CN210866197U

CN210866197U - Solar cell and photovoltaic module

Info

Publication number: CN210866197U
Application number: CN201922226986.5U
Authority: CN
Inventors: 李兵; 邓伟伟; 蒋方丹
Original assignee: CSI Cells Co Ltd; CSI Solar Power Group Co Ltd
Current assignee: Canadian Solar Inc; CSI Cells Co Ltd
Priority date: 2019-12-12
Filing date: 2019-12-12
Publication date: 2020-06-26
Anticipated expiration: 2029-12-12

Abstract

The utility model discloses a solar cell and photovoltaic module, wherein the solar cell has a back electric field and a back electrode which are arranged on the back of a silicon wafer, the back electric field comprises a plurality of metal wires which are arranged in parallel at intervals, each metal wire comprises a plurality of metal sections which are distributed at intervals along the length direction, and the metal sections penetrate through a passivation layer on the back of the silicon wafer along the thickness direction of the solar cell to form electric connection with the back of the silicon wafer; the back electrode comprises a plurality of auxiliary grids which are arranged on the back surface of the passivation layer and correspond to the metal wires one by one, and each auxiliary grid is connected with a plurality of metal sections of the corresponding metal wire in series; the utility model discloses back of body electric field and back electrode's cooperation mode can effectively reduce solar wafer's back complex, then can set up the vice bars body resistivity that concatenates a plurality of metal sections on this basis more and more lowly, the width sets up more narrowly for corresponding photovoltaic module has higher photoelectric conversion efficiency and two-sided rate when having lower series resistance.

Description

Solar cell and photovoltaic module

Technical Field

The utility model relates to a solar photovoltaic technology field especially relates to a solar wafer and photovoltaic module.

Background

The double-sided perc solar cell is a device with a front side and a back side capable of receiving light to generate current. The double-sided assembly manufactured by the double-sided perc solar cell piece has the advantages that the back side can also generate electricity, and compared with a single-sided battery assembly, the total generated energy can be greatly increased. Collecting current through an aluminum wire on the back surface of the double-sided perc solar cell, and transmitting the collected current to a back electrode; however, in the prior art, since the aluminum wire has a high bulk resistivity, the aluminum wire generally needs to be provided with a large width in order to avoid affecting the series resistance of the battery cell. This great aluminium line width has reduced the effective photic area of battery piece back to a great extent, and then influences battery efficiency and the two-sided rate of two-sided subassembly.

In view of the above, it is necessary to provide a technical solution to solve the above technical problems.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving one of the technical problem that prior art exists at least, for realizing the above-mentioned utility model purpose, the utility model provides a solar wafer, its concrete design mode as follows.

A solar cell comprises a silicon wafer and a passivation layer formed on the back surface of the silicon wafer, and further comprises a back electric field and a back electrode which are arranged on the back surface of the silicon wafer; the back electric field comprises a plurality of metal wires which are arranged in parallel at intervals, each metal wire is composed of a plurality of metal sections which are distributed at intervals along the length direction of the metal wire, and the metal sections penetrate through the passivation layer along the thickness direction of the solar cell to form electrical connection with the back of the silicon wafer; the back electrode comprises a plurality of auxiliary grids which are arranged on the back surface of the passivation layer and correspond to the metal wires one by one, and each auxiliary grid is connected with a plurality of metal sections of the corresponding metal wire in series.

Further, the width of the sub-gate is not greater than the width of the metal line, and the bulk resistivity of the sub-gate is not greater than the bulk resistivity of the metal line.

Further, the width of the sub-gate ranges from 20 to 60 μm.

Further, the metal sections forming the metal wire are circular or long-strip-shaped.

Furthermore, the metal section is in a strip shape, the length direction of the metal section is consistent with the length direction of the corresponding metal wire, the length range of the metal section is 0.03-10 mm, and the width range of the metal section is 30-300 μm.

Further, the distance between two adjacent metal sections on the same metal wire ranges from 0.02mm to 10 mm.

Furthermore, the solar cell piece also comprises a main grid which is arranged on the back surface of the passivation layer and is connected with the auxiliary grids, and a plurality of bonding pads are distributed on the main grid at intervals.

Further, the area of the pad close to the end region of the main gate is larger than the area of the pad far away from the end region of the main gate.

Furthermore, a blank area is reserved in the area where the pad is located by the back electric field.

Further, the back electric field is an aluminum back field, and the back electrode is a silver electrode, a silver-aluminum electrode, a copper electrode or a silver-copper electrode.

Furthermore, a groove penetrating through the passivation layer to form the metal section is formed in the back surface of the silicon wafer.

The utility model also provides a photovoltaic module, this photovoltaic module include above the solar wafer.

The utility model has the advantages that: the utility model provides a back of solar wafer carries out electric connection through adopting the interval distribution metal section and the silicon chip back, can effectively reduce the back complex of solar wafer, then can set up the vice bars body resistivity that concatenates a plurality of metal sections on this basis lower, the width sets up more narrowly for corresponding photovoltaic module has higher photoelectric conversion efficiency and two-sided rate when having lower series resistance.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 is a schematic view illustrating the arrangement of the back electric field of the solar cell of the present invention;

FIG. 2 is an enlarged view of a portion a of FIG. 1;

fig. 3 is a schematic structural view of the solar cell according to the present invention, in which a back electrode is formed on the back surface of the solar cell;

FIG. 4 is an enlarged view of portion b of FIG. 3;

FIG. 5 is a schematic cross-sectional view taken at the position A-A' in FIG. 4;

FIG. 6 is a schematic cross-sectional view taken at the position B-B' in FIG. 4;

FIG. 7 is a schematic view of a half cell of the solar cell shown in FIG. 3 after being divided;

fig. 8 is a schematic view showing another arrangement of the back electric field of the solar cell of the present invention.

In the figure, 11 is a silicon wafer, 110 is a passivation layer, 12 is a metal line, 120 is a metal segment, 121 is a blank region, 13 is a back electrode, 130 is a bonding pad, 131 is a sub-gate, 132 is a main gate, 141 is a first positioning point, and 142 is a second positioning point.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Referring to fig. 1, fig. 2, fig. 3, fig. 4, and fig. 5, the solar cell provided by the present invention includes a silicon wafer 11 and a passivation layer 110 formed on the back surface of the silicon wafer 11; the solar cell further includes a back electric field and a back electrode 13 disposed on the back surface of the silicon wafer 11. The back electric field comprises a plurality of metal wires 12 arranged in parallel at intervals, each metal wire 12 is composed of a plurality of metal sections 120 distributed at intervals along the length direction of the metal wire, and the metal sections 120 penetrate through the passivation layer 110 along the thickness direction of the solar cell to form electrical connection with the back surface of the silicon wafer 11; the back electrode 13 includes a plurality of sub-gates 131 disposed on the back of the passivation layer 110 and corresponding to the metal lines 12, and each sub-gate 131 is connected in series to a plurality of metal segments 120 of the corresponding metal line 12.

The utility model also provides a photovoltaic module of solar wafer related above has.

In the specific implementation process, the utility model relates to a solar wafer is two-sided perc battery. Based on the utility model provides a concrete structure of solar wafer, its back adopts interval distribution metal section 120 and the 11 backs of silicon chip to carry out electric connection, can effectively reduce the back complex of solar wafer, and the corresponding efficiency that can improve solar wafer.

Furthermore, the utility model discloses with the tradition aluminum wire replacement that is used for solar wafer back side current to collect for a plurality of interval distribution's metal section 120 and concatenate the vice bars 131 of a plurality of metal sections 120, so at the concrete implementation in-process, set up lower, the width sets up more narrowly through setting up vice bars 131 bulk resistivity, can make corresponding photovoltaic module have higher photoelectric conversion efficiency and two-sided rate when having lower series resistance promptly.

As a preferable aspect of the present invention, referring to fig. 6, the width D of the sub-gate 131 is not greater than the width D of the metal line 120, and the bulk resistivity of the sub-gate 131 is not greater than the bulk resistivity of the metal line 120.

In some more particularly preferred embodiments, the back electric field is an aluminum back field, i.e., the metal segments 120 that make up the metal lines 12 are each formed by printing and sintering aluminum paste. The back electrode 13 is an electrode having a conductivity higher than that of the metal wire 12, such as a silver electrode, a silver-aluminum electrode, a copper electrode, or a silver-copper electrode, that is, the sub-grid 131 may be formed by printing and sintering conductive paste such as silver paste, silver-aluminum paste, copper paste, or silver-clad copper paste; in the specific implementation, the conductive paste used for printing the back electrode 13 is a non-burn-through type paste.

In the implementation process, in order to ensure that the sub-grid 131 has a better current collection capability and reduce the light-receiving shielding area of the back surface of the cell, the width d of the sub-grid 131 is set to be 20-60 μm.

In the present invention, the metal segment 120 constituting the metal wire 12 is in a circular shape, a long strip shape, or other shapes. Referring to fig. 2 and 4, the metal segment 120 in the present embodiment is preferably elongated and has a length direction corresponding to the length direction of the corresponding metal wire 12. Wherein the length L of the metal segment 120 ranges from 0.03mm to 10mm, and the width D ranges from 30 μm to 300 μm.

Referring to fig. 5, in the present embodiment, the distance L' between two adjacent metal segments 120 on the same metal wire 12 ranges from 0.02mm to 10 mm.

It is understood that, in the implementation of the present invention, the metal segment 120 penetrates the passivation layer 110 along the thickness direction of the solar cell to form an electrical connection with the back surface of the silicon wafer 11 can be implemented by the following two embodiments.

In one embodiment, the aluminum paste for back-field printing is a non-fire through paste, and now referring to fig. 5 and 6, a groove (not shown) is formed on the back surface of the silicon wafer 11 to penetrate the passivation layer 110 to form the metal segment 120. The recess is typically formed by laser firing the back side of silicon wafer 11.

In another embodiment, the passivation layer 110 is fully spread on the entire back surface of the silicon wafer 11, and the aluminum paste for back electric field printing is a fire-through type paste, so that during the subsequent sintering process of the solar cell, the aluminum paste reacts with the passivation layer 110 to penetrate through the passivation layer 110 to form the metal segment 120 electrically connected to the back surface of the silicon wafer 11.

Referring to fig. 3, the solar cell of the present invention further includes a main grid 132 disposed on the back surface of the passivation layer 110 and connected to a plurality of sub-grids 131, and a plurality of pads 130 are spaced apart from the main grid 132. Generally, the main grid 132 and the pad 130 are printed and sintered with the same paste as the sub-grid 131.

The solar cell of the present invention can also be a half cell, as shown in fig. 7, in this embodiment, the solar cell of the present invention is formed by dividing the whole solar cell shown in fig. 3 along the middle dividing line O-O', and in this half solar cell, the area of the pad 130 near the end region of the main grid 132 is larger than the area of the pad 130 far away from the end region of the main grid 132. Therefore, in the welding and assembling process of the photovoltaic module, the probability of welding deviation caused by position deviation between the welding strip and the main grid 132 can be effectively reduced.

As a preferred embodiment of the present invention, as shown in fig. 3 and 8, a blank area 121 is left in the area where the pad 130 is located in the back electric field. That is, the metal wire 12 is not provided with the metal segment 120 in the region where the pad 130 is located, so that the pad 130 formed in the region is more flat, and the welding strength between the solder strip and the pad 130 in the photovoltaic module can be further improved.

Furthermore, can understand, the utility model provides a solar wafer related in the concrete manufacture process, back of the body electric field and back electrode 13 adopt different printing half tone respectively to carry out the printing of corresponding conductive paste, for the position deviation appears between the auxiliary grid 131 of the metal wire 12 of avoiding back of the body electric field and back electrode 13, the utility model discloses a solar wafer related still has and prints fashioned first setpoint 141 and prints fashioned second setpoint 142 with back of the body electrode 13 synchronization with back of the body electric field synchronization, wherein, second setpoint 142 and the coincidence of first setpoint 141 position.

It should be understood that although the present description refers to embodiments, not every embodiment contains only a single technical solution, and such description is for clarity only, and those skilled in the art should make the description as a whole, and the technical solutions in the embodiments can also be combined appropriately to form other embodiments understood by those skilled in the art.

The above list of details is only for the practical implementation of the present invention, and they are not intended to limit the scope of the present invention, and all equivalent implementations or modifications that do not depart from the technical spirit of the present invention should be included in the scope of the present invention.

Claims

1. A solar cell comprises a silicon wafer and a passivation layer formed on the back surface of the silicon wafer, and is characterized by further comprising a back electric field and a back electrode which are arranged on the back surface of the silicon wafer; the back electric field comprises a plurality of metal wires which are arranged in parallel at intervals, each metal wire is composed of a plurality of metal sections which are distributed at intervals along the length direction of the metal wire, and the metal sections penetrate through the passivation layer along the thickness direction of the solar cell to form electrical connection with the back of the silicon wafer; the back electrode comprises a plurality of auxiliary grids which are arranged on the back surface of the passivation layer and correspond to the metal wires one by one, and each auxiliary grid is connected with a plurality of metal sections of the corresponding metal wire in series.

2. The solar cell piece of claim 1, wherein the width of the sub-grid is not greater than the width of the metal line, and the bulk resistivity of the sub-grid is not greater than the bulk resistivity of the metal line.

3. The solar cell sheet according to claim 2, wherein the width of the sub-grid is in the range of 20-60 μm.

4. The solar cell sheet according to any one of claims 1 to 3, wherein the metal segments constituting the metal wires are circular or elongated.

5. The solar cell sheet according to claim 4, wherein the metal segment is in a shape of a long strip, the length direction of the metal segment is consistent with the length direction of the corresponding metal wire, the length range of the metal segment is 0.03mm-10mm, and the width range of the metal segment is 30 μm-300 μm.

6. The solar cell sheet according to claim 4, wherein the distance between two adjacent metal segments on the same metal wire is in the range of 0.02mm-10 mm.

7. The solar cell piece according to any one of claims 1 to 3, further comprising a main grid arranged on the back surface of the passivation layer and connected with the plurality of auxiliary grids, wherein a plurality of bonding pads are distributed on the main grid at intervals.

8. The solar cell piece of claim 7, wherein the area of the land proximate to the end region of the main grid is greater than the area of the land distal to the end region of the main grid.

9. The solar cell of claim 7, wherein the back electric field is provided with a blank area in the region where the bonding pad is located.

10. The solar cell sheet according to any one of claims 1 to 3, wherein the back electric field is an aluminum back field, and the back electrode is a silver electrode, a silver aluminum electrode, a copper electrode or a silver copper electrode.

11. The solar cell of any one of claims 1-3, wherein the back surface of the silicon wafer is provided with a groove penetrating the passivation layer to form the metal segment.

12. A photovoltaic module comprising the solar cell sheet according to any one of claims 1 to 11.