical terms "length", "width", "thickness", "upper", etc. are based on the orientation or positional relationship shown in the drawings, and are merely for convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the apparatus or element in question must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the embodiments of the present application.

In the description of the embodiments of the present application, unless explicitly specified and limited otherwise, the term "coupled" is to be construed broadly, and may be, for example, fixedly coupled, detachably coupled, or integrally formed; or may be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the embodiments of the present application will be understood by those of ordinary skill in the art according to the specific circumstances.

The current solar cell generally adopts SE laser to open grooves only in the area of the cell surface for forming the auxiliary grid line electrode, so that the auxiliary grid line is in ohmic contact with the diffusion layer. However, the inventor finds that the contact between the grid line structure and the cell piece in the existing solar cell is poor, especially the contact between the grid line structure at the lap joint position (namely, the centipede angle position) of the main grid line and the auxiliary grid line and the cell piece is poor, so that the existing solar cell meets the requirements of the industry on higher current collection effect and photoelectric conversion efficiency.

Therefore, the solar cell is further improved, so that the contact property between the grid line structure and the cell piece can be improved to a certain extent. In order to make the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.

Fig. 1 shows a schematic structural view of a solar cell 10 provided in an embodiment of the present application, fig. 2 shows an enlarged view at a in fig. 1, fig. 3 shows a cross-sectional view along a B-B direction of fig. 2, and referring to fig. 1 to 3, the embodiment provides a solar cell 10, the solar cell 10 includes a cell sheet 100, a main grid line 200 and a plurality of sub grid lines 300 located on at least one surface of the cell sheet 100 in a thickness direction.

Fig. 4 illustrates a schematic structural view of a battery sheet provided in an embodiment of the present application, fig. 5 illustrates an enlarged view at C in fig. 4, fig. 6 illustrates an enlarged view at D in fig. 5, and referring to fig. 1 to 6, the battery sheet 100 includes a passivation layer 110, a diffusion layer 120, and a silicon substrate 130 stacked in sequence in a thickness direction; the main gate line 200 and the sub gate line 300 are disposed on a side of the passivation layer 110 remote from the silicon substrate 130. At least one surface of the battery sheet 100 in the thickness direction has a plurality of first, second and third grooves 140, 150 and 160 penetrating the passivation layer 110 in the thickness direction.

The extending direction of the first groove 140 is parallel to the sub-gate line 300 and is located in the sub-gate region 101 (the sub-gate region 101 is a dotted line region denoted by reference numeral 101 shown in fig. 5); the third recess 160 is located in the main gate region 102 (the main gate region 102 is a dotted line region indicated by reference numeral 102 shown in fig. 5); the second groove 150 is located at the intersection of the main gate line 200 and the sub gate line 300, i.e., the second groove 150 is located at the intersection of the main gate region 102 and the sub gate region 101. The second grooves 150 are located at opposite sides of the first grooves 140, and the third grooves 160 connect two second grooves 150 located between two adjacent first grooves 140.

In the present application, the sub-gate region 101 refers to a region where the sub-gate line 300 covers the surface of the battery cell 100, and the main gate region 102 refers to a region where the main gate line 200 covers the surface of the battery cell 100. The first groove 140, the second groove 150, and the third groove 160 are all formed by grooving the surface of the battery plate 100 by means of SE laser.

The sub-gate line 300 is at least partially received in the first and second grooves 140 and 150 and is in ohmic contact with the diffusion layer 120, so that the contact resistance between the sub-gate line 300 and the battery cell 100 can be effectively reduced; the main gate line 200 is at least partially received in the second recess 150 and the third recess 160 and is in ohmic contact with the diffusion layer 120, so that the contact resistance between the main gate line 200 and the battery cell 100 can be effectively reduced; in addition, the arrangement of the second grooves 150 is also beneficial to improving the contact between the grid line structure at the lap joint position (i.e. the centipede angle position) of the main grid line 200 and the auxiliary grid line 300 and the battery plate 100, and is beneficial to improving the collecting effect of carriers.

Through the arrangement of the first groove 140, the second groove 150 and the third groove 160, the current collection effect of the main grid line 200 and the auxiliary grid line 300 is effectively improved, the short circuit current, the open circuit voltage and the filling factor of the battery are improved, and therefore the photoelectric conversion efficiency of the solar battery 10 is improved.

In the present application, the first groove 140 is located at the axis of the sub-grid line 300, which is advantageous for further reducing the contact resistance between the sub-grid line 300 and the battery cell 100.

Further, the number of the first grooves 140 is equal to the number of the auxiliary grid lines 300, and the positions of the plurality of the first grooves 140 are respectively in one-to-one correspondence with the positions of the plurality of auxiliary grid lines 300; in other words, in the solar cell 10, one sub-gate line 300 covers one first groove 140.

By the above arrangement, each sub-grid line 300 can be electrically connected with the diffusion layer 120 through the corresponding first groove 140, which is beneficial to further reducing the contact resistance between the whole sub-grid line 300 structure and the cell 100, and further improving the photoelectric conversion efficiency of the solar cell 10.

As an example, the pitch of two adjacent first grooves 140 (e.g., L in fig. 6 ₂ The indicated distance) is 1.02-1.2mm; the width of the first groove 140 is 17-35 μm in the extending direction perpendicular to the sub-gate line 300.

In this application, the extending direction of the second groove 150 is parallel to the sub-gate line 300, which is beneficial to further reducing the contact resistance between the sub-gate line 300 and the battery cell 100.

Further, the second grooves 150 are symmetrically disposed about the main gate line 200, i.e., the second grooves 150 are symmetrically disposed about the axis of the main gate line 200. The above arrangement is beneficial to further improving the contact between the grid line structure at the lap joint position (i.e. the centipede angle position) of the main grid line 200 and the auxiliary grid line 300 and the battery piece 100, and further beneficial to further improving the collecting effect of the main grid line 200 and the auxiliary grid line 300 on current carriers.

Further, the two second grooves 150 located at opposite sides of the first groove 140 are axially symmetrically disposed in the extending direction of the first groove 140. The above arrangement is beneficial to further improving the contact between the grid line structure at the lap joint position (i.e. the centipede angle position) of the main grid line 200 and the auxiliary grid line 300 and the battery piece 100, and further beneficial to further improving the collecting effect of the main grid line 200 and the auxiliary grid line 300 on current carriers.

Illustratively, in the present application, the lengths of the second grooves 150 are each 0.6-0.64mm along the extending direction of the sub-gate line 300.

In this application, the extending direction of the third groove 160 is parallel to the main gate line 200, which is beneficial to further reduce the contact resistance between the main gate line 200 and the battery cell 100.

Further, the opposite ends of the third groove 160 are connected to the two second grooves 150 between the two adjacent first grooves 140, and the distance between the opposite ends of the third groove 160 and the first grooves 140 (L in fig. 6) ₁ The indicated distance) is 10-30 μm.

The distance between the opposite ends of the third groove 160 and the first groove 140 is 10-30 μm, which not only can effectively increase the doping concentration, but also is beneficial to avoiding damaging the suede structure of the battery plate 100. If the distance from the opposite ends of the third groove 160 to the first groove 140 is too large, the doping concentration is not increased, resulting in a decrease in the photoelectric conversion efficiency; if the distance from the opposite ends of the third groove 160 to the first groove 140 is too small, the texture of the battery piece 100 is easily damaged, which adversely affects the solar cell 10.

As an example, the length of each third groove 160 is 0.988-1.16mm along the extension direction of the main gate line 200; the distance between two adjacent third grooves 160 along the extension direction of the sub gate line 300 is 11.3-23mm.

In this application, the first, second and third grooves 140, 150 and 160 together occupy 2.5-4.4% of the total area of the surface of the battery sheet 100. The above arrangement is beneficial to effectively reducing the contact resistance between the grid line structure (including the main grid line 200 and the auxiliary grid line 300) and the battery plate 100, so as to improve the photoelectric conversion efficiency of the solar cell 10.

Illustratively, in this application, the SE laser forming the first groove 140, the second groove 150, and the third groove 160 has a power of 42W, a rate of 47000mm/s, a frequency of 420KHz, a pulse width of 3.5mm, an on laser delay of 0.32ms, a laser corner delay of 0.12ms, an off laser delay of 0.25ms, and a laser engraving delay of 0.3ms.

Preferred embodiments of the present application are as follows:

the first groove 140 is located at the axis of the auxiliary grid line 300, which is beneficial to further reducing the contact resistance between the auxiliary grid line 300 and the battery plate 100; the number of the first grooves 140 is equal to that of the auxiliary grid lines 300, and the positions of the plurality of first grooves 140 are in one-to-one correspondence with the positions of the plurality of auxiliary grid lines 300, so that each auxiliary grid line 300 can be electrically communicated with the diffusion layer 120 through the corresponding first groove 140, which is beneficial to further reducing the contact resistance between the whole auxiliary grid line 300 structure and the battery piece 100, and further improving the photoelectric conversion efficiency of the solar cell 10.

The extending direction of the second groove 150 is parallel to the auxiliary grid line 300, which is beneficial to further reducing the contact resistance between the auxiliary grid line 300 and the battery plate 100; the second grooves 150 are symmetrically arranged with the main grid line 200 as an axis, and the two second grooves 150 positioned at two opposite sides of the first groove 140 are symmetrically arranged with the extending direction axis of the first groove 140, which is beneficial to further improving the contact between the grid line structure at the lap joint position (i.e. the centipede angle position) of the main grid line 200 and the auxiliary grid line 300 and the battery piece 100, and further is beneficial to further improving the collecting effect of the main grid line 200 and the auxiliary grid line 300 on current carriers.

The extending direction of the third groove 160 is parallel to the main gate line 200, which is advantageous for further reducing the contact resistance between the main gate line 200 and the battery cell 100, and opposite ends of the third groove 160 are connected to the two second grooves 150 between the two adjacent first grooves 140 and to the two second grooves 150 between the two adjacent first grooves 140. The distance between the opposite ends of the third groove 160 and the first groove 140 is 10-30 μm, which not only can effectively increase the doping concentration, but also is beneficial to avoiding damaging the suede structure of the battery plate 100. If the distance from the opposite ends of the third groove 160 to the first groove 140 is too large, the doping concentration is not increased, resulting in a decrease in the photoelectric conversion efficiency; if the distance from the opposite ends of the third groove 160 to the first groove 140 is too small, the texture of the battery piece 100 is easily damaged, which adversely affects the solar cell 10.

The above preferred method can effectively improve the current collection effect of the main gate line 200 and the sub gate line 300, and improve the short circuit current, the open circuit voltage and the fill factor of the battery, thereby improving the photoelectric conversion efficiency (by more than 0.02%).

The foregoing description is only of the preferred embodiments of the present application and is not intended to limit the same, but rather, various modifications and variations may be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims (10)

1. A solar cell, comprising: the device comprises a battery piece, a main grid line and a plurality of auxiliary grid lines, wherein the main grid line and the auxiliary grid lines are positioned on at least one surface of the battery piece in the thickness direction; the battery sheet includes a diffusion layer and a passivation layer stacked in the thickness direction;

wherein the surface of the battery piece is provided with a plurality of first grooves, second grooves and third grooves which penetrate through the passivation layer along the thickness direction;

the extending direction of the first groove is parallel to the auxiliary grid line and is positioned in the auxiliary grid region; the second grooves are positioned at the intersections of the main grid lines and the auxiliary grid lines and are positioned on two opposite sides of the first grooves; the third groove is positioned in the main gate region and is connected with the two second grooves positioned between the two adjacent first grooves;

the auxiliary grid line is at least partially accommodated in the first groove and the second groove and is in ohmic contact with the diffusion layer; the main grid line is at least partially accommodated in the second groove and the third groove and is in ohmic contact with the diffusion layer.

2. The solar cell according to claim 1, wherein an extending direction of the second groove is parallel to the sub-grid line.

3. The solar cell according to claim 1 or 2, wherein the extension direction of the third groove is parallel to the main grid line.

4. The solar cell according to claim 2, wherein the second grooves are symmetrically arranged with respect to the main grid line.

5. The solar cell according to claim 1 or 2, wherein two of the second grooves located on opposite sides of the first groove are symmetrically arranged with respect to an extending direction of the first groove as an axis.

6. The solar cell according to claim 5, wherein opposite ends of the third groove connect two of the second grooves located between two adjacent ones of the first grooves.

7. The solar cell according to claim 6, wherein the distance from the opposite ends of the third groove to the first groove is 10-30 μm.

8. The solar cell according to claim 1 or 2, wherein the number of the first grooves is equal to the number of the sub-grids, and the positions of the plurality of first grooves are in one-to-one correspondence with the positions of the plurality of sub-grids, respectively.

9. The solar cell according to claim 1 or 2, wherein the second grooves each have a length of 0.6-0.64mm along the extending direction of the sub-grid line.

10. The solar cell according to claim 1 or 2, wherein the first, second and third grooves together comprise 2.5-4.4% of the total area of the surface.