IBC battery interconnection structure

Abstract

The IBC battery interconnection structure comprises battery pieces, each battery piece is provided with a positive electrode main grid line, a negative electrode main grid line, a positive electrode fine grid line and a negative electrode fine grid line, the positive electrode main grid line and the negative electrode main grid line which are relatively close to each other are arranged in parallel to form a main grid line pair, the distance between the positive electrode main grid line and the negative electrode main grid line in the main grid line pair is D1, and the distance between the positive electrode fine grid line and the negative electrode fine grid line in the main grid line pair is D2. The distance between the positive electrode main grid line and the negative electrode main grid line which are located in the two adjacent main grid line pairs and adjacent to each other is D2, and D1 is smaller than D2; the fine grid lines are perpendicular to the main grid lines, the positive fine grid lines and the negative fine grid lines are alternately arranged in parallel, the positive fine grid lines are connected with the positive main grid lines, the positive fine grid lines are insulated from the negative main grid lines, the negative fine grid lines are connected with the negative main grid lines, and the negative fine grid lines are insulated from the positive main grid lines. The positive main grid line and the negative main grid line in the main grid line pair are arranged close to each other as far as possible, so that the distribution of positive and negative carrier collection areas is changed, the current is better collected, and the current collection efficiency is improved.

Description

[0001] This application is a divisional application of the application with the application number 201710046890.3 and the invention creation name "IBC cell interconnection structure for improving power". The filing date of the patent application with the application number 201710046890.3 is January 22, 2017. Technical Field

[0002] The present invention relates to an IBC cell interconnection structure. Background Art

[0003] IBC (Interdigitated back contact) cells refer to cells without electrodes on the front side, and the positive and negative metal grid lines are arranged in a finger-like cross pattern on the back of the cell. The biggest feature of IBC cells is that both the PN junction and the metal contact are on the back of the cell, and there is no influence of metal electrode shielding on the front side. Therefore, they have a higher short-circuit current Jsc. At the same time, a relatively wide metal grid line can be allowed on the back to reduce the series resistance Rs and thus increase the fill factor FF; coupled with the open-circuit voltage gain brought by the front surface field (FSF) of the cell and good passivation effect, such cells without front-side shielding not only have high conversion efficiency but also look more beautiful. At the same time, fully back-electrode components are easier to assemble. IBC cells are one of the technical directions for realizing high-efficiency crystalline silicon cells currently.

[0004] Currently, the component packaging of IBC cells adopts the method of conductive backplane or solder ribbon welding. The cost of the conductive backplane is relatively high. In small-area cells, the main grids of the positive and negative electrodes are located at both ends of the cell, and welding or edge interconnection can be conveniently realized. However, for large-area cells, this main grid design will cause an increase in series resistance and loss of efficiency. At the same time, due to the relatively high current of IBC cells themselves, the resistance loss of the components will increase. Summary of the Invention

[0005] The purpose of the present invention is to provide an IBC cell interconnection structure to reduce the series resistance of the cell, improve the carrier collection efficiency, and increase the power of the component by re-designing the main grid line.

[0006] In a first aspect, the present invention provides an IBC cell interconnection structure, including cell wafers. Each cell wafer is provided with a positive main grid line, a negative main grid line, positive fine grid lines, and negative fine grid lines. The relatively closely spaced positive main grid line and negative main grid line are arranged in parallel to form a main grid line pair. The spacing between the positive main grid line and the negative main grid line in the main grid line pair is D1, and the spacing between the positive main grid line and the negative main grid line that are adjacent and located in two adjacent main grid line pairs respectively is D2, where D1 < D2. The fine grid lines are arranged perpendicular to the main grid lines. The positive fine grid lines and the negative fine grid lines are arranged alternately in parallel. The positive fine grid lines are connected to the positive main grid lines with the same polarity, and the positive fine grid lines are insulated from the negative main grid lines with opposite polarities. The negative fine grid lines are connected to the negative main grid lines with the same polarity, and the negative fine grid lines are insulated from the positive main grid lines with opposite polarities.

[0007] In some possible implementation manners, in the direction perpendicular to the main grid line pair, the positive main grid lines and the negative main grid lines are arranged alternately in sequence.

[0008] In some possible implementation manners, the distance from the outermost main grid line of the cell wafer to the end of the adjacent fine grid line with the same polarity is D3, where D1 < D3 < D2.

[0009] In some possible implementation manners, the cell wafer is an IBC cell evenly divided into 2 - 5 independent cell wafers.

[0010] In some possible implementation manners, the vertical separation structure is that the IBC cell is evenly divided into 2 - 5 independent cell wafers in the direction perpendicular to the main grid line pair. The adjacent cell wafers are arranged in central symmetry. The conductive connecting member uses a conductive tape or a copper tape plated with In or Sn. The main grid line pairs of the adjacent cell wafers remain parallel to each other, and the positive main grid lines and the negative main grid lines with opposite polarities are located on the same straight line.

[0011] In some possible implementation manners, insulating glue is provided between the positive fine grid lines and the negative main grid lines with opposite polarities, and insulating glue is provided between the negative fine grid lines and the positive main grid lines with opposite polarities.

[0012] In some possible implementation manners, the spacing between adjacent cell wafers is 0.5 mm - 3 mm.

[0013] In some possible implementation manners, the parallel separation structure is that the IBC cell is evenly divided into 2 - 5 independent cell wafers in the direction parallel to the main grid line pair. Each cell wafer is provided with a set of positive main grid lines and negative main grid lines with opposite polarities, and the positive main grid lines and the negative main grid lines are arranged at both ends of the cell wafer.

[0014] In some possible implementation manners, there is a gap between the positive fine grid lines and the negative main grid lines with opposite polarities, and there is a gap between the negative fine grid lines and the positive main grid lines with opposite polarities.

[0015] In some possible implementation manners, the distance between adjacent solar cells is 0.2 mm - 3 mm.

[0016] In some possible implementation manners, the conductive connection member is made of a metal plate or a conductive tape.

[0017] In some possible implementation manners, the surface of the conductive connection member is coated with a reflective medium layer.

[0018] In some possible implementation manners, the number of solar cells is the same as the number of main grid lines.

[0019] The beneficial effects of the present invention are as follows: In this IBC cell interconnection structure, the positive main grid lines and the negative main grid lines that are relatively close to each other are arranged in parallel to form a main grid line pair. The distance between the positive main grid line and the negative main grid line in the main grid line pair is D1, and the distance between the positive main grid line and the negative main grid line that are adjacent and located in two adjacent main grid line pairs respectively is D2, and D1 < D2; by arranging the positive main grid line and the negative main grid line in each main grid line pair as close as possible, the distribution of the positive and negative carrier collection regions is changed to better converge the current and improve the current collection efficiency. Moreover, the main grid lines with opposite polarities are arranged with unequal intervals, optimizing the electrode layout and reducing the series resistance of the cell, thereby improving the power of the module. Description of the Drawings

[0020] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0021] Figure 1 is a schematic diagram of the main grid line design of the IBC cell;

[0022] Figure 2 is a schematic diagram of the IBC cell in Embodiment 1 being evenly divided into 2 solar cells and adopting a vertical division structure;

[0023] Figure 3 is a schematic diagram of the IBC cell in Embodiment 2 being evenly divided into 3 solar cells and adopting a vertical division structure;

[0024] Figure 4 is a schematic diagram of the IBC cell in Embodiment 3 being evenly divided into 3 solar cells and adopting a parallel division structure;

[0025] Figure 5It is a schematic diagram of Example 4 where the IBC cell is evenly divided into 5 cell pieces and adopts a parallel division structure;

[0026] Among them: 1 - positive fine grid line, 2 - negative fine grid line, 3 - positive main grid line, 4 - negative main grid line, 5 - insulating glue, 6 - conductive connecting piece. Specific implementation manners

[0027] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0029] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined. "Several" means one or more unless otherwise specifically defined.

[0030] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention.

[0031] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0032] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0033] As shown Figures 1 - 3 in the figure, an IBC cell interconnection structure provided by an embodiment of the present invention includes cell wafers. Each cell wafer is provided with a positive main grid line 3, a negative main grid line 4, a positive fine grid line 1, and a negative fine grid line 2. The relatively close positive main grid line 3 and negative main grid line 4 are arranged in parallel to form a main grid line pair. The distance between the positive main grid line 3 and the negative main grid line 4 in the main grid line pair is D1, and the distance between the adjacent positive main grid line 3 and negative main grid line 4 located in two adjacent main grid line pairs is D2, and D1 < D2. The fine grid lines are arranged perpendicular to the main grid lines. The positive fine grid lines 1 and the negative fine grid lines 2 are arranged alternately in parallel. The positive fine grid line 1 is connected to the positive main grid line 3 with the same polarity, and the positive fine grid line 1 is insulated from the negative main grid line 4 with the opposite polarity. The negative fine grid line 2 is connected to the negative main grid line 4 with the same polarity, and the negative fine grid line 2 is insulated from the positive main grid line 3 with the opposite polarity. It should be noted that the structures of the positive main grid line 3, the negative main grid line 4, and the main grid line in this application can have the following several forms. The first form can be a continuous and uninterrupted grid line; or, the second form includes a continuous and uninterrupted grid line and electrical bonding parts (the electrical bonding parts can be pads on the fine grid lines with the same polarity, end lines corresponding to the vicinity of both ends of the fine grid lines, or thickened segments corresponding to the fine grid lines) arranged at intervals on the grid line; or, the third form only includes electrical bonding parts arranged at intervals (the electrical bonding parts can be pads on the fine grid lines with the same polarity, end lines corresponding to the vicinity of both ends of the fine grid lines, or thickened segments corresponding to the fine grid lines), that is, there is no main grid.

[0034] In the case of adopting the above technical solution, in the IBC cell interconnection structure, the relatively close positive main grid line 3 and negative main grid line 4 are arranged in parallel to form a main grid line pair. The distance between the positive main grid line 3 and the negative main grid line 4 in the main grid line pair is D1, and the distance between the adjacent positive main grid line 3 and negative main grid line 4 located in two adjacent main grid line pairs is D2, and D1 < D2. By arranging the positive main grid line 3 and the negative main grid line 4 in each main grid line pair as close as possible, the distribution of the positive and negative carrier collection regions of the cell wafer is changed to better collect current and improve the current collection efficiency. Moreover, the main grid lines with opposite polarities are arranged at unequal intervals, optimizing the electrode layout and reducing the series resistance of the cell, thereby improving the power of the component.

[0035] In some embodiments, in the direction perpendicular to the main grid line pair, the positive main grid line 3 and the negative main grid line 4 are alternately arranged in sequence. In this way, the positive main grid line 3 and the negative main grid line 4 are alternately arranged in sequence, which can make the positive and negative carrier collection regions arranged alternately, reduce the carrier transmission distance, and improve the current collection efficiency.

[0036] As shown Figures 1 - 3As shown, in some possible implementation manners, the distance from the main grid line at the outermost side of the cell to the end of the adjacent fine grid line with the same polarity is D3, where D1 < D3 < D2. For example, the two main grid lines at the outermost side of the cell are a positive main grid line 3 and a negative main grid line 4 respectively. Among them, the distance from the outermost positive main grid line 3 to the end of the adjacent positive fine grid line 1 with the same polarity is D3, and the distance from the outermost negative main grid line 4 to the end of the adjacent negative fine grid line 2 with the same polarity is D3. D1 < D3, so that there is a certain distance between the main grid line at the outermost side of the cell and the end of the adjacent fine grid line with the same polarity. This distance D3 can prevent the outermost main grid line from exceeding the end of the fine grid line, which is beneficial to the connection between the outermost main grid line and the conductive connection member 6, and avoid the risk of fragmentation of the cell edge caused by the conductive connection member 6. At the same time, D3 < D2 to prevent D3 from being too large and affecting the current collection efficiency at the cell edge.

[0037] In some possible implementation manners, the cell is an IBC cell evenly divided into 2 - 5 independent cells. The IBC cell adopts a vertical division structure or a parallel division structure. The IBC cell is evenly divided into 2 - 5 independent cells, that is, the cell is obtained by evenly dividing an IBC cell into 2 - 5 parts. It can be a half cell, a third - divided cell, a quarter - divided cell or a fifth - divided cell. Adjacent cells are connected by a conductive connection member 6 for electrodes with opposite polarities.

[0038] Specifically, the vertical division structure is that the IBC cell is evenly divided into 2 - 5 independent cells in the direction perpendicular to the main grid line pair. Adjacent cells are symmetrically arranged at the center. The conductive connection member 6 uses conductive tape or a copper tape plated with In or Sn. The main grid line pairs of adjacent cells remain parallel to each other, and the positive main grid line 3 and the negative main grid line 4 with opposite polarities are located on the same straight line. There is an insulating glue 5 between the positive fine grid line 1 and the negative main grid line 4 with opposite polarities, and there is an insulating glue 5 between the negative fine grid line 2 and the positive main grid line 3 with opposite polarities.

[0039] The parallel division structure is that the IBC cell is evenly divided into 2 - 5 independent cells in the direction parallel to the main grid line pair. Each cell is provided with a set of positive main grid line 3 and negative main grid line 4 with opposite polarities, and the positive main grid line 3 and the negative main grid line 4 are arranged at both ends of the cell. There is a gap between the positive fine grid line 1 and the negative main grid line 4 with opposite polarities, and there is a gap between the negative fine grid line 2 and the positive main grid line 3 with opposite polarities.

[0040] The IBC cell interconnection structure can increase the power of the module by at least 2%-3%. The present invention reduces the power loss caused by large current by dividing the cell into half or multiple pieces, and also reduces the series resistance of the cell through the redesign of the main grid lines of the cell, reducing the process complexity during the printing of the main grid, thereby maximizing the power of the module. The interconnection of the cell wafers can be achieved using conductive tape or conductive copper plates.

[0041] Example 1

[0042] As Figure 2 , the main grid lines of the IBC cell are equally spaced on the metallization area. The distance between the positive main grid line 3 and the negative main grid line 4 is 4 mm. An insulating adhesive 5 is used for insulation between the main grid lines with opposite polarities and the sub-grid lines. The large-area multi-main-grid cell after screen printing and sintering is divided into 1 / 2 by a laser in the direction perpendicular to the main grid, obtaining two cell wafers. One of the cell wafers is rotated 180°, and the positive and negative main grids in the vertical direction of the adjacent cell wafers are connected using a solder strip.

[0043] Example 2

[0044] The structure of Example 2 is basically the same as that of Example 1. The difference between Example 2 and Example 1 is that: the large-area multi-main-grid cell after screen printing and sintering is divided into 1 / 3 by a laser in the direction perpendicular to the main grid, as Figure 3 , obtaining three cell wafers, and the middle cell wafer is rotated 180°.

[0045] Example 3

[0046] As Figure 4 , positive main grid lines 3 and negative main grid lines 4 are respectively provided at both ends of the IBC cell. There is a 0.5 mm gap between the main grid lines with opposite polarities and the fine grid lines. During the preparation of the cell, the emitter and back surface field regions terminate within each 1 / 3 cell, and the emitter and back surface field regions of adjacent cells are not connected. The distance between adjacent positive and negative main grids is 1 mm. After screen printing and sintering, along the direction parallel to the main grid, the adjacent main grids inside the cell are divided into 3 cells by a laser, and the main grids of the adjacent cells are welded using a conductive copper plate, with a distance of 1.5 mm.

[0047] Example 4

[0048] As Figure 5, on both ends of the IBC battery, a positive main grid line 3 and a negative main grid line 4 are respectively provided, and there is a 0.5 mm gap between the main grid lines and the fine grid lines with opposite polarities. During battery preparation, the emitter and back surface field regions terminate within each 1 / 5 battery, and the emitter and back surface field regions of adjacent batteries are not connected. The distance between adjacent positive and negative main grids is 1 mm. After screen printing and sintering, along the direction parallel to the main grid, the adjacent main grids inside the battery are divided into 5 batteries by a laser, and after division, the main grids of adjacent batteries are welded with a conductive copper plate, and the distance is 1 mm.

[0049] The principle of the embodiment is as follows:

[0050] For the power loss of the component, it comes from P = I 2 Rs. After adopting the design of half cells or 1 / 3 or 1 / 5 cells, the loss caused by current is 1 / 4 or 1 / 25 of the original. At the same time, since the current transmission distance is shortened to 1 / 3 or 1 / 5 of the original, the series resistance is also significantly reduced, so the power loss is reduced and the component power is increased.

[0051] In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in a suitable manner in any one or more embodiments or examples.

[0052] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claimed rights.

Claims

1. An IBC cell interconnection structure, characterized in that: It includes cell wafers. Each cell wafer is provided with a positive main grid line, a negative main grid line, positive fine grid lines and negative fine grid lines. The relatively close positive main grid line and the negative main grid line are arranged in parallel to form a main grid line pair. The distance between the positive main grid line and the negative main grid line in the main grid line pair is D1, and the distance between the positive main grid line and the negative main grid line that are adjacent and located in two adjacent main grid line pairs respectively is D2, and D1 < D2; the fine grid lines are arranged perpendicular to the main grid lines, the positive fine grid lines and the negative fine grid lines are arranged in parallel and alternately. The positive fine grid lines are connected to the positive main grid lines with the same polarity, the positive fine grid lines and the negative main grid lines with opposite polarities are insulated from each other, the negative fine grid lines are connected to the negative main grid lines with the same polarity, and the negative fine grid lines and the positive main grid lines with opposite polarities are insulated from each other.

2. The IBC cell interconnection structure according to claim 1, characterized in that, In the direction perpendicular to the main grid line pair, the positive main grid lines and the negative main grid lines are arranged alternately in sequence.

3. The IBC cell interconnection structure according to claim 2, characterized in that, The distance from the outermost main grid line of the cell wafer to the end of the adjacent fine grid line with the same polarity is D3, and D1 < D3 < D2.

4. The IBC cell interconnection structure according to claim 1, characterized in that, The cell wafer is an IBC cell evenly divided into 2 - 5 independent cell wafers.

5. The IBC cell interconnection structure according to claim 4, characterized in that, The vertical separation structure is that the IBC cell is evenly divided into 2 - 5 independent cell wafers in the direction perpendicular to the main grid line pair. The adjacent cell wafers are arranged in central symmetry. The conductive connection member uses a conductive tape or a copper tape plated with In or Sn. The main grid line pairs of adjacent cell wafers remain parallel to each other, and the positive main grid lines and the negative main grid lines with opposite polarities are located on the same straight line.

6. The IBC cell interconnection structure according to claim 5, characterized in that, There is insulating glue between the positive fine grid lines and the negative main grid lines with opposite polarities, and there is insulating glue between the negative fine grid lines and the positive main grid lines with opposite polarities.

7. The IBC cell interconnection structure according to claim 5, characterized in that, The distance between adjacent cell wafers is 0.5 mm - 3 mm.

8. The IBC cell interconnection structure according to claim 4, characterized in that, The parallel separation structure is that the IBC cell is evenly divided into 2 - 5 independent cell wafers in the direction parallel to the main grid line pair. Each cell wafer is provided with a set of positive main grid lines and negative main grid lines with opposite polarities, and the positive main grid lines and the negative main grid lines are arranged at both ends of the cell wafer.

9. The IBC cell interconnection structure according to claim 8, characterized in that, There is a gap between the positive fine grid lines and the negative main grid lines with opposite polarities, and there is a gap between the negative fine grid lines and the positive main grid lines with opposite polarities.

10. The IBC cell interconnection structure according to claim 9, characterized in that, The distance between adjacent cell wafers is 0.2 mm - 3 mm.

11. The IBC cell interconnection structure according to claim 8, characterized in that, the conductive connecting member is a metal plate or a conductive tape.

12. The IBC cell interconnection structure according to any one of claims 4-11, characterized in that, a reflective medium layer is coated on the surface of the conductive connecting member.

13. The IBC cell interconnection structure according to any one of claims 8-11, characterized in that, the number of the cell pieces is the same as the number of the main grid lines.

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