Busbar-less back contact battery, battery string, battery assembly, and photovoltaic system

Abstract

The present disclosure is applicable to the technical field of solar cells. Provided are a busbar-less back contact battery, a battery string, a battery assembly, and a photovoltaic system. In a solar cell, a first soldering section is provided at an intersection position between each first fine grid and a first series connection area, all the first soldering sections are located in the first series connection area, and there is at least one first soldering section in the first series connection area that is staggered, in a first direction, to the remaining first soldering sections. In an arrangement sequence of the first soldering sections in the first direction, a first line segment formed by sequentially connecting the center points of all the first soldering sections is a nonlinear line segment, and the first line segment has at least one first recess section. Thus, when a first pre-adhesive is used to pre-fix a solder ribbon, the first pre-adhesive can be arranged at a position towards which the opening of a first recess section faces, in this way, the distance between the first pre-adhesive and a first soldering section in the first recess section corresponding to the first pre-adhesive is relatively large, and thus a cold solder joint in a subsequent soldering process can be effectively avoided.

Description

Gridless back-contact cells, cell strings, cell modules and photovoltaic systems

[0001] This disclosure takes priority from the patent application filed on April 26, 2024, with application number 202410515997.8 entitled "Gridless Back Contact Battery, Battery String, Battery Module and Photovoltaic System", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to the field of solar cell technology, and more particularly to a gridless back-contact cell, cell string, cell module and photovoltaic system. Background Technology

[0003] In related technologies, in gridless back-contact solar cells, solder paste pads are provided at the positions on each fine grid for connection with the solder ribbon. To prevent the solder ribbon from shifting during lamination, pre-adhesive is applied near the solder paste pads to pre-fix the ribbon. To ensure accurate bonding, the pre-adhesive is typically placed near the center of the solder ribbon, close to the solder paste pad. In this case, due to the height difference between the pre-adhesive and the solder paste pad, if the pre-adhesive is too high, even with stable solder ribbon bonding, the close distance between the pre-adhesive and the solder paste pad can prevent the solder ribbon from making contact during pre-fixation, leading to cold solder joints in subsequent soldering processes. Conversely, if the solder paste pad is too high, even with contact between the solder ribbon and the pad, the close distance between the pre-adhesive and the pad can reduce the adhesion between the solder ribbon and the pre-adhesive, potentially causing bonding failure.

[0004] Therefore, how to effectively avoid incomplete soldering of gridless back contact cells during lamination welding while ensuring the stability of the pre-fixation of the solder strip has become a technical problem for engineers to study. Summary of the Invention

[0005] This disclosure provides a gridless back contact cell, cell string, cell module, and photovoltaic system, aiming to solve the technical problem of how to effectively avoid incomplete soldering in gridless back contact cells during lamination welding while ensuring the stability of the pre-fixed solder strip.

[0006] This disclosure is implemented as follows: the gridless back contact battery of this disclosure embodiment includes:

[0007] The device includes a silicon substrate and a plurality of first fine gates and a plurality of second fine gates disposed on the back side of the silicon substrate. The plurality of first fine gates and the plurality of second fine gates are arranged alternately along a first direction and all extend along a second direction, which intersects the first direction. The back side has a plurality of first serial connection areas and a plurality of second serial connection areas for setting solder strips. The plurality of first serial connection areas and the plurality of second serial connection areas extend along the first direction and intersect with all the first fine gates and all the second fine gates. The plurality of first serial connection areas and the plurality of second serial connection areas are arranged alternately along the second direction.

[0008] Each of the first fine gates has a first welded segment at the intersection with the first serial connection area, and all the first welded segments are located within the first serial connection area. Each of the second fine gates has a second welded segment at the intersection with the second serial connection area, and all the second welded segments are located within the second serial connection area.

[0009] In the first serial connection area, at least one of the first welding segments is misaligned with at least one other first welding segment in the first direction;

[0010] According to the arrangement order of the first welded segments in the first direction, the first line segment formed by connecting the center points of all the first welded segments in sequence is a non-linear line segment, and the first line segment has at least one first recessed segment.

[0011] Furthermore, the two first welded segments that are misaligned in the first direction have an overlapping portion in the first direction.

[0012] Furthermore, the length of the overlapping portion in the second direction is 50um-200um.

[0013] Furthermore, the two first welded segments that are misaligned in the first direction are spaced apart from each other in the second direction.

[0014] Furthermore, the two first welded segments that are staggered in the first direction are spaced 100um-2.5mm apart in the second direction.

[0015] Furthermore, there are multiple first welded segments corresponding to the first recessed segment.

[0016] Furthermore, the first line segment also has at least one first straight line segment, which is arranged parallel to the first direction, and the first recessed segment is offset relative to the first straight line segment along the second direction.

[0017] Furthermore, the first recessed segment includes a first sub-straight line segment parallel to the first straight line segment and a first inclined segment connecting the first sub-straight line segment and the first straight line segment.

[0018] Furthermore, there are multiple first straight segments and multiple first recessed segments, which are arranged alternately and at intervals.

[0019] Furthermore, in the two first recessed segments at both ends of the first straight segment, one of the first recessed segments is recessed to one side of the first straight segment, and the other first recessed segment is recessed to the other side of the first straight segment.

[0020] Furthermore, the first line segment is a wavy line.

[0021] Furthermore, each of the second fine grids has a second welded segment at the intersection of the second fine grid and the second serial connection area, and all the second welded segments are located within the second serial connection area. Within the second serial connection area, at least one second welded segment is offset from at least one other second welded segment in the first direction.

[0022] Wherein, according to the arrangement order of the second welding segments in the first direction, the second line segment formed by connecting the center points of all the second welding segments in sequence is a non-linear line segment, and the second line segment has at least one second concave segment.

[0023] Furthermore, the two second welded segments that are misaligned in the first direction have an overlapping portion in the first direction.

[0024] Furthermore, the length of the overlapping portion in the second direction is 50um-200um.

[0025] Furthermore, the two second welded segments, which are staggered in the first direction, are spaced apart from each other in the second direction.

[0026] Furthermore, the two second welded segments that are staggered in the first direction are spaced 100um-2.5mm apart in the second direction.

[0027] Furthermore, the second line segment also has at least one second straight line segment, which is arranged parallel to the second direction, and the second recessed segment is offset relative to the second straight line segment along the second direction.

[0028] Furthermore, the second recessed segment includes a second sub-straight segment parallel to the second straight segment and a second inclined segment connecting the second sub-straight segment and the second straight segment.

[0029] Furthermore, there are multiple second straight segments and multiple second recessed segments, which are arranged alternately and at intervals.

[0030] Furthermore, in the two second concave segments at both ends of the second straight segment, one of the second concave segments is concave to one side of the second straight segment, and the other second concave segment is concave to the other side of the second straight segment.

[0031] Furthermore, the second line segment is a wavy line.

[0032] This disclosure also provides a battery string, including:

[0033] Several of the above-described gridless back contact batteries;

[0034] A welding layer disposed on the first welding section and the second welding section;

[0035] A first pre-adhesive is disposed within the first serial connection area and corresponding to the first recessed section, with the opening of the first recessed section facing the first pre-adhesive.

[0036] A second pre-adhesive is disposed within the second serial connection area;

[0037] The solder ribbons covering the first tandem area and the second tandem area are bonded to the first pre-adhesive and in contact with the welding layer on the first welding segment, and the solder ribbons on the second tandem area are bonded to the second pre-adhesive and in contact with the welding layer on the second welding segment.

[0038] Furthermore, the distance between the first pre-adhesive and the first welded section located on the first recessed section is 100µm-2mm; and / or

[0039] The length of the first pre-adhesive in the second direction is 300um-2mm.

[0040] Furthermore, the number of first pre-adhesive segments corresponding to a single first recessed segment is multiple.

[0041] Furthermore, within the second cascading area, at least one of the second welded segments is offset from at least one other second welded segment in the first direction;

[0042] Wherein, according to the arrangement order of the second welding segments in the first direction, the second line segment formed by connecting the center points of all the second welding segments in sequence is a non-linear line segment, the second line segment has at least one second recessed segment, the second pre-adhesive is provided corresponding to the second recessed segment, and the opening of the second recessed segment faces the second pre-adhesive.

[0043] Furthermore, the distance between the second pre-adhesive and the first welded section located on the second recessed section is 100µm-2mm; and / or

[0044] The length of the second pre-adhesive in the second direction is 300um-2mm.

[0045] This disclosure also provides a battery assembly comprising a plurality of battery strings as described above.

[0046] This disclosure also provides a photovoltaic system comprising the aforementioned battery module.

[0047] In the gridless back-contact battery, battery string, battery module, and photovoltaic system of this disclosure, each first grid and first series connection area has a first welding segment at the intersection. Within the first series connection area, at least one first welding segment is offset from the remaining first welding segments in a first direction. Following the arrangement order of the first welding segments in the first direction, the first line segment formed by sequentially connecting the center points of all the first welding segments is a non-linear line segment, and the first line segment has at least one first recessed segment. Thus, as shown in Figures 1 and 2, during the welding process, a welding layer can be provided on the first welding segment. When using a first pre-adhesive to pre-fix the solder strip, the first pre-adhesive can be positioned at the opening orientation of the first recessed segment. This results in a greater distance between the first pre-adhesive and the first welding segment in the corresponding first recessed segment. Even if the height of the first pre-adhesive is higher than the height of the welding layer, the greater distance effectively prevents incomplete welding during subsequent welding processes and ensures the adhesion of the first pre-adhesive to the solder strip, thereby guaranteeing the stability of the solder strip's pre-fixation.

[0048] Additional aspects and advantages of this disclosure 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 disclosure. Attached Figure Description

[0049] Figure 1 is a schematic diagram of the modules of the photovoltaic system provided in an embodiment of this disclosure;

[0050] Figure 2 is a schematic diagram of the battery assembly provided in an embodiment of this disclosure;

[0051] Figure 3 is a schematic diagram of the battery string structure provided in an embodiment of this disclosure;

[0052] Figure 4 is a schematic diagram of the back surface structure of the gridless solar cell provided in the embodiment of this disclosure;

[0053] Figure 5 is a schematic diagram of the arrangement of the first welding segment and the first pre-adhesive in the first series area of ​​the gridless solar cell provided in the embodiment of this disclosure.

[0054] Figure 6 is a schematic diagram of the arrangement of the first welding segment of the gridless solar cell provided in the first series area according to an embodiment of the present disclosure.

[0055] Figure 7 is a schematic diagram of another arrangement of the first welding segment of the gridless solar cell provided in the first series area according to an embodiment of the present disclosure.

[0056] Figure 8 is a schematic diagram of another arrangement of the first welding segment of the gridless solar cell provided in the first series area according to an embodiment of the present disclosure;

[0057] Figure 9 is a schematic diagram of the arrangement of the second welding segment and the second pre-adhesive in the second series area of ​​the gridless solar cell provided in the embodiment of this disclosure. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of this disclosure 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 disclosure, and should not be construed as limiting it. Furthermore, it should be understood that the specific embodiments described herein are merely illustrative of this disclosure and are not intended to limit it.

[0059] In the description of this disclosure, 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 disclosure 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 disclosure.

[0060] 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 disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0061] In the description of this disclosure, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linkage" 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 disclosure according to the specific circumstances.

[0062] In this disclosure, 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 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 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.

[0063] The following disclosure provides numerous different embodiments or examples for implementing various structures of this disclosure. 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 disclosure. 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 disclosure, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0064] Please refer to Figures 1 and 2. The photovoltaic system 1000 in this embodiment of the present disclosure may include the battery module 300, which may include a plurality of battery strings 200. The battery strings 200 in the battery module 300 may be connected in series, in parallel, or in a series-parallel combination to achieve current collection and output. For example, the connection between the battery strings 200 may be achieved through busbars. The battery string 200 includes a plurality of gridless back-contact cells 100 in this embodiment of the present disclosure.

[0065] Please refer to Figure 3. The battery string may include several gridless back contact batteries 100 as described in this disclosure embodiment, several welding layers (not shown), several first pre-adhesives 201, several second pre-adhesives 202, and several solder strips 203.

[0066] Referring to Figures 3 and 4, the gridless back contact battery 100 in this embodiment may include a silicon substrate 10, a plurality of first fine gates 20, and a plurality of second fine gates 30. The silicon substrate 10 has opposing front and back sides 11. The plurality of first fine gates 20 and the plurality of second fine gates 30 are all disposed on the back side 11 of the silicon substrate 10. The plurality of first fine gates 20 and the plurality of second fine gates 30 are arranged alternately and alternately along a first direction. Furthermore, the first fine gates 20 and the second fine gates 30 both extend along a second direction, which intersects the first direction.

[0067] Specifically, as shown in Figure 4, the first direction and the second direction can be the longitudinal direction and the transverse direction of the gridless back contact battery 100, respectively. Of course, in other embodiments, the first direction and the second direction can also be other directions, for example, they can be the diagonal directions of the silicon substrate 10, and no specific limitation is made here.

[0068] As shown in Figure 4, the back side 11 has a plurality of first serial connection areas 111 and second serial connection areas 112 for setting the solder strip 203. The plurality of first serial connection areas 111 and the plurality of second serial connection areas 112 extend along a first direction and intersect with all the first fine grids 20 and all the second fine grids 30. The plurality of first serial connection areas 111 and the plurality of second serial connection areas 112 are arranged alternately and at intervals along a second direction.

[0069] Each first fine gate 20 has a first welding segment 21 at the intersection with the first serial connection area 111, and all first welding segments 21 are located within the first serial connection area 111. Each second fine gate 30 has a second welding segment 31 at the intersection with the second serial connection area 112, and all second welding segments 31 are located within the second serial connection area 112.

[0070] Referring to Figure 4, in the first connection area 111, at least one first welding segment 21 is misaligned with at least one other first welding segment 21 in the first direction. That is to say, in the first direction, at least one first welding segment 21 is not completely aligned with at least one other first welding segment 21 in the first direction (i.e., not completely located on the same straight line parallel to the first direction).

[0071] As shown in Figure 4, in the embodiments of this disclosure, according to the arrangement order of the first welding segments 21 in the first serial connection area 111 in the first direction (e.g., from top to bottom or from bottom to top), the first line segment 113 formed by sequentially connecting the center points of all the first welding segments 21 is a non-linear line segment, and the first line segment 113 has at least one first recessed segment 1131. A non-linear line segment refers to a first line segment in which at least a part is not on the same straight line as other parts. If the same description appears below, it can be understood with reference to this.

[0072] As shown in Figure 3, in the battery string, a welding layer is disposed on the first welding section 21 and the second welding section 31. The welding layer can be a material layer that can achieve welding, such as a solder paste welding layer. The first pre-adhesive 201 is disposed in the first connection area 111 and corresponds to the first recessed section 1131. The opening of the first recessed section 1131 faces the first pre-adhesive 201 (as shown in Figures 3 and 5). The first pre-adhesive 201 can be completely located outside the first recessed section 1131 or partially located inside the first recessed section 1131.

[0073] Referring to Figures 3 and 4, the second pre-adhesive 202 is disposed within the second tandem area 112, and the solder ribbon 203 covers the first tandem area 111 and the second tandem area 112. The solder ribbon 203 on the first tandem area 111 is bonded to the first pre-adhesive 201 and contacts the welding layer on the first welding segment 21. The solder ribbon 203 on the second tandem area 112 is bonded to the second pre-adhesive 202 and contacts the welding layer on the second welding segment 31.

[0074] In the battery string 200, in two adjacent gridless back contact batteries 100, the solder strip 203 on the first connection area 111 of the previous one is located on the second connection area 112 of the next one, and the solder strip 203 on the second connection area 112 of the previous one is located on the first connection area 111 of the next one. That is, the solder layer (first solder segment 21) in the first connection area 111 of the previous gridless back contact battery 100 and the solder layer (second solder segment 31) in the second connection area 112 of the next gridless back contact battery 100 are soldered to the same solder strip.

[0075] It is understandable that in the process of forming the battery module 300, the battery string 200 can be welded first, and then the battery string 200 can be laminated to form the module. Alternatively, the gridless back contact battery 100 can be placed on the front panel and the adhesive film according to the module pattern, and then the solder ribbon 203 can be placed for bonding and pre-fixing. Finally, lamination and welding can be performed to directly form the battery module 300. During the lamination process, the gridless back contact batteries 100 naturally form the battery string 200.

[0076] It should be noted that the first serial connection area 111 and the second serial connection area 112 of this disclosure refer to the area covered by the solder ribbon 203 on the back side 11 and the area covered by the solder ribbon 203 on the back side 11. They are not areas strictly divided on the back side 11 by physical marking, but rather virtual defined areas.

[0077] Furthermore, it should be noted that the first line segment 113 in this disclosure is not a physical line segment existing on the battery cell, but rather a virtual line. The first line segment 113 can be a smooth curve, a combination of curves and straight lines, or a combination of curves and broken lines. No specific limitations are imposed here. For example, if the center point of the first welding segment 21 in the area corresponding to the first recessed segment 1131 is a curved outline, then the first recessed segment 1131 can be a broken line segment formed by connecting straight lines in sequence, or it can be a smooth curve segment. Figure 4 shows a broken line segment.

[0078] Furthermore, in this disclosure, the center point of the first welded segment 21 refers to the point that divides the first welded segment 21 into two symmetrical halves in the second direction, that is, the midpoint of the first welded segment 21 in the second direction. It is easy to understand that in this disclosure, all the first welded segments 21 have essentially the same length.

[0079] Additionally, it should be noted that in some embodiments, an insulating layer is provided at the position where the first serial connection area 111 intersects with the second fine gate 30. That is, an insulating layer can be provided at the position where each second fine gate 30 intersects with the solder ribbon 203, thereby preventing the solder ribbon 203 from contacting fine gates of different polarities.

[0080] In the gridless back-contact battery 100, battery string 200, battery module 300, and photovoltaic system 1000 of this disclosure, each first fine grid 20 has a first welding segment 21 at the intersection with the first series connection area 111. All first welding segments 21 are located within the first series connection area 111, and at least one first welding segment 21 within the first series connection area 111 is offset from the other first welding segments 21 in a first direction. According to the arrangement order of the first welding segments 21 in the first direction, the first line segment 113 formed by sequentially connecting the center points of all the first welding segments 21 is a non-linear line segment, and the first line segment 113 has at least one first recessed segment 1131. Thus, as shown in Figures 3 and 5, during the welding process, a welding layer can be set on the first welding segment 21. When the first pre-adhesive 201 is used to pre-fix the welding strip 203, the first pre-adhesive 201 can be set at the position facing the opening of the first recessed segment 1131. In this way, the distance between the first pre-adhesive 201 and the first welding segment 21 in the first recessed segment 1131 corresponding to the first pre-adhesive 201 is relatively large. Even if the height of the first pre-adhesive 201 is higher than the height of the welding layer, the large distance between the two can effectively avoid the occurrence of false welding in the subsequent welding process. At the same time, it can also ensure the adhesion of the first pre-adhesive 201 to the welding strip 203, thereby ensuring the stability of the pre-fixation of the welding strip.

[0081] It is not difficult to understand that in traditional technology, the adhesive bonding points are usually set on the grid line segment used for soldering, and solder paste pads are set on the soldering segment. The bonding points should be located as close as possible to the center point of the solder strip. Due to the close distance, the height of the bonding point is greater than the height of the soldering position. In order to ensure the adhesion, it is easy for the solder strip to fail to contact the corresponding soldering point near the bonding point, which can easily lead to cold solder joints.

[0082] However, in this disclosure, by setting the portion of the first welding segment 21 corresponding to the first pre-adhesive 201 in a recessed contour arrangement, and setting the opening of the first pre-adhesive 201 corresponding to the recess, the distance between the first pre-adhesive 201 and its corresponding first welding segment 21 will be increased, which can effectively avoid the phenomenon of incomplete welding during the welding process.

[0083] In some embodiments, both the first welding segment 21 and the second welding segment 31 are coarse gate segments, that is, the first welding segment 21 is coarser than other parts of the first fine gate 20, and the second welding segment 31 is coarser than other parts of the second fine gate 30. In some embodiments, the length (i.e., the length in the second direction) of the first welding segment 21 and the second welding segment 31 can be 250um-350um, and the width (i.e., the length in the second direction) can be 25um-50um. This ensures the contact area between the first welding segment 21 and the second welding segment 31 and the welding strip 203, thereby improving the stability of the welding.

[0084] Referring to Figure 6, in some embodiments, two first welded segments 21 that are staggered in the first direction have an overlapping portion in the first direction. Further, in such embodiments, the length L1 of the overlapping portion in the second direction can be 50µm-200µm, for example, 50µm, 60µm, 70µm, 80µm, 85µm, 90µm, 95µm, 100µm, 105µm, 115µm, 120µm, 130µm, 140µm, 150µm, 160µm, 170µm, 180µm, 190µm, 200µm, etc. This allows the first welded segments 21 to be arranged more closely.

[0085] Of course, as shown in Figures 7 and 8, in some embodiments, the two first weld segments 21 that are staggered in the first direction may also be spaced apart in the second direction, and this is not specifically limited here. In such embodiments, the distance L2 between the two first weld segments 21 that are staggered in the first direction and in the second direction can be 100um-1mm, for example, 100um, 200um, 300um, 350um, 400um, 500um, 600um, 700um, 800um, 900um, 1mm, etc.

[0086] Referring to Figures 3 and 5, in some embodiments, there are multiple first weld segments 21 corresponding to the first recessed segment 1131. This allows the first pre-adhesive 201 to be spaced further away from the multiple nearby first weld segments 21, thereby better preventing incomplete soldering.

[0087] Of course, as shown in Figures 6 to 8, in some embodiments, the first recessed segment 1131 may correspond to only a single first welded segment 21, and there is no specific limitation here.

[0088] Please continue to refer to Figures 4 and 5. In some embodiments, each of the above-mentioned first recessed segments 1131 corresponds to at least one first pre-adhesive 201. That is, at least one first pre-adhesive 201 is provided in the range corresponding to the first recessed segment 1131 in the second direction. The first pre-adhesive 201 may be located inside the first recessed segment 1131 near the center line of the solder strip 203, or it may be located outside the first recessed segment 1131.

[0089] Please refer to Figure 5. In some embodiments, the first line segment 113 further has at least one first straight line segment 1132, which is arranged parallel to the first direction, and the first recessed segment 1131 is offset relative to the first straight line segment 1132 along the second direction.

[0090] Thus, by setting the first straight segment 1132, the first welding segment 21 on the first straight segment 1132 is located on the same straight line parallel to the first direction, which can improve welding efficiency during welding (e.g., laser welding). At the same time, having multiple welding points on the same straight line of the welding strip 203 can improve the reliability and stability of welding.

[0091] Please refer to 5. In some embodiments, the first recessed segment 1131 may include a first sub-straight segment 11311 parallel to the first straight segment 1132 and a first inclined segment 11312 connecting the first sub-straight segment 11311 and the first straight segment 1132.

[0092] Thus, the first sub-straight segment 11311 and the first inclined segment 11312 constitute the first recessed segment 1131. The first welding segment 21 corresponding to the first sub-straight segment 11311 is located on the same straight line parallel to the first direction. This can increase the number of welding points on the same straight line of the welding strip 203, thereby improving the reliability and stability of the welding.

[0093] Please refer to Figure 5 again. In some embodiments, there are multiple first straight segments 1132 and first recessed segments 1131, and the multiple first straight segments 1132 and first recessed segments 1131 are arranged alternately in sequence.

[0094] Thus, by setting multiple first straight segments 1132 and first recessed segments 1131, at least one first pre-adhesive 201 can be set at the corresponding position of each first recessed segment 1131, thereby arranging multiple first pre-adhesives 201 while effectively avoiding false soldering, and improving the stability and adhesion of the pre-fixation of the solder strip 203.

[0095] Further, referring to Figure 5, in such an embodiment, of the two first recessed segments 1131 at both ends of the first straight segment 1132, one of the first recessed segments 1131 is recessed to one side of the first straight segment 1132, and the other first recessed segment 1131 is recessed to the other side of the first straight segment 1132.

[0096] Thus, the concave directions of two adjacent first concave segments 1131 are opposite (i.e., the opening directions of two adjacent first concave segments 1131 are opposite). In this way, the positions of the first pre-adhesive 201 corresponding to the two adjacent first concave segments 1131 are also opposite (located on both sides of the first straight segment 1132 respectively), which can prevent all the first pre-adhesive 201 from being concentrated on one side of the first straight segment 1132.

[0097] Of course, it is understood that in some embodiments, the first recessed segment 1131 may also be an arc segment, that is, the first line segment 113 may be composed of the first straight line segment 1132 and the arc segment.

[0098] In addition, in some embodiments, the first line segment 113 may also be in other forms. For example, in some embodiments, the first line segment 113 may be a wavy line, that is, in the up and down direction of the first direction, the arrangement outline of the first welding segment 21 is wavy, and the first line segment 113 as a whole is an arc curve, which will not be described in detail here.

[0099] Please refer to Figures 3, 4 and 9. In some embodiments, each second fine grid 30 has a second welded segment 31 at the intersection with the second serial area 112. All second welded segments 31 are located within the second serial area 112. Within the second serial area 112, at least one second welded segment 31 is offset from at least one other second welded segment 31 in a first direction.

[0100] Wherein, according to the arrangement order of the second welding segments 31 in the first direction, the second line segment 114 formed by connecting the center points of all the second welding segments 31 in sequence is a non-straight line segment, and the second line segment 114 has at least one second recessed segment 1141.

[0101] Thus, during the welding process, a welding layer can be set on the second welding section 31. When the second pre-adhesive 202 is used to pre-fix the welding strip 203, the second pre-adhesive 202 can be set at the position where the opening of the second recessed section 1141 faces. In this way, the distance between the second pre-adhesive 202 and the second welding section 31 in the second recessed section 1141 corresponding to the second pre-adhesive 202 is relatively far, which can effectively avoid the occurrence of false welding in the subsequent welding process, and at the same time ensure the adhesion of the second pre-adhesive 202 to the welding strip 203.

[0102] In some embodiments, the two second welding segments 31 that are staggered in the first direction have an overlapping portion in the first direction (similar to the structure of the first welding segment 21 shown in FIG. 6). Further, in such embodiments, the length of the overlapping portion in the second direction can be 50µm-200µm, for example, 50µm, 60µm, 70µm, 80µm, 85µm, 90µm, 95µm, 100µm, 105µm, 115µm, 120µm, 130µm, 140µm, 150µm, 160µm, 170µm, 180µm, 190µm, 200µm, etc. This allows the welding strips 203 to be arranged more densely.

[0103] Of course, in some embodiments, the two second welding segments 31 that are staggered in the first direction may also be spaced apart in the second direction (similar to the structure of the first welding segment 21 shown in FIG. 7), and no specific limitation is made here. In such embodiments, the distance between the two second welding segments 31 that are staggered in the first direction and in the second direction is 100um-1mm, for example, 100um, 200um, 300um, 350um, 400um, 500um, 600um, 700um, 800um, 900um, 1mm, etc.

[0104] Referring to Figures 3, 4, and 9, in some embodiments, there are multiple second weld segments 31 corresponding to the second recessed segment 1141. This allows the second pre-adhesive 202 to be spaced further away from the multiple nearby second weld segments 31, thereby better preventing incomplete soldering.

[0105] Of course, in some embodiments, the second recessed segment 1141 may correspond to only a single second welded segment 31 (similar to Figure 8), and there are no specific limitations here.

[0106] Please refer to Figures 4 and 9. In some embodiments, each of the above-mentioned second recessed segments 1141 corresponds to at least one second pre-adhesive 202. That is, at least one second pre-adhesive 202 is provided in the range corresponding to the second direction of the second recessed segment 1141. The second pre-adhesive 202 may be located inside the second recessed segment 1141 near the center line of the solder strip 203, or it may be located outside the second recessed segment 1141.

[0107] Referring to Figure 9, in some embodiments, the second line segment 114 further has at least one second straight line segment 1142, which is arranged parallel to the first direction, and the second recessed segment 1141 is offset relative to the second straight line segment 1142 along the second direction.

[0108] Thus, by setting the second straight segment 1142, the second welding segment 31 on the second straight segment 1142 is located on the same straight line parallel to the first direction, which can improve the welding efficiency during the welding process (e.g., laser welding). At the same time, having multiple welding points on the same straight line of the welding strip 203 can improve the reliability and stability of the welding.

[0109] Please continue to refer to Figure 9. In some embodiments, the second recessed segment 1141 includes a second sub-straight segment 11411 parallel to the second straight segment 1142 and a second inclined segment 11412 connecting the second sub-straight segment 11411 and the second straight segment 1142.

[0110] Thus, the second sub-straight segment 11411 and the second inclined segment 11412 constitute the second recessed segment 1141. The corresponding second welding segment 31 on the second sub-straight segment 11411 is located on the same grid line parallel to the first direction. This can increase the number of welding points on the same straight line of the welding strip 203, thereby improving the reliability and stability of welding.

[0111] Please refer to Figure 9. In some embodiments, there are multiple second straight segments 1142 and second recessed segments 1141, and the multiple second straight segments 1142 and second recessed segments 1141 are arranged alternately and at intervals.

[0112] Thus, by setting multiple second straight segments 1142 and second recessed segments 1141, at least a second pre-adhesive 202 can be set at the corresponding position of each second recessed segment 1141, thereby arranging multiple second pre-adhesives 202 while effectively avoiding false soldering, and improving the stability and adhesion of the pre-fixation of the solder strip 203.

[0113] Further, referring to Figure 9, in such an embodiment, of the two second recessed segments 1141 at both ends of the second straight segment 1142, one second recessed segment 1141 is recessed to one side of the second straight segment 1142, and the other second recessed segment 1141 is recessed to the other side of the second straight segment 1142.

[0114] Thus, the concave directions of two adjacent second recessed segments 1141 are opposite (i.e., the opening directions of two adjacent second recessed segments 1141 are opposite). In this way, the positions of the second pre-adhesive 202 corresponding to the two adjacent second recessed segments 1141 are also opposite (located on both sides of the second straight segment 1142 respectively), which can prevent all the second pre-adhesive 202 from being concentrated on one side of the second straight segment 1142.

[0115] Of course, it is understood that in some embodiments, the second recessed segment 1141 may also be an arc segment, that is, the second line segment 114 may be composed of a second straight line segment 1142 and an arc segment.

[0116] In addition, in some embodiments, the second line segment 114 may also be in other forms. For example, the second line segment 114 may also be a wavy line. That is, in the up and down direction of the first direction, the arrangement outline of the second welding segment 31 is wavy, and the second line segment 114 is an arc curve as a whole. No specific limitation is made here.

[0117] 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 above embodiments or examples is included in at least one embodiment or example of this disclosure. 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.

[0118] Although embodiments of this disclosure 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 disclosure, the scope of which is defined by the claims and their equivalents.

Claims

1. A gridless back contact battery, wherein, The device includes a silicon substrate and a plurality of first fine gates and a plurality of second fine gates disposed on the back side of the silicon substrate. The plurality of first fine gates and the plurality of second fine gates are arranged alternately along a first direction and all extend along a second direction, which intersects the first direction. The back side has a plurality of first serial connection areas and a plurality of second serial connection areas for setting solder strips. The plurality of first serial connection areas and the plurality of second serial connection areas extend along the first direction and intersect with all the first fine gates and all the second fine gates. The plurality of first serial connection areas and the plurality of second serial connection areas are arranged alternately along the second direction. Each of the first fine gates has a first welded segment at the intersection with the first serial connection area, and all the first welded segments are located within the first serial connection area. Each of the second fine gates has a second welded segment at the intersection with the second serial connection area, and all the second welded segments are located within the second serial connection area. In the first serial connection area, at least one of the first welding segments is misaligned with at least one other first welding segment in the first direction; According to the arrangement order of the first welded segments in the first direction, the first line segment formed by connecting the center points of all the first welded segments in sequence is a non-linear line segment, and the first line segment has at least one first recessed segment.

2. The gridless back contact battery according to claim 1, wherein, The two first welded segments that are misaligned in the first direction have an overlapping portion in the first direction.

3. The gridless back contact battery according to claim 2, wherein, The length of the overlapping portion in the second direction is 50um-200um.

4. The gridless back contact battery according to claim 1, wherein, The two first welded segments, which are staggered in the first direction, are spaced apart from each other in the second direction.

5. The gridless back contact battery according to claim 4, wherein, The distance between the two first welded segments that are staggered in the first direction and in the second direction is 100um-2.5mm.

6. The gridless back contact battery according to claim 1, wherein, There are multiple first welded segments corresponding to the first recessed segment.

7. The gridless back contact battery according to claim 1, wherein, The first line segment also has at least one first straight line segment, which is arranged parallel to the first direction, and the first recessed segment is offset relative to the first straight line segment along the second direction.

8. The gridless back contact battery according to claim 7, wherein, The first recessed segment includes a first sub-straight segment parallel to the first straight segment and a first inclined segment connecting the first sub-straight segment and the first straight segment.

9. The gridless back contact battery according to claim 7 or 8, wherein, There are multiple first straight segments and multiple first recessed segments, which are arranged alternately and at intervals.

10. The gridless back contact battery according to claim 9, wherein, Of the two first recessed segments at both ends of the first straight segment, one of the first recessed segments is recessed to one side of the first straight segment, and the other of the first recessed segments is recessed to the other side of the first straight segment.

11. The gridless back contact battery according to claim 1, wherein, The first line segment is a wavy line.

12. The gridless back contact battery according to claim 1, wherein, Each of the second fine grids has a second welded segment at the intersection of the second fine grid and the second serial connection area. All the second welded segments are located within the second serial connection area. Within the second serial connection area, at least one second welded segment is offset from at least one other second welded segment in the first direction. Wherein, according to the arrangement order of the second welding segments in the first direction, the second line segment formed by connecting the center points of all the second welding segments in sequence is a non-linear line segment, and the second line segment has at least one second concave segment.

13. The gridless back contact battery according to claim 12, wherein, The two second welded segments, which are staggered in the first direction, have an overlapping portion in the first direction.

14. The gridless back contact battery according to claim 13, wherein, The length of the overlapping portion in the second direction is 50um-200um.

15. The gridless back contact battery according to claim 12, wherein, The two second welded segments, which are staggered in the first direction, are spaced apart from each other in the second direction.

16. The gridless back contact battery according to claim 15, wherein, The distance between the two second welded segments that are staggered in the first direction is 100um-2.5mm in the second direction.

17. The gridless back contact battery according to claim 12, wherein, The second line segment also has at least one second straight line segment, which is arranged parallel to the second direction, and the second recessed segment is offset relative to the second straight line segment along the second direction.

18. The gridless back contact battery according to claim 17, wherein, The second recessed segment includes a second sub-straight segment parallel to the second straight segment and a second inclined segment connecting the second sub-straight segment and the second straight segment.

19. The gridless back contact battery according to claim 17 or 18, wherein, There are multiple second straight segments and multiple second concave segments, which are arranged alternately and at intervals.

20. The gridless back contact battery according to claim 19, wherein, In the two second recessed segments at both ends of the second straight segment, one of the second recessed segments is recessed to one side of the second straight segment, and the other second recessed segment is recessed to the other side of the second straight segment.

21. The gridless back contact battery according to claim 12, wherein, The second line segment is a wavy line.

22. A battery string, wherein, include: The gridless back contact battery according to any one of claims 1-21; A welding layer disposed on the first welding section and the second welding section; A first pre-adhesive is disposed within the first serial connection area and corresponding to the first recessed section, with the opening of the first recessed section facing the first pre-adhesive. A second pre-adhesive is disposed within the second serial connection area; The solder ribbons covering the first tandem area and the second tandem area are bonded to the first pre-adhesive and in contact with the welding layer on the first welding segment, and the solder ribbons on the second tandem area are bonded to the second pre-adhesive and in contact with the welding layer on the second welding segment.

23. The battery string according to claim 22, wherein, The distance between the first pre-adhesive and the first welded section located on the first recessed section is 100µm-2mm; and / or The length of the first pre-adhesive in the second direction is 300um-2mm.

24. The battery string according to claim 22, wherein, The number of first pre-adhesive segments corresponding to a single first recessed segment is multiple.

25. The battery string according to claim 22, wherein, Within the second cascading area, at least one of the second welded segments is offset from at least one other second welded segment in the first direction; Wherein, according to the arrangement order of the second welding segments in the first direction, the second line segment formed by connecting the center points of all the second welding segments in sequence is a non-linear line segment, the second line segment has at least one second recessed segment, the second pre-adhesive is provided corresponding to the second recessed segment, and the opening of the second recessed segment faces the second pre-adhesive.

26. The battery string according to claim 25, wherein, The distance between the second pre-adhesive and the first weld section located on the second recessed section is 100µm-2mm; and / or The length of the second pre-adhesive in the second direction is 300um-2mm.

27. A battery assembly, wherein, Includes the battery string as described in any one of claims 22-26.

28. A photovoltaic system, wherein, Includes the battery assembly as described in claim 27.

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