Back contact cell assembly and photovoltaic system

Abstract

The present disclosure is applicable to the technical field of solar cells, and provides a back contact cell assembly and a photovoltaic system. The back contact cell assembly comprises a cell string, a solder ribbon, a conductive connecting structure, and an insulating structure. A first cell and a second cell are distributed in a first direction. The first cell and the second cell are at least partially stacked together. First grid lines and second grid lines extend in a second direction and are alternately arranged in the first direction. The solder ribbon is arranged on a back surface of the first cell and extends in the first direction. An accommodating space is formed between the side of the first cell close to the second cell and the solder ribbon. The conductive connecting structure is at least partially laid in the accommodating space and connects a first grid line to the solder ribbon in the accommodating space. In this way, the solder ribbon can be connected to the first grid line in the accommodating space by means of the conductive connecting structure, so that a current in the accommodating space can be collected, thereby improving the power generation efficiency of the back contact cell assembly.

Description

Back contact cell assembly and photovoltaic system

[0001] Cross-reference to related applications

[0002] The present disclosure claims priority to the Chinese patent application No. 202411104383.7, filed on August 12, 2024, entitled "Back contact cell assembly and photovoltaic system", and the Chinese patent application No. 202411205553.0, filed on August 29, 2024, entitled "Back contact cell assembly and photovoltaic system", the contents of which are incorporated herein by reference in their entirety. TECHNICAL FIELD

[0003] The present disclosure belongs to the technical field of solar cells, and particularly relates to a back contact cell assembly and a photovoltaic system. BACKGROUND

[0004] At present, the back contact cell refers to a solar cell in which the light-receiving surface of the cell is free of electrodes, and the positive and negative electrodes are arranged on the back side of the cell, so that the shading of the electrodes on the cell can be reduced, the short-circuit current of the cell can be increased, and the energy conversion efficiency of the cell can be improved. In the related technology, a plurality of back contact cells are arranged in a stacked manner at the edges, which can increase the light-receiving area of the cell. However, the stacked back contact cells cannot collect the current at the edge position of one of the back contact cells, which leads to a decrease in the power generation efficiency of the cell. SUMMARY

[0005] The present disclosure provides a back contact cell assembly and a photovoltaic system, which aims to solve the problem that the current at the edge position of a photovoltaic cell cannot be collected when using a stacked structure.

[0006] The back contact cell assembly provided by the present disclosure includes a cell string, a solder strip, a conductive connection structure, and an insulating structure. The cell string includes adjacent first and second cell pieces. The first and second cell pieces are arranged in a first direction. The first and second cell pieces are at least partially arranged in a stacked manner. The back surface of each of the first and second cell pieces is formed with a first grid line and a second grid line. The first and second grid lines extend in a second direction and are alternately arranged in the first direction. The first and second grid lines have opposite polarities. The solder strip is arranged on the back surface of the first cell piece and extends in the first direction. A receiving space is formed between the side of the first cell piece close to the second cell piece and the solder strip. The conductive connection structure is at least partially laid in the receiving space and connects the first grid line and the solder strip in the receiving space. The insulating structure covers the second grid line. The insulating structure is arranged in the receiving space and located between the second grid line and the solder strip.

[0007] In some embodiments, the length L of the conductive connecting structure along the first direction satisfies the following relationship: 0 < L ≤ D / tan α, where α is the included angle between the direction of the solder strip lifting and the first direction, and D is the thickness of the second battery piece along the third direction, which is perpendicular to the second direction and the first direction.

[0008] In some embodiments, the solder strip includes a first solder strip, the first solder strip extends along the first direction and connects the back surface of the first battery piece and the back surface of the second battery piece, and a receiving space is formed between the side of the first battery piece close to the second battery piece and the first solder strip.

[0009] In some embodiments, when the back surface of the first battery piece and the front surface of the second battery piece are at least partially laminated together, the receiving space is formed at the side of the back surface of the first battery piece close to the second battery piece, and the solder strip further includes a second solder strip and a third solder strip, the second solder strip is arranged on the back surface of the first battery piece and at least partially extends into the back surface of the second battery piece, and the third solder strip is located on the back surface of the second battery piece.

[0010] In some embodiments, the back contact battery assembly further includes a bus bar, the bus bar is arranged on the back surface of the second battery piece;

[0011] The bus bar connects the second solder strip and is located at the side of the second solder strip away from the second battery piece;

[0012] The bus bar connects the second solder strip and is located at the side of the second solder strip close to the second battery piece.

[0013] In some embodiments, when the front surface of the first battery piece and the back surface of the second battery piece are at least partially laminated together, the receiving space is formed at the side of the back surface of the first battery piece close to the second battery piece, and the solder strip further includes a second solder strip and a third solder strip, the second solder strip is arranged on the back surface of the first battery piece and at least partially extends into the back surface of the second battery piece, and the third solder strip is located on the back surface of the second battery piece.

[0014] In some embodiments, the back contact battery assembly further includes a bus bar, the bus bar is arranged on the back surface of the first battery piece;

[0015] The bus bar connects the second solder strip and is located at the side of the second solder strip away from the first battery piece;

[0016] The bus bar connects the second solder strip and is located at the side of the second solder strip close to the first battery piece.

[0017] In some embodiments, the insulating structure is prepared by laying or coating.

[0018] In some embodiments, the conductive connecting structure is tin paste or conductive glue or other metal conductive materials.

[0019] In some embodiments, the length of the conductive connection structure along the first direction is greater than 6 mm.

[0020] In some embodiments, the thickness of the conductive connection structure along the third direction is 30 μm-300 μm, wherein the third direction is perpendicular to the first direction and the second direction.

[0021] In some embodiments, the width of the solder strip in the second direction is greater than the width of the conductive connection structure.

[0022] In some embodiments, the width of the insulating structure in the second direction is greater than the width of the conductive connection structure.

[0023] In some embodiments, the thickness of the insulating structure is 25 μm-40 μm.

[0024] In some embodiments, the conductive connection structure is formed with an inclined surface on the side away from the first cell piece, and the inclined surface connects the solder strip.

[0025] In some embodiments, the back contact cell assembly further comprises an insulating layer, which is arranged between the bus bar and the third solder strip.

[0026] In some embodiments, the included angle α between the direction in which the solder strip is lifted and the first direction is adjusted according to the yield strength of the solder strip.

[0027] In some embodiments, the yield strength of the solder strip is less than or equal to 75 Mpa.

[0028] In some embodiments, the thickness D of the second cell piece along the third direction is 90 μm-200 μm.

[0029] The photovoltaic system provided by the embodiments of the present disclosure comprises the back contact cell assembly of any one of the above embodiments.

[0030] In the back contact cell assembly and the photovoltaic system of the embodiments of the present disclosure, the back contact cell assembly comprises a cell string, a solder strip, a conductive connection structure and an insulating structure, the cell string comprises adjacent first and second cell pieces, the first and second cell pieces are arranged in a first direction, the first and second cell pieces are at least partially stacked together, the back surface of each of the first and second cell pieces is formed with a first and a second grid line, the first and second grid lines extend in a second direction and are alternately arranged in the first direction, the first and second grid lines are opposite in polarity, the solder strip is arranged on the back surface of the first cell piece and extends in the first direction, a receiving space is formed between the side of the first cell piece close to the second cell piece and the solder strip, the conductive connection structure is at least partially laid in the receiving space and connects the first grid line in the receiving space and the solder strip, and the insulating structure covers the second grid line, the insulating structure is arranged in the receiving space and between the second grid line and the solder strip. In this way, the solder strip can be connected with the first grid line in the receiving space through the conductive connection structure, so that the current in the receiving space can be collected, thereby improving the power generation efficiency of the back contact cell assembly, and meanwhile, the insulating structure can be arranged between the second grid line and the conductive connection structure to avoid short circuit. BRIEF DESCRIPTION OF DRAWINGS

[0031] FIG. 1 is a schematic diagram of a partial planar structure of a back contact cell according to an embodiment of the present disclosure;

[0032] FIG. 2 is a schematic diagram of a partial cross-sectional structure of a back contact cell according to an embodiment of the present disclosure;

[0033] FIG. 3 is another schematic diagram of a partial cross-sectional structure of a back contact cell according to an embodiment of the present disclosure;

[0034] FIG. 4 is an enlarged schematic diagram of A in FIG. 3 according to an embodiment of the present disclosure;

[0035] FIG. 5 is still another schematic diagram of a partial cross-sectional structure of a back contact cell according to an embodiment of the present disclosure;

[0036] FIG. 6 is still another schematic diagram of a partial cross-sectional structure of a back contact cell according to an embodiment of the present disclosure;

[0037] FIG. 7 is still another schematic diagram of a partial cross-sectional structure of a back contact cell according to an embodiment of the present disclosure;

[0038] FIG. 8 is still another schematic diagram of a partial cross-sectional structure of a back contact cell according to an embodiment of the present disclosure;

[0039] FIG. 9 is a schematic diagram of a module structure of a back contact cell according to an embodiment of the present disclosure;

[0040] FIG. 10 is a schematic diagram of a module structure of a photovoltaic system according to an embodiment of the present disclosure.

[0041] Explanation of main element symbols:

[0042] Back contact cell assembly 100, first cell 10, front surface 11, back surface 12, first grid line 121, second grid line 122, second cell 20, solder strip 30, accommodation space 31, first solder strip 32, second solder strip 33, third solder strip 34, conductive connection structure 40, inclined surface 41, insulating structure 50, busbar 60, insulating layer 70, cell string 200, photovoltaic system 300. DETAILED DESCRIPTION

[0043] In order to make the objects, technical solutions and advantages of the present disclosure clearer, the present disclosure will be further described in detail below with reference to the drawings and embodiments. Examples of the embodiments are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present disclosure, and cannot be understood as a limitation on the present disclosure. In addition, it should be understood that the specific embodiments described herein are only used to explain the present disclosure and do not limit the present disclosure.

[0044] In the description of the present disclosure, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present disclosure.

[0045] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more features. In the description of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0046] In the description of the present disclosure, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present disclosure can be understood according to the specific circumstances.

[0047] In the present disclosure, unless specifically defined and limited otherwise, a first feature "on" or "under" a second feature can include that the first and second features are directly in contact, or that the first and second features are not directly in contact but are in contact through another feature between them. Also, the first feature "over", "above" and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or only means that the first feature is higher in horizontal height than the second feature. The first feature "under", "below" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or only means that the first feature is lower in horizontal height than the second feature.

[0048] The disclosure below provides many different embodiments or examples for implementing different structures of the present disclosure. For the sake of brevity, the descriptions of the specific examples below are described in terms of the specific examples. Of course, they are merely examples and are not intended to limit the present disclosure in any way. Moreover, the present disclosure provides examples of various specific processes and materials. One of ordinary skill in the art, however, can recognize that other processes and / or materials can be used without departing from the present disclosure.

[0049] In the related art, a solar cell is a semiconductor device that directly converts the energy of sunlight into electricity. The solar cell utilizes the photovoltaic effect to excite electrons by absorbing photons, and to guide these electrons out to generate current by the built-in electric field. The back contact cell refers to a solar cell in which the light-receiving surface of the cell piece is free of electrodes, and the positive and negative electrodes are arranged on the back light side of the cell piece, so that the shading of the cell piece by the electrodes can be reduced, the short-circuit current of the cell piece can be increased, and the energy conversion efficiency of the cell piece can be improved. In the prior art, in order to obtain a larger light receiving area and eliminate the gap between different cell pieces, the edge portion of two adjacent cell pieces is overlapped. However, this will cause the fine grid located in the edge portion to be unable to be connected by the solder ribbon, and the current at the edge position cannot be collected, resulting in a decrease in the power generation efficiency of the cell. In the embodiment of the present disclosure, a conductive connection structure is arranged at the edge portion to connect the solder ribbon and the corresponding fine grid, so that all the current of the cell piece can be collected and the power generation efficiency is improved.

[0050] Embodiment one

[0051] Referring to FIGS. 1-4, a back contact battery assembly 100 provided by embodiments of the present disclosure includes a battery string 200, a solder strip 30, a conductive connection structure 40, and an insulating structure 50. The battery string 200 includes adjacent first and second battery pieces 10 and 20, which are arranged along a first direction and at least partially stacked together. The back surface 12 of each of the first and second battery pieces 10 and 20 is formed with first and second grid lines 121 and 122, which extend along a second direction and are alternately arranged along the first direction. The first and second grid lines 121 and 122 are opposite in polarity. The solder strip 30 is arranged on the back surface 12 of the first battery piece 10 and extends along the first direction. An accommodation space 31 is formed between the side of the first battery piece 10 close to the second battery piece 20 and the solder strip 30. The conductive connection structure 40 is at least partially laid in the accommodation space 31 and connects the first grid line 121 and the solder strip 30 in the accommodation space 31. The insulating structure 50 covers the second grid line 122 and is arranged in the accommodation space 31 between the second grid line 122 and the solder strip 30.

[0052] In some embodiments, the length L of the conductive connection structure 40 along the first direction satisfies the following relationship: 0 < L ≤ D / tan α, where α is the included angle between the direction in which the solder strip 30 is lifted and the first direction, and D is the thickness of the second battery piece 20 along a third direction perpendicular to the second and first directions.

[0053] In some embodiments, the solder strip 30 includes a first solder strip 32, which extends along the first direction and connects the back surface 12 of the first battery piece 10 and the back surface 12 of the second battery piece 20. An accommodation space 31 is formed between the side of the first battery piece 10 close to the second battery piece 20 and the first solder strip 32.

[0054] In the back contact battery assembly 100 of the embodiment of the present disclosure, the back contact battery assembly 100 comprises a battery string 200, a solder strip 30, a conductive connection structure 40 and an insulating structure 50, the battery string 200 comprises adjacent first and second battery pieces 10 and 20, the first and second battery pieces 10 and 20 are arranged in a first direction, the first and second battery pieces 10 and 20 are at least partially stacked together, the back surface 12 of each of the first and second battery pieces 10 and 20 is formed with a first and second grid line 121 and 122, the first and second grid lines 121 and 122 extend in a second direction and are alternately arranged in the first direction, the first and second grid lines 121 and 122 are opposite in polarity, the solder strip 30 is arranged on the back surface 12 of the first battery piece 10 and extends in the first direction, the first battery piece 10 and the solder strip 30 on the side close to the second battery piece 20 form a containing space 31, the conductive connection structure 40 is at least partially laid in the containing space 31 and connects the first grid line 121 in the containing space 31 and the solder strip 30, and the insulating structure 50 covers the second grid line 122, the insulating structure 50 is arranged in the containing space 31 and between the second grid line 122 and the solder strip 30. In this way, the solder strip 30 can be connected to the first grid line 121 in the containing space 31 through the conductive connection structure 40, so that the current in the containing space 31 can be collected, thereby improving the power generation efficiency of the back contact battery assembly 100, and at the same time, the insulating structure 50 can be arranged between the second grid line 122 and the conductive connection structure 40 to avoid the problem of short circuit.

[0055] In the present embodiment, the front surface 11 of the battery piece is used to receive light, and the back surface 12 of the battery piece comprises a plurality of first and second doped layers (not shown in the figure) arranged alternately, the first doped layer is provided with the first grid line 121, and the second doped layer is provided with the second grid line 122. The first and second grid lines 121 and 122 extend in the second direction and are alternately arranged in the first direction, and at the same time, the first and second doped layers also extend in the second direction and are alternately arranged in the first direction to form a photoelectric current.

[0056] In the embodiment of the present disclosure, the back surface 12 of the battery piece has no main grid, and the first grid line 121 and the second grid line 122 can directly realize the convergence of current through the solder strip 30. The solder strip 30 includes a first solder strip 32 and a second solder strip 33, the first solder strip 32 and the second solder strip 33 extend along a first direction and are alternately distributed along a second direction; at the same time, the first grid line 121 and the second grid line 122 are opposite in polarity, the first solder strip 32 can connect the first grid line 121 of the first battery piece 10 and the second grid line 122 of the second battery piece 20, so as to connect the first battery piece 10 and the second battery piece 20 in series. At the same time, there is another second solder strip 33 to connect the first grid line 121 of the second battery piece 20 and the bus bar 60, in the embodiment of the present disclosure, the relative position between the bus bar 60 and the second solder strip 33 is not limited, so as to meet various needs. At this time, the first solder strip 32 and the second grid line 122 of the first battery piece 10 are provided with an insulating structure 50 to realize insulation, and the first solder strip 32 and the first grid line 121 of the second battery piece 20 are provided with an insulating structure 50 to realize insulation.

[0057] In the embodiment of the present disclosure, the first battery piece 10 and the second battery piece 20 are at least partially stacked together, so as to avoid the waste of component space and the increase of cost caused by too large spacing. The side of the first battery piece 10 close to the second battery piece 20 and the solder strip 30 form an accommodation space 31, the conductive connection structure 40 is at least partially laid in the accommodation space 31 and connects the first grid line 121 in the accommodation space 31 and the solder strip 30, the insulating structure 50 covers the second grid line 122, and the insulating structure 50 is arranged in the accommodation space 31 and located between the second grid line 122 and the solder strip 30. In this way, the current generated by the corresponding first doped layer of the first grid line 121 in the accommodation space 31 can also be conducted out by the solder strip 30, so as to realize that all the doped layers of the battery piece generate electric energy, and further improve the power generation efficiency of the back contact battery component 100. Of course, in some embodiments, the conductive connection structure 40 is filled in all the accommodation spaces 31, so as to connect all the first grid lines 121 in the accommodation spaces 31 and conduct them out through the solder strip 30.

[0058] Specifically, when the first grid line 121 is a positive grid line and the second grid line 122 is a negative grid line, the first solder strip 32 can span the first battery piece 10 and the second battery piece 20, and the first solder strip 32 can connect the first grid line 121 of the first battery piece 10 and the second grid line 122 of the second battery piece 20, that is, the first solder strip 32 can connect the positive grid line of the first battery piece 10 and the negative grid line of the second battery piece 20. At this time, the insulating structure 50 can be arranged on the second grid line 122 of the first battery piece 10 and on the first grid line 121 of the second battery piece 20, so as to realize the series connection of the first battery piece 10 and the second battery piece 20.

[0059] In some embodiments, the battery string 200 can further include a busbar structure to converge the current of the plurality of battery pieces. The busbar structure can connect the bus ribbons 30 of the same polarity to form a loop with the battery string 200 to guide the current energy out. The plurality of battery pieces can be connected in series by the bus ribbons 30 to form the battery string 200 distributed along the first direction. Of course, in some embodiments, the bus ribbons 30 at the ends of the battery string 200 can only connect the grid lines on one battery piece and extend relative to the battery piece to connect the busbar 60 or the like structure. In addition, in the embodiments of the present disclosure, the form of the busbar structure is not limited to meet different needs. For example, the busbar structure can be a wire, a busbar 60, a conductive tape, or the like conductive material.

[0060] In some embodiments, the included angle a between the direction in which the bus ribbon 30 is lifted and the first direction is adjusted according to the yield of the bus ribbon 30. In this way, bus ribbons 30 with different yields can be selected to adjust the size of the included angle a, and the specific size of the length L of the conductive connection structure 40 along the first direction can be calculated according to the thickness of the battery piece. In this way, the length of the conductive connection structure 40 along the first direction in the accommodation space 31 can be adjusted, and the amount of the conductive connection structure 40 can be adjusted, which not only ensures that the conductive connection structure 40 can connect the bus ribbon 30 and the first grid line 121 in the accommodation space 31, but also avoids waste of the material of the conductive connection structure 40.

[0061] In some embodiments, the yield of the bus ribbon 30 is less than or equal to 75 MPa. In this way, the yield of the bus ribbon 30 is less than or equal to 75 MPa, which ensures that the bus ribbon 30 can be bent and formed under a pressure of 75 MPa, and avoids affecting other components.

[0062] In some embodiments, the thickness D of the second battery piece 20 along the third direction is 90 μm-200 μm. For example, the thickness D of the second battery piece 20 along the third direction can be 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, or 200 μm.

[0063] In this way, the thickness D of the second battery piece 20 along the third direction is set in this range, which can ensure to cover a variety of specifications of battery pieces to meet different needs.

[0064] Specifically, the thickness D of the second battery piece 20 along the third direction is preferably 90 μm-150 μm, which ensures the stability of the battery piece structure and work without increasing the thickness of the back contact battery assembly 100.

[0065] Exemplarily, the thickness D of the second battery piece 20 along the third direction can be 120 pm, and the yield of the solder strip 30 can be 70 MPa, so as to ensure the manufacturing stability in the process and not to affect other components, and to compress the size of the accommodation space 31, so as to ensure the reasonable amount of the material of the conductive connection structure 40, and to realize the stable connection of the conductive connection structure 40 between the solder strip 30 and the first grid line 121 in the accommodation space 31.

[0066] It should be noted that the yield of the solder strip 30 refers to the pressure size of bending the solder strip 30 to the required shape.

[0067] It can be understood that the "first" and "second" in the first battery piece 10 and the second battery piece 20 are relative concepts, which refer to the difference between two back contact batteries. For example, in the example of FIG. 1, the battery piece on the left side is marked as the second battery piece 20, and the battery piece on the right side is marked as the first battery piece 10.

[0068] It can be understood that in the battery string 200, the battery string 200 can include two battery pieces in series, three battery pieces in series, or more battery pieces in series, and the number of battery pieces to be connected in series can be determined according to actual use. In addition, in the embodiments of the present disclosure, the size and type of the battery piece are not limited, and the specifications and sizes of adjacent battery pieces can be the same or different to meet different needs.

[0069] In the embodiments of the present disclosure, the doping types of the first doped layer and the second doped layer are not limited, for example, the first doped layer and the second doped layer can be a P-type doped layer and an N-type doped layer respectively; or the first doped layer can be an N-type doped layer, and the second doped layer can be a P-type doped layer, as long as the polarities of the two are opposite to meet different needs. In some embodiments, the first doped layer can be a P-type polysilicon layer, a P-type amorphous silicon layer, or a P-type microcrystalline silicon layer, which is not limited herein. Similarly, the second doped layer can be an N-type polysilicon layer, an N-type amorphous silicon layer, or an N-type microcrystalline silicon layer, which is not limited herein. When the first doped layer is a P-type doped layer and the second doped layer is an N-type doped layer, a P-type grid line can be further provided on the first doped layer, and an N-type grid line can be further provided on the second doped layer, which is not limited herein.

[0070] In some embodiments, P-type doping refers to doping group III elements, including boron, aluminum, gallium, indium, thallium, and the like; and N-type doping refers to doping group V elements, including nitrogen, phosphorus, arsenic, antimony, bismuth, and the like, which is not limited herein.

[0071] In addition, in some embodiments, the first doped layer and the second doped layer can also be a complex type of doping, for example, N-type doping also includes a small amount of P-type doping elements. Among them, the content of N-type doping elements of the second doped layer is 20% higher than the content of P-type doping elements, so as to ensure that the polarity is opposite to that of the first doped layer.

[0072] It can be understood that in such embodiments, the back contact battery assembly 100 can also include a frame, a back plate, photovoltaic glass, and a film. The film can be filled between the front surface 11 and the back surface 12 of the cell sheet, photovoltaic glass, adjacent cell sheets, etc., as a filler, which can be a transparent adhesive with good light transmission performance and aging resistance, for example, the film can use EVA film or POE film, which can be selected according to actual conditions, and is not limited here.

[0073] The photovoltaic glass can be covered on the film of the front surface 11 of the cell sheet, and the photovoltaic glass can be super white glass, which has high light transmittance, high transparency, and superior physical, mechanical, and optical properties. For example, the light transmittance of super white glass can be more than 92%, which can protect the cell sheet as much as possible without affecting the efficiency of the cell sheet. At the same time, the film can bond the photovoltaic glass and the cell sheet together, and the presence of the film can seal and insulate the cell sheet and prevent water and moisture.

[0074] The back plate can be attached to the film on the back surface 12 of the cell sheet, and the back plate can protect and support the cell sheet, has reliable insulation, water resistance and aging resistance, and the back plate can have multiple choices, which can be tempered glass, organic glass, aluminum alloy TPT composite film, etc., which can be set according to actual conditions, and is not limited here. The whole composed of the back plate, the cell sheet, the film and the photovoltaic glass can be set on the frame, and the frame can be the main external support structure of the whole back contact battery assembly 100, and can stably support and install the back contact battery assembly 100, for example, the back contact battery assembly 100 can be installed at the position required to be installed through the frame.

[0075] Embodiment two

[0076] Please refer to FIG. 1 and FIG. 2, in some optional embodiments, at least part of the first grid line 121 and the second grid line 122 are arranged in the accommodation space 31, and all the first grid lines 121 arranged in the accommodation space 31 are connected with the solder strip 30 through the conductive connection structure 40.

[0077] In this way, the first grid line 121 and the second grid line 122 are alternately arranged along the first direction in the accommodation space 31, which can conduct the current of the first doped layer and the second doped layer in the accommodation space 31, and further improve the power generation efficiency of the cell sheet.

[0078] Specifically, part of the first gate lines 121 and part of the second gate lines 122 are arranged in the accommodation space 31 and connected with the solder strip 30 through the conductive connection structure 40. The first gate lines 121 and the second gate lines 122 are alternately arranged in the first direction in the accommodation space 31, and all the first gate lines 121 arranged in the accommodation space 31 are connected with the solder strip 30 through the conductive connection structure 40, which can effectively conduct the current of the first doped layer and the second doped layer in the accommodation space 31, and further improve the power generation efficiency of the battery piece. In this way, by optimizing the connection design of the gate lines and the solder strip 30, the current of the doped layer can be more fully collected and conducted, and the power generation efficiency of the battery piece is improved. The conductive connection structure 40 in the accommodation space 31 reduces the impedance in the current conduction path, reduces the power loss, and improves the overall power generation performance. The existence of the conductive connection structure 40 not only ensures the efficient conduction of the current, but also improves the connection stability between the battery piece and the solder strip 30, preventing the problem of poor contact caused by mechanical stress or environmental changes.

[0079] Embodiment three

[0080] Referring to FIGS. 1 and 2, in some optional embodiments, the insulating structure 50 is prepared by laying or coating.

[0081] In this way, the insulating structure 50 can be prepared by laying or coating, so that the insulating structure 50 can be accurately arranged on the corresponding gate lines. In addition, the insulating structure 50 can be prepared on the battery piece by using various preparation methods, thereby meeting the needs of various scenes.

[0082] It can be understood that the first gate lines 121 and the second gate lines 122 extend along the second direction and are alternately laid on the battery piece along the first direction. The two end portions of the first gate lines 121 and the second gate lines 122 in the second direction can extend into a position close to the edge of the battery piece. At this time, a plurality of solder strips 30 can be arranged on the battery piece to connect the gate lines of the same polarity on one battery piece together, and since the solder strip 30 extends along the first direction, it will continuously pass through a plurality of first gate lines 121 and second gate lines 122. At this time, the insulating structure 50 is arranged on the position of the second gate line 122 covered by the solder strip 30 to avoid connection with the second gate line 122, and the insulating structure 50 is arranged between the second gate line 122 and the solder strip 30 to avoid the connection between the solder strip 30 and the second gate line 122, thereby avoiding the problem of short circuit.

[0083] In the embodiments of the present disclosure, the form and preparation method of the insulation structure 50 are not limited to meet different needs. In one embodiment, the insulation structure 50 is an insulation glue layer arranged on the corresponding grid line by a spraying process. In this way, the arrangement position of the insulation structure 50 is more accurate, the speed of arranging the insulation structure 50 is faster, and the spraying equipment does not need to be in direct contact with the battery piece, which can reduce the pollution and damage to the battery piece. Further, the insulation glue layer can be at least one of light-cured and heat-cured, and the light-curing time is less than or equal to 2s.

[0084] Embodiment Four

[0085] Please refer to FIG. 1 and FIG. 2, in some optional embodiments, the conductive connection structure 40 is tin paste or conductive glue or other metal conductive materials.

[0086] In this way, the conductive connection structure 40 uses tin paste or conductive glue and other materials that are easy to deform, which can cope with irregular accommodation spaces 31 that occur in the process of process preparation, so as to ensure that the conductive connection structure 40 can connect the first grid line 121 and the solder strip 30 together.

[0087] In the embodiments of the present disclosure, the type of the conductive connection structure 40 is not limited to meet different needs. In one example, when the conductive connection structure 40 is tin paste, the tin paste has good wettability and flowability, which is suitable for filling irregular spaces and ensuring the stability of electrical connection. In another example, when the conductive connection structure 40 is conductive glue, the conductive glue has softness and good adhesion, which can tightly fit between the grid line and the solder strip 30, and adapt to accommodation spaces 31 of different shapes and sizes. In yet another example, when the conductive connection structure 40 is other metal conductive materials, the metal material has excellent electrical conductivity, which can ensure efficient conduction of current. By using the flexibility and electrical conductivity of these materials, it can ensure smooth conduction of current and further improve the power generation efficiency of the back contact battery assembly 100.

[0088] Further, due to the stretching of the solder strip 30 arranged on the first battery piece 10 and the second battery piece 20 during the process preparation, irregular accommodation spaces 31 are prone to occur. When the conductive connection structure 40 uses tin paste or conductive glue or other metal conductive materials, the flexibility of the process preparation can be improved. Tin paste and conductive glue can be completed by simple coating or dispensing process during use, which is simple to operate and low in cost. At the same time, due to the flowability and plasticity of the materials themselves, they can adapt to irregular accommodation spaces 31 that occur during preparation, ensuring the integrity and reliability of the conductive connection structure 40.

[0089] Embodiment Five

[0090] Referring to FIG. 1 and FIG. 2, in some optional embodiments, the length of the conductive connecting structure 40 in the first direction is greater than 6 mm. For example, the length of the conductive connecting structure 40 in the first direction can be 6.1 mm, 6.2 mm, 6.3 mm, 6.4 mm, 6.5 mm, 6.6 mm, 6.7 mm, 6.8 mm, 6.9 mm, 7 mm, 7.5 mm, 8 mm.

[0091] Therefore, during the process of preparation, the solder strip 30 can be connected to the first cell piece 10 and the second cell piece 20, and the size of the accommodation space 31 is often not the same. Therefore, the length of the conductive connecting structure 40 in the first direction is greater than 6 mm, so that the conductive connecting structure 40 can connect all the first grid lines 121 in the accommodation structure under different process errors.

[0092] Specifically, in the embodiments of the present disclosure, the type of the solder strip 30 is not limited to meet different needs. For example, the solder strip 30 can be a round solder strip 30, or a flat wide solder strip 30. It should be noted that when the solder strip 30 is arranged on the first cell piece 10 and the second cell piece 20, the length of the accommodation space 31 in the first direction will not be uniform due to process errors. The length of the accommodation space 31 in the first direction is 0.5 mm-6 mm, so the length of the conductive connecting structure 40 in the first direction only needs to be greater than 6 mm. For example, the length of the conductive connecting structure 40 in the first direction is 7 mm, which can effectively connect the first grid line 121 in the accommodation space 31 and the solder strip 30, and ensure stable connection.

[0093] Embodiment six

[0094] Referring to FIG. 2 and FIG. 3, in some optional embodiments, the thickness of the conductive connecting structure 40 in the third direction is 30 μm-300 μm, wherein the third direction is perpendicular to the first direction and the second direction. For example, the thickness of the conductive connecting structure 40 in the third direction can be 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 120 μm, 140 μm, 160 μm, 180 μm, 200 μm, 220 μm, 240 μm, 260 μm, 280 μm, 300 μm.

[0095] Therefore, the thickness of the conductive connecting structure 40 is set in this range, which can avoid the problem of virtual welding and missed welding caused by too thin conductive connecting structure 40, and can also avoid the influence of too thick conductive connecting structure 40 on the overall thickness of the back contact battery assembly 100.

[0096] Embodiment seven

[0097] Referring to FIG. 1 and FIG. 2, in some optional embodiments, in the second direction, the width of the solder strip 30 is greater than the width of the conductive connection structure 40.

[0098] In this way, the solder strip 30 can shield the conductive connection structure 40, avoiding the exposure of the conductive connection structure 40, which affects the normal operation of the back contact battery assembly 100. The exposed conductive connection structure 40 is easy to contact with other conductive components or lines, causing short circuit. At the same time, since the material used by the conductive connection structure 40 has a certain softness and elasticity, by shielding the conductive connection structure 40 with the solder strip 30, it is avoided that the conductive connection structure 40 is pressed out of exposure when the solder strip 30 is pressed on the conductive connection structure 40. In this way, not only the durability and reliability of the assembly are improved, but also the conductive connection structure 40 is prevented from being mechanically damaged or oxidized, etc., further improving the service life and performance stability of the back contact battery assembly 100.

[0099] Embodiment Eight

[0100] Referring to FIG. 1 and FIG. 2, in some optional embodiments, in the second direction, the width of the insulating structure 50 is greater than the width of the conductive connection structure 40.

[0101] In this way, in the second direction, the width of the insulating structure 50 is greater than the width of the conductive connection structure 40, so as to avoid the short circuit of the conductive connection structure 40 and the second grid line 122.

[0102] Specifically, the wider insulating structure 50 provides a larger physical isolation area, enhances the electrical insulation effect, and avoids possible electrical interference and current leakage. In the actual production process, process errors may cause slight deviation of the position of the conductive connection structure 40. The wider insulating structure 50 can compensate for these deviations, ensuring that the insulation effect is not affected. At the same time, the wider insulating structure 50 can avoid insulation failure caused by process variation, aging, etc., enhancing the stability and reliability of the back contact battery assembly 100 in long-term use.

[0103] Embodiment Nine

[0104] Referring to FIG. 1 and FIG. 2, in some optional embodiments, the thickness of the insulating structure 50 is 25-40 μm. For example, the thickness of the insulating structure 50 can be 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm, 35 μm, 36 μm, 37 μm, 38 μm, 39 μm, 40 μm.

[0105] In this way, the thickness of the insulating structure 50 is set in this range, on the one hand, the second grid line 122 and the physical isolation are realized, and the insulation between the second grid line 122 and the conductive connection structure 40 is ensured.

[0106] Exemplarily, the thickness of the insulation structure 50 can be set as 30 μm, which can ensure effective physical isolation and good insulation between the second grid line 122 and the conductive connecting structure 40, and improve the overall electrical performance and reliability of the back contact battery assembly 100.

[0107] Embodiment Ten

[0108] Please refer to FIG. 5 and FIG. 6, in some optional embodiments, when the back surface 12 of the first battery piece 10 and the front surface 11 of the second battery piece 20 are at least partially laminated together, the accommodation space 31 is formed on the side of the back surface 12 of the first battery piece 10 close to the second battery piece 20, and the solder strip 30 further comprises a second solder strip 33 and a third solder strip 34, the second solder strip 33 is arranged on the back surface 12 of the first battery piece 10 and at least partially extends into the back surface 12 of the second battery piece 20, and the third solder strip 34 is located on the back surface 12 of the second battery piece 20.

[0109] In this way, the edge portions of the back surface 12 of the first battery piece 10 and the front surface 11 of the second battery piece 20 are laminated together, which can effectively improve the light receiving area of the back contact battery assembly 100.

[0110] Embodiment Eleven

[0111] Please refer to FIG. 1 and FIG. 3, in some optional embodiments, the conductive connecting structure 40 is formed with an inclined surface 41 on the side away from the first battery piece 10, and the inclined surface 41 connects the solder strip 30.

[0112] In this way, the inclined surface 41 is consistent with the inclined direction of the solder strip 30, so that the conductive connecting structure 40 can better fit and connect the solder strip 30, and ensure the stable connection between the conductive connecting structure 40 and the solder strip 30.

[0113] Embodiment Twelve

[0114] Please refer to FIG. 5 and FIG. 6, in some optional embodiments, the back contact battery assembly 100 further comprises a bus bar 60, the bus bar 60 is arranged on the back surface 12 of the second battery piece 20.

[0115] The bus bar 60 connects the second solder strip 33 and is located on the side of the second solder strip 33 away from the second battery piece 20.

[0116] The bus bar 60 connects the second solder strip 33 and is located on the side of the second solder strip 33 close to the second battery piece 20.

[0117] Specifically, the bus bar 60 is arranged on the side of the second solder strip 33 away from the second battery sheet 20, which can avoid affecting the accommodation space 31 and the components inside the accommodation space 31. The bus bar 60 is arranged on the side of the second solder strip 33 close to the second battery sheet 20, which can increase the volume of the accommodation space 31, and thus the size of the conductive connection structure 40 can be reasonably adjusted to ensure stable connection.

[0118] Embodiment Thirteen

[0119] Referring to FIGS. 7 and 8, in some optional embodiments, when the front surface 11 of the first battery sheet 10 and the back surface 12 of the second battery sheet 20 are at least partially laminated together, the accommodation space 31 is formed on the side of the back surface 12 of the first battery sheet 10 close to the second battery sheet 20, and the solder strip 30 further includes a second solder strip 33 and a third solder strip 34. The second solder strip 33 is arranged on the back surface 12 of the first battery sheet 10 and at least partially extends into the back surface 12 of the second battery sheet 20, and the third solder strip 34 is located on the back surface 12 of the second battery sheet 20.

[0120] Referring to FIGS. 7 and 8, in some optional embodiments, the back contact battery assembly 100 further includes a bus bar 60, and the bus bar 60 is arranged on the back surface 12 of the first battery sheet 10;

[0121] The bus bar 60 is connected to the second solder strip 33 and located on the side of the second solder strip 33 away from the second battery sheet 20;

[0122] The bus bar 60 is connected to the second solder strip 33 and located on the side of the second solder strip 33 close to the second battery sheet 20.

[0123] Specifically, the bus bar 60 is arranged on the side of the second solder strip 33 away from the second battery sheet 20, which can avoid affecting the accommodation space 31 and the components inside the accommodation space 31. The bus bar 60 is arranged on the side of the second solder strip 33 close to the second battery sheet 20, which can eliminate the volume of the accommodation space 31 to a certain extent, and also make the second solder strip 33 have a smaller lifting radius to ensure stable connection.

[0124] It should be noted that when the bus bar 60 is arranged between the battery sheet and the second solder strip 33, insulation treatment needs to be performed on the bus bar 60 and part of the grid lines to avoid short circuit at the position of the bus bar 60.

[0125] In addition, in the embodiments of the present disclosure, the specific position of the bus bar 60 is not limited to meet different needs.

[0126] In some embodiments, referring to FIGS. 5-8, the back contact cell assembly 100 further comprises an insulation layer 70 disposed between the bus bar 60 and the third solder ribbon 34. Also shown in FIGS. 5-8 are the first and second grid lines 121 and 122, which are described in the above embodiments and will not be repeated here.

[0127] It should be noted that in such a manner, the end of the second cell sheet 20 away from the first cell sheet 10 can be provided with the bus bar 60 and the insulation layer 70, and the solder ribbon 30 extending from the first cell sheet 10 to the side of the second cell sheet 20 can make the accommodation space 31 larger.

[0128] In some embodiments, the length L of the conductive connection structure 40 along the first direction satisfies the following relationship: 0 < L ≤ (D + d) / tan α, where α is the included angle between the direction in which the solder ribbon 30 is lifted and the first direction, D is the thickness of the second cell sheet 20 along the third direction, and d is the thickness of other components along the third direction, and the third direction is perpendicular to the second direction and the first direction. At this time, the length L of the conductive connection structure 40 along the first direction can be calculated by the thickness of the second cell sheet 20 and other components such as the third solder ribbon 34, the bus bar 60, and the insulation layer 70 along the third direction, and thus the accurate calculation of the accommodation space 31 can be achieved.

[0129] Embodiment Fourteen

[0130] Referring to FIGS. 9 and 10, the photovoltaic system 300 provided by the embodiments of the present disclosure comprises the back contact cell assembly 100 of any one of the above embodiments.

[0131] In the back contact cell assembly 100 and the photovoltaic system 300 of the embodiments of the present disclosure, the back contact cell assembly 100 comprises a cell string 200, a solder strip, a conductive connection structure and an insulating structure, the cell string 200 comprises adjacent first and second cell pieces, the first and second cell pieces are arranged in a first direction, the first and second cell pieces are at least partially stacked together, the back surface of each of the first and second cell pieces is formed with a first and a second grid line, the first and second grid lines extend in a second direction and are alternately arranged in the first direction, the first and second grid lines are opposite in polarity, the solder strip is arranged on the back surface of the first cell piece and extends in the first direction, a receiving space is formed between the side of the first cell piece close to the second cell piece and the solder strip 30, the conductive connection structure is at least partially laid in the receiving space and connects the first grid line and the solder strip in the receiving space, and the insulating structure covers the second grid line and is arranged in the receiving space between the second grid line and the solder strip. In this way, the solder strip can be connected with the first grid line in the receiving space through the conductive connection structure, so that the current in the receiving space can be collected, thereby improving the power generation efficiency of the back contact cell assembly 100, and meanwhile, the insulating structure can be arranged between the second grid line and the conductive connection structure to avoid short circuit.

[0132] In the present embodiment, the photovoltaic system 300 can be applied in a photovoltaic power station, such as a ground power station, a roof power station, a water surface power station, etc., and can also be applied in a device or apparatus that utilizes solar energy for power generation, such as a user solar power source, a solar street lamp, a solar car, a solar building, etc. Of course, it can be understood that the application scenarios of the photovoltaic system 300 are not limited to this, that is, the photovoltaic system 300 can be applied in all fields that need to utilize solar energy for power generation. Taking a photovoltaic power generation system network as an example, the photovoltaic system 300 can comprise a photovoltaic array, a combiner box and an inverter, the photovoltaic array can be an array combination of a plurality of back contact cell assemblies 100, for example, a plurality of back contact cell assemblies 100 can constitute a plurality of photovoltaic arrays, the photovoltaic arrays are connected to the combiner box, the combiner box can combine the current generated by the photovoltaic arrays, the combined current flows through the inverter to be converted into alternating current required by a power grid, and then is connected to a power network to realize solar power supply.

[0133] In the description of the present specification, the description of the terms "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present disclosure. In the present specification, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0134] In addition, the above merely describes preferred embodiments of the present disclosure and is not intended to limit the present disclosure, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A back contact cell assembly, comprising: a cell string comprising a first cell sheet and a second cell sheet adjacent to each other, the first cell sheet and the second cell sheet are arranged in a first direction, the first cell sheet and the second cell sheet are at least partially laminated together, the back surface of the first cell sheet and the second cell sheet are formed with a first grid line and a second grid line, the first grid line and the second grid line extend in a second direction and are alternately arranged in the first direction, the first grid line and the second grid line are opposite in polarity; a solder strip arranged on the back surface of the first cell sheet and extending in the first direction, a space is formed between the side of the first cell sheet close to the second cell sheet and the solder strip; a conductive connection structure at least partially laid in the space and connecting the first grid line and the solder strip in the space; an insulating structure covering the second grid line, the insulating structure is arranged in the space and between the second grid line and the solder strip. 2.The back contact cell assembly of claim 1, a length L of the conductive connection structure in the first direction satisfies the following relationship: 0<L≤D / tanα; wherein α is an included angle between a direction in which the solder strip is lifted and the first direction, D is a thickness of the second cell sheet in a third direction, the third direction is perpendicular to the second direction and the first direction.

3. The back contact solar cell assembly of claim 1, wherein, The solder strip comprises a first solder strip extending in the first direction and connecting the back surface of the first cell sheet and the back surface of the second cell sheet, a space is formed between the side of the first cell sheet close to the second cell sheet and the first solder strip.

4. The back contact solar cell assembly of claim 1, wherein, When the back surface of the first cell sheet and the front surface of the second cell sheet are at least partially laminated together, the space is formed on the side of the back surface of the first cell sheet close to the second cell sheet, the solder strip further comprises a second solder strip and a third solder strip, the second solder strip is arranged on the back surface of the first cell sheet and at least partially extends into the back surface of the second cell sheet, and the third solder strip is located on the back surface of the second cell sheet.

5. The back contact solar cell assembly of claim 4, wherein, The back contact cell assembly further comprises a bus bar arranged on the back surface of the second cell sheet; The bus bar connects the second solder strip and is located on the side of the second solder strip away from the second cell sheet; Or the bus bar connects the second solder strip and is located on the side of the second solder strip close to the second cell sheet.

6. The back contact solar cell assembly of claim 1, wherein, When the front surface of the first cell sheet and the back surface of the second cell sheet are at least partially laminated together, the space is formed on the side of the back surface of the second cell sheet close to the first cell sheet, the solder strip further comprises a second solder strip and a third solder strip, the second solder strip is arranged on the back surface of the first cell sheet and at least partially extends into the back surface of the second cell sheet, and the third solder strip is located on the back surface of the second cell sheet.

7. The back contact solar cell assembly of claim 6, wherein, The back contact cell assembly further comprises a bus bar arranged on the back surface of the first cell sheet; The bus bar is connected to the second solder ribbon and located on a side of the second solder ribbon away from the first battery piece. Or the bus bar is connected to the second solder ribbon and located on a side of the second solder ribbon close to the first battery piece.

8. The back contact solar cell assembly of any of claims 1-7, wherein, The insulating structure is prepared by laying or coating.

9. The back contact solar cell assembly of any of claims 1-7, wherein, The conductive connection structure is tin paste, conductive glue or other metal conductive materials.

10. The back contact solar cell assembly of any of claims 1-7, wherein, The length of the conductive connection structure along the first direction is greater than 6mm.

11. The back contact solar cell assembly of any of claims 1-7, wherein, The thickness of the conductive connection structure along the third direction is 30μm-300μm, wherein the third direction is perpendicular to the first direction and the second direction.

12. The back contact solar cell assembly of any of claims 1-7, wherein, In the second direction, the width of the solder ribbon is greater than the width of the conductive connection structure.

13. The back contact solar cell assembly of any of claims 1-7, wherein, In the second direction, the width of the insulating structure is greater than the width of the conductive connection structure.

14. The back contact solar cell assembly of any of claims 1-7, wherein, The thickness of the insulating structure is 25μm-40μm.

15. The back contact solar cell assembly of any of claims 1-7, wherein, The conductive connection structure is formed with an inclined surface on a side away from the first battery piece, and the inclined surface is connected to the solder ribbon.

16. The back contact solar cell assembly of claim 5 or 7, wherein, The back contact battery assembly further comprises an insulating layer arranged between the bus bar and the third solder ribbon.

17. The back contact solar cell assembly of claim 2, wherein, The included angle α between the direction in which the solder ribbon is lifted and the first direction is adjusted according to the yield strength of the solder ribbon.

18. The back contact solar cell assembly of claim 17, wherein, The yield strength of the solder ribbon is less than or equal to 75Mpa.

19. The back contact solar cell assembly of claim 1, wherein, The thickness D of the second battery piece along the third direction is 90μm-200μm.

20. A photovoltaic system, wherein, The back contact battery assembly comprises any one of claims 1-19. The back contact battery assembly comprises any one of claims 1-19.

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