CN209119120U - Double-side cell piece and photovoltaic module - Google Patents

Abstract

The utility model provides a kind of double-side cell piece and photovoltaic module, the double-side cell piece, including silicon wafer and it is formed in the pad and secondary grid line of silicon chip back side, the pair grid line includes: the first secondary grid line, it is arranged in the double-side cell leaf length or width direction, the pad of each column or row is correspondingly connected at least two the described first secondary grid lines；Several afflux pair grid lines are distributed in the described first secondary grid line two sides, wherein the part afflux pair grid line is directly connected to the pad, and the part afflux pair grid line is separately connected the distance is relatively close to described first secondary grid line.Compared to the prior art, the beneficial effects of the utility model are: reducing the transmission resistance of double-side cell piece and photovoltaic module, the loss in efficiency of electric current transmission is reduced.

Description

Bifacial cells and photovoltaic modules

technical field

The utility model relates to the field of solar cell manufacturing, in particular to a double-sided cell sheet and a photovoltaic assembly.

Background technique

Existing crystalline silicon solar cells mostly collect current through grid line electrodes made by printing, sintering, etc. on the surface of the silicon wafer. By optimizing the design of the grid line electrodes, the power gain of the cells can be improved.

FIG. 1 shows a back electrode structure of a double-sided cell 10 , which includes a plurality of spaced welding points 101 , a plurality of longitudinally extending aluminum busbars 103 , and a plurality of laterally extending aluminum secondary grids 105 . The soldering point 101 can be connected to a soldering tape (not shown) by soldering.

The aluminum auxiliary grid lines 105 are arranged perpendicular to the aluminum main grid lines 103 , and the current is collected by the aluminum auxiliary grid lines 105 and then concentrated to the aluminum main grid lines 103 , and then conducted to the welding point 101 by the aluminum main grid lines 103 . , so that the current can be conducted to the welding ribbon through the welding point 101, and then to the external circuit.

In addition, in order to reduce poor welding and improve the welding tension between the welding ribbon and the double-sided cell, along the longitudinal extension direction of the aluminum busbar 103, a hollow portion is provided between the welding point 101 and the aluminum busbar 103 107.

However, such a back electrode structure will make the current on the aluminum busbar 103 larger, resulting in an increase in transmission resistance and an increase in the efficiency loss of current transmission. If the resistance is to be reduced, limited by the conductivity of aluminum, a wider aluminum busbar is required for transmission, so that the shading area of the aluminum busbar is difficult to reduce, which will limit the utilization rate of the backside of the double-sided cell.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a double-sided cell and a photovoltaic module containing the double-sided cell. The back electrode structure of the double-sided cell does not have a dedicated aluminum busbar for convergent transmission, which can be used to reduce the number of double-sided cells. Efficiency loss of current transfer in the chip.

In order to achieve the purpose of the above utility model, an embodiment of the present utility model provides a double-sided cell, including a silicon wafer, a welding point and an auxiliary grid line disposed on the back of the silicon wafer, wherein the auxiliary grid line includes:

The first auxiliary grid lines are arranged in the length or width direction of the double-sided cell, and the welding points of each column or row are correspondingly connected to at least two of the first auxiliary grid lines;

A plurality of current collecting auxiliary grid lines are distributed on both sides of the first auxiliary grid line, wherein some of the current collecting auxiliary grid lines are directly connected to the welding point, and some of the current collecting auxiliary grid lines are respectively connected at relatively close distances the first sub-grid line;

The polarities of the welding points and the secondary grid lines are both negative polarities.

Further, in an embodiment of the present invention, the auxiliary gate line further includes:

The second sub-grid line is arranged perpendicular to the first sub-grid line, and the welding point of each row or column is correspondingly connected to at least one of the second sub-grid lines; some current-collecting sub-grid lines are connected to the The secondary gate line is connected.

Further, in an embodiment of the present invention, the first sub grid line is a vertical sub grid line arranged in the length direction of the battery sheet, and the second sub grid line is a width of the battery sheet. The lateral subgrid lines set in the direction.

Further, in an embodiment of the present invention, the current collecting sub-grid line includes a first part arranged in two vertical sub-grid lines corresponding to the same row of welding points and parallel to the vertical sub-grid line, along the vertical sub-grid line. A second portion of the lines distributed radially, and a third portion distributed radially along the lateral subgrid lines.

Further, in an embodiment of the present invention, at least one of the vertical sub-grid lines, the horizontal sub-grid lines, and the current-collecting sub-grid lines is set to have a gradual width, and the end closer to the welding point is wider than the end farther away from the welding point. .

Further, in an embodiment of the present invention, the welding point divides the vertical sub-grid line and the horizontal sub-grid line into multiple sections, and each vertical sub-grid line or horizontal sub-grid line is connected with at most four current collecting sub-grids. Line electrical connection.

Further, in an embodiment of the present invention, the vertical auxiliary grid lines, the horizontal auxiliary grid lines, and the current collecting auxiliary grid lines are made of aluminum, and the welding point material is silver.

Further, in an embodiment of the present invention, the double-sided battery sheet further includes: a hollow portion disposed between two vertical auxiliary grid lines corresponding to a row of welding points.

Further, in an embodiment of the present invention, at least a part of the vertical sub-grid line and/or the lateral sub-grid line is made of silver, and the vertical sub-grid line and/or the silver paste part of the silver paste part are made of silver. The lateral auxiliary grid lines are connected with the solder joints.

In order to achieve the purpose of the above utility model, an embodiment of the present utility model further provides a photovoltaic module, comprising a welding strip electrically connected to the welding point, and a plurality of the above-mentioned solutions electrically connected through the welding strip. Double-sided cells.

Compared with the prior art, the utility model has the beneficial effects of reducing the transmission resistance of double-sided cells and photovoltaic modules, and reducing the efficiency loss of current transmission.

Description of drawings

1 is a schematic diagram of grid electrode distribution of a bifacial battery back electrode structure in the prior art;

2 is a schematic diagram of the grid electrode distribution of the back electrode structure of a double-sided battery in an embodiment of the present invention;

3 is a schematic diagram of the grid electrode distribution of the back electrode structure of a double-sided battery including three-part current-collecting sub-grid lines according to an embodiment of the present invention.

Detailed ways

The present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings. However, this embodiment does not limit the present invention, and the structural, method, or functional transformations made by those of ordinary skill in the art according to this embodiment are all included in the protection scope of the present invention.

Generally, the photovoltaic modules are sequentially stacked from top to bottom: a front plate, a front-layer encapsulation film, a battery string layer, a rear-layer encapsulation film, and a back plate.

Wherein, the battery string layer includes battery slice strings placed in rows, and each battery slice string includes a plurality of battery slices placed in rows, and these battery slices can be electrically connected by welding strips.

In an embodiment of the present invention, the cells of the photovoltaic module are double-sided cells.

As shown in FIG. 2 , the double-sided cell 20 includes a silicon wafer 201 , and a back electrode structure formed on the back of the silicon wafer 201 . The back electrode structure includes several rows of solder joints 203 and sub-grid lines distributed at intervals. The polarities of the welding points and the secondary grid lines are both negative polarities. The width of the auxiliary gate lines is 100-500 microns.

The back electrode structure can be formed on the back side of the silicon wafer 201 by printing, electroplating, sintering, etc., and the solder joints 203 and the sub-grid lines 2051/2053/2055, the sub-grid lines 2051/2053/2055 and the sub-grid lines 2051/2052 /2053, if there is a physical connection, there is an electrical connection.

The sub-grid line includes: the first sub-grid line 2051, in the length or width direction of the double-sided cell 20 (X direction or Y direction in the figure, wherein the X direction is the extension direction of the ribbon connection, and the Y direction is the direction of the X direction. The direction is vertical), and each column or row of welding points 203 is correspondingly connected to at least two of the first auxiliary grid lines 2051;

A plurality of current-collecting sub-grid lines 2053 are distributed on both sides of the first sub-grid line 2051 , wherein some of the current-collecting sub-grid lines 2053 are directly connected to the welding point 203 , and some of the current-collecting sub-grid lines 2053 The first sub-gate lines 2051 with relatively close distances are respectively connected.

In the case where the sub-grid line is only provided with the first sub-grid line 2051 and the current-collecting sub-grid line 2053, the current-collecting sub-grid line 2053 can be divided into two parts, and a part of the current collected on the sub-grid line 2053 is collected. Convergence to the welding point 203 through the first auxiliary grid line 2051; the current collected on the other part of the current collecting auxiliary grid line 2053 is directly concentrated to the welding point 203, instead of being all converged through the main grid, reducing the number of currents on the main grid. The size of the current reduces the transmission resistance of the bifacial cell and reduces the efficiency loss of current transmission.

At this time, as shown in FIG. 3 , the current-collecting sub-grid line 2053 may include the first portion 20511 , along the first sub-grid line 2051 , which is disposed in two first sub-grid lines 2051 corresponding to the same row of welding points and parallel to the first sub-grid line 2051 . The first sub-grid lines 2051 are radially distributed in the second portion 20513 .

Of course, the first auxiliary gate line 2051 can also play a role of collecting current, and the collected current can be directly transmitted to the welding point 203 .

In an embodiment of the present invention, the sub-gate line 205 further includes: a second sub-gate line 2055, and the second sub-gate line 2055 and the first sub-gate line 2051 are perpendicular to each other, and each row or column has a Each of the welding points 203 is correspondingly connected to at least one of the second auxiliary gate lines 2055 ; some current collecting auxiliary gate lines 2053 are connected to the second auxiliary gate lines 2055 .

In the case that the sub-grid line is provided with a first sub-grid line 2051, a current-collecting sub-grid line 2053 and a second sub-grid line 2055, the current-collecting sub-grid line 2053 can be divided into three parts, and a part of the current-collecting sub-grid line The current collected on 2053 is concentrated on the welding point 203 through the first auxiliary grid line 2051; a part of the current collected on the current collecting auxiliary grid line 2053 is concentrated on the welding point 203 through the second auxiliary grid line 2055, and a part of the current collecting auxiliary grid line 2053. The current collected on the gate line 2053 is directly concentrated on the bonding point 203 . In this way, the magnitude of the current on the first sub-grid line 2051 can be greatly reduced, the transmission resistance of the double-sided cell can be reduced, and the efficiency loss of current transmission can be reduced.

Of course, the first sub-grid line 2051 and the second sub-grid line 2055 can also play the role of collecting current, and the collected current can be directly transmitted to the welding point 203 .

Hereinafter, the first sub grid lines 2051 are vertical sub grid lines arranged in the length direction (X direction) of the cell, and the second sub grid lines 2055 are vertical sub grid lines arranged in the cell width direction (Y direction). ) as an example of the horizontal sub-grid line provided on the ), and the description will be given. Of course, the first auxiliary gate line 2051 can also be a horizontal auxiliary gate line, and the second auxiliary gate line can also be a vertical auxiliary gate line. The so-called vertical and horizontal, can paper as a reference.

Hereinafter, the first sub-gate line 2051 will be referred to as a vertical sub-gate line 2051 , and the second sub-gate line 2055 will be referred to as a lateral sub-gate line 2055 .

Further, in this embodiment, the current collecting auxiliary grid lines 2053 diverge outwardly symmetrically with the center of the welding point of the welding point 203 as the center.

Specifically, as shown in FIG. 3 , the current collecting sub-grid line 2053 includes a first portion 20511 arranged in two vertical sub-grid lines 2051 corresponding to the same row of welding points and parallel to the vertical sub-grid line 2051 , along the vertical direction. The second portion 20513 of the sub-grid lines 2051 is radially distributed, and the third portion 20551 is radially distributed along the lateral sub grid lines 2055 .

The radial shape of the radial distribution is a triangle, and the base of the triangle is a vertical sub-grid line 2051 or a horizontal sub-grid line 2055 .

Further, in this embodiment, the welding point 203 divides the vertical sub-grid line 2051 and the horizontal sub-grid line 2055 into multiple sections, and each vertical sub-grid line 2051 or horizontal sub-grid line 2055 is connected with at most four current collectors The auxiliary gate lines 2053 are electrically connected, that is, the vertical auxiliary gate lines 2051 and the lateral auxiliary gate lines 2055 between the adjacent welding points 203 of each column and each row are connected to at most four current collecting auxiliary gate lines 2053 . In this way, the magnitude of the current on the vertical sub-gate lines 2051 and the lateral sub-gate lines 2055 can be controlled more precisely.

The current collecting sub-grid lines 2053 are radially distributed outward from the middle of each vertical sub grid line 2051 and each lateral sub grid line 2055 .

Preferably, in this embodiment, at least one of the vertical sub-grid lines, lateral sub-grid lines, and current-collecting sub-grid lines is set to have a gradual width, and the end closer to the welding point is wider than the end farther away from the welding point. In this way, the current transmission is facilitated, and the current transmission efficiency is increased at the end of the welding point where the current is larger.

In this embodiment, only the material of the welding point is silver, and the materials of the vertical sub-grid lines, the horizontal sub-grid lines, and the current collecting sub-grid lines are all aluminum. In this way, the silver paste used in bifacial cells and photovoltaic modules can be greatly saved, and the cost of bifacial cells and photovoltaic modules can be reduced.

Further, in order to eliminate the problem of easy virtual welding caused by the height difference between the aluminum vertical auxiliary grid line 2051 and the welding point 203, the double-sided cell further includes: two vertical welding points corresponding to a row of welding points. The hollow portion 207 between the auxiliary gate lines 2051 . That is, a plurality of hollow parts 207 are provided in the longitudinal direction of the double-sided cell, and are divided into multiple sections by the row of welding points 203 , and the vertical auxiliary grid lines 2051 are arranged on both sides of the hollow parts 207 .

In another embodiment of the present invention, it is different from the above-mentioned embodiments in that: in this embodiment, at least a part of the material of the vertical sub-grid lines 2051 and/or the lateral sub-grid lines 2055 is silver Specifically, the part of the vertical sub-grid line and the horizontal sub-grid line connected with the welding point 203 is the silver paste part. Since silver has better electrical conductivity, the current carrying capacity of the vertical sub-grid lines 2051 and/or the lateral sub-grid lines 2055 can be improved, and the transmission resistance and the efficiency loss of current transmission can be reduced. Of course, at least the part of the current collecting sub-grid line 2053 that is connected to the welding point 203 can also be silver.

To sum up, compared with the prior art, the present invention reduces the number of sub-grid lines mainly connected to the welding point by the electrode layout of the first sub-grid line and/or the second sub-grid line and the current-collecting sub-grid line The current on the bifacial cells and photovoltaic modules reduces the transmission resistance and the efficiency loss of current transmission.

In addition, the current carried becomes smaller, so the width of the auxiliary grid lines can be correspondingly narrowed, the shielding of the backside becomes smaller, and the utilization rate of the backside of the battery can also be improved.

It should be understood that although this specification is described in terms of embodiments, not every embodiment only includes an independent technical solution, and this description in the specification is only for the sake of clarity, and those skilled in the art should take the specification as a whole, and each The technical solutions in the embodiments can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

The series of detailed descriptions listed above are only specific descriptions for the feasible embodiments of the present invention, and they are not intended to limit the protection scope of the present invention. Any equivalents made without departing from the technical spirit of the present invention Embodiments or changes should all be included within the protection scope of the present invention.

Claims (10)

1. A double-sided cell, comprising a silicon wafer and a welding point and a secondary grid line formed on the back of the silicon wafer, wherein the secondary grid line comprises: The first auxiliary grid lines are arranged in the length or width direction of the double-sided cell, and the welding points of each column or row are correspondingly connected to at least two of the first auxiliary grid lines; A plurality of current collecting auxiliary grid lines are distributed on both sides of the first auxiliary grid line, wherein some of the current collecting auxiliary grid lines are directly connected to the welding point, and some of the current collecting auxiliary grid lines are respectively connected at relatively close distances the first sub-grid line; The polarities of the welding points and the secondary grid lines are both negative polarities. 2 . The double-sided solar cell according to claim 1 , wherein the secondary grid line further comprises: 2 . The second sub-grid line is arranged perpendicular to the first sub-grid line, and the welding point of each row or column is correspondingly connected to at least one of the second sub-grid lines; some current-collecting sub-grid lines are connected to the The secondary gate line is connected. 3 . The double-sided battery sheet according to claim 2 , wherein the first sub-grid line is a vertical sub-grid line arranged in the length direction of the battery sheet, and the second sub-grid line is 3 . Transverse sub-grid lines arranged in the width direction of the battery sheet. 4 . The bifacial battery sheet according to claim 3 , wherein the current collecting sub-grids comprise a first portion arranged in two vertical sub-grids corresponding to the welding points in the same row and parallel to the vertical sub-grids. 5 . , a second portion radially distributed along the vertical subgrid lines, and a third portion radially distributed along the lateral secondary gridlines. 5 . The double-sided cell according to claim 3 , wherein at least one of the vertical sub-grid lines, the horizontal sub-grid lines, and the current-collecting sub-grid lines is set to have a gradual width, and is close to one end of the welding point. 6 . wider than the end away from the solder joint. 6 . The double-sided cell according to claim 3 , wherein the welding point divides the vertical sub-grid line and the horizontal sub-grid line into multiple sections, and each section of the vertical sub-grid line or the horizontal sub-grid line has the largest number of sections. 7 . It is electrically connected with the four current collecting sub-gate lines. 7 . The double-sided battery sheet according to claim 3 , wherein the material of the vertical sub-grid line, the horizontal sub-grid line and the current-collecting sub-grid line is aluminum, and the material of the welding point is aluminum. 8 . silver. 8 . The double-sided battery sheet according to claim 7 , wherein the double-sided battery sheet further comprises: a hollow portion disposed between two vertical auxiliary grid lines corresponding to a row of welding points. 9 . 9 . The double-sided battery sheet according to claim 3 , wherein at least a part of the vertical sub-grid lines and/or the lateral sub-grid lines are made of silver, and the vertical sub-grid lines of the silver paste part are made of silver. 10 . And/or the lateral subgrid lines of the silver paste portion are connected to the solder joints. 10 . A photovoltaic module, comprising a welding strip electrically connected to the welding point, and a plurality of double-sided solar cells according to any one of claims 1 to 9 electrically connected through the welding strip. 11 .