Back contact cell assembly and photovoltaic system

Abstract

The application is suitable for the technical field of solar cells, and provides a back contact cell assembly and a photovoltaic system. In the back contact cell assembly, the back surface of each back contact cell is provided with a plurality of first interconnection ribbons and a plurality of second interconnection ribbons. The plurality of first interconnection ribbons and the plurality of second interconnection ribbons are alternately and spacedly arranged along a second direction and extend along a first direction. The first interconnection ribbons are welded with first pads, and the end portions of the first interconnection ribbons exceed a first edge in the first direction. The end portions of the second interconnection ribbons towards the first edge are welded with second pads, and the end portions of the second interconnection ribbons do not exceed the second pads in the first direction. In this way, the bifaciality of the back contact cell assembly is improved, and the cost of the ribbons is reduced.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and more particularly to a back-contact battery module and photovoltaic system. Background Technology

[0002] In solar cell technology, back-contact solar cells have high power generation efficiency because they place both the emitter and base contact electrodes on the back of the cell, eliminating any metal electrodes that block the light-receiving surface. These cells typically have a doped layer and electrode structure on the back, and are connected in series via solder ribbons.

[0003] However, the arrangement of solder ribbons on the back side in existing technologies creates a large area of ​​shading on the back of the battery, which affects the light absorption capacity of the back side of the battery, resulting in a low bifacial ratio. Therefore, the bifacial ratio of back-contact battery modules needs to be improved. Summary of the Invention

[0004] This application provides a back-contact battery module and a photovoltaic system.

[0005] This application is implemented as follows: the back contact battery assembly of this application embodiment includes a plurality of battery strings, the battery strings including a plurality of back contact batteries arranged along a first direction, a plurality of first interconnect solder strips and a plurality of second interconnect solder strips;

[0006] The back contact battery has a first edge and a second edge opposite to each other in the first direction. The back side of the back contact battery has a plurality of first fine grids, a plurality of second fine grids, a plurality of first pads and a plurality of second pads. The plurality of first fine grids and the plurality of second fine grids are arranged alternately and at intervals along the first direction and all extend along the second direction, which intersects the first direction.

[0007] Both the first pad and the second pad are located close to the first edge. The first pad and the space between the first pad and the first edge each have a plurality of first fine gates and a plurality of second fine gates. The plurality of first pads and the plurality of second pads are arranged alternately along the second direction. At least two first fine gates are connected to the first pad, and the first pad is also electrically connected to the first fine gate located between the first pad and the first edge. At least two second fine gates are connected to the second pad, and the second pad is also electrically connected to all the second fine gates located between the second pad and the second edge. The first fine gates are insulated from the second pad, and the second fine gates are insulated from the first pad.

[0008] Each of the back contact batteries has a plurality of first interconnect solder strips and a plurality of second interconnect solder strips on its back side. The plurality of first interconnect solder strips and the plurality of second interconnect solder strips are arranged alternately at intervals along the second direction and all extend along the first direction. The first interconnect solder strips are welded to the first pad and the first interconnect solder strips extend beyond the first edge in the first direction. The ends of the second interconnect solder strips facing the first edge are welded to the second pad and the ends of the second interconnect solder strips do not extend beyond the second pad in the first direction.

[0009] In some embodiments, the back contact battery has a plurality of first busbars and a plurality of second busbars on its back side;

[0010] Each of the first pads is connected to a first bus gate line, which is located between the first pad and the first edge. The first bus gate line is electrically connected to the first fine gate located between the first pad and the first edge and is insulated from the second fine gate.

[0011] Each of the second pads is connected to a second bus gate line, which is located between the second pad and the first edge. The second bus gate line is electrically connected to the second fine gate located between the second pad and the first edge and is insulated from the first fine gate.

[0012] The first busbar is completely covered by the first interconnect solder strip, and the second busbar and the second interconnect solder strip do not overlap.

[0013] In some embodiments, the length of the first busbar in the first direction is 2mm-10mm; and / or

[0014] The length of the second busbar in the first direction is 2mm-10mm.

[0015] In some embodiments, the ratio between the length of the first busbar in the first direction and the length of the back contact battery in the first direction is 2% to 15%; and / or

[0016] The ratio between the length of the second busbar in the first direction and the length of the back contact battery in the first direction is 2% to 15%.

[0017] In some embodiments, the first busbar has at least one first adhesive dot, which is bonded to the first interconnecting solder strip, while the second busbar does not have an adhesive dot.

[0018] In some embodiments, the length of the second pad in the first direction is greater than the length of the first pad in the first direction, the second pad includes a first portion and a second portion, the second portion is located on the side of the first portion facing the first edge, and the second interconnect solder strip does not extend beyond the second portion;

[0019] The first part is provided with a second adhesive dot, which is bonded to the second interconnecting solder strip; or the second part is provided with a second adhesive dot, which is bonded to the second interconnecting solder strip.

[0020] In some embodiments, the area of ​​the second portion is greater than or equal to the area of ​​the first pad.

[0021] In some embodiments, the back contact battery also has a plurality of third pads and a plurality of fourth pads on its back side;

[0022] The third pad and the third pad are both located close to the second edge. A plurality of third pads and a plurality of fourth pads are arranged alternately along the second direction. The third pad and the third pad and the second edge each have a plurality of first fine gates and a plurality of second fine gates. The third pad and the first pad correspond one-to-one in the first direction and are arranged collinearly. The third pad and the first pad are soldered to the same first interconnect solder strip. The fourth pad and the second pad correspond one-to-one in the first direction and are arranged collinearly. The fourth pad and the second pad are soldered to the same second interconnect solder strip.

[0023] At least two first fine gates are connected to the third pad, and the third pad is also electrically connected to the first fine gate located between the third pad and the second edge. At least two second fine gates are connected to the fourth pad, and the fourth pad is also electrically connected to the second fine gate located between the fourth pad and the second edge. The first fine gate is insulated from the fourth pad, and the second fine gate is insulated from the third pad.

[0024] Wherein, the end of the first interconnect solder strip facing the second edge is soldered to the third pad and the end of the first interconnect solder strip does not extend beyond the third pad in the first direction, and the second interconnect solder strip is soldered to the fourth pad and the first interconnect solder strip extends beyond the second edge in the first direction.

[0025] In some embodiments, the back contact battery has a plurality of third busbars and a plurality of fourth busbars on its back side.

[0026] Each of the third pads is connected to a third bus line, which is located between the third pad and the second edge, and is electrically connected to the first fine gate located between the third pad and the second edge;

[0027] Each of the fourth pads is connected to a fourth bus line, which is located between the fourth pad and the second edge, and is electrically connected to the second fine gate located between the fourth pad and the second edge;

[0028] The third busbar and the first interconnect solder strip do not overlap in the thickness direction, and the fourth busbar is completely covered by the second interconnect solder strip in the thickness direction.

[0029] In some embodiments, at least one third adhesive dot is provided on the fourth busbar, the third adhesive dot is bonded to the second interconnecting solder strip, and the third busbar does not have an adhesive dot.

[0030] In some embodiments, the length of the third pad in the first direction is greater than the length of the fourth pad in the first direction, the third pad includes a third portion and a fourth portion, the fourth portion is located on the side of the third portion facing the second edge, and the first interconnect solder strip does not extend beyond the fourth portion;

[0031] The third part is provided with a fourth adhesive dot, which is bonded to the first interconnect solder strip; or the fourth part is provided with a fourth adhesive dot, which is bonded to the first interconnect solder strip.

[0032] In some embodiments, the area of ​​the fourth portion is greater than or equal to the area of ​​the fourth pad.

[0033] This application also provides a photovoltaic system, which includes the above-described battery components.

[0034] In the back contact battery module and photovoltaic system of this application embodiment, each of the first and second pads has a plurality of first fine grids and a plurality of second fine grids between the first pad and the first edge. Each back contact battery has a plurality of first interconnect solder strips and a plurality of second interconnect solder strips on its back side. The plurality of first interconnect solder strips and the plurality of second interconnect solder strips are arranged alternately and spaced along the second direction and all extend along the first direction. The first interconnect solder strips are welded to the first pad, and the second interconnect solder strips are welded to the second pad. The end of the first interconnect solder strip extends beyond the first edge in the first direction, and the end of the second interconnect solder strip facing the first edge is welded to the second pad, and the end of the second interconnect solder strip does not extend beyond the second pad in the first direction. Thus, the first interconnecting ribbon extends beyond the first edge, enabling it to connect with the busbar or the ribbon of the other polarity on an adjacent cell (e.g., the second interconnecting ribbon on an adjacent cell) to ensure stable current output. The second interconnecting ribbon extends only to the location of the second pad, with its end not exceeding the second pad. This reduces the area on the back of the back contact cell that is blocked by the second interconnecting ribbon, thereby improving the light absorption efficiency on the back side, increasing the bifaciality of the back contact cell assembly, and also reducing the cost of the second interconnecting ribbon.

[0035] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of a photovoltaic system module provided in an embodiment of this application;

[0037] Figure 2 This is a schematic diagram of the planar structure of the back contact battery assembly provided in an embodiment of this application;

[0038] Figure 3 This is a schematic diagram of a planar structure with interconnecting solder strips on the back contact battery provided in an embodiment of this application;

[0039] Figure 4 This is another planar structural diagram of a battery with interconnecting solder strips on the back contact provided in this application embodiment;

[0040] Figure 5 yes Figure 4 A magnified schematic diagram of the back contact battery at point V;

[0041] Figure 6 yes Figure 4 Another enlarged schematic diagram of the back contact battery at point VI.

[0042] Explanation of key component symbols:

[0043] Photovoltaic system 1000, back contact cell module 100, cell string 10, back contact cell 11, first edge 101, second edge 102, first interconnect solder strip 12, second interconnect solder strip 13, first grid 14, second grid 15, first pad 16, second pad 17, first busbar 18, second busbar 19, third pad 110, fourth pad 111, third busbar 112, fourth busbar 113, first busbar 20, second busbar 30. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Furthermore, it should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0045] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "top", "bottom", "lateral", "longitudinal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0046] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "several," "multiple," and "more than" mean two (roots) or more, unless otherwise explicitly specified.

[0047] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0048] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0049] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0050] Please see Figure 1 and Figure 2 The photovoltaic system 1000 in this application embodiment may include the back contact battery module 100 in this application embodiment. The back contact battery module 100 in this application embodiment may include a plurality of battery strings 10, and the plurality of battery strings 10 may be arranged in a rectangular array. Figure 2 As shown, in some embodiments, the back contact battery assembly 100 may further include a plurality of first busbars 20 and a plurality of second busbars 30. In a first direction, one end of the battery string 10 is provided with a first busbar 20 and the other end is provided with a second busbar 30. The two ends of the battery string 10 are respectively connected to the first busbar 20 and the second busbar 30. Each battery string 10 in the back contact battery assembly 100 can be connected in series and in parallel through the first busbars 20 and the second busbars 30 to achieve current collection and output.

[0051] The battery string 10 may include a plurality of back contact batteries 11, a plurality of first interconnecting solder strips 12 and a plurality of second interconnecting solder strips 13. In the battery string 10, the plurality of back contact batteries 11 are arranged along a first direction, which is the stringing direction of the battery string 10.

[0052] Please see Figure 3The back contact battery 11 has a first edge 101 and a second edge 102 opposite to each other in a first direction, and the back side of the back contact battery 11 has a plurality of first fine grids 14, a plurality of second fine grids 15, a plurality of first pads 16 and a plurality of second pads 17.

[0053] A plurality of first fine gates 14 and a plurality of second fine gates 15 are arranged alternately at intervals along a first direction and all extend along a second direction, which intersects the first direction. A first pad 16 and a second pad 17 are both disposed close to a first edge 101. A plurality of first fine gates 14 and a plurality of second fine gates 15 are provided on the first pad 16 and between the first pad 16 and the first edge 101. The plurality of first pads 16 and the plurality of second pads 17 are arranged alternately at intervals along the second direction.

[0054] Specifically, such as Figure 2 As shown, the first direction can be the longitudinal direction of the back-contact battery assembly 100, that is, the serial connection direction of the battery string 10, and the second direction can be the transverse direction of the back-contact battery assembly 100, and the two are perpendicular to each other. At least two first fine gates 14 are connected to the first pad 16, and the first pad 16 is also electrically connected to all the first fine gates 14 located between the first pad 16 and the first edge 101 (e.g., through the first bus line 18 described below). In some embodiments, the first pad 16 is connected to all the first fine gates 14 located between the first pad 16 and the first edge 101.

[0055] At least two second fine gates 15 are connected to the second pad 17, and the second pad 17 is also electrically connected to the second fine gates 15 located between the second pad 17 and the first edge 101 (e.g., through the second bus line 19 hereinafter). In some embodiments, the second pad 17 is connected to all the second fine gates 15 located between the second pad 17 and the first edge 101.

[0056] The first fine gate 14 is insulated from the second pad 17, and the second fine gate 15 is insulated from the first pad 16. Specifically, in some embodiments, the first fine gate 14 may be disconnected at the second pad 17, and the second fine gate 15 may be disconnected at the first pad 16.

[0057] Among them, such as Figure 3 As shown, each back contact battery 11 has a plurality of first interconnect solder strips 12 and a plurality of second interconnect solder strips 13 on its back side. The plurality of first interconnect solder strips 12 and the plurality of second interconnect solder strips 13 are arranged alternately and at intervals along the second direction and all extend along the first direction.

[0058] The first interconnect solder strip 12 is soldered to the first solder pad 16, and the first interconnect solder strip 12 extends beyond the first edge 101 in the first direction. The first interconnect solder strip 12 extends beyond the first edge 101 in the first direction, and the end of the first interconnect solder strip 12 located on the side of the first edge 101 extends beyond the first edge 101.

[0059] The second interconnect solder strip 13 is soldered to the second pad 17. Specifically, the end of the second interconnect solder strip 13 facing the first edge is soldered to the second pad 17, and the end of the second interconnect solder strip 13 does not extend beyond the second pad 17 in the first direction. That is, the second interconnect solder strip 13 only extends to the location of the second pad 17, and its end is soldered to the second pad 17. There is no second interconnect solder strip 13 between the second pad 17 and the first edge 101.

[0060] In the back contact battery assembly 100 and photovoltaic system 1000 of this application embodiment, the first pad 16 and the second pad 17 each have a plurality of first fine grids 14 and a plurality of second fine grids 15 between them and the first edge 101. Each back contact battery 11 has a plurality of first interconnect solder ribbons 12 and a plurality of second interconnect solder ribbons 13 on its back side. The plurality of first interconnect solder ribbons 12 and the plurality of second interconnect solder ribbons 13 are arranged alternately and spaced along the second direction and all extend along the first direction. The first interconnect solder ribbons 12 are welded to the first pad 16, and the second interconnect solder ribbons 13 are welded to the second pad 17. The end of the first interconnect solder ribbon 12 extends beyond the first edge 101 in the first direction, and the end of the second interconnect solder ribbon 13 facing the first edge is welded to the second pad 17, and the end of the second interconnect solder ribbon 13 does not extend beyond the second pad 17 in the first direction. Thus, the first interconnecting solder strip 13 extends beyond the first edge 101, enabling it to connect with the busbar or the solder strip of the other polarity on an adjacent battery (e.g., the second interconnecting solder strip on an adjacent battery cell) to ensure a stable current output. The second interconnecting solder strip 13 extends only to the location of the second pad 17, with its end not exceeding the second pad 17. This reduces the area on the back side of the back contact battery 11 that is blocked by the second interconnecting solder strip 13, thereby improving the light absorption efficiency on the back side and increasing the bifaciality of the back contact battery assembly 100. It also reduces the cost of the second interconnecting solder strip 13.

[0061] Specifically, in the embodiments of this application, the back contact cell 11 may be a gridless back contact cell. The back contact cell 11 includes a silicon substrate (not shown) and a first doped layer (not shown) and a second doped layer (not shown) stacked on the back side of the silicon substrate and alternately arranged along a first direction. Both the first and second doped layers have a back passivation layer. The first fine gate 14 corresponds one-to-one with the first doped layer and at least partially penetrates the passivation layer to form an ohmic contact with the first doped layer. The second fine gate 15 corresponds one-to-one with the second doped layer and at least partially penetrates the back passivation layer to form an ohmic contact with the second doped layer. In some possible embodiments, a doped layer with the same polarity as the first doped layer may be provided below the region corresponding to the first pad 16 and the first bus line 18, and the second doped layer is disconnected at the location of this region. Similarly, a doped layer with the same polarity as the second doped layer may be provided below the region corresponding to the second pad 17 and the second bus line 19, and the first doped layer is disconnected at the location of this region. No specific limitations are imposed here.

[0062] Furthermore, in this application, in the back contact battery assembly 100, the number of battery strings 10 is several strings, such as... Figure 2 As shown, Figure 2 The diagram shows 12 battery strings 10. The back-contact battery assembly 100 is divided into upper and lower halves in a first direction, and each half includes six battery strings 10 arranged along a second direction. A first busbar 20 may be an end busbar, disposed at the upper and lower ends of the back-contact battery assembly 100 in the first direction, for connecting adjacent battery strings 10 in series in the second direction. A second busbar 30 may be an intermediate busbar, disposed between the upper and lower halves, for connecting the upper and lower halves together in parallel.

[0063] like Figure 2As shown, in the upper half, from left to right, the first battery string 10 and the second battery string 10 are connected in series via a first bus bar 20, the third battery string 10 and the fourth battery string 10 are connected in series via a first bus bar 20, and the fifth battery string 10 and the sixth battery string 10 are connected in series via a first bus bar 20. Similarly, in the lower half, from left to right, the first battery string 10 and the second battery string 10 are connected in series via a first bus bar 20, the third battery string 10 and the fourth battery string 10 are connected in series via a first bus bar 20, and the fifth battery string 10 and the sixth battery string 10 are connected in series via a first bus bar 20. In this case, there can be four second busbars 30. From left to right, the first battery string 10 in the upper half and the first battery string 10 in the lower half are connected to the first second busbar 30. The second and third battery strings in the upper half and the second and third battery strings in the lower half are connected to the second second busbar 30. The fourth and fifth battery strings in the upper half and the fourth and fifth battery strings in the lower half are connected to the third second busbar 30. The sixth battery string 10 in the upper half and the sixth battery string 10 in the lower half are connected to the fourth second busbar 30. A bypass diode can be provided between two adjacent second busbars 30.

[0064] In addition, such as Figure 2 As shown, it is easy to understand that in the battery string 10, two adjacent back contact batteries 11 are connected in series through a first interconnecting solder strip 12 and a second interconnecting solder strip 13. For example, in some embodiments, the first interconnecting solder strip 12 on the first back contact battery 11 closest to the first busbar 20 in the battery string 10 is an independent solder strip and is connected to the first busbar 20. Then, the second interconnecting solder strip 13 on the first back contact battery 11 is connected to the first interconnecting solder strip 12 on the second back contact battery 11, the second interconnecting solder strip 13 on the second back contact battery 11 is connected to the first interconnecting solder strip 12 on the third back contact battery 11, and so on. The second interconnecting solder strip on the last back contact battery 11 is an independent solder strip and is connected to the second busbar 30, and the second interconnecting solder strip 13 on the second-to-last back contact battery 11 is connected to the first interconnecting solder strip 12 on the last back contact battery 11. That is, in the battery string 10, if the interconnecting solder strip connected to the first bus bar 20 is the first interconnecting solder strip 12, then the interconnecting solder strip connected to the second bus bar 30 is the second interconnecting solder strip 13; if the interconnecting solder strip connected to the first bus bar 20 is the second interconnecting solder strip 13, then the interconnecting solder strip connected to the second bus bar 30 is the first interconnecting solder strip 12.

[0065] In some embodiments, in two adjacent back contact batteries 11 of the battery string 10, the first pad 16 of one battery and the second pad 17 of the other battery are collinearly arranged in a first direction. That is, in two adjacent back contact batteries 11, the first interconnect solder strip 12 of one battery and the second interconnect solder strip 13 of the other battery are collinearly arranged in a first direction. In this case, the first interconnect solder strip 12 and the second interconnect solder strip 13 connected to each other can be a single long solder strip, while the isolated first interconnect solder strip 12 and the second interconnect solder strip 13 are short solder strips.

[0066] Furthermore, it should be noted that in the embodiments of this application, the battery strings 10 in the upper and lower halves of the back contact battery assembly 100 are symmetrical structures. That is, the lower half battery string 10 can be obtained by rotating the upper half battery string 10 by 180°. Therefore, it is easy to understand that in the back contact battery assembly 100, the back contact batteries 11 in the two corresponding battery strings 10 in the upper and lower halves in the first direction have opposite orientations. For example, taking the first battery string 10 in the upper half and the first battery string 10 in the lower half as examples, the first edge 101 of the back contact battery 11 in the first battery string 10 in the upper half can be the edge of the back contact battery 11 facing upward (i.e., facing the first busbar 20 in the upper half), and the second edge 102 of the back contact battery 11 in the first battery string 10 in the upper half is the edge of the back contact battery 11 facing downward (i.e., facing the second busbar 30). In this case, the first edge 101 and the second edge 102 of the back contact battery 11 in the first battery string 10 in the lower half are opposite, that is, the first edge 101 of the back contact battery 11 in the first battery string 10 in the lower half is the edge of the back contact battery 11 facing downward (i.e., facing the first busbar 20 in the lower half), and the second edge 102 of the back contact battery 11 in the first battery string 10 in the lower half is the edge of the back contact battery 11 facing upward (i.e., facing the second busbar 30).

[0067] Furthermore, it is easy to understand that in the back contact battery assembly 100, since two adjacent battery strings 10 connected to the same first busbar 20 need to be connected in series, and two adjacent battery strings 10 connected to the same second busbar 30 also need to be connected in series, in any half-region, in the two adjacent battery strings 10 in the second direction, one battery string 10 is obtained by rotating the other battery string 10 by 180°. That is, in the two adjacent battery strings 10 in the second direction, the orientation of the back contact battery 11 in one battery string 10 is opposite to the orientation of the other back contact battery 11. In other words, the first edge 101 of the back contact battery 11 in one battery string 10 is the edge facing upward, while the first edge 101 of the back contact battery 11 in the other battery string 10 is the edge facing downward.

[0068] Please see Figure 3 In some embodiments, the back contact battery 11 has a plurality of first busbars 18 and a plurality of second busbars 19 on its back side.

[0069] Each first pad 16 is connected to a first bus gate line 18, which extends along a first direction and is located between the first pad 16 and the first edge 101. The first bus gate line 18 is connected to a first fine gate 14 located between the first pad 16 and the first edge 101 and is insulated from a second fine gate 15. Specifically, in some embodiments, the insulation between the two can be achieved by setting the second fine gate 15 to be disconnected at the first bus gate line 18.

[0070] Each second pad 17 is connected to a second busbar 19, which extends along a first direction and is located between the second pad 17 and the first edge 101. The second busbar 19 is connected to a second fine gate 15 located between the second pad 17 and the first edge 101 and is insulated from the first fine gate 14. Specifically, in some embodiments, the insulation between the two can be achieved by setting the first fine gate 14 to be disconnected at the second busbar 19.

[0071] Among them, such as Figure 3 As shown, the first busbar 18 is completely covered by the first interconnect ribbon 12 in the thickness direction (i.e., the stacking direction of the interconnect ribbons and the battery cells), and the second busbar 19 and the second interconnect ribbon 13 do not overlap in the thickness direction. In this document, "thickness direction" refers to the thickness direction of the back contact battery 11.

[0072] It is easy to understand that in some embodiments, the width of the first busbar 18 is smaller than the width of the first interconnect solder strip 12, and the width of the second busbar 19 is smaller than the width of the second interconnect solder strip 13. Overall, the width of the busbars is smaller than the width of the interconnect solder strips.

[0073] In embodiments of this application, the current collected by the first fine gate 14 located between the first pad 16 and the first edge 101 can be channeled through the first bus gate line 18 to the first interconnect solder strip 12 soldered to the first pad 16, thereby achieving current collection on the first fine gate 14 between the first pad 16 and the first edge 101. The current collected by the second fine gate 15 located between the second pad 17 and the first edge 101 can be channeled through the second bus gate line 19 to the second interconnect solder strip 13 soldered to the second pad 17, thereby achieving current collection on the second fine gate 15 between the second pad 17 and the first edge 101.

[0074] Each first pad 16 corresponds to a first busbar 18, and the number of first busbars 18 corresponds to the number of first pads 16. Each second pad 17 corresponds to a second busbar 19, and the number of second busbars 19 corresponds to the number of second pads 17. The number of first interconnect solder ribbons 12 on each back contact battery 11 also corresponds to the number of first pads 16 and first busbars 18, and the number of second interconnect solder ribbons 13 on each back contact battery 11 also corresponds to the number of second pads 17 and second busbars 19.

[0075] Thus, due to the presence of the first busbar 18 and the second busbar 19, the first interconnect solder ribbon 12 can collect the current on the first fine gate 14 in the vicinity of the first edge 101 without soldering it to the first fine gate 14 between the first pad 16 and the first edge 101. Similarly, the second interconnect solder ribbon 13 can collect the current on the second fine gate 15 in the vicinity of the first edge 101 without soldering it to the solder ribbon between the second pad 17 and the first edge 101. There are no soldering points on the first fine gate 14 between the first pad 16 and the first edge 101, and there are no soldering points on the second fine gate 15 between the second pad 17 and the first edge 101. This effectively reduces the risk of microcracks in the edge region while ensuring current collection efficiency, thus guaranteeing the quality of the component.

[0076] In other words, in the back contact battery module 100 of this application embodiment, the risk of microcracks in the edge area can be reduced while ensuring current collection efficiency, and the bifaciality of the back contact battery module 100 can be increased and the cost of solder strips can be reduced.

[0077] Please see Figure 3 In some embodiments, in the second direction, a plurality of first pads 16 are arranged collinearly, and a plurality of second pads 17 are also arranged collinearly.

[0078] Thus, the collinear arrangement of the first pad 16 allows the current collected by the first interconnect solder ribbon 12 to be evenly distributed in the second direction, and the collinear arrangement of the second pad 17 allows the current collected by the second interconnect solder ribbon 13 to be evenly distributed in the second direction, reducing series mismatch caused by pad position deviation.

[0079] Specifically, in such an embodiment, the collinear arrangement of the first pads 16 means that the first pads 16 are arranged in a straight line in the second direction, which can be achieved by aligning the center point of each first pad 16 with the same horizontal axis. The collinear arrangement of the second pads 17 means that the second pads 17 are arranged in another independent straight line in the second direction, which can also be achieved by aligning the center point of each first pad 16 with the same horizontal axis.

[0080] In some embodiments, the length of the first busbar 18 in the first direction may be 2mm-10mm.

[0081] In this way, we can avoid the situation where the length of the first busbar 18 is too short, resulting in an insufficient distance between the first pad 16 and the first edge 101, which could easily lead to microcracks at the edge during soldering, thus reducing the risk of microcracks. We can also avoid the situation where the length of the first busbar 18 is too long, resulting in an excessively long busbar path in the edge region and excessive current loss. In other words, by optimizing the design of the length of the first busbar 18, we can reduce the risk of microcracks while avoiding excessive current loss.

[0082] Specifically, the length of the first busbar 18 in the first direction may be, for example, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm or other values ​​between 2mm and 10mm, without any specific limitation.

[0083] In some embodiments, the length of the second busbar 19 in the first direction may be 2mm-10mm.

[0084] In this way, we can avoid the situation where the length of the second bus gate 19 is too short, resulting in an insufficient distance between the second pad 17 and the first edge 101, which could easily lead to microcracks at the edge during soldering, thus reducing the risk of microcracks. We can also avoid the situation where the length of the second bus gate 19 is too long, resulting in an excessively long bus path in the edge region and excessive losses. In other words, by optimizing the design of the length of the second bus gate 19, we can reduce the risk of microcracks while avoiding excessive bus losses.

[0085] Specifically, the length of the second busbar 19 in the first direction may be, for example, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm or other values ​​between 2mm and 10mm, without any specific limitation.

[0086] In some embodiments, the ratio between the length of the first busbar 18 in the first direction and the length of the back contact battery 11 in the first direction may be 2%-15%, such as 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or other values ​​of 2%-15%, which are not limited herein.

[0087] In this way, we can avoid the risk of microcracks appearing at the edge during welding due to the short length of the first busbar 18 being too small, and also avoid the risk of excessive busbar loss due to the long length of the first busbar 18 being too large.

[0088] In some embodiments, the ratio between the length of the second busbar 19 in the first direction and the length of the back contact battery 11 in the first direction may also be 2%-15%, such as 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% or other values ​​of 2%-15%, which are not limited herein.

[0089] In this way, we can avoid the risk of microcracks appearing at the edges during welding due to the length of the second busbar 19 being too small, and also avoid the risk of excessive busbar loss due to the length of the second busbar 19 being too long.

[0090] Specifically, in this application, the back contact battery 11 can be a full cell battery, a half cell battery, a one-third slice battery, or a one-quarter slice battery; no specific limitation is made here.

[0091] In some embodiments, when the back contact battery 11 is a full-cell battery, the ratio between the length of the first busbar 18 in the first direction and the length of the back contact battery 11 in the first direction is preferably 2%-3%, such as 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, or other values ​​between 2% and 3%, without specific limitations. The ratio between the length of the second busbar 19 in the first direction and the length of the back contact battery 11 in the first direction is also preferably 2%-3%, such as 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, or other values ​​between 2% and 3%, without specific limitations.

[0092] In some embodiments, when the back contact battery 11 is a half-cell battery, the ratio between the length of the first busbar 18 in the first direction and the length of the back contact battery 11 in the first direction is preferably 3%-7%, such as 3%, 4%, 5%, 6%, 7%, or other values ​​between 3% and 7%, without specific limitation herein. The ratio between the length of the second busbar 19 in the first direction and the length of the back contact battery 11 in the first direction is also preferably 3%-7%, such as 3%, 4%, 5%, 6%, 7%, or other values ​​between 3% and 7%, without specific limitation herein.

[0093] When the back contact battery 11 is a one-third slice battery, the ratio between the length of the first busbar 18 in the first direction and the length of the back contact battery 11 in the first direction is preferably 5%-9%, such as 5%, 6%, 7%, 8%, 9%, or other values ​​between 5% and 9%, and is not specifically limited herein. The ratio between the length of the second busbar 19 in the first direction and the length of the back contact battery 11 in the first direction is also preferably 5%-9%, such as 5%, 6%, 7%, 8%, 9%, or other values ​​between 5% and 9%, and is not specifically limited herein.

[0094] When the back contact battery 11 is a quarter-slice battery, the ratio between the length of the first busbar 18 in the first direction and the length of the back contact battery 11 in the first direction is preferably 8%-15%, such as 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or other values ​​between 8% and 15%, which are not specifically limited here. The ratio between the length of the second busbar 19 in the first direction and the length of the back contact battery 11 in the first direction is also preferably 8%-15%, such as 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or other values ​​between 8% and 15%, which are not specifically limited here.

[0095] Please see Figure 3 In some embodiments, the first bus gate line 18 is centrally connected to the first pad 16, that is, the first bus gate line 18 extends from the center of the first pad 16 toward the first edge 101.

[0096] Specifically, the centerline of the first pad 16 in the second direction coincides with the centerline of the first bus gate 18 in the second direction. That is to say, in such an embodiment, the first bus gate 18 is directly connected to the center of the first pad 16, and the first pad 16 has a symmetrical structure about the first bus gate 18 in the second direction.

[0097] Thus, when the first interconnect solder strip 12 is soldered to the center of the first pad 16, the first interconnect solder strip 12 can overlap with the first bus gate 18 as much as possible, thereby reducing the light-shielding area. At the same time, centering the first bus gate 18 can also reduce the bus transmission loss.

[0098] Of course, it is understood that in some possible embodiments, the first bus gate 18 may not be located at the center of the first pad 16, and no specific limitation is made here.

[0099] In addition, in some embodiments, the second bus gate line 19 is centrally connected to the second pad 17, that is, the second bus gate line 19 extends from the center of the first pad 16 toward the first edge 101.

[0100] Specifically, the centerline of the second pad 17 in the second direction coincides with the centerline of the second bus gate 19 in the second direction. That is to say, in such an embodiment, the second bus gate 19 is directly connected to the center of the second pad 17, and the second pad 17 has a symmetrical structure about the second bus gate 19 in the second direction.

[0101] Thus, when the second interconnect solder strip 13 is soldered to the center of the second pad 17, the second interconnect solder strip 13 and the second bus gate line 19 can overlap as much as possible, thereby reducing the light-shielding area. At the same time, centering the second bus gate line 19 can also reduce the bus transmission loss.

[0102] Of course, it is understood that in some possible embodiments, the second bus gate 19 may not be located at the center of the second pad 17, and no specific limitation is made here.

[0103] Please see Figure 3 and Figure 4 In some embodiments, at least one first adhesive dot 40 is provided on the first busbar 18, preferably one first adhesive dot 40, which is bonded to the first interconnecting solder strip 12, and the second busbar 19 does not have an adhesive dot.

[0104] Thus, during the preparation process, the first adhesive 40 can pre-fix the end of the first interconnecting solder strip 12 facing the first edge 101, while no adhesive is applied to the second busbar 19, which can reduce the occlusion area and also avoid increasing the risk of edge microcracks due to excessive adhesive application at the edge.

[0105] Please see Figure 4 and Figure 5 In some embodiments, the length of the second pad 17 in the first direction is greater than the length of the first pad 16 in the first direction. The second pad 17 includes a first portion 171 and a second portion 172. The second portion 172 is located on the side of the first portion 171 facing the first edge 101. The second interconnect solder strip 13 does not extend beyond the second portion 172.

[0106] The first part 171 is provided with a second adhesive 50, which is bonded to the second interconnecting solder strip 13.

[0107] Thus, by lengthening the second pad 17, a second adhesive 50 is provided on the first part 171. The second adhesive 50 can pre-fix the end region of the second interconnect solder strip 13 toward the first edge 101 to prevent it from shifting position. The second part 172 can then be used to solder with the second interconnect solder strip 13.

[0108] Specifically, in such an embodiment, the entire first portion 171 may be covered with the second adhesive 50, or the second adhesive 50 may only cover a portion of the first portion 171. The first portion 171 may not be used for welding with the second interconnect solder strip 13 or may only be partially welded to the second interconnect solder strip 13. The second portion 172 is welded to the second interconnect solder strip 13.

[0109] In some embodiments, the area of ​​the second portion 172 is greater than or equal to the area of ​​the first pad 16.

[0110] This ensures the welding area between the second interconnect solder strip 13 and the second solder pad 17, improving the stability of the welding process.

[0111] In some embodiments, a first auxiliary connection layer (not shown) may be provided on the second portion 172. The height of the first auxiliary connection layer is flush with the height of the second adhesive dispensing 50 or the absolute value of the difference between the height of the first auxiliary connection layer and the height of the second adhesive dispensing 50 is less than 15 μm. The second interconnecting solder strip 13 can be soldered to the second portion 172 through the first auxiliary connection layer.

[0112] In this way, the presence of the second adhesive 50 can be effectively avoided, which would cause the interconnecting solder strip to have a poor solder joint when it is soldered to the second part 172, thus reducing the risk of poor solder joint and improving the stability of the soldering.

[0113] Of course, it is understood that in some possible embodiments, the second adhesive 50 may be disposed on the second portion 172, and the second adhesive 50 may be soldered to the second interconnect solder strip 13. In such a case, the first portion 172 is used to dispose of the adhesive, and the first portion 171 is used to solder to the second interconnect solder strip 13.

[0114] It is easy to understand that, in this case, the area of ​​the first portion 171 can be set to be larger than the area of ​​the first pad 16. Furthermore, the first auxiliary connection layer can be disposed on the first portion 171.

[0115] Please see Figure 3 , Figure 4 as well as Figure 6 In some embodiments, the back contact battery 11 also has a plurality of third pads 110 and a plurality of fourth pads 111 on the back side.

[0116] Both the third pad 110 and the third pad 111 are located close to the second edge 102. A plurality of third pads 110 and a plurality of fourth pads 111 are arranged alternately along the second direction. The third pad 110 and the space between the third pad 110 and the second edge 102 each have a plurality of first fine gates 14 and a plurality of second fine gates 15.

[0117] The third pad 110 and the first pad 16 are one-to-one correspondences and collinear in the first direction. The third pad 110 and the first pad 16 are soldered to the same first interconnect solder strip 12. The fourth pad 111 and the second pad 17 are one-to-one correspondences and collinear in the first direction. The fourth pad 111 and the second pad 17 are soldered to the same second interconnect solder strip 13.

[0118] At least two first fine gates 14 are connected to the third pad 110, and the third pad 110 is also electrically connected to the first fine gates 14 located between the third pad 110 and the second edge 102 (e.g., through the third bus 112 hereinafter referred to as the conductive connection). In some embodiments, the third pad 110 is connected to all the first fine gates 14 located between the third pad 110 and the second edge 102.

[0119] At least two second fine gates 15 are connected to the fourth pad 111, and the fourth pad 111 is also electrically connected to the second fine gates 15 located between the fourth pad 111 and the second edge 102 (e.g., through the fourth bus gate line 113 hereinafter). In some embodiments, the fourth pad 111 may be connected to all the second fine gates 15 located between the fourth pad 111 and the second edge 102.

[0120] The first fine gate 14 is insulated from the fourth pad 111, and the second fine gate 15 is insulated from the third pad 110. Specifically, in some embodiments, the first fine gate 14 may be disconnected at the second pad 17, and the second fine gate 15 may be disconnected at the first pad 16.

[0121] Specifically, the first interconnect solder strip 12 is soldered to the third pad 110. The end of the first interconnect solder strip 12 facing the second edge 102 is soldered to the third pad 110 and the end of the first interconnect solder strip 12 does not extend beyond the third pad 110 in the first direction. That is, the first interconnect solder strip 12 only extends to the location of the third pad 110 and its end is soldered to the third pad 110. There is no first interconnect solder strip 12 between the third pad 110 and the second edge 102.

[0122] The second interconnect solder strip 13 is soldered to the fourth solder pad 111. The second interconnect solder strip 13 extends beyond the second edge 102 in the first direction. The second interconnect solder strip 13 extends beyond the second edge 102 in the first direction. The end of the second interconnect solder strip 13 located on the side of the second edge 102 extends beyond the second edge 102 in the first direction.

[0123] In this way, while ensuring the transmission of current, the area on the back side of the back contact battery 11 that is blocked by the first interconnect solder ribbon 12 can be reduced, thereby improving the light absorption efficiency on the back side, increasing the bifaciality of the back contact battery assembly 100, and also reducing the cost of the first interconnect solder ribbon 12.

[0124] Please see Figure 3 In some embodiments, the back contact battery 11 may also have a plurality of third busbars 112 and fourth busbars 113 on the back side.

[0125] Each third pad 110 is connected to a third bus gate line 112, which extends continuously along a first direction and is located between the third pad 110 and the second edge 102. The third bus gate line 112 is connected to a first fine gate 14 located between the third pad 110 and the second edge 102 and is insulated from a second fine gate 15. Specifically, in some embodiments, the insulation between the two can be achieved by setting the second fine gate 15 to be disconnected at the third bus gate line 112.

[0126] Each fourth pad 111 is connected to a fourth bus gate line 113, which extends continuously along a first direction and is located between the fourth pad 111 and the second edge 102. The fourth bus gate line 113 is connected to a second fine gate 15 located between the fourth pad 111 and the second edge 102 and is insulated from the first fine gate 14. Specifically, in some embodiments, the insulation between the two can be achieved by setting the first fine gate 14 to be disconnected at the fourth bus gate line 113.

[0127] Among them, such as Figure 3 As shown, the third busbar 112 is not overlapped with the first interconnect ribbon 12 in the thickness direction (i.e., the stacking direction of the interconnect ribbons and the battery cells), and the fourth busbar 113 is completely covered by the second interconnect ribbon 13 in the thickness direction. In other words, in this document, in the thickness direction of the back contact battery 11, the first interconnect ribbon 12 does not cover the third busbar 112, and the second interconnect ribbon 13 completely covers the fourth busbar 113.

[0128] It is easy to understand that in some embodiments, the width of the third busbar 112 is smaller than the width of the first interconnect solder strip 12, and the width of the fourth busbar 113 is smaller than the width of the second interconnect solder strip 13. Overall, the width of the busbars is smaller than the width of the interconnect solder strips.

[0129] In embodiments of this application, the current collected by the first fine gate 14 located between the third pad 110 and the second edge 102 can be channeled through the third bus gate line 112 to the first interconnect solder strip 12 soldered to the third pad 110, thereby achieving current collection on the first fine gate 14 between the third pad 110 and the second edge 102. The current collected by the second fine gate 15 located between the fourth pad 111 and the second edge 102 can be channeled through the fourth bus gate line 113 to the second interconnect solder strip 13 soldered to the fourth pad 111, thereby achieving current collection on the second fine gate 15 between the fourth pad 111 and the second edge 102.

[0130] Each third pad 110 corresponds to one third busbar 112, and the number of third busbars 112 corresponds to the number of third pads 110. Each fourth pad 111 corresponds to one fourth busbar 113, and the number of fourth busbars 113 corresponds to the number of fourth pads 111. The number of first interconnect solder ribbons 12 on each back contact battery 11 also corresponds to the number of third pads 110 and third busbars 112, and the number of second interconnect solder ribbons 13 on each back contact battery 11 also corresponds to the number of fourth pads 111 and fourth busbars 113.

[0131] Thus, due to the presence of the third busbar 112 and the fourth busbar 113, the second interconnect solder ribbon 13 does not need to be soldered to the first fine gate 14 between the third pad 110 and the first edge 101 to collect the current on the first fine gate 14 in the vicinity of the first edge 101. The first interconnect solder ribbon 12 does not need to be soldered to the solder ribbon between the fourth pad 111 and the first edge 101 to collect the current on the second fine gate 15 in the vicinity of the first edge 101. There are no soldering points on the first fine gate 14 between the third pad 110 and the first edge 101, and there are no soldering points on the second fine gate 15 between the fourth pad 111 and the first edge 101. This can effectively reduce the risk of microcracks in the edge area while ensuring the current collection efficiency, thus ensuring the quality of the component.

[0132] Please see Figure 3 and Figure 4 In some embodiments, in the second direction, a plurality of third pads 110 are arranged collinearly, and a plurality of fourth pads 111 are also arranged collinearly.

[0133] Thus, the collinear arrangement of the third pad 110 allows the current collected by the first interconnect solder strip 12 to be evenly distributed in the second direction, and the collinear arrangement of the fourth pad 111 allows the current collected by the second interconnect solder strip 13 to be evenly distributed in the second direction, reducing series mismatch caused by pad position deviation.

[0134] Specifically, in such an embodiment, the collinear arrangement of the third pads 110 means that the third pads 110 are arranged in a straight line in the second direction, which can be achieved by aligning the center point of each third pad 110 with the same horizontal axis. The collinear arrangement of the fourth pads 111 means that the fourth pads 111 are arranged in another independent straight line in the second direction, which can also be achieved by aligning the center point of each third pad 110 with the same horizontal axis.

[0135] In some embodiments, the length of the third busbar 112 in the first direction may be 2mm-10mm.

[0136] In this way, the length of the third busbar 112 can be optimized to avoid the situation where the distance between the fourth pad 111 and the second edge 102 is too small due to an excessively short length, which could easily lead to microcracks at the edge during soldering, thus reducing the risk of microcracks. Conversely, the length of the third busbar 112 can also be optimized to avoid excessive current loss due to an excessively long busbar path in the edge region. In other words, by optimizing the length of the third busbar 112, the risk of microcracks can be reduced while avoiding excessive current loss.

[0137] Specifically, the length of the third busbar 112 in the first direction can be, for example, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm or other values ​​between 2mm and 10mm, without any specific limitation.

[0138] In some embodiments, the length of the fourth busbar 113 in the first direction may be 2mm-10mm.

[0139] In this way, the length of the fourth bus gate 113 can be optimized to avoid the situation where the distance between the third pad 110 and the second edge 102 is too small due to an excessively short length, which could easily lead to microcracks at the edge during soldering, thus reducing the risk of microcracks. Conversely, the length of the fourth bus gate 113 can also be optimized to avoid excessive current loss due to an excessively long bus path in the edge region. In other words, by optimizing the design of the length of the fourth bus gate 113, the risk of microcracks can be reduced while avoiding excessive current loss.

[0140] Specifically, the length of the fourth busbar 113 in the first direction can be, for example, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm or other values ​​between 2mm and 10mm, without any specific limitation.

[0141] In some embodiments, the ratio between the length of the fourth busbar 113 in the first direction and the length of the back contact battery 11 in the first direction may be 2%-15%, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% or other values ​​of 2%-15%, and is not limited herein.

[0142] In this way, we can avoid the risk of microcracks appearing at the edge during welding due to the excessively small length of the fourth bus gate line 113, and also avoid the risk of excessive bus loss due to the excessively long length of the fourth bus gate line 113.

[0143] In some embodiments, the ratio between the length of the third busbar 112 in the first direction and the length of the back contact battery 11 in the first direction may also be 2%-15%, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% or other values ​​of 2%-15%, and no specific limitation is made herein.

[0144] In this way, we can avoid the risk of microcracks appearing at the edge during welding due to the excessively small length of the third busbar 112, and also avoid the risk of excessive busbar loss due to the excessively long length of the third busbar 112.

[0145] Specifically, in this application, the back contact battery 11 can be a full cell battery, a half cell battery, a one-third slice battery, or a one-quarter slice battery; no specific limitation is made here.

[0146] In some embodiments, when the back contact battery 11 is a full-cell battery, the ratio between the length of the third busbar 112 in the first direction and the length of the back contact battery 11 in the first direction is preferably 2%-3%, such as 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, or other values ​​between 2% and 3%, without specific limitations. The ratio between the length of the fourth busbar 113 in the first direction and the length of the back contact battery 11 in the first direction is also preferably 2%-3%, such as 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, or other values ​​between 2% and 3%, without specific limitations.

[0147] In some embodiments, when the back contact battery 11 is a half-cell battery, the ratio between the length of the third busbar 112 in the first direction and the length of the back contact battery 11 in the first direction is preferably 3%-7%, such as 3%, 4%, 5%, 6%, 7%, or other values ​​between 3% and 7%, without specific limitation herein. The ratio between the length of the fourth busbar 113 in the first direction and the length of the back contact battery 11 in the first direction is also preferably 3%-7%, such as 3%, 4%, 5%, 6%, 7%, or other values ​​between 3% and 7%, without specific limitation herein.

[0148] When the back contact battery 11 is a one-third slice battery, the ratio between the length of the third busbar 112 in the first direction and the length of the back contact battery 11 in the first direction is preferably 5%-9%, such as 5%, 6%, 7%, 8%, 9%, or other values ​​between 5% and 9%, and is not specifically limited herein. The ratio between the length of the fourth busbar 113 in the first direction and the length of the back contact battery 11 in the first direction is also preferably 5%-9%, such as 5%, 6%, 7%, 8%, 9%, or other values ​​between 5% and 9%, and is not specifically limited herein.

[0149] When the back contact battery 11 is a quarter-slice battery, the ratio between the length of the third busbar 112 in the first direction and the length of the back contact battery 11 in the first direction is preferably 8%-15%, such as 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or other values ​​between 8% and 15%, which are not specifically limited here. The ratio between the length of the fourth busbar 113 in the first direction and the length of the back contact battery 11 in the first direction is also preferably 8%-15%, such as 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or other values ​​between 8% and 15%, which are not specifically limited here.

[0150] Please see Figure 3 In some embodiments, the third bus gate line 112 is centrally connected to the third pad 110, that is, the third bus gate line 112 extends from the center of the third pad 110 toward the second edge 102.

[0151] Specifically, the centerline of the third pad 110 in the second direction coincides with the centerline of the third bus gate 112 in the second direction. That is to say, in such an embodiment, the third bus gate 112 is directly cross-connected to the center of the third pad 110, and the third pad 110 has a symmetrical structure about the third bus gate 112 in the second direction.

[0152] Thus, when the first interconnect solder strip 12 is soldered at the center of the third pad 110, the first interconnect solder strip 12 and the third bus gate line 112 can overlap as much as possible, thereby reducing the light-shielding area. At the same time, centering the third bus gate line 112 can also reduce the bus transmission loss.

[0153] Of course, it is understood that in some possible embodiments, the third bus gate 112 may not be located at the center of the third pad 110, and no specific limitation is made here.

[0154] In addition, in some embodiments, the fourth bus gate line 113 is centrally connected to the fourth pad 111, that is, the fourth bus gate line 113 extends from the center of the first pad 16 toward the first edge 101.

[0155] Specifically, the centerline of the fourth pad 111 in the second direction coincides with the centerline of the fourth bus gate 113 in the second direction. That is to say, in such an embodiment, the fourth bus gate 113 is directly cross-connected to the center position of the fourth pad 111, and the fourth pad 111 has a symmetrical structure about the fourth bus gate 113 in the second direction.

[0156] Thus, when the second interconnect solder strip 13 is soldered at the center of the fourth pad 111, the second interconnect solder strip 13 and the fourth bus gate line 113 can overlap as much as possible, thereby reducing the light-shielding area. At the same time, centering the fourth bus gate line 113 can also reduce the bus transmission loss.

[0157] Of course, it is understood that in some possible embodiments, the fourth bus gate 113 may not be located at the center of the fourth pad 111, and no specific limitation is made here.

[0158] Please see Figure 3 and Figure 4 In some embodiments, at least one third adhesive 60 is provided on the fourth busbar 113, preferably one third adhesive 60, which is bonded to the second interconnecting solder strip 13, and the third busbar 112 does not have adhesive.

[0159] Thus, during the preparation process, the end of the second interconnecting solder strip 13 facing the second edge 102 can be pre-fixed by the third adhesive 60, while no adhesive is applied to the third busbar 112, which can reduce the occlusion area and also avoid the risk of increased edge microcracks caused by too much adhesive applied at the edge.

[0160] Please see Figure 4 and Figure 6In some embodiments, the length of the third pad 110 in the first direction is greater than the length of the first pad 16 in the first direction. The third pad 110 includes a third portion 1101 and a fourth portion 1102. The fourth portion 1102 is located on the side of the third portion 1101 facing the second edge 102. The second interconnect solder strip 13 does not extend beyond the fourth portion 1102.

[0161] The third part 1101 is provided with a fourth adhesive 70, which is bonded to the first interconnecting solder strip 12.

[0162] Thus, by lengthening the third pad 110, a fourth adhesive 70 is provided on the third part 1101. The fourth adhesive 70 can pre-fix the end region of the first interconnect solder strip 12 toward the second edge 102 to prevent it from shifting position. The fourth part 1102 can then be used to solder with the first interconnect solder strip 12.

[0163] Specifically, in such an embodiment, the entire third part 1101 may be covered with the fourth adhesive 70, or the fourth adhesive 70 may only cover a portion of the third part 1101. The third part 1101 may not be used for welding with the first interconnect solder strip 12 or may only be partially welded to the first interconnect solder strip 12. The fourth part 1102 is welded to the first interconnect solder strip 12.

[0164] In some embodiments, the area of ​​the fourth portion 1102 is greater than or equal to the area of ​​the fourth pad 111.

[0165] In this way, the welding area between the first interconnect solder strip 12 and the third solder pad 110 can be guaranteed, thus improving the stability of the welding.

[0166] In some embodiments, a second auxiliary connection layer (not shown) may be provided on the fourth part 1102. The height of the first auxiliary connection layer is flush with the height of the fourth adhesive 70, or the absolute value of the difference between the height of the second auxiliary connection layer and the height of the fourth adhesive 70 is less than 15 μm. The first interconnect solder strip 12 can be soldered to the fourth part 1102 through the second auxiliary connection layer.

[0167] In this way, the presence of the fourth adhesive 70 can be effectively avoided, which would cause the interconnecting solder strip to have a poor solder joint when it is soldered to the fourth part 1102, thus reducing the risk of poor solder joint and improving the stability of the soldering.

[0168] Of course, it is understood that in some possible embodiments, a fourth adhesive 70 may be provided on the fourth portion 1102, and the fourth adhesive 70 may be soldered to the first interconnect solder strip 12. In such a case, the fourth portion 1102 is used to provide the adhesive, and the third portion 1101 is used to solder to the second interconnect solder strip 13.

[0169] It is easy to understand that, in this case, the area of ​​the third part 1101 can be set to be larger than the area of ​​the fourth pad 111. Furthermore, the second auxiliary connection layer can be disposed on the third part 1101.

[0170] It is not difficult to understand that, such as Figure 4 As mentioned above, in Figure 4 In the embodiment shown, during the component fabrication process, the first interconnecting ribbon 12 is bonded to the battery via the first adhesive 40 and the fourth adhesive 70, and the second interconnecting ribbon 13 is bonded to the battery via the second adhesive 50 and the third adhesive 60, thereby pre-fixing the interconnecting ribbons.

[0171] Please see Figure 3 and Figure 4 In some embodiments, there is no adhesive dot between the first pad 16 and the third pad 110.

[0172] In this way, it is possible to avoid the adhesive being placed between the first pad 16 and the third pad 110, which would block the first fine gate 14 between them, preventing the first interconnect solder ribbon 12 from making contact with the first fine gate 14 blocked by the adhesive and thus resulting in efficiency loss.

[0173] In some embodiments, there is no adhesive dot between the second pad 17 and the fourth pad 111.

[0174] In this way, it is possible to avoid the adhesive being placed between the second pad 17 and the fourth pad 111, which would block the second fine gate 15 between them, thus preventing the second interconnect solder ribbon 13 from making contact with the second fine gate 15 blocked by the adhesive and resulting in efficiency loss.

[0175] Furthermore, it should be noted that in some possible embodiments, the first adhesive 40, second adhesive 50, third adhesive 60, and fourth adhesive 70 may not be present in the back contact battery assembly 100. Instead, during the assembly process, each interconnecting solder ribbon is pre-fixed by covering the back of the back contact battery 11 with a pre-fixing film layer. For example, after placing the interconnecting solder ribbons, a pre-fixing film layer can be covered on the back of each back contact battery 11, and the pre-fixing film layer can be bonded to the back contact battery 11 by light heating to fix the interconnecting solder ribbons. Of course, it is understood that in some possible embodiments, when using a pre-fixing film layer to pre-fix the interconnecting solder ribbons, the first adhesive 40 and fourth adhesive 70 may also be retained.

[0176] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with the described embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0177] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A back-contact battery assembly, characterized in that, The back contact battery assembly includes a plurality of battery strings, each battery string including a plurality of back contact batteries arranged along a first direction, a plurality of first interconnecting solder strips, and a plurality of second interconnecting solder strips. The back contact battery has a first edge and a second edge opposite to each other in the first direction. The back side of the back contact battery has a plurality of first fine grids, a plurality of second fine grids, a plurality of first pads and a plurality of second pads. The plurality of first fine grids and the plurality of second fine grids are arranged alternately and at intervals along the first direction and all extend along the second direction, which intersects the first direction. Both the first pad and the second pad are located close to the first edge. The first pad and the space between the first pad and the first edge each have a plurality of first fine gates and a plurality of second fine gates. The plurality of first pads and the plurality of second pads are arranged alternately along the second direction. At least two first fine gates are connected to the first pad, and the first pad is also electrically connected to the first fine gate located between the first pad and the first edge. At least two second fine gates are connected to the second pad, and the second pad is also electrically connected to all the second fine gates located between the second pad and the second edge. The first fine gates are insulated from the second pad, and the second fine gates are insulated from the first pad. Each of the back contact batteries has a plurality of first interconnect solder strips and a plurality of second interconnect solder strips on its back side. The plurality of first interconnect solder strips and the plurality of second interconnect solder strips are arranged alternately at intervals along the second direction and all extend along the first direction. The first interconnect solder strips are welded to the first pad and the first interconnect solder strips extend beyond the first edge in the first direction. The ends of the second interconnect solder strips facing the first edge are welded to the second pad and the ends of the second interconnect solder strips do not extend beyond the second pad in the first direction.

2. The back contact battery assembly according to claim 1, characterized in that, The back contact battery has a plurality of first busbars and a plurality of second busbars on its back side. Each of the first pads is connected to a first bus gate line, which is located between the first pad and the first edge. The first bus gate line is electrically connected to the first fine gate located between the first pad and the first edge and is insulated from the second fine gate. Each of the second pads is connected to a second bus gate line, which is located between the second pad and the first edge. The second bus gate line is electrically connected to the second fine gate located between the second pad and the first edge and is insulated from the first fine gate. The first busbar is completely covered by the first interconnect solder strip, and the second busbar and the second interconnect solder strip do not overlap.

3. The back contact battery assembly according to claim 2, characterized in that, The length of the first busbar in the first direction is 2mm-10mm; and / or The length of the second busbar in the first direction is 2mm-10mm.

4. The back contact battery assembly according to claim 2, characterized in that, The ratio between the length of the first busbar in the first direction and the length of the back contact battery in the first direction is 2% to 15%; and / or The ratio between the length of the second busbar in the first direction and the length of the back contact battery in the first direction is 2% to 15%.

5. The back contact battery assembly according to claim 2, characterized in that, The first busbar has at least one first adhesive dot, which is bonded to the first interconnecting solder strip, while the second busbar does not have an adhesive dot.

6. The back contact battery assembly according to claim 1, characterized in that, The length of the second pad in the first direction is greater than the length of the first pad in the first direction. The second pad includes a first part and a second part. The second part is located on the side of the first part facing the first edge. The second interconnect solder strip does not extend beyond the second part. The first part is provided with a second adhesive dot, which is bonded to the second interconnecting solder strip; or the second part is provided with a second adhesive dot, which is bonded to the second interconnecting solder strip.

7. The back contact battery assembly according to claim 6, characterized in that, The area of ​​the second part is greater than or equal to the area of ​​the first pad.

8. The back contact battery assembly according to claim 1, characterized in that, The back of the back contact battery also has several third solder pads and several fourth solder pads. The third pad and the third pad are both located close to the second edge. A plurality of third pads and a plurality of fourth pads are arranged alternately along the second direction. The third pad and the third pad and the second edge each have a plurality of first fine gates and a plurality of second fine gates. The third pad and the first pad correspond one-to-one in the first direction and are arranged collinearly. The third pad and the first pad are soldered to the same first interconnect solder strip. The fourth pad and the second pad correspond one-to-one in the first direction and are arranged collinearly. The fourth pad and the second pad are soldered to the same second interconnect solder strip. At least two first fine gates are connected to the third pad, and the third pad is also electrically connected to the first fine gate located between the third pad and the second edge. At least two second fine gates are connected to the fourth pad, and the fourth pad is also electrically connected to the second fine gate located between the fourth pad and the second edge. The first fine gate is insulated from the fourth pad, and the second fine gate is insulated from the third pad. Wherein, the end of the first interconnect solder strip facing the second edge is soldered to the third pad and the end of the first interconnect solder strip does not extend beyond the third pad in the first direction, and the second interconnect solder strip is soldered to the fourth pad and the first interconnect solder strip extends beyond the second edge in the first direction.

9. The back contact battery assembly according to claim 8, characterized in that, The back contact battery has several third busbars and several fourth busbars on its back side. Each of the third pads is connected to a third bus line, which is located between the third pad and the second edge, and is electrically connected to the first fine gate located between the third pad and the second edge; Each of the fourth pads is connected to a fourth bus line, which is located between the fourth pad and the second edge, and is electrically connected to the second fine gate located between the fourth pad and the second edge; The third busbar and the first interconnect solder strip do not overlap in the thickness direction, and the fourth busbar is completely covered by the second interconnect solder strip in the thickness direction.

10. The back contact battery assembly according to claim 9, characterized in that, At least one third adhesive dot is provided on the fourth busbar, and the third adhesive dot is bonded to the second interconnecting solder strip. The third busbar does not have an adhesive dot.

11. The back contact battery assembly according to claim 9, characterized in that, The length of the third pad in the first direction is greater than the length of the fourth pad in the first direction. The third pad includes a third part and a fourth part. The fourth part is located on the side of the third part facing the second edge. The first interconnect solder strip does not extend beyond the fourth part. The third part is provided with a fourth adhesive dot, which is bonded to the first interconnect solder strip; or the fourth part is provided with a fourth adhesive dot, which is bonded to the first interconnect solder strip.

12. The back contact battery assembly according to claim 11, characterized in that, The area of ​​the fourth part is greater than or equal to the area of ​​the fourth pad.

13. A photovoltaic system, characterized in that, Includes the back contact battery assembly as described in any one of claims 1-12.

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