Full-screen photovoltaic module

Abstract

The application discloses a full-screen photovoltaic module, which comprises a cell string formed by a plurality of cell pieces connected in series, and an overlapping area between adjacent cell pieces; a bus bar welded to the back surface of the first cell piece at the head of the cell string, the back surface of the last cell piece at the tail of the cell string, and the back surface of the cell piece corresponding to the position of the intermediate junction box in the middle part of the cell string; wherein the cell piece with the bus bar welded in each cell string is the first cell piece, the cell piece without the bus bar welded in each cell string is the second cell piece, and the front surface short-circuit current of the first cell piece in each cell string is higher than that of the second cell piece in the same string, so as to make up for the loss of the back surface short-circuit current of the first cell piece caused by the shielding of the bus bar. The application solves the problem of short-circuit current mismatch caused by the shielding of the cell piece by the back surface bus bar of the existing full-screen photovoltaic module.

Description

Technical Field

[0001] This invention relates to the field of photovoltaics, and in particular to a full-screen photovoltaic module. Background Technology

[0002] Currently, to increase the screen-to-body ratio of photovoltaic cells and improve module power output, front-side shading is reduced by folding the front busbars to the back of the cells. However, the back busbars create substantial optical shading on the back of cells at the beginning, end, and corresponding positions in the junction box. Due to this shading, cells in this area cannot effectively receive back-side irradiation, resulting in a significantly lower short-circuit current on the back of the shaded cells compared to those not shaded within the same string. This leads to severe back-side current mismatch, reducing the module's back-side power and bifaciality, thus diminishing the core competitiveness of full-screen photovoltaic modules. Summary of the Invention

[0003] The purpose of this invention is to solve the problem of back-side current mismatch in existing full-screen photovoltaic modules. This invention provides a full-screen photovoltaic module that solves the problem of short-circuit current mismatch caused by the back-side busbars obstructing the cells by changing the front-side short-circuit current of the cells with welded busbars.

[0004] To address the aforementioned technical problems, embodiments of the present invention disclose a full-screen photovoltaic module, comprising:

[0005] A battery string is composed of multiple battery cells connected in series, with overlapping areas between adjacent battery cells;

[0006] A busbar is welded to the back of the first battery cell at the head of the battery string and the back of the last battery cell at the tail, as well as to the back of the battery cell in the middle of the battery string corresponding to the intermediate junction box position; wherein,

[0007] The battery cells with the busbar welded to them in each battery string are called first battery cells, and the battery cells without the busbar welded to them in each battery string are called second battery cells. The front short-circuit current of the first battery cell in each battery string is higher than the front short-circuit current of the second battery cell in the same string, so as to compensate for the back short-circuit current loss of the first battery cell due to the back being blocked by the busbar.

[0008] By adopting the above technical solution, the front short-circuit current of the first cell is increased to offset the back current loss of the first cell caused by the busbar shading. This makes the total output current of the first cell in the same string match the total output current of the second cell. This allows the first cell in the same string to output power similar to that of the second cell without busbar shading when the full-screen photovoltaic module is simultaneously exposed to light from both the front and back. This reduces the power loss caused by current mismatch, improves the overall output power of the module, and alleviates the problems of back current mismatch and low bifaciality.

[0009] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a full-screen photovoltaic module, wherein the first cell includes a non-tail-end first cell and a tail-end first cell; the overlap size of the non-tail-end first cell and the adjacent second cell in each string of the cells is W1, and the overlap size between the second cells in each string of the cells is W2, wherein W1 < W2.

[0010] By adopting the above technical solution, by reducing the overlap size between the first battery cell and the adjacent second battery cell, the effective photosensitive area of ​​the first battery cell is made larger than that of the second battery cell, thereby increasing the front short-circuit current of the first battery cell and compensating for the back short-circuit current loss caused by the busbar blocking the back of the first battery cell.

[0011] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a full-screen photovoltaic module, wherein the adjustment amount of the overlap size of the non-tail end first cell and the adjacent second cell in each string of cells is δW, wherein δW=W2-W1 and satisfies: δW=W×η×E / 1000;

[0012] Wherein, W is the width of the busbar, η is the short-circuit current bifaciality of the full-screen photovoltaic module, and E is the available light intensity on the back of the full-screen photovoltaic module.

[0013] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a full-screen photovoltaic module, wherein the effective light-receiving length of the front side of the first cell in each battery string is L1, and the effective light-receiving length of the front side of the second cell in each battery string is L2, wherein L1 > L2.

[0014] By adopting the above technical solution, without changing the arrangement of the battery cells, the effective photosensitive area on the front of the first battery cell is increased to increase the front short-circuit current of the first battery cell, thereby compensating for the back short-circuit current loss caused by the busbar blocking the back of the first battery cell and improving the current matching within the series.

[0015] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a full-screen photovoltaic module, wherein the value of L1 minus L2 is δL, and the value of δL satisfies: δL=W×η×E / 1000;

[0016] Wherein, W is the width of the busbar, η is the short-circuit current bifaciality of the full-screen photovoltaic module, and E is the available light intensity on the back of the full-screen photovoltaic module.

[0017] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a full-screen photovoltaic module, wherein the current density of the first cell in each battery string is I1, and the current density of the second cell in each battery string is I2, wherein I1 > I2.

[0018] By adopting the above technical solution, by selecting a battery cell with a higher current density as the first battery cell, the front short-circuit current of the first battery cell is increased without changing its geometric dimensions, which makes up for the back short-circuit current loss caused by the busbar blocking the back of the first battery cell and improves the current matching within the string.

[0019] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a full-screen photovoltaic module, wherein the value of I1 minus I2 is δI, and δI satisfies:

[0020] δI=I2×W×η×E / 1000 / (L2+L2×η×E / 1000-W×η×E / 1000);

[0021] Wherein, W is the width of the busbar, η is the short-circuit current bifaciality of the full-screen photovoltaic module, E is the available light intensity on the back of the full-screen photovoltaic module, and L2 is the effective light-receiving length of the front of the second cell in each of the battery strings.

[0022] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a full-screen photovoltaic module, wherein the size of the overlapping area between adjacent second cells in each string of cells is 0.2mm to 2.0mm.

[0023] By adopting the above technical solution, the second adjacent cells in each battery string overlap, so that there is no visible gap between adjacent cells in the front field of view, eliminating the occupation of the front light-receiving area by the spacing between cells, and further improving the screen ratio and power output of the module; at the same time, the negative spacing structure adapts to the appearance requirements of full screen, and visual integration can be achieved without additional shielding strips.

[0024] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a full-screen photovoltaic module, wherein each of the plurality of solar cells is a half-cell formed by laser cutting a whole crystalline silicon solar cell.

[0025] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a full-screen photovoltaic module, wherein each of the plurality of solar cells is a one-third solar cell formed by laser cutting a whole crystalline silicon solar cell.

[0026] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a full-screen photovoltaic module, wherein each of the plurality of solar cells is a quarter-cell solar cell formed by laser cutting a whole crystalline silicon solar cell.

[0027] To make the above description of the present invention more apparent and understandable, preferred embodiments are described below in conjunction with the accompanying drawings. Attached Figure Description

[0028] Figure 1 A layout diagram of a full-screen photovoltaic module provided by the present invention is shown;

[0029] Figure 2 The diagram shows a structural schematic of one of the battery strings in a full-screen photovoltaic module provided by the present invention.

[0030] In the attached figures, the following labels are used:

[0031] 100 full-screen photovoltaic modules;

[0032] 110 Battery string; 111 Battery cell; 112 First battery cell; 113 First battery cell (not at the tail end); 114 First battery cell (at the tail end); 115 Second battery cell; 116 Front view of the battery cell; 117 Back view of the battery cell;

[0033] 120 busbar. Detailed Implementation

[0034] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0035] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0036] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of the invention is usually placed in during use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0037] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0038] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0039] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0040] refer to Figure 1 and Figure 2This application provides a full-screen photovoltaic module 100, including a battery string 110 and a busbar 120. The battery string 110 is composed of multiple battery cells 111 connected in series, with overlapping areas between adjacent battery cells 111. The busbar 120 is welded to the back surface 117 of the first battery cell 111 at the beginning and the last battery cell 111 at the end of the battery string 110, as well as the back surface 117 of the battery cell 111 in the middle of the battery string 110 corresponding to the position of the intermediate junction box. The busbar 120 is welded to the back surface 117 of the battery cells 111 to achieve a full-screen effect by eliminating the need for a busbar 120 on the front of the module. This full-screen photovoltaic module 100 can effectively increase the screen-to-body ratio of the battery cells 111 and improve the output power of the full-screen photovoltaic module 100. In each battery string 110, the battery cell 111 with the busbar 120 welded on is the first battery cell 112, and the battery cell 111 without the busbar 120 welded on in each battery string 110 is the second battery cell 115. The short-circuit current of the front side 116 of the first battery cell 112 in each battery string 110 is higher than the short-circuit current of the front side 116 of the second battery cell 115 in the same string, so as to compensate for the short-circuit current loss of the back side 117 of the first battery cell 112 due to being blocked by the busbar 120.

[0041] For example, each of the plurality of solar cells 111 is a half-cell 111 formed by laser cutting a whole crystalline silicon solar cell. Alternatively, each of the plurality of solar cells 111 is a one-third-cell 111 formed by laser cutting a whole crystalline silicon solar cell. Alternatively, each of the plurality of solar cells 111 is a quarter-cell 111 formed by laser cutting a whole crystalline silicon solar cell.

[0042] For example, the first battery cell 112 includes a non-tail first battery cell 113 and a tail first battery cell 114; the overlap size between the non-tail first battery cell 113 and its adjacent second battery cell 115 in each battery string 110 is W1, and the overlap size between the second battery cells 115 in each battery string 110 is W2, where W1 < W2. By reducing the overlap size between the first battery cell 112 and its adjacent second battery cell 115, the effective photosensitive area of ​​the first battery cell 112 is made larger than the effective photosensitive area of ​​the second battery cell 115, thereby increasing the short-circuit current of the front side 116 of the first battery cell 112 and compensating for the short-circuit current loss of the back side 117 of the first battery cell 112 due to being blocked by the busbar 120. For example, the overlap size between the tail first battery cell 114 and its adjacent second battery cell 115 in each battery string 110 is also W2. For example, when welding the battery cell 111 using an automatic stringer, the non-tail end first battery cell 113 does not use negative spacing or reduces negative spacing measures to reduce the influence of the adjacent second battery cell 115 covering its front side 116. The light-receiving area of ​​the front side 116 of the non-tail end first battery cell 113 is reduced, that is, the short-circuit current of its front side 116 is increased without changing the geometry of the first battery cell 112.

[0043] For example, the size of the overlapping area between adjacent second battery cells 115 in each battery string 110 is 0.2mm to 2.0mm. That is, W2 is 0.2mm to 2.0mm. For example, the size of the overlapping area between adjacent second battery cells 115 in each battery string 110 is 0.2mm, 0.35mm, 0.98mm, 1.2mm, 1.52mm, 2.0mm, etc.

[0044] For example, the adjustment amount of the overlap size between the non-tail end first solar cell 113 and its adjacent second solar cell 115 in each solar cell string 110 is δW, where δW = W2 - W1 and satisfies: δW = W × η × E / 1000; where W is the width of the busbar 120, η is the short-circuit current bifaciality of the full-screen photovoltaic module 100, and E is the available light intensity of the back side 117 of the full-screen photovoltaic module 100. It should be noted that the specific value of W is related to factors such as the rated current of the full-screen photovoltaic module 100, the material of the busbar 120, and the size of the first solar cell 112, and can be selected according to actual needs. For example, W can be 2mm, 4mm, 6mm, 10mm, 12mm, 15mm, etc. The specific value of η is related to factors such as the type of solar cell 111 and the manufacturing process of the full-screen photovoltaic module 100. Therefore, it can be selected according to actual needs. For example, η can be 50%, 60%, 65%, 75%, 80%, 82%, 92%, etc. The specific value of E is related to factors such as the reflectivity of the installation scene, the height of the full-screen photovoltaic module 100 above the ground, and the geographical location. For example, E can be 100W / m², 150 W / m², 180 W / m², 240 W / m², 300 W / m², etc.

[0045] For example, if W=6mm, η=80%, and E=100W / m², then δW=0.48mm. Where δW=W2-W1, for example, if W2=1.2mm, then W1=0.72mm. That is, by simply increasing the overlap size of the non-tail-end first battery cell 113 and its adjacent second battery cell 115 in each battery string 110 by 0.48 mm compared to the overlap area between adjacent second battery cells 115 in each battery string 110, the electrical loss caused by the 6mm busbar 120 shading the back surface 117 of the non-tail-end first battery cell 113 can be compensated. Furthermore, the required adjustment is small and easily implemented industrially.

[0046] For example, the effective light-receiving length of the front side 116 of the first battery cell 112 in each battery string 110 is L1, and the effective light-receiving length of the front side 116 of the second battery cell 115 in each battery string 110 is L2, where L1 > L2. Without changing the arrangement of the battery cells 111, an uneven cutting method is used to increase the effective photosensitive area of ​​the front side 116 of the first battery cell 112, thereby increasing the short-circuit current of the front side 116 of the first battery cell 112. This compensates for the short-circuit current loss of the back side 117 of the first battery cell 112 due to being blocked by the busbar 120, improving the current matching within the string. In other words, the first battery cell 112 in each battery string 110 can be a large-size battery cell. By increasing the length L1 of the first battery cell 112, the current value of the front side 116 of the first battery cell 112 is increased to compensate for the current loss due to the blocking of the back side 117. Then, an automatic stringer is used to weld multiple battery cells 111 into a battery string 110, and finally, they are arranged and laminated to obtain a photovoltaic laminate.

[0047] For example, the value of L1 minus L2 is δL, which satisfies: δL = W × η × E / 1000; where W is the width of the busbar 120, η is the short-circuit current bifaciality of the full-screen photovoltaic module 100, and E is the available light intensity on the back side 117 of the full-screen photovoltaic module 100. Similarly, the specific values ​​of W, η, and E can be selected according to actual needs.

[0048] For example, if W=6mm, η=80%, and E=100W / m², then δW=0.48mm. Where δL=L1-L2, for example, if L2=60mm, then L1=60.48mm. That is, by simply increasing the effective light-receiving length of the front side 116 of the first battery cell 113 in each battery string 110 by 0.48 mm compared to the effective light-receiving length of the front side 116 of the second battery cell 115 in each battery string 110, the electrical loss caused by the 6mm busbar 120 blocking the back side 117 of the first battery cell 113 can be compensated. Furthermore, the required adjustment is small and easily implemented industrially.

[0049] For example, the current density of the first cell 112 in each battery string 110 is I1, and the current density of the second cell 115 in each battery string 110 is I2, where I1 > I2. By selecting a cell 111 with a higher current density as the first cell 112, the short-circuit current of its front side 116 is increased without changing the geometry of the first cell 112, compensating for the short-circuit current loss on the back side 117 of the first cell 112 due to the shielding by the busbar 120, thus improving the current matching within the string. In other words, the first cell 112 in each battery string 110 can be a high-efficiency cell of the same size, increasing the current value of the front side 116 of the first cell 112 to compensate for the current loss due to the shielding of the back side 117. Then, multiple cells 111 are welded into a battery string 110 using an automatic stringer, and finally, they are arranged and laminated to obtain a photovoltaic laminate.

[0050] For example, the value of I1 minus I2 is δI, and δI satisfies: δI=I2×W×η×E / 1000 / (L2+L2×η×E / 1000-W×η×E / 1000); where W is the width of busbar 120, η is the short-circuit current bifaciality of full-screen photovoltaic module 100, E is the available light intensity of the back side 117 of full-screen photovoltaic module 100, and L2 is the effective light-receiving length of the front side 116 of the second cell 115 in each cell string 110.

[0051] For example, W=6mm, η=80%, E=100W / m², L²=60mm, I²=41mA / cm 2 Therefore, δI≈0.31mA / cm 2 Where δI = I1 - I2, for example, I2 = 41 mA / cm 2 Therefore, I1 = 41.31 mA / cm 2 In other words, simply replacing the first cell 112 in each battery string 110 with a cell with a higher current density can electrically compensate for the shading loss of the 6 mm busbar 120 on the back side 117 of the first cell 113.

[0052] While the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the invention to these descriptions. Various changes in form and detail can be made by those skilled in the art, including several simple deductions or substitutions, without departing from the spirit and scope of the invention.

Claims

1. A full-screen photovoltaic module, characterized in that, include: A battery string is composed of multiple battery cells connected in series, with overlapping areas between adjacent battery cells; A busbar is welded to the back of the first battery cell at the head of the battery string and the back of the last battery cell at the tail, as well as to the back of the battery cell in the middle of the battery string corresponding to the intermediate junction box position; wherein, The battery cells with the busbar welded to them in each battery string are called first battery cells, and the battery cells without the busbar welded to them in each battery string are called second battery cells. The front short-circuit current of the first battery cell in each battery string is higher than the front short-circuit current of the second battery cell in the same string, so as to compensate for the back short-circuit current loss of the first battery cell due to the back being blocked by the busbar.

2. The full-screen photovoltaic module according to claim 1, characterized in that, The first battery cell includes a non-tail-end first battery cell and a tail-end first battery cell; the overlap size between the non-tail-end first battery cell and the adjacent second battery cell in each battery string is W1, and the overlap size between the second battery cells in each battery string is W2, wherein W1 < W2.

3. The full-screen photovoltaic module according to claim 2, characterized in that, The adjustment amount of the overlap size between the non-tail end first battery cell and the adjacent second battery cell in each battery string is δW, where δW = W2 - W1 and satisfies: δW = W × η × E / 1000. Wherein, W is the width of the busbar, η is the short-circuit current bifaciality of the full-screen photovoltaic module, and E is the available light intensity on the back of the full-screen photovoltaic module.

4. The full-screen photovoltaic module according to claim 1, characterized in that, The effective light-receiving length of the first battery cell in each battery string is L1, and the effective light-receiving length of the second battery cell in each battery string is L2, wherein L1 > L2.

5. The full-screen photovoltaic module according to claim 4, characterized in that, The value of L1 minus L2 is δL, and δL satisfies: δL=W×η×E / 1000; Wherein, W is the width of the busbar, η is the short-circuit current bifaciality of the full-screen photovoltaic module, and E is the available light intensity on the back of the full-screen photovoltaic module.

6. The full-screen photovoltaic module according to claim 1, characterized in that, The current density of the first cell in each battery string is I1, and the current density of the second cell in each battery string is I2, where I1 > I2.

7. The full-screen photovoltaic module according to claim 6, characterized in that, The value of I1 minus I2 is δI, and δI satisfies: δI=I2×W×η×E / 1000 / (L2+L2×η×E / 1000-W×η×E / 1000); Wherein, W is the width of the busbar, η is the short-circuit current bifaciality of the full-screen photovoltaic module, E is the available light intensity on the back of the full-screen photovoltaic module, and L2 is the effective light-receiving length of the front of the second cell in each of the battery strings.

8. The full-screen photovoltaic module according to claim 1, characterized in that, The size of the overlapping area between adjacent second battery cells in each battery string is 0.2 mm to 2.0 mm.

9. The full-screen photovoltaic module according to claim 1, characterized in that, Each of the plurality of solar cells is a half-cell formed by laser cutting a whole crystalline silicon solar cell.

10. The full-screen photovoltaic module according to claim 1, characterized in that, Each of the plurality of said solar cells is a one-third solar cell formed by laser cutting a whole crystalline silicon solar cell.

11. The full-screen photovoltaic module according to claim 1, characterized in that, Each of the plurality of solar cells is a quarter-cell solar cell formed by laser cutting a whole crystalline silicon solar cell.

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