CN218123420U - Solar cell and solar cell string group - Google Patents

Abstract

The utility model provides a solar cell and a solar cell string group, which comprises a cell main body and an auxiliary grid structure arranged on the first surface of the cell main body, wherein the first surface of the cell main body is divided into a conventional area and a reinforced area surrounding the conventional area; the auxiliary grid structure comprises at least four first auxiliary grid lines which are parallel to each other, and the central section of each first auxiliary grid line and the edge sections positioned on the two sides of the central section are respectively positioned in the conventional area and the reinforcing area; the average sectional area of different positions of the edge section of the first secondary grid line is a first area; the average sectional area of the central section of the first auxiliary grid line at different positions is a second area, and the first area is larger than the second area. The utility model provides a solar wafer can delay the speed of solar wafer's power output decay.

Description

Solar cell and solar cell string set

Technical Field

The utility model relates to a photovoltaic technology field specifically, relates to a solar wafer and solar cell cluster group.

Background

Photovoltaic energy has become an important component in human energy structures, and the core factor driving the large-scale application of photovoltaic energy derives from the continuous drop in electricity costs. The electricity consumption cost of the photovoltaic system is reduced, and the development and the industrial application of an efficient technology and a low-cost technology are mainly benefited. However, the precondition for the application of the high-efficiency technology and the low-cost technology is that the two technologies are applied, so that the component product has the characteristic of high reliability; therefore, the high-reliability technical research is an important technical direction to be explored by researchers of photovoltaic modules and battery technologies.

At present, in a photovoltaic module adopting a backboard packaging structure, the thin grid slurry on the front surface of a battery piece of the photovoltaic module adopts a low-unit-consumption metallization design, the power output of the photovoltaic module is attenuated along with the prolonging of the service time, and the attenuation is more serious in a humid place of a service environment. Therefore, how to delay the power output of the photovoltaic module from being attenuated is an urgent problem to be solved.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving one of the technical problem that exists among the prior art at least, provide a solar wafer and solar cell cluster group, it can alleviate the blackening phenomenon of wafer edge, delay the line resistance of vice grid line and the rising of vice grid line and the contact resistance on battery surface, delay the speed of the power output decay of solar wafer.

The solar cell comprises a cell main body and a secondary grid structure arranged on the first surface of the cell main body, wherein the first surface of the cell main body is divided into a conventional area and a reinforcing area surrounding the conventional area; the normal region is a central region of the first surface, and the reinforced region is an annular edge region surrounding the central region;

the auxiliary grid structure comprises at least four first auxiliary grid lines which are parallel to each other, and the central section of each first auxiliary grid line and the edge sections positioned on two sides of the central section are respectively positioned in the conventional area and the reinforcing area;

the average sectional area of different positions of the edge section of the first secondary grid line is a first area; the average sectional area of different positions of the central section of the first secondary grid line is a second area, and the first area is larger than the second area.

Optionally, the sub-gate structure further includes at least four second sub-gate lines parallel to the first sub-gate lines, and the at least four second sub-gate lines are located in the reinforcing region; the average sectional area of different positions of the second auxiliary grid line is a third area, and the third area is larger than the second area.

Optionally, a ratio of the first area to the second area is greater than 1 and less than or equal to 3; the ratio of the third area to the second area is greater than 1 and less than or equal to 3.

Optionally, the range of the first area is 0.0001-0.001 mm ² (ii) a The value range of the third area is 0.0001-0.001 mm ² (ii) a The value range of the second area is 0.000045-0.00075 mm ² 。

Optionally, a distance L between an intersection of the normal region and the reinforced region and the corresponding edge of the cell main body satisfies the following relation:

wherein A is ₁ Is the second area; c ₁ Is the lower limit coefficient of the distance L, and the lower limit coefficient is 0.0001mm ³ ；C ₂ Is the upper limit coefficient of the distance L, the upper limit coefficient is 0.01mm ³ 。

Optionally, the cross-sectional areas of the edge segments of the first secondary grid line at different positions are the same.

Optionally, the edge section of the first sub-gate line is divided into a plurality of sub-edge sections along the extending direction of the edge section, the sectional areas of different positions of each sub-edge section are the same, and the sectional areas of the plurality of sub-edge sections decrease gradually from the boundary of the reinforced area to the boundary between the corresponding normal area and the reinforced area.

Optionally, the cross-sectional areas of the edge segments of the first secondary grid line at different positions decrease linearly or nonlinearly from the boundary of the reinforced region to the boundary of the corresponding conventional region and the reinforced region.

Optionally, the cross-sectional areas of the second pair of gate lines at different positions are the same.

Optionally, the sub-gate structure further includes a third sub-gate line parallel to the first sub-gate line, at least one third sub-gate line is located in the reinforcing region, and/or a central segment of at least one third sub-gate line and edge segments located at two sides of the central segment are respectively located in the normal region and the reinforcing region;

the average sectional area of the third auxiliary grid line at different positions is the same as that of the first area.

As another technical scheme, the embodiment of the utility model provides a still provide a solar cell cluster group, including a plurality of solar cell cluster, every the solar cell cluster all includes a plurality of the embodiment of the utility model provides an above-mentioned solar wafer, it is a plurality of solar wafer electric connection.

The utility model discloses following beneficial effect has:

the utility model provides a solar wafer, it is regional with the enhancement that encircles around this conventional region through dividing the first surface with the wafer main part, and through making the average sectional area (i.e. first area) that is located the edge section different positions department of single first secondary grid line in the reinforcing region, all be greater than the average sectional area (i.e. the second area) that is located the central segment different positions department of single first secondary grid line in the conventional region, can improve the unit consumption of at least part secondary grid thick liquids in the reinforcing region for the secondary grid in the conventional region, thereby can increase steam and permeate the route inside from the secondary grid line surface, delay the emergence of grid line corrosion, and then can delay the line resistance of secondary grid line and the rise of the contact resistance on secondary grid line and battery surface, delay the speed of power output decay of solar wafer.

The utility model provides a solar cell string group, it is through adopting the utility model provides an above-mentioned solar wafer can delay the line resistance of vice grid line and the rise of vice grid line and the contact resistance on battery surface, delays the speed of solar wafer's power output decay.

Drawings

Fig. 1 is a schematic diagram of the path of moisture permeating through the backsheet of a photovoltaic module into the interior of the module in a direction perpendicular to the surface of the cell sheet;

fig. 2 is a schematic diagram of the path of water vapor permeating through the back sheet of the photovoltaic module into the interior of the module in a direction parallel to the surface of the cell sheet;

fig. 3A is a schematic front view of one cell body of a conventional solar cell;

FIG. 3B is an electroluminescence diagram of a conventional solar cell after a wet heat test;

fig. 4A is a schematic front view of one of the cell bodies of the solar cell provided in the embodiment of the present invention;

fig. 4B is a schematic structural diagram of a battery string formed by solar cells according to an embodiment of the present invention;

fig. 4C is another schematic front view of one of the cell bodies of the solar cell provided in the embodiment of the present invention;

fig. 5 is a cross-sectional comparison view of a center section and an edge section of a first secondary grid line used in an embodiment of the present invention;

fig. 6A is a cross-sectional comparison view of a first shape of a center section and an edge section of a first secondary grid line used in an embodiment of the present invention;

fig. 6B is a cross-sectional comparison view of a second shape of the central section and the edge section of the first secondary grid line used in an embodiment of the present invention;

fig. 6C is a cross-sectional comparison view of a third shape of the center section and the edge section of the first secondary grid line used in the embodiment of the present invention;

fig. 6D is a cross-sectional comparison view of a fourth shape of the center section and the edge section of the first secondary grid line used in the embodiment of the present invention;

fig. 6E is a cross-sectional comparison view of a fifth shape of the central section and the edge section of the first secondary grid line used in the embodiment of the present invention;

fig. 7A is a comparison of an axial cross-section of a center section of a first secondary grid line and an edge section of a first shape as employed in an embodiment of the present invention;

fig. 7B is a comparison of the axial cross-section of the center section of the first secondary grid line and the edge section of the second shape in accordance with an embodiment of the present invention;

fig. 7C is a comparison graph of the axial cross-section of the central section of the first secondary grid line and the edge section of the third shape adopted in the embodiment of the present invention;

fig. 7D is a comparison diagram of the axial cross section of the central section of the first secondary grid line and the edge section of the fourth shape adopted in the embodiment of the present invention;

fig. 8A is a cross-sectional curve comparison diagram of a center section of a first secondary grid line and an edge section of a first shape according to an embodiment of the present invention;

fig. 8B is a cross-sectional curve comparison diagram of the central section of the first secondary grid line and the edge section of the second shape adopted in the embodiment of the present invention;

fig. 8C is a cross-sectional curve comparison diagram of the central section of the first secondary grid line and the edge section of the third shape adopted in the embodiment of the present invention;

fig. 8D is a cross-sectional curve comparison diagram of the central section of the first secondary grid line and the edge section of the fourth shape adopted in the embodiment of the present invention;

fig. 9 is an electroluminescence diagram of a solar cell provided in an embodiment of the present invention after a wet heat test.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the following describes the solar cell and the solar cell string set provided by the present invention in detail with reference to the accompanying drawings.

The utility model discloses the people discovery: at present, when a photovoltaic module adopting a back plate packaging structure works in a damp and hot environment for a long time, water vapor can continuously permeate into the module through a back plate on the back surface of the module and gradually diffuse to a central area along the edge of the front surface of a battery piece through the gap position of the battery piece and the battery piece, so that the contact resistance between an auxiliary grid and a silicon wafer is increased, and the power output of the photovoltaic module is attenuated.

Fig. 3A is a schematic front view of one cell body of a conventional solar cell. As shown in fig. 3A, the cross-sectional area of each of the finger lines at different positions on the main body of the cell is uniform. Fig. 3B is an EL picture of the solar cell shown in fig. 3A after a wet heat test, and it can be clearly seen from fig. 3B that there is an obvious blackening phenomenon at the edge of each cell main body, which is caused by that high-concentration water vapor is more easily accumulated at the edge position of the front side of the cell, and the water vapor accelerates the precipitation of an acidic component in a packaging material, so that an obvious grid line corrosion occurs at the edge position of the front side (i.e., a light receiving surface) of the cell, thereby causing a contact resistance between a sub-grid and a silicon wafer to increase, and causing a power output of a photovoltaic module to be attenuated.

In order to solve the above problem, referring to fig. 4A, an embodiment of the present invention provides a solar cell, which includes a cell main body 1 and a sub-grid structure disposed on a first surface of the cell main body 1, for example, a light receiving surface (also referred to as a front surface) of the cell main body 1. Wherein the cell body 1 is the smallest unit cell of the solar cell, fig. 4A only shows a single cell body 1 and a sub-grid structure on the first surface thereof.

The first surface of the cell main body 1 is divided into a regular region E0 and a reinforced region E1 surrounding the regular region E0, and optionally, the regular region E0 is a central region of the first surface, and the reinforced region E1 is an annular edge region surrounding the central region. The above-mentioned secondary gate structure includes at least four first secondary gate lines 3 parallel to each other, a central section 31 of the first secondary gate line 3 and edge sections 32 located at both sides of the central section 31 are located in the normal region E0 and the reinforced region E1, respectively, i.e., each first secondary gate line 3 intersects with a boundary between the normal region E0 and the reinforced region E1, and is divided into three sections.

The average cross-sectional area of the edge segment 32 of a single first subgrid 3 at different positions is a first area; the average cross-sectional area of the central segment 31 of a single first subgrid 3 at different locations is a second area, the first area being greater than the second area. The average cross-sectional area of the edge segment 32 of the first minor grid line 3 at different positions is the quotient of the sum of the cross-sectional areas of M different positions of the edge segment 32 of a single first minor grid line 3 in the extending direction thereof divided by M, wherein M is an integer greater than 1; the average cross-sectional areas of the central segments 31 of the first secondary grid lines 3 at different positions are the quotient of the sum of the cross-sectional areas of R different positions of the central segment 31 of a single first secondary grid line 3 in the extending direction thereof divided by R, wherein R is an integer greater than 1.

By making the average cross-sectional area (i.e., the first area) at different positions of the edge section 32 of a single first secondary grid line 3 in the reinforced region larger than the average cross-sectional area (i.e., the second area) at different positions of the central section 31 of a single first secondary grid line 3 in the conventional region E0, on the premise that the unit consumption of the conventional region E0 remains unchanged, the unit consumption of at least part of the secondary grid paste in the reinforced region E1 is increased, i.e., the average cross-sectional area at different positions of the edge section 32 of a single first secondary grid line 3 in the reinforced region E1 is increased, and under the same water vapor corrosion depth, the larger the average cross-sectional area is, the retention rate of the line resistance of the secondary grid line and the retention rate of the surface contact resistance of the secondary grid line with the cell body 1 are higher, that is, even if the secondary grid line in the reinforced region E1 has corrosion to a certain degree, the secondary grid line resistance and the surface contact resistance do not rise, and under the corrosion condition of the same degree, the secondary grid line resistance and the average cross-sectional area of the secondary grid line can be increased from the inner surface of the secondary grid line, and the water vapor corrosion path can be attenuated, so that the power output of the solar cell can be reduced. In addition, by adopting a smaller average cross-sectional area for the secondary grid lines in the conventional region E0, the unit consumption of the conventional region E0 can be made smaller, and thus the cost of the battery can be reduced.

It should be noted that, in practical applications, the sub-grid structure (including at least four first sub-grid lines 3 parallel to each other) in fig. 4A may be applied to the solar cell string shown in fig. 4B, where the solar cell string is formed by stacking and welding a plurality of solar cells, and the stacked and welded area is the blank area except for the area where the edge section 32 of the first sub-grid line 3 is located in the reinforced area E1, and the stacked and welded area may be covered by another solar cell and may play a role in isolating moisture, in this case, the sub-grid line may be disposed or may not be disposed in the blank area except for the area where the edge section 32 of the first sub-grid line 3 is located in the reinforced area E1.

In some optional embodiments, as shown in fig. 4C, the above-mentioned secondary gate structure further includes at least four second secondary gate lines 2 parallel to the first secondary gate line 3 on the basis of the first secondary gate line 3, where the at least four second secondary gate lines 2 are all located in the reinforced area E1 (i.e. located in the above-mentioned blank area), and the borders of each second secondary gate line 2 and the reinforced area E1 closest to the second secondary gate line are parallel to the regular area E0. The average cross-sectional area of the single second sub-gate line 2 at different positions is a third area, the average cross-sectional area is a quotient of the sum of the cross-sectional areas of the single second sub-gate line 2 at N different positions in the extending direction thereof divided by N, and N is an integer greater than 1. The second pair of grid lines 2 can be used for isolating water vapor in the blank area. The sub-grid structure shown in fig. 4C may be applied to the solar cell string shown in fig. 4B, or the solar cell string shown in fig. 1 and 2 (in which a plurality of solar cells are arranged at intervals).

In some optional embodiments, a ratio of the first area to the second area is greater than 1 and less than or equal to 3; the ratio of the third area to the second area is greater than 1 and less than or equal to 3. By setting the above ratio within this range, the unit consumption of at least part of the sub-grid paste in the reinforcing region E1 can be effectively increased, and the excess unit consumption in this region can be avoided, thereby reducing the battery cost. Optionally, the value of the first area is selectedThe range is 0.0001-0.001 mm ² (ii) a The value range of the third area is 0.0001-0.001 mm ² (ii) a The value range of the second area is 0.000045-0.00075 mm ² 。

In some alternative embodiments, the distance L between the boundary of the regular region E0 and the reinforced region E1 and the edge (parallel to the boundary line) of the corresponding cell main body 1 satisfies the following relationship:

wherein A is ₁ Is the second area (unit is mm) ² )；C ₁ Is a lower limit coefficient of the distance L, the lower limit coefficient being 0.0001mm ³ ；C ₂ Is the upper limit coefficient of the distance L, and the upper limit coefficient is 0.01mm ³ 。

By enabling the distance L to satisfy the relational expression, the situation that the auxiliary grid lines in the conventional area E0 are corroded due to the fact that water vapor with large concentration penetrates through the reinforced area E1 can be avoided, the excessive unit consumption of auxiliary grid slurry in the reinforced area E1 can be avoided, and therefore the cost of the battery can be reduced. It should be noted that the boundary of the reinforced region E1 is usually located at a position adjacent to the edge of the cell main body 1, but in practical applications, the boundary of the reinforced region E1 may be overlapped with the edge of the cell main body 1 according to specific needs.

It should be noted that, in practical applications, the distance L may be set according to the composition, structure, size, and other relevant factors of the finger (i.e., the central segment 31 of the first finger 3) in the conventional area E0, for example, when the height and width of the finger in the conventional area E0 are small, the distance L needs to be correspondingly increased; on the contrary, the distance L can be correspondingly reduced, as long as the secondary grid lines in the reinforced area E1 can have sufficient waterproof effect, and vapor with larger concentration is prevented from permeating. Alternatively, the distance L is equal to 20mm or 30mm, for example.

There are various ways to realize the first area larger than the second area and the third area larger than the second area, for example, the width and height of the sub-gate line may be increased or a cross-sectional shape with a larger cross-sectional area may be adopted. In a specific embodiment, as shown in fig. 5, the cross-sectional shapes of the central section 31 and the edge section 32 of the first finger 3 are both isosceles trapezoids, the width B2 of the edge section 32 of the first finger 3 is greater than the width B1 of the central section 31, and the height H2 of the edge section 32 of the first finger 3 is greater than the height H1 of the central section 31, so that the first area is greater than the second area. The implementation manner in which the third area is larger than the second area is the same as that of the specific embodiment.

In some alternative embodiments, the cross-sectional shapes of the first grating minor lines 3 may be the same or different; the cross-sectional shapes of the second sub-gate lines 2 may be the same or different. Moreover, the cross-sectional shape may include, but is not limited to, five cross-sectional shapes shown in fig. 6A to 6E, in addition to an isosceles trapezoid, and the contour lines of the cross-sectional shapes contacting with the first surface of the cell main body 1 may be straight lines, and the contour line shapes not contacting with the first surface may include sine-like shapes, arc shapes, semi-circular shapes, rectangular shapes, irregular polygonal shapes, curved shapes, triangular shapes, polygonal shapes, combinations of curved and straight lines, curved shapes, and the like, which are not particularly limited by the embodiment of the present invention.

In some alternative embodiments, as shown in fig. 7A and 8A, the ordinate a in fig. 7A represents the cross-sectional area of the finger; the abscissa D in fig. 8A represents the distance between different positions on any of the sub-grid lines and the corresponding edge of the cell main body 1. In the region corresponding to D < L, the sectional areas of different positions of the edge section 32 of the single first secondary grid line 3 are the same, and are all A ₂ (i.e., the first area); in the region corresponding to D is larger than or equal to L, the sectional areas of different positions of the central section 31 are the same and are A ₁ (i.e., second area), and A ₂ Greater than A ₁ . Optionally, A ₂ /A ₁ Greater than 1 and less than or equal to 3.

In a particular embodiment, said distance L is equal to 20mm; the cross sections of the central section 31 and the edge section 32 are both isosceles trapezoids, and the average width and the average height of the cross sections at different positions of the central section 31 in the conventional area E0 are respectively 30 μm and 6 μm; the edge segments 32 in the reinforced area E1 have a cross-sectional average width of 35 μm and an average height of 7 μm. The cross-sectional design of the second auxiliary grid line 2 is the same as that of the edge section 32, and after a periodic damp-heat test is performed by adopting the auxiliary grid structure, as shown in fig. 9, the problem of blackening of the edge of each cell body in the solar cell is remarkably reduced, and the power output attenuation is reduced to be within 3% from the level of 5% -10% of the attenuation of the cell shown in fig. 3B.

In other alternative embodiments, the cross-sectional areas of the edge segments 32 of a single first sub-grid line 3 at different positions may also be different, and the different manners are many, for example, the edge segment 32 of the first sub-grid line 3 is divided into a plurality of sub-edge segments along the extending direction thereof, wherein the cross-sectional areas of the different positions of each sub-edge segment are the same, and the cross-sectional areas of the plurality of sub-edge segments decrease from the boundary of the reinforced area E1 to the boundary of the corresponding regular area E0 and the reinforced area E1 one by one. Specifically, an ordinate a in fig. 7B represents a sectional area of the finger; the abscissa D in fig. 8B represents the distance between different positions on any of the sub-grid lines and the corresponding edge of the cell main body 1. As shown in fig. 7B and 8B, the edge segment 32 of a single first sub-grid line 3 is divided into two sub-edge segments (32a, 32b) along the extending direction, and in the region where D < L1, the cross-sectional areas of the sub-edge segments 32a at different positions are the same, and are all a _2max (ii) a In the corresponding region where L1 is more than or equal to D and less than L, the cross-sectional areas of different positions of the sub-edge section 32b are the same and are all A _2min And A is _2min ＜A _2max (ii) a In the region corresponding to D is larger than or equal to L, the cross sections of different positions of the central section 31 are the same and are A1, and A is _2min Is greater than A1. Optionally, (A) _2max +A _2min )/2A ₁ Greater than 1 and less than or equal to 3.

For another example, the cross-sectional areas of the edge segments 32 of a single first secondary grid line 3 at different positions decrease linearly from the boundary of the reinforced area E1 to the boundary of the corresponding regular area E0 and the reinforced area E1. Specifically, an ordinate a in fig. 7C represents a sectional area of the finger; the abscissa D in fig. 8C represents the distance between different positions on any of the sub-grid lines and the corresponding edge of the cell main body 1. As shown in FIGS. 7C and 8C, at D <L, the cross-sectional area of the edge segment 32 of the single first sub-grid line 3 at the boundary of the reinforced area E1 is the maximum value A _2max And the sectional area is linearly decreased as approaching the boundary between the regular area E0 and the reinforced area E1. In the region corresponding to D is larger than or equal to L, the sectional areas of different positions of the central section 31 are the same and are A ₁ And A is _2max Greater than A ₁ 。

Similarly, the cross-sectional area of the edge segment 32 of a single first minor grid line 3 at different positions decreases from the boundary of the reinforced region E1 to the boundary of the regular region E0 in a non-linear manner. Specifically, an ordinate a in fig. 7D represents a sectional area of the sub-grid line; the abscissa D in fig. 8D represents the distance between different positions on any of the sub-grid lines and the corresponding edge of the cell main body 1. As shown in FIGS. 7D and 8D, in the region corresponding to D < L, the sectional area of the edge segment 32 of the single first subgrid 3 at the boundary of the reinforced region E1 is maximum A _2max And the cross-sectional area decreases in a non-linear manner (e.g., a curve) as the boundary between the regular region E0 and the reinforced region E1 is gradually approached. In the region corresponding to D is larger than or equal to L, the sectional areas of different positions of the central section 31 are the same and are A ₁ And A is _2max Greater than A ₁ 。

In some alternative embodiments, in order to simplify the manufacturing process and reduce the cost, the cross-sectional area of the single second pair of gate lines 2 at different positions is the same, and the cross-sectional area is the third area. Of course, in practical applications, the cross-sectional area of the single second sub-gate line 2 at different positions may also be different.

In some optional embodiments, a third pair of grid lines parallel to the first pair of grid lines 3 may be further added, at least one third pair of grid lines may be located in the reinforced region E1, and/or a central segment of at least one third pair of grid lines and edge segments located at two sides of the central segment are located in the normal region E0 and the reinforced region E1, respectively. The average cross-sectional area of the single third minor grid line at different positions is the same as the first area, i.e., minor grid lines with lower energy consumption can also be mixed in the reinforcing area E1. With the aid of the third auxiliary grid line, the grid line arrangement density can be increased or other specific requirements can be met by additionally arranging the third auxiliary grid line on the basis of ensuring that the auxiliary grid line in the reinforced area E1 can have a sufficient waterproof effect. The cross-sectional design of the third finger may be identical to that of the finger in the conventional region E0.

The embodiment of the utility model provides a solar wafer, it can be applied to the battery piece of TOPCon structure for example.

To sum up, the embodiment of the utility model provides a solar wafer, it is through dividing the first surface of cell main part into conventional region and encircle the enhancement region around this conventional region, and through making the average sectional area (i.e. first area) that is located the edge section different positions department of single first secondary grid line in the region of strengthening all be greater than the average sectional area (i.e. second area) that is located the central section different positions department of single first secondary grid line in conventional region, can improve the unit consumption of at least part secondary grid thick liquids in the enhancement region for the secondary grid in the conventional region, thereby can increase steam and permeate to inside route from the secondary grid line surface, delay the emergence of grid line corrosion, and then can delay the line resistance of secondary grid line and the contact resistance's of secondary grid line and battery surface rising, delay the speed of power output decay of solar wafer.

As another technical scheme, the embodiment of the utility model provides a still provide a solar cell cluster group, including a plurality of solar cell clusters, every the solar cell cluster all includes the embodiment of the utility model provides an above-mentioned solar wafer, a plurality of solar wafer electric connection (for example parallelly connected or establish ties).

In some alternative embodiments, a plurality of solar cells may be arranged at intervals, as shown in fig. 1 and 2; alternatively, a plurality of solar cells are stacked and welded, as shown in fig. 4B.

The embodiment of the utility model provides a solar cell string group, it is through adopting the utility model provides an above-mentioned solar wafer can delay the line resistance of vice grid line and the rising of vice grid line and the contact resistance on battery surface, delays the speed of solar wafer's power output decay.

It is to be understood that the above embodiments are merely exemplary embodiments that have been employed to illustrate the principles of the present invention, and that the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.

Claims (11)

1. The solar cell is characterized by comprising a cell main body and a secondary grid structure arranged on a first surface of the cell main body, wherein the first surface of the cell main body is divided into a conventional area and a reinforcing area surrounding the conventional area; the normal region is a central region of the first surface, and the reinforced region is an annular edge region surrounding the central region;

the auxiliary grid structure comprises at least four first auxiliary grid lines which are parallel to each other, and the central section of each first auxiliary grid line and the edge sections positioned on two sides of the central section are respectively positioned in the conventional area and the reinforcing area;

the average sectional area of different positions of the edge section of the first secondary grid line is a first area; the average cross-sectional area of the central section of the first auxiliary grid line at different positions is a second area, and the first area is larger than the second area.

2. The solar cell of claim 1, wherein the secondary grid structure further comprises at least four second secondary grid lines parallel to the first secondary grid lines, the second secondary grid lines being located in the reinforcement region; the average sectional area of different positions of the second auxiliary grid line is a third area, and the third area is larger than the second area.

3. The solar cell sheet according to claim 2, wherein a ratio of the first area to the second area is greater than 1 and equal to or less than 3; the ratio of the third area to the second area is greater than 1 and less than or equal to 3.

4. The solar cell of claim 3, wherein the first area ranges from 0.0001mm to 0.001mm ² (ii) a The value range of the third area is 0.0001-0.001 mm ² (ii) a The value range of the second area is 0.000045-0.00075 mm ² 。

5. The solar cell piece according to claim 1, wherein a distance L between the boundary of the regular region and the reinforced region and the corresponding edge of the cell piece main body satisfies the following relation:

wherein A is ₁ Is the second area; c ₁ Is the lower limit coefficient of the distance L, and the lower limit coefficient is 0.0001mm ³ ；C ₂ Is the upper limit coefficient of the distance L, the upper limit coefficient is 0.01mm ³ 。

6. The solar cell slice as claimed in any one of claims 1 to 5, wherein the cross-sectional area of the edge segments of the first secondary grid line at different positions is the same.

7. The solar cell sheet according to any one of claims 1 to 5, wherein the edge segment of the first sub-grid line is divided into a plurality of sub-edge segments along the extending direction thereof, the cross-sectional area of each sub-edge segment at different positions is the same, and the cross-sectional areas of the plurality of sub-edge segments decrease from the boundary of the reinforced region to the boundary of the corresponding normal region and the reinforced region one by one.

8. The solar cell sheet according to any one of claims 1 to 5, wherein the cross-sectional area of the edge segment of the first minor grid line at different positions decreases linearly or non-linearly from the boundary of the reinforced region to the boundary of the corresponding regular region and the reinforced region.

9. The solar cell sheet according to any one of claims 2 to 4, wherein the cross-sectional area of the second sub-grid lines at different positions is the same.

10. The solar cell sheet according to any one of claims 1 to 5, wherein the secondary grid structure further comprises a third secondary grid line parallel to the first secondary grid line, at least one third secondary grid line is located in the reinforcing region, and/or a central section and edge sections located at two sides of the central section of at least one third secondary grid line are respectively located in the normal region and the reinforcing region;

the average sectional area of the third auxiliary grid line at different positions is the same as that of the first area.

11. A solar cell string set comprising a plurality of solar cell strings, wherein each solar cell string comprises a plurality of solar cells according to any one of claims 1 to 10, and the plurality of solar cells are electrically connected.

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