Main-grid-free back contact battery, battery string, battery assembly and photovoltaic system

Abstract

The utility model is suitable for the technical field of solar cells, and provides a main-grid-free back contact cell, a cell string, a cell assembly and a photovoltaic system, in a solar cell, a first welding section is arranged at the intersection position of each first fine grid and a first series connection area, and all the first welding sections are located in the first series connection area; at least one first welding section and the other first welding sections are staggered in the first direction in the first serial connection area. According to the arrangement sequence of the first welding sections in the first direction, a first line segment formed by sequentially connecting the center points of all the first welding sections is a nonlinear line segment, and the first line segment is provided with at least one first sunken section. Therefore, when the first pre-adhesive glue is adopted to pre-fix the welding strip, the first pre-adhesive glue can be arranged at the position where the opening of the first concave section faces, so that the distance between the first pre-adhesive glue and the first welding section in the first concave section corresponding to the first pre-adhesive glue is far, and pseudo soldering in the subsequent welding process can be effectively avoided.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a main grid-free back contact cell, a cell string, a cell assembly and a photovoltaic system. Background Art

[0002] In the related art, in a main grid-free back contact solar cell, a solder paste pad is provided at the position on each fine grid for connecting with the solder strip. At the same time, in order to prevent the solder strip from being offset during lamination welding, it is necessary to set a pre-adhesive near the solder paste pad to pre-fix the solder strip. In order to ensure accurate bonding, it is usually necessary to set the pre-adhesive near the center of the solder strip, which is close to the position of the solder paste pad. In such a case, since there is a height difference between the height of the pre-adhesive and the solder paste pad, if the height of the pre-adhesive is high, while ensuring stable bonding of the solder strip, due to the close distance between the pre-adhesive and the solder paste pad, it will cause the solder strip to be unable to contact the solder paste pad when pre-fixing the solder strip, thereby causing a cold solder joint in the subsequent welding process; and if the height of the solder paste pad is high, while ensuring that the solder strip is in contact with the solder paste pad, due to the close distance between the pre-adhesive and the solder paste pad, it will cause the adhesion between the solder strip and the pre-adhesive to decrease or even fail.

[0003] Therefore, how to effectively avoid the occurrence of cold solder joints in the lamination welding of the main grid-less back contact battery while ensuring the stability of the pre-fixation of the soldering tape has become a technical problem studied by technicians. Utility Model Content

[0004] The present application provides a main grid-free back contact cell, a cell string, a cell assembly and a photovoltaic system, aiming to solve the technical problem of how to effectively avoid the occurrence of cold solder joints in the lamination welding of the main grid-free back contact cell while ensuring the stability of the pre-fixation of the solder strip.

[0005] The present application is implemented in this way. The busbar-free back contact battery of the embodiment of the present application includes:

[0006] The invention comprises a silicon substrate and a plurality of first fine grids and a plurality of second fine grids arranged on the back side of the silicon substrate, wherein the plurality of first fine grids and the plurality of second fine grids are arranged alternately and spaced in sequence along a first direction and all extend along a second direction, the second direction intersects with the first direction, the back side is provided with a plurality of first series connection areas and a second series connection areas for arranging welding strips, the first series connection areas and the second series connection areas extend along the first direction and intersect with all the first fine grids and the second fine grids, and the plurality of first series connection areas and the plurality of second series connection areas are arranged alternately and spaced in sequence along the second direction;

[0007] Each of the first fine grids has a first welding section at the intersection of the first series connection area, and all of the first welding sections are located in the first series connection area; each of the second fine grids has a second welding section at the intersection of the second series connection area, and all of the second welding sections are located in the second series connection area;

[0008] Wherein, in the first series connection area, at least one of the first welding segments and at least one of the other first welding segments are mutually offset in the first direction;

[0009] According to the arrangement order of the first welding segments in the first direction, a 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 concave segment.

[0010] Furthermore, two first welding sections that are offset from each other in the first direction have overlapping portions in the first direction.

[0011] Furthermore, the length of the overlapping portion in the second direction is 50um-200um.

[0012] Furthermore, the two first welding sections that are offset from each other in the first direction are spaced apart from each other in the second direction.

[0013] Furthermore, a distance between two first welding sections that are offset from each other in the first direction in the second direction is 100 um-2.5 mm.

[0014] Furthermore, there are multiple first welding sections corresponding to the first recessed sections.

[0015] Furthermore, the first line segment further has at least one first straight line segment, the first straight line segment is arranged parallel to the first direction, and the first concave segment is offset along the second direction compared to the first straight line segment.

[0016] Furthermore, 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.

[0017] Furthermore, there are a plurality of the first straight line segments and the first concave segments, and the plurality of the first straight line segments and the first concave segments are alternately arranged in sequence.

[0018] Furthermore, among the two first recessed sections at both ends of the first straight line segment, one of the first recessed sections is recessed toward one side of the first straight line segment, and the other first recessed section is recessed toward the other side of the first straight line segment.

[0019] Furthermore, the first line segment is a wavy line.

[0020] Furthermore, each second fine grid has a second welding section at the intersection of the second fine grid and the second series connection area, all the second welding sections are located in the second series connection area, and at least one second welding section and at least one other second welding section in the second series connection area are mutually offset in the first direction;

[0021] Wherein, according to the arrangement order of the second welding segments in the first direction, the second line segment formed by sequentially connecting the center points of all the second welding segments is a non-linear line segment, and the second line segment has at least one second concave segment.

[0022] Furthermore, two second welding sections that are offset from each other in the first direction have overlapping portions in the first direction.

[0023] Furthermore, the length of the overlapping portion in the second direction is 50um-200um.

[0024] Furthermore, the two second welding sections that are offset from each other in the first direction are spaced apart from each other in the second direction.

[0025] Furthermore, a distance between two second welding sections that are offset from each other in the first direction is 100 um-2.5 mm in the second direction.

[0026] Furthermore, the second line segment further has at least one second straight line segment, the second straight line segment is arranged parallel to the second direction, and the second concave segment is offset along the second direction compared to the second straight line segment.

[0027] 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.

[0028] Furthermore, there are a plurality of the second straight line segments and the second recessed segments, and the plurality of the second straight line segments and the second recessed segments are alternately arranged in sequence.

[0029] Furthermore, among the two second recessed sections at both ends of the second straight line segment, one of the second recessed sections is recessed toward one side of the second straight line segment, and the other second recessed section is recessed toward the other side of the second straight line segment.

[0030] Furthermore, the second line segment is a wavy line.

[0031] The present application also provides a battery string, comprising:

[0032] Several busbar-free back contact cells as described in any of the above items;

[0033] A welding layer disposed on the first welding section and the second welding section;

[0034] A first pre-adhesive adhesive is disposed in the first serial connection area and corresponds to the first recessed section, wherein the opening of the first recessed section faces the first pre-adhesive adhesive;

[0035] A second pre-adhesive disposed in the second serial connection area;

[0036] The welding strip covering the first series connection area and the second series connection area, the welding strip on the first series connection area is bonded to the first pre-adhesive and contacts the welding layer on the first welding section, and the welding strip on the second series connection area is bonded to the second pre-adhesive and contacts the welding layer on the second welding section.

[0037] Furthermore, the distance between the first pre-adhesive and the first welding section located on the first recessed section is 100um-2mm; and / or

[0038] The length of the first pre-adhesive in the second direction is 300um-2mm.

[0039] Furthermore, a single first recessed section corresponds to a plurality of first pre-adhesives.

[0040] Furthermore, each second fine grid has a second welding section at the intersection of the second fine grid and the second series connection area, all the second welding sections are located in the second series connection area, and at least one second welding section and at least one other second welding section in the second series connection area are mutually offset in the first direction;

[0041] Among them, according to the arrangement order of the second welding segments in the first direction, the second line segment formed by sequentially connecting the center points of all the second welding segments is a non-linear line segment, the second line segment has at least one second recessed segment, the second pre-adhesive is arranged corresponding to the second recessed segment, and the opening of the second recessed segment faces the second pre-adhesive.

[0042] Furthermore, the distance between the second pre-adhesive and the first welding section located on the second recessed section is 100um-2mm; and / or

[0043] The length of the second pre-adhesive in the second direction is 300um-2mm.

[0044] The present application also provides a battery assembly, which includes a plurality of battery strings as described in any one of the above items.

[0045] The present application also provides a photovoltaic system, which includes the above-mentioned battery assembly.

[0046] In the embodiment of the present application, the main grid-free back contact cell, cell string, cell assembly and photovoltaic system have a first welding section at the intersection of each first fine grid and the first series connection area, and each first fine grid has a first welding section at the intersection of the first series connection area. At least one first welding section is mutually displaced with the other first welding sections in the first direction in the first series connection area. According to the arrangement order of the first welding sections in the first direction, the first line segment formed by the center points of all the first welding sections connected in sequence is a non-linear line segment, and the first line segment has at least one first concave section. In this way, as shown in the figure and the figure, during the welding process, a welding layer can be set on the first welding section. When the first pre-adhesive is used to pre-fix the welding strip, the first pre-adhesive can be set at the position facing the opening of the first concave section. In this way, the distance between the first pre-adhesive and the first welding section in the first concave section corresponding to the first pre-adhesive is relatively far. Even if the height of the first pre-adhesive is higher than the height of the welding layer, the distance between the two can effectively avoid the occurrence of cold welding in the subsequent welding process, and at the same time, it can also ensure the adhesion of the first pre-adhesive to the welding strip, thereby ensuring the stability of the pre-fixation of the welding strip.

[0047] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a module schematic diagram of a photovoltaic system provided in an embodiment of the present application;

[0049] Figure 2 is a module schematic diagram of a battery assembly provided in an embodiment of the present application;

[0050] Figure 3 is a schematic diagram of the structure of a battery string provided in an embodiment of the present application;

[0051] Figure 4 It is a schematic diagram of the planar structure of the back side of a busbar-free solar cell provided in an embodiment of the present application;

[0052] Figure 5 Schematic diagram of the arrangement of the first welding section and the first pre-adhesive of the busbar-free solar cell in the first series connection area provided by an embodiment of the present application;

[0053] Figure 6 is a schematic diagram of the arrangement of the first welding section of the busbar-free solar cell provided in the first series connection area in an embodiment of the present application;

[0054] Figure 7is another schematic diagram of the arrangement of the first welding section of the busbar-free solar cell provided in the first series connection area in an embodiment of the present application;

[0055] Figure 8 It is another schematic diagram of the arrangement and setting of the first welding section of the busbar-free solar cell provided in the embodiment of the present application in the first series connection area;

[0056] Fig. 9 It is a schematic diagram of the arrangement of the second welding section and the second pre-adhesive of the busbar-free solar cell sheet in the second series connection area provided in an embodiment of the present application. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below 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 the present application, and should not be construed as limiting the present application. In addition, it should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0058] In the description of the present application, it should be understood that the terms "length", "width", "up", "down", "top", "bottom", "lateral", "longitudinal", etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0059] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0060] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0061] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0062] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, and does not indicate the relationship between the various embodiments and / or settings discussed in itself. In addition, the various specific processes and examples of materials provided by the present application, but those of ordinary skill in the art can be aware of the application of other processes and / or the use scenarios of other materials.

[0063] See also Figure 1-Figure 2 The photovoltaic system 1000 in the embodiment of the present application may include the battery assembly 300 in the embodiment of the present application. The battery assembly 300 in the embodiment of the present application may include a plurality of battery strings 200. The battery strings 200 in the battery assembly 300 may be connected in series, in parallel, or in series-parallel combination to realize current bus output. For example, the connection between the battery strings 200 may be realized through a bus bar.

[0064] See also Figure 3 The battery string 200 may include several busbar-free back contact batteries 100 in the embodiments of the present application, several welding layers (not shown in the figure), several first pre-adhesives 201, several second pre-adhesives 202 and several welding strips 203.

[0065] Please combine Figure 4 The busbar-free back contact cell 100 in the embodiment of the present application may include a silicon substrate 10, a plurality of first fine grids 20 and a plurality of second fine grids 30. The silicon substrate 10 has a front surface and a back surface 11 opposite to each other, the plurality of first fine grids 20 and the plurality of second fine grids 30 are both arranged on the back surface 11 of the silicon substrate 10, the plurality of first fine grids 20 and the plurality of second fine grids 30 are alternately arranged in sequence along a first direction, and the first fine grids 20 and the second fine grids 30 both extend along a second direction, and the second direction intersects the first direction.

[0066] Specifically, Figure 4As shown, the first direction and the second direction may be the longitudinal direction and the lateral direction of the main-gate-less back-contact battery 100, respectively. Of course, in other embodiments, the first direction and the second direction may also be other directions, for example, both may be the diagonal directions of the silicon substrate 10, respectively, and no specific limitation is made here.

[0067] like Figure 4 As shown, the back side 11 has a plurality of first series connection areas 111 and second series connection areas 112 for setting the welding strips 203. The first series connection areas 111 and the second series connection areas 112 extend along the first direction and intersect with all the first fine grids 20 and the second fine grids 30. The plurality of first series connection areas 111 and the plurality of second series connection areas 112 are alternately arranged in sequence along the second direction.

[0068] Each first fine grid 20 has a first welding section 21 at the intersection of the first series connection area 111, and all the first welding sections 21 are located in the first series connection area 111. Each second fine grid 30 has a second welding section 31 at the intersection of the second series connection area 112, and all the second welding sections 31 are located in the second series connection area 112.

[0069] Please also refer to Figure 3-Figure 5 In the first series connection area 111, there is at least one first welding segment 21 that 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 (that is, not completely located on the same straight line parallel to the first direction).

[0070] like Figure 4 and Figure 5 As shown, in the embodiment of the present application, according to the arrangement order of the first welding segments 21 in the first series connection area 111 in the first direction (for example, 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 concave segment 1131. A non-linear line segment refers to a first line segment where at least a portion is not on the same straight line as other portions, and if the same description appears below, it can be understood by referring to this.

[0071] In the battery string 200, the welding layer is arranged on the first welding section 21 and the second welding section 31. The welding layer can be a material layer capable of welding, such as a solder paste welding layer. The first pre-adhesive 201 is arranged in the first serial 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 (such as Figure 3 and Figure 5 As shown in FIG. 1 , the first pre-adhesive 201 may be completely located outside the first recessed section 1131 , or may be partially located inside the first recessed section 1131 .

[0072] Please combine Figure 3 and Figure 4 The second pre-adhesive 202 is arranged in the second series connection area 112, and the welding strip 203 covers the first series connection area 111 and the second series connection area 112. The welding strip 203 on the first series connection area 111 is bonded to the first pre-adhesive 201 and contacts the welding layer on the first welding section 21. The welding strip 203 on the second series connection area 112 is bonded to the second pre-adhesive 202 and contacts the welding layer on the second welding section 31.

[0073] In the battery string 200, in two adjacent mainbar-free back-contact batteries 100, the welding strip 203 on the first series connection area 111 of the previous one is located on the second series connection area 112 of the next one, and the welding strip 203 on the second series connection area 112 of the previous one is located on the first series connection area 111 of the next one, that is, the welding layer 21 located in the first series connection area 111 of the previous mainbar-free back-contact battery 100 and the welding layer 31 located in the second series connection area 112 of the next previous mainbar-free back-contact battery 100 are welded to the same welding strip.

[0074] It can be understood that in the process of forming the battery assembly 300, the battery strings 200 can be welded first and then laminated to form an assembly, or the main-grid-free back-contact battery 100 can be placed on the front plate and the adhesive film according to the assembly layout, and then the welding strip 203 is placed for bonding and pre-fixing, and finally laminated and welded to directly form the battery assembly 300. During the lamination process, each main-grid-free back-contact battery 100 naturally forms a battery string 200.

[0075] It should be noted that the first serial connection area 111 and the second serial connection area 112 of the present application refer to the area covered by the soldering ribbon 203 on the back surface 11 and the area covered by the soldering ribbon 203 on the back surface 11, which are not strictly divided by physical lines on the back surface 11, but are virtual defined areas;

[0076] In addition, it should be pointed out that the first line segment 113 in the present application is not a physical line segment that physically exists on the battery cell, but a virtual line. The first line segment 113 can be a smooth curve, a combination of a curve and a straight line, or a combination of a curve and a broken line. There is no specific limitation here. For example, the center point of the first welding segment 21 in the area corresponding to the first recessed segment 1131 is a curved contour. Then, the first recessed segment 1131 can be a broken line segment formed by connecting straight lines in sequence, or a smooth curved segment. Figure 4 What is shown in is a broken line segment.

[0077] Furthermore, in the present application, the center point of the first welding section 21 refers to the point that divides the first welding section 21 into two symmetrical halves in the second direction, that is, the midpoint of the first welding section 21 in the second direction. It is not difficult to understand that in the present application, the lengths of all the first welding sections 21 are substantially the same.

[0078] In addition, it should be noted that, in some embodiments, within the first series region 111, an insulating layer is provided at the intersection of the first series region 111 and the second fine grid 30, that is, an insulating layer can be provided at the intersection of each second fine grid 30 and the welding strip 203, so as to prevent the welding strip 203 from contacting the fine grids of different polarities.

[0079] In the main grid-free back contact cell 100, cell string 200, cell assembly 300 and photovoltaic system 1000 of the embodiment of the present application, each first fine grid 20 has a first welding section 21 at the intersection of the first series connection area 111, and all first welding sections 21 are located in the first series connection area 111. In the first series connection area 111, there is at least one first welding section 21 that is misaligned with the other first welding sections 21 in the first direction. According to the arrangement order of the first welding sections 21 in the first direction, the first line segment 113 formed by connecting the center points of all the first welding sections 21 in sequence is a non-linear line segment, and the first line segment 113 has at least one first recessed section 1131. In this way, Figure 3 and Figure 5 As shown, during the welding process, a welding layer can be set on the first welding section 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 a position facing the opening of the first recessed section 1131. In this way, the distance between the first pre-adhesive 201 and the first welding section 21 in the first recessed section 1131 corresponding to the first pre-adhesive 201 is relatively far. Even if the height of the first pre-adhesive 201 is higher than the height of the welding layer, the distance between the two can effectively avoid the occurrence of cold welding in the subsequent welding process, and 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.

[0080] It is not difficult to understand that in traditional technology, the glue bonding points are usually set on the grid line segments of the fine grid used for welding, and the solder paste pads are set on the welding segments. The bonding points need to be located as close as possible to the center point of the soldering tape. Due to the close distance, the height of the bonding points is greater than the height at the welding position. In order to ensure the bonding strength, it is easy for the soldering tape to be unable to contact the corresponding welding points near the bonding points, which can easily lead to cold solder joints.

[0081] However, in the present application, by setting the portion of the first welding section 21 corresponding to the first pre-adhesive 201 into a concave contour arrangement, the first pre-adhesive 201 is set corresponding to the concave opening. In this way, the distance between the first pre-adhesive 201 and the corresponding first welding section 21 will be increased, which can effectively avoid the phenomenon of cold welding during the welding process.

[0082] In some embodiments, the first welding segment 21 and the second welding segment 31 are both coarse grid segments, that is, the first welding segment 21 is coarser than other portions of the first fine grid 20, and the second welding segment 31 is coarser than other portions of the second fine grid 30. In some embodiments, the length of the first welding segment 21 and the second welding segment 31 (i.e., the length in the second direction) may be 250um-350um, and the width (i.e., the length in the second direction) may be 25um-50um, so that the contact area between the first welding segment 21 and the second welding segment 31 and the welding strip 203 can be ensured, thereby improving the stability of welding.

[0083] See also Figure 6 In some embodiments, two first welding segments 21 that are offset from each other in the first direction have an overlapping portion in the first direction. Further, in such an embodiment, the length L1 of the overlapping portion in the second direction may be 50um-200um, such as 50um, 60um, 70um, 80um, 85um, 90um, 95um, 100um, 105um, 115um, 120um, 130um, 140um, 150um, 160um, 170um, 180um, 190um, 200um, etc. In this way, the first welding segments 21 can be arranged more closely.

[0084] Of course, if Figure 7 As shown, in some embodiments, the two first welding segments 21 that are offset from each other in the first direction may also be spaced apart from each other in the second direction, which is not specifically limited herein. In such an embodiment, the spacing L2 between the two first welding segments 21 that are offset from each other in the first direction in the second direction may be 100um-1mm, for example, 100um, 200um, 300um, 350um, 400um, 500um, 600um, 700um, 800um, 900um, 1mm, 1.5mm, etc.

[0085] See also Figure 3 and Figure 5 In some embodiments, there are multiple first welding sections 21 corresponding to the first recessed section 1131. In this way, the first pre-adhesive 201 can be far away from multiple nearby first welding sections 21, thereby better avoiding cold welding.

[0086] Of course, if Figure 8As shown, in some embodiments, the first recessed section 1131 may also correspond to only a single first welding section 21, which is not specifically limited herein.

[0087] Please continue reading Figure 4 and Figure 5 In some embodiments, each of the first recessed sections 1131 corresponds to at least one first pre-adhesive 201, that is, the first recessed section 1131 is provided with at least one first pre-adhesive 201 within the range corresponding to the second direction, and the first pre-adhesive 201 can be located inside the first recessed section 1131 close to the center line of the welding strip 203, or outside the first recessed section 1131.

[0088] See also Figure 5 In some embodiments, the first line segment 113 further has at least one first straight line segment 1132 , the first straight line segment 1132 is arranged parallel to the first direction, and the first recessed segment 1131 is offset along the second direction compared to the first straight line segment 1132 .

[0089] In this way, by setting the first straight line segment 1132, the first welding segment 21 on the first straight line segment 1132 is located on the same straight line parallel to the first direction, which can improve the welding efficiency during the welding process (such as 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.

[0090] Please continue to refer to 5. In some embodiments, the first recessed segment 1131 may include a first sub-straight segment 1131 parallel to the first straight segment 1132 and a first inclined segment 1132 connecting the first sub-straight segment 1131 and the first straight segment 1132.

[0091] In this way, the first sub-straight segment 1131 and the first inclined segment 1132 constitute the first recessed segment 1131, and the corresponding first welding segment 21 on the first sub-straight segment 1131 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 to improve the reliability and stability of welding.

[0092] Please refer again Figure 5 In some embodiments, there are multiple first straight line segments 1132 and first recessed segments 1131, and the multiple first straight line segments 1132 and first recessed segments 1131 are alternately arranged in sequence.

[0093] In this way, by setting multiple first straight line segments 1132 and first recessed segments 1131, at least a first pre-adhesive 201 can be set at the position corresponding to each first recessed segment 1131, so that multiple first pre-adhesives 201 can be arranged while effectively avoiding cold solder joints, thereby improving the stability and adhesion of the pre-fixation of the welding strip 203.

[0094] For further information, see Figure 5 In such an embodiment, among the two first recessed sections 1131 at both ends of the first straight line segment 1132 , one of the first recessed sections 1131 is recessed toward one side of the first straight line segment 1132 , and the other first recessed section 1131 is recessed toward the other side of the first straight line segment 1132 .

[0095] In this way, the recessed directions of two adjacent first recessed sections 1131 are opposite (that is, the openings of two adjacent first recessed sections 1131 are oriented in opposite directions). In this way, the positions of the first pre-adhesives 201 corresponding to the two adjacent first recessed sections 1131 are also opposite (respectively located on both sides of the first straight line section 1132), which can avoid the first pre-adhesives 201 being concentrated on one side of the first straight line section 1132.

[0096] Of course, it can be 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 a first straight line segment 1132 and an arc segment.

[0097] 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 directions of the first direction, the arrangement profile of the first welding segment 21 is wavy, and the first line segment 113 is an arc curve as a whole. The details are not given here.

[0098] See also Figure 4 and Fig. 9 In some embodiments, each second fine grid 30 has a second welding section 31 at the intersection of the second series connection area 112, all the second welding sections 31 are located in the second series connection area 112, and at least one second welding section 31 in the second series connection area 112 is offset from the other at least one second welding section 31 in the first direction;

[0099] The second line segment 114 formed by sequentially connecting the center points of all the second welding segments 31 in the first direction according to the arrangement order of the second welding segments 31 is a non-linear line segment, and the second line segment 114 has at least one second concave segment 1141 .

[0100] In this way, 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 a position facing the opening of the second recessed section 1141. 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 cold welding in the subsequent welding process, and at the same time, it can also ensure the adhesion of the second pre-adhesive 202 to the welding strip 203.

[0101] In some embodiments, two second welding segments 31 that are offset from each other in the first direction have overlapping portions in the first direction (same direction). Figure 6 ). Further, in such an embodiment, the length of the overlapping portion in the second direction may be 50um-200um, such as 50um, 60um, 70um, 80um, 85um, 90um, 95um, 100um, 105um, 115um, 120um, 130um, 140um, 150um, 160um, 170um, 180um, 190um, 200um, etc. In this way, the welding strips 203 can be arranged more closely.

[0102] Of course, in some embodiments, the two second welding segments 31 that are offset from each other in the first direction may also be spaced apart from each other in the second direction (same direction). Figure 7 In such an embodiment, the spacing between the two second welding segments 31 that are offset from each other in the first direction is 100um-1mm, such as 100um, 200um, 300um, 350um, 400um, 500um, 600um, 700um, 800um, 900um, 1mm, 1.5mm, etc.

[0103] See also Figure 4 and Fig. 9 In some embodiments, there are multiple second welding sections 31 corresponding to the second recessed section 1141. In this way, the second pre-adhesive 202 can be far away from multiple nearby second welding sections 31, thereby better avoiding cold welding.

[0104] Of course, in some embodiments, the second recessed section 1141 may also correspond to only a single second welding section 31 (with Figure 8 Similar), no specific limitation is given here.

[0105] See also Figure 4 and Fig. 9 In some embodiments, each of the second recessed sections 1141 corresponds to at least one second pre-adhesive 202, that is, the second recessed section 1141 is provided with at least one second pre-adhesive 202 within the range corresponding to the second direction, and the second pre-adhesive 202 can be located inside the second recessed section 1141 close to the center line of the welding strip 203, or outside the second recessed section 1141.

[0106] See also Fig. 9In some embodiments, the second line segment 114 further has at least one second straight line segment 1142 , the second straight line segment 1142 is arranged parallel to the first direction, and the second recessed segment 1141 is offset along the second direction compared to the second straight line segment 1142 .

[0107] In this way, by setting the second straight line segment 1142, the second welding segment 31 on the second straight line segment 1142 is located on the same straight line parallel to the first direction, which can improve the welding efficiency during the welding process (such as 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.

[0108] Please continue to refer to 9. In some embodiments, the second recessed segment 1141 includes a segment 11411 parallel to the second straight segment 1142 and a segment 11412 connecting the segment 11411 and the second straight segment 1142.

[0109] Thus, 11411 and 11412 constitute a second recessed section 1141, and the corresponding second welding section 31 on 11411 is located on the same grid line parallel to the first direction, so that multiple welding points can be added on the same straight line of the welding strip 203 to improve the reliability and stability of welding.

[0110] See also Fig. 9 In some embodiments, there are multiple second straight line segments 1142 and second recessed segments 1141 , and the multiple second straight line segments 1142 and second recessed segments 1141 are alternately arranged in sequence.

[0111] In this way, by setting a plurality of second straight line segments 1142 and second recessed segments 1141, at least a second pre-adhesive 202 can be set at the position corresponding to each second recessed segment 1141, thereby arranging a plurality of second pre-adhesives 202 while effectively avoiding cold solder joints, thereby improving the stability and adhesion of the pre-fixation of the welding strip 203.

[0112] For further information, see Fig. 9 In such an embodiment, among the two second recessed sections 1141 at both ends of the second straight line segment 1142 , one second recessed section 1141 is recessed toward one side of the second straight line segment 1142 , and the other second recessed section 1141 is recessed toward the other side of the second straight line segment 1142 .

[0113] In this way, the recessed directions of two adjacent second recessed sections 1141 are opposite (that is, the openings of two adjacent second recessed sections 1141 are oriented in opposite directions). In this way, the positions of the second pre-adhesives 202 corresponding to the two adjacent second recessed sections 1141 are also opposite (respectively located on both sides of the second straight line section 1142), which can avoid the second pre-adhesives 202 being concentrated on one side of the second straight line section 1142.

[0114] Of course, it can be 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.

[0115] 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 directions of the first direction, the arrangement profile of the second welding segment 31 is wavy, and the second line segment 114 is an arc curve as a whole. The details are not given here.

[0116] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0117] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A busbar-free back contact battery, characterized in that: The invention comprises a silicon substrate and a plurality of first fine grids and a plurality of second fine grids arranged on the back side of the silicon substrate, wherein the plurality of first fine grids and the plurality of second fine grids are arranged alternately and spaced in sequence along a first direction and all extend along a second direction, the second direction intersects with the first direction, the back side is provided with a plurality of first series connection areas and a second series connection areas for arranging welding strips, the first series connection areas and the second series connection areas extend along the first direction and intersect with all the first fine grids and the second fine grids, and the plurality of first series connection areas and the plurality of second series connection areas are arranged alternately and spaced in sequence along the second direction; Each of the first fine grids has a first welding section at the intersection of the first series connection area, and all of the first welding sections are located in the first series connection area; each of the second fine grids has a second welding section at the intersection of the second series connection area, and all of the second welding sections are located in the second series connection area; Wherein, in the first series connection area, at least one of the first welding segments and at least one of the other first welding segments are mutually offset in the first direction; According to the arrangement order of the first welding segments in the first direction, a 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 concave segment.

2. The busbar-free back contact cell according to claim 1, characterized in that: The two first welding sections that are offset from each other in the first direction have overlapping portions in the first direction.

3. The busbar-free back contact cell according to claim 2, characterized in that: The length of the overlapping portion in the second direction is 50um-200um.

4. The busbar-free back contact cell according to claim 1, characterized in that: The two first welding sections that are offset from each other in the first direction are spaced apart from each other in the second direction.

5. The busbar-free back contact cell according to claim 4, characterized in that: The distance between the two first welding sections that are offset from each other in the first direction in the second direction is 100 um-2.5 mm.

6. The busbar-free back contact cell according to claim 1, characterized in that: There are multiple first welding sections corresponding to the first recessed sections.

7. The busbar-free back contact cell according to claim 1, characterized in that: The first line segment further has at least one first straight line segment, the first straight line segment is arranged parallel to the first direction, and the first concave segment is offset along the second direction compared to the first straight line segment.

8. The busbar-free back contact cell according to claim 7, characterized in that: The first concave 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 busbar-free back contact cell according to claim 7 or 8, characterized in that: There are a plurality of the first straight line segments and the first concave segments, and the plurality of the first straight line segments and the first concave segments are alternately arranged in sequence.

10. The busbar-free back contact cell according to claim 9, characterized in that: Among the two first recessed sections at both ends of the first straight line segment, one of the first recessed sections is recessed toward one side of the first straight line segment, and the other first recessed section is recessed toward the other side of the first straight line segment.

11. The busbar-free back contact cell according to claim 1, characterized in that: The first line segment is a wavy line.

12. The busbar-free back contact cell according to claim 1, characterized in that: A second welding section is provided at the intersection of each of the second fine grids and the second series connection area, all of the second welding sections are located in the second series connection area, and at least one of the second welding sections and at least one of the other second welding sections in the second series connection area are mutually offset 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 sequentially connecting the center points of all the second welding segments is a non-linear line segment, and the second line segment has at least one second concave segment.

13. The busbar-free back contact cell according to claim 12, characterized in that: The two second welding sections that are offset from each other in the first direction have overlapping portions in the first direction.

14. The busbar-free back contact cell according to claim 13, characterized in that: The length of the overlapping portion in the second direction is 50um-200um.

15. The busbar-free back contact cell according to claim 12, characterized in that: The two second welding sections that are offset from each other in the first direction are spaced apart from each other in the second direction.

16. The busbar-free back contact cell according to claim 15, characterized in that: The distance between the two second welding sections that are offset from each other in the first direction is 100 um-2.5 mm in the second direction.

17. The busbar-free back contact cell according to claim 12, characterized in that: The second line segment further has at least one second straight line segment, the second straight line segment is arranged parallel to the second direction, and the second concave segment is offset along the second direction compared to the second straight line segment.

18. The busbar-free back contact cell according to claim 17, characterized in that: The second concave 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 busbar-free back contact cell according to claim 17 or 18, characterized in that: There are a plurality of the second straight line segments and the second concave segments, and the plurality of the second straight line segments and the second concave segments are alternately arranged in sequence.

20. The busbar-free back contact cell according to claim 19, characterized in that: Of the two second recessed segments at both ends of the second straight line segment, one of the second recessed segments is recessed toward one side of the second straight line segment, and the other second recessed segment is recessed toward the other side of the second straight line segment.

21. The busbar-free back contact cell according to claim 12, characterized in that: The second line segment is a wavy line.

22. A battery string, characterized in that: include: The busbar-free back contact battery according to any one of claims 1 to 21; A welding layer disposed on the first welding section and the second welding section; A first pre-adhesive adhesive is disposed in the first serial connection area and corresponds to the first recessed section, wherein the opening of the first recessed section faces the first pre-adhesive adhesive; A second pre-adhesive disposed in the second serial connection area; The welding strip covering the first series connection area and the second series connection area, the welding strip on the first series connection area is bonded to the first pre-adhesive and contacts the welding layer on the first welding section, and the welding strip on the second series connection area is bonded to the second pre-adhesive and contacts the welding layer on the second welding section.

23. The battery string according to claim 22, characterized in that: The distance between the first pre-adhesive and the first welding section located on the first recessed section is 100um-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, characterized in that: A single first recessed section corresponds to a plurality of first pre-adhesives.

25. The battery string according to claim 22, characterized in that: A second welding section is provided at the intersection of each of the second fine grids and the second series connection area, all of the second welding sections are located in the second series connection area, and at least one of the second welding sections and at least one of the other second welding sections in the second series connection area are mutually offset in the first direction; Among them, according to the arrangement order of the second welding segments in the first direction, the second line segment formed by sequentially connecting the center points of all the second welding segments is a non-linear line segment, the second line segment has at least one second recessed segment, the second pre-adhesive is arranged 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, characterized in that: The distance between the second pre-adhesive and the first welding section located on the second recessed section is 100um-2mm; and / or The length of the second pre-adhesive in the second direction is 300um-2mm.

27. A battery assembly, characterized in that: A battery string comprising any one of claims 21-26.

28. A photovoltaic system, characterized in that: Comprising the battery string as claimed in claim 27.

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