Solar cell and photovoltaic module

Abstract

Solar cell, featuring: a cell base (110) defining several first regions (z1) arranged along a first direction (F1), wherein at least one of the several first regions (z1) is a target region (z0); several fingers (120) spaced apart along a second direction (F2); and several solder joint structures (130) connected to one of the several fingers (120), wherein the several solder joint structures (130) are placed in the target region (z0) and arranged along the second direction (F2), wherein the several solder joint structures (130) have a first solder joint (W1a), the first solder joint (W1a) has a middle section (W11) and edge sections (W12) provided at both ends of the middle section (W11) along the first direction (F1), and the size of the middle section (W11) along the second direction (F2) is smaller than the size of the edge section (W12) along the second direction (F2).

Description

TECHNICAL AREA

[0001] This application relates to the technical field of solar cells, in particular to a solar cell and a photovoltaic module. BACKGROUND

[0002] In the manufacturing process of photovoltaic assemblies, several cells are connected to form a cell string using solder strips. These cells are then laminated, framed, and undergo other related processes to create a photovoltaic module. The reliability of the connection between the solder strip and the corresponding cell directly impacts the reliability of the photovoltaic module. Therefore, the reliability of this connection must be further improved. SUMMARY

[0003] Depending on the specific design, a solar cell and a photovoltaic module are provided.

[0004] According to one aspect of this application, a solar cell is provided comprising a cell base, multiple fingers, and multiple solder joint structures. The cell base defines multiple first regions arranged along a first direction, and at least one of the multiple first regions is a target region. The multiple fingers are spaced apart along the second direction. The multiple solder joint structures are connected to one of the multiple fingers. The multiple solder joint structures are located in the target region and are positioned along the second direction. The multiple solder joint structures comprise a first solder joint. The first solder joint comprises a central section and edge sections provided at both ends of the central section along the first direction. The size of the central section along the second direction is smaller than the size of the edge section along the second direction.

[0005] In some embodiments, the multiple solder joint structures comprise multiple first solder joints, and in the target region, two middle sections of two adjacent first solder joints have different sizes along the second direction.

[0006] In some embodiments, a direction in which an initial end of the middle section points towards a final end of the middle section is parallel to the first direction.

[0007] In some embodiments, the size of the middle section along the second direction is larger than the size of the finger along the second direction.

[0008] In some embodiments, the ratio between the size of the middle section and the size of the finger in the second direction is between 3 and 6.

[0009] In some embodiments, the size of the middle section along the second direction is between 40 µm and 55 µm.

[0010] In some embodiments, the edge section extends along the second direction, a connecting region is defined at a connection between the edge section and the middle section, and the edge section is arranged symmetrically with respect to the connecting region.

[0011] In some embodiments, the size of the edge section in the second direction is between 0.1 mm and 0.3 mm.

[0012] In some embodiments, the middle section extends linearly or in a curve from the beginning end to the end end.

[0013] In some embodiments, the multiple solder joint structures include a second solder joint, wherein the shape of the second solder joint differs from the shape of the first solder joint and the area of ​​an orthographic projection of the first solder joint on the cell base is smaller than the area of ​​an orthographic projection of the second solder joint on the cell base.

[0014] In some embodiments, the multiple solder joint structures include multiple second solder joints, and the areas of two adjacent second solder joints along the second direction are different.

[0015] In some embodiments, the target region comprises a central region and marginal sections placed on both sides of the central region along the second direction, and from the central region to the marginal sections, the areas of the orthographic protrusions of the multiple second solder joints on the cell base are gradually enlarged.

[0016] In some embodiments, at least one first solder joint is provided between two adjacent second solder joints along the second direction, or the first solder joint is provided on each of the two sides of the second solder joint along the second direction.

[0017] In some embodiments, the multiple solder joint structures comprise multiple second solder joints, and the areas of the orthographic protrusions of the multiple second solder joints on the cell base are equal.

[0018] In some embodiments, the multiple solder joint structures comprise multiple second solder joints, the multiple second solder joints are symmetrical with respect to a center of the target region, or the multiple second solder joints are placed in a central region of the target region.

[0019] In some embodiments, the orthographic projection of the second solder joint on the cell base is rectangular.

[0020] In some embodiments, the size of the second solder joint along the first direction is less than or equal to the size of the middle section along the first direction.

[0021] In some embodiments, the size of the second solder joint along the first direction is larger than the size of the second solder joint along the second direction.

[0022] In some embodiments, the multiple solder joint structures comprise two third solder joints, each placed at both ends of the target region along the second direction, wherein an area of ​​an orthographic projection of each third solder joint on the cell base is larger than the area of ​​the orthographic projection of the second solder joint on the cell base.

[0023] In some embodiments, the ratio between the area of ​​the orthographic projection of the second solder joint on the cell base and the area of ​​the orthographic projection of the third solder joint on the cell base is in the range of 0.35 to 0.5.

[0024] In some embodiments, the size of the second solder joint along the first direction is smaller than the size of the third solder joint along the first direction, and the size of the second solder joint along the second direction is smaller than the size of the third solder joint along the second direction.

[0025] In some embodiments, the shape of the orthographic projection of the third solder point on the cell base is rectangular.

[0026] In some embodiments, the solar cell further comprises a connecting line in the target region that connects at least one section of the multiple solder joint structures.

[0027] In some embodiments, the solar cell further comprises several transition connection sections, the finger connected to the first solder joint comprises several subfingers spaced apart along the first direction, and two adjacent subfingers along the first direction are each connected to both ends of the first solder joint along the first direction in a one-to-one correspondence by two transition connection sections.

[0028] In some embodiments, the size of the transition section is gradually reduced along the second direction, in the direction in which one end of the transition section connected to the first solder joint points to another end of the transition section connected to the lower finger.

[0029] According to another aspect of this application, a photovoltaic module is further provided comprising the solar cell in one of the above embodiments and a solder strip, wherein the solder strip is connected to several solder joint structures and covers at least one section of the several solder joint structures.

[0030] In the solar cell and photovoltaic module described above, the solar cell comprises the cell base, several fingers, and multiple solder joint structures. Since the solder joint structure is provided on the cell base, the solder strip can form an electrical connection with the finger through alloying with the solder joint structure. The finger can then transfer the collected current via the solder joint structure to the solder strip and output the current through the solder strip. By setting the size of the central section of the first solder joint along the second direction smaller than the size of the edge section along the second direction, the first solder joint forms a structure with broad ends and a narrow center.With such a structure, the bond strength between the solder strip and the first solder joint can be improved by the edge section, the risk of separation between the middle section and the solder strip can be reduced, and the risk of brittle fracture of the first solder joint can be reduced by the middle section. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Several other advantages and benefits will become apparent to those skilled in the field upon reading the detailed description of the following embodiments. The drawings serve solely to illustrate the embodiments and are not intended to limit this application. Furthermore, the same reference numerals are used in all drawings to designate the same components. Fig. Figure 1 is a schematic structural view of a solar cell according to some embodiments of this application. Fig. Figure 2 is a schematic structural view of solder joint structures in the same target region according to some embodiments of this application. Fig. Figure 3 is a schematic structural view of a first solder joint according to some embodiments of this application. Fig. Figure 4 is a schematic structural view of solder joint structures in the same target region according to other embodiments of this application. Fig. Figure 5 is a schematic structural view of solder joint structures in the same target region according to further embodiments of this application. Fig. Figure 6 is a schematic structural view of a solar cell according to other embodiments of this application. Fig. Figure 7 is a schematic structural view of solder joint structures in the same target region according to further embodiments of this application. Fig. Figure 8 is a schematic structural view of solder joint structures in the same target region according to other embodiments of this application. Fig. Figure 9 is a schematic structural view of solder joint structures in the same target region according to further embodiments of this application. Fig. Figure 10 is a schematic structural view of solder joint structures in the same target region according to further embodiments of this application. Fig. Figure 11 is a schematic structural view of solder joint structures in the same target region according to other embodiments of this application. Fig. Figure 12 is a schematic structural view of solder joint structures in the same target region according to other embodiments of this application. Fig. Figure 13 is a schematic structural view of a second solder joint according to some embodiments of this application. Fig. Figure 14 is a schematic structural view of a third solder joint according to some embodiments of this application. Fig. Figure 15 is a schematic structural view of a section of a finger according to some embodiments of this application. Fig. Figure 16 is a schematic structural view of solder joint structures in the same target region according to a further embodiment of this application. Fig. Figure 17 is a schematic structural view of solder joint structures in the same target region according to other embodiments of this application. Fig. Figure 18 is a schematic structural view of a solar cell according to a further embodiment of this application. Fig. Figure 19 is a schematic structural view of solder joint structures in the same target region according to further embodiments of this application. Fig. Figure 20 is a schematic structural view of solder joint structures in the same target region according to other embodiments of this application. Fig. Figure 21 is a schematic structural view of a solar cell according to a further embodiment of this application. Fig. Figure 22 is a schematic structural view of a section structure of a solar cell according to a further embodiment of this application. Fig. Figure 23 is a schematic structural view of a photovoltaic module according to some embodiments of this application. Reference numbers:

[0032] Solar cell 100a, 100b, 100c, 100d; Cell base 110, First region z1, Target region z0; Finger 120, lower finger 121; Solder joint structure 130, First solder joint W1a, W1b, W1c, middle section W11, First middle section W11a, Second middle section W11b, Third middle section W11c, Edge section W12, Reinforcement section W13, Second solder joint W2, First solder joint W2a, Second solder joint W2b, Third solder joint W3; Connecting line 140a, 140b, 140c; Transition link section 150; Solder strips 200; First size d1, Second size d2, Third size d3, Fourth size d4, Fifth size d5, Sixth size d6, Seventh size d7, Eighth size d8, Ninth size d9; First direction F1, second direction F2, third direction F3; Photovoltaic module 10, cell string 11, encapsulation layer 12, cover plate 13. DETAILED DESCRIPTION OF THE EXECUTION FORMS

[0033] To clarify the aforementioned objectives, elements, and advantages of this application, the specific embodiments of this application are described in detail below in conjunction with the accompanying drawings. Many specific details are included in the following description to facilitate understanding of this application. However, this application can be implemented in many ways that differ from those described herein, and those skilled in the art can make similar improvements without altering the meaning of this application. Therefore, this application is not limited by the specific embodiments disclosed below.

[0034] In the description of this application, the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" are based on the azimuths or positional relationships shown in the accompanying drawings. These terms serve only to simplify the description of this application and do not imply that the devices or elements mentioned must have specific azimuths or be designed or operated at specific azimuths; therefore, these terms cannot be construed as limitations of this application.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying a relative meaning or the number of specified technical features. Thus, the elements defined as "first" and "second" may explicitly or implicitly include at least one of the elements. In the description of this application, "several" means at least two, such as two, three, etc., unless specifically defined otherwise.

[0036] In this application, the terms "assemble," "connect," "couple," "fasten," and the like are to be interpreted broadly, unless specifically indicated and limited otherwise. For example, these terms may mean a permanent connection, a detachable connection, or integration. They may mean mechanical or electrical connections. They may mean a direct connection or an indirect connection via an intermediate medium. They may mean a connection within two elements or an interaction between two elements, unless specifically limited otherwise. For those skilled in the field, the specific meaning of the aforementioned terms in this application is to be understood according to the specific situation.

[0037] In this application, unless specifically stated and limited otherwise, a first feature may be located "above" or "below" a second feature in direct contact with the second feature, or the first and second features may be in indirect contact via an intermediary. Furthermore, the first feature may be located "above" the second feature, either directly above or diagonally above the second feature, or the first feature may simply be positioned at a higher level than the second feature. The first feature may be located "below" the second feature, either directly below or diagonally below the second feature, or the first feature may simply be positioned at a lower level than the second feature.

[0038] It should be noted that an element described as "mounted" or "attached" to another element can be positioned either directly on top of that element or on an intermediate element. Similarly, when an element is considered "connected" to another element, it can be directly attached or there can be an intermediate element. The terms "vertical," "horizontal," "upward," "downward," "left," "right," and similar expressions used here are for illustrative purposes only and do not represent the only possible implementations.

[0039] Reference is made to Fig. Figure 1, which shows a schematic structural view of a solar cell 100a according to some embodiments of this application. The solar cell 100a comprises a cell base 110, several fingers 120 and several solder joint structures 130.

[0040] The cell base 110 is a basic structure for realizing the photovoltaic effect. The cell base 110 can be configured as needed to obtain the desired type of solar cell 100a. For example, the solar cell 100a can be a TOPCon cell (Tunnel Oxide Passivating Contacts cell), a BC cell (Back Contact cell), an HJT cell (Heterojunction with Intrinsic Thin Layer cell), a perovskite cell, or a tandem cell, etc. The tandem cell can be a perovskite cell stacked with a TOPCon cell, a BC cell, or an HJT cell; this is not a limitation. The solar cell 100a can be a whole cell, a half cell, or even a smaller cell; this is not a limitation. Furthermore, the cell base 110 is a prefabricated composite product containing several functional structures, and not a single conventional silicon wafer.

[0041] With reference to Fig. 1 defines the cell base 110 as having several first regions z1 arranged along a first direction F1. In this embodiment, the first region z1 is a region configured for the placement of a solder strip 200, so that the first region z1 can be understood as a welding area of ​​the cell base 110. Fig. Figure 1 illustrates the first region z1 and a boundary of the first region z1, and the solder strip 200 is provided on a first region z1 but is not limited to it, and the number of first regions z1 is not specifically limited.

[0042] Finger 120 is a conductive structure printed onto a surface of cell base 110, capable of collecting detached charge carriers within the cell base 110. Solder joint structure 130 is a conductive structure located in the first region z1 and connected to finger 120. Through a welding process, it forms a metallurgical connection with solder strip 200. Thus, charge carriers collected by finger 120 can be transferred to solder strip 200 via solder joint structure 130. (With reference to...) Fig. 1 The multiple fingers 120 are spaced apart from each other along a second direction F2, and the multiple solder joint structures 130 arranged along the first direction F1 are connected to a finger 120.

[0043] For example, each finger extends 120 along the first direction F1, and the first direction F1 and the second direction F2 intersect.

[0044] For example, the thickness direction of the cell base 110 is parallel to a third direction F3, and the first direction F1, the second direction F2, and the third direction F3 are perpendicular to each other. The finger 120 can be provided on a front and a back side of the cell base 110, or only on the back side. The front and back sides of the cell base 110 are opposite each other in the third direction F3.

[0045] Reference is made to Fig. 1 in conjunction with Fig. Figure 2, which shows a schematic structural view of the solder joint structures 130 in the same target region z0 according to some embodiments of this application. At least one of the multiple first regions z1 is defined as the target region z0. Several solder joint structures 130, arranged along the second direction F2, are provided in the target region z0. In the same target region z0, the multiple solder joint structures 130 comprise a first solder joint W1a.

[0046] Examples include the Fig. 1 and Fig. 2, that a section of the solder joint structures 130 in the same target region z0 are set up as the first solder joints W1a. Alternatively, all solder joint structures 130 in the same target region z0 can be set up as the first solder joints W1a, which is not specifically restricted here.

[0047] The target region z0 refers to a first region z1 from the multiple first regions z1, in which the first solder point W1a is provided. The target region z0 is not a new structure independent of the first region z1, but a functional region of the first region z1, whose functions differ from those of the non-target regions. (Illustrated by example) Fig. 1. A case in which all first regions z1 are target regions z0. Alternatively, a first region z1 can be set up as a target region z0, or a section of the first regions z1 can be set up as a target region z0, which is not specifically restricted here.

[0048] Reference is made to Fig. 2 in conjunction with Fig. Figure 3, which shows a schematic structural view of the first solder joint W1a according to some embodiments of this application. The first solder joint W1a comprises a central section W11 and two edge sections W12. The two edge sections W12 are provided at both ends of the central section W11 along the first direction F1, and the size of the central section W11 along the second direction F2 is smaller than the size of the edge section W12 along the second direction F2. In the example of Fig. 3 is the size of the middle section W11 along the second direction F2 defined as a first size d1, the size of the edge sections W12 along the second direction F2 defined as a second size d2, and d1 < d2.

[0049] The shape of the first solder joint W1a can be, for example, dumbbell-shaped, hourglass-shaped, double trapezoidal, or H-shaped, without any specific restrictions here. The dumbbell shape generally refers to a shape where the central section W11 is a straight section and the outer sections W12 are wide ends in a circular, elliptical, etc. shape. The hourglass shape generally refers to a shape where the central section W11 is linearly narrowed and the outer sections W12 have wide ends in a circular, elliptical, etc. shape. The double trapezoidal shape generally refers to a shape where the central section W11 is a straight section and the outer sections W12 are wide ends in a trapezoidal shape. The H-shape generally refers to a shape where the central section W11 is a straight section and the outer sections W12 are rectangular strips. For example, in Fig. 1 to 3 The shape of the first solder joint W1a can be roughly considered an H-shape. Alternatively, the shape of the first solder joint W1a in the same target region z0 can also be a different shape than the dumbbell shape, hourglass shape, double trapezoid shape or H-shape described above, which is not specifically restricted here.

[0050] It should be noted that the above descriptions of the shape of the first solder joint W1a are only exemplary representations and do not illustrate the sole or exclusive limitation of the specific structural shape of the first solder joint W1a, as long as the first dimension d1 mentioned above is smaller than the second dimension d2.

[0051] Since the solder joint structure 130 is provided on the cell base 110, the solder strip 200 can establish an electrical connection with the finger 120 by alloying with the solder joint structure 130, and the finger 120 can transfer the collected current through the solder joint structure 130 to the solder strip 200 and output the current through the solder strip 200. Since the size of the central section W11 of the first solder joint W1a along the second direction F2 is smaller than the size of the edge section W12 along the second direction F2, the first solder joint W1a forms approximately a structure with wide ends and a narrow center.In such a structure, the bond strength between the solder strip 200 and the first solder joint W1a can be improved by the edge section W12, the risk of separation between the middle section W11 and the solder strip 200 can be reduced, and the risk of brittle fracture of the first solder joint W1a can be reduced by the middle section W11.

[0052] According to some embodiments of this application, several first solder joints W1a are provided in the target region z0, and the sizes of the middle sections W11 of the several first solder joints W1a along the second direction F2 have at least two types. As in Fig. As shown in Figure 1, such a facility can be used for all target regions z0 or a section of the target regions z0, which is not specifically restricted here.

[0053] In the example of Fig. 1 and Fig. In the same target region z0, if the sizes of the mean sections W11 along the second direction F2 have two types, one of the mean sections W11 in the same target region z0 is defined as the first mean section W11a, and the other of the mean sections W11 is defined as the second mean section W11b. The size of the first mean section W11a along the second direction F2 is smaller than the size of the second mean section W11b along the second direction F2.

[0054] Fig. Figure 4 is a schematic structural view of the solder joint structures 130 in the same target region z0 according to other embodiments of this application. Fig. Figure 4 illustrates a case where the sizes of the mean segments W11 along the second direction F2 exhibit three types in the same target region z0. In the same target region z0, one mean segment W11 is defined as the first mean segment W11a, another as the second mean segment W11b, and the third as the third mean segment W11c. The size of the first mean segment W11a along the second direction F2 is smaller than the size of the second mean segment W11b along the second direction F2, and the size of the second mean segment W11b along the second direction F2 is smaller than the size of the third mean segment W11c along the third direction F3.

[0055] Fig. Figure 5 is a schematic structural view of the solder joint structures 130 in the same target region z0 according to further embodiments of this application. Fig. Figure 5 illustrates a case in which the sizes of the mean segments W11 along the second direction F2 have six types in the same target region z0. Alternatively, the sizes of the mean segments W11 along the second direction F2 in the same target region z0 can also have other sizes, which are not specifically restricted here.

[0056] Due to the varying stress levels in different regions of the target area z0, the sizes of the intermediate sections W11 in the target region z0 differ along the second direction F2. This helps control the stress risk in different regions and thereby improves the reliability of the solder strip 200 connection. Compared to the case where the sizes of the intermediate sections W11 in the same target region z0 along the second direction F2 are of the same type, the case where the sizes of the intermediate sections W11 in the same target region z0 along the second direction F2 are of at least two types is beneficial for increasing the weld tensile strength of the solder strip 200 by means of the larger intermediate sections W11 along the second direction F2, thereby further improving the connection reliability of the solder strip 200.

[0057] Therefore, in the embodiment of this application, the connection reliability of the solder strip 200 can be improved by providing the first solder joint W1 and by allowing the sizes of the middle sections W11 to have at least two types in at least one target region z0 along the second direction F2. Furthermore, in the solar cell 100a according to the embodiment of this application, the adhesive points for fixing the solder strip 200 can be omitted, which not only simplifies the manufacturing process but also reduces the reliability risk caused by the aging of the adhesive points.

[0058] With reference to Fig. 2, Fig. 4 and Fig. 5 According to some embodiments of this application, in at least one target region z0, two adjacent central sections W11 of different sizes along the second direction F2 are present. As in Fig. As shown in Figure 1, such a facility can be used for all target regions z0 or a section of the target regions z0, which is not specifically restricted here.

[0059] In the example of Fig. 2 and Fig. Figure 5 illustrates that in the same target region z0, the sizes of two adjacent middle sections W11 along the second direction F2 are different.

[0060] When the same solder strip 200 is subjected to thermal cycling or mechanical vibrations, stresses are transmitted between adjacent solder joint structures 130 along one longitudinal direction of the solder strip 200. If, at this time, at least one group of two adjacent central sections W11 has different dimensions along the second direction F2, the stress transmission path can be interrupted here, thereby reducing the risk of stress superposition in a region between adjacent solder joint structures 130, improving the mechanical shock resistance, and thus improving the connection stability and reliability of the solder strip 200.

[0061] With reference to Fig. 2 According to some embodiments of this application, in at least one target region z0 the sizes of the central sections W11 along the second direction F2 have two types, and two adjacent central sections W11 have different sizes along the second direction F2. As in Fig. As shown in Figure 1, such a facility can be used for all target regions z0 or a section of the target regions z0, which is not specifically restricted here.

[0062] In the example of Fig. 2. Along the second direction F2, the first middle sections W11a and the second middle sections W11b are arranged alternately.

[0063] Since the two central sections W11 of different sizes are arranged alternately in at least one target region z0, a continuous structure can be constructed to interrupt the voltage transmission path, thereby further improving the mechanical shock resistance and thus the connection stability and reliability of the solder strip 200. Because the central sections W11 of at least one target region z0 are arranged regularly, manufacturing is simpler and process costs are reduced.

[0064] With reference to Fig. 5. According to some embodiments of this application, the sizes of the central sections W11 increase sequentially along the second direction F2, from the center of the target region z0 to its edge. That is, the closer to the center of the target region z0, the smaller the size of the central section W11 along the second direction F2; conversely, the closer to the edge of the target region z0, the larger the size of the central section W11 along the second direction F2. It should be noted that the center of the target region z0 and the edge of the target region z0 refer to the second direction F2.

[0065] Thus, the welding tensile force between the section that is closer to the edge of the solder strip 200 and the solder joint structure 130 is greater, which reduces the risk of the edge of the solder strip 200 detaching from the cell base 110 due to stresses.

[0066] As an alternative to the arrangements of the middle sections W11 of the first solder joint W1a shown in the embodiments above, other arrangements, such as those in Fig. The four shown can be assumed, which is not specifically restricted here.

[0067] With reference to Fig. 6 and Fig. 7 is Fig. 6 a schematic structural view of a solar cell 100b according to other embodiments of this application, and Fig. Figure 7 is a schematic structural view of the solder joint structures 130 in the same target region z0 according to further embodiments of this application. In at least one target region z0, the solder joint structure 130 further comprises a second solder joint W2. The shape of the second solder joint W2 differs from that of the first solder joint W1, and an area of ​​an orthographic projection of the first solder joint W1 on the cell base 110 is smaller than an area of ​​an orthographic projection of the second solder joint W2 on the cell base 110. As shown in Figure 7, the solder joint structure W2 is formed by the first solder joint W1 on the cell base 110. Fig. As shown in Figure 6, such a facility can be used for all target regions z0 or a section of the target regions z0, which is not specifically restricted here.

[0068] In the target region z0 of the cell base 110, the multiple solder joint structures 130 comprise the first solder joint W1a and the second solder joint W2. That is, both the first solder joint W1a and the second solder joint W2 are solder joint structures 130 on the target region z0, and the first solder joint W1a and the second solder joint W2 are solder joint structures 130 of different types. Depending on the different number of first solder joints W1a and second solder joints W2 in the target region z0, the connection reliability between the cell base 110 and the solder strip 200 can be improved through the different synergistic effects of both. In the example of Fig. 6 and Fig. In equation 7, the number of first solder joints W1a in the target region z0 is greater than the number of second solder joints W2. The first solder joint W1a can be used as the main solder joint, and the second solder joint W2 as an auxiliary or extended functional solder joint. Thus, the differentiated connection between the first solder joint W1a, the second solder joint W2, and the solder strip 200 can be achieved through the different shapes and sizes of the first solder joint W1a and the second solder joint W2.

[0069] The larger second solder joint W2 improves the connection stiffness of the solder strip 200. Therefore, the interaction of the first solder joint W1a and the second solder joint W2 allows not only the edge section W12 of the first solder joint W1a and the second solder joint W2 to cooperate in distributing stresses and reducing the risk of stress concentration at the second solder joint W2, but also enables the first solder joint W1a and the second solder joint W2, which differ from each other, to adapt to multidirectional stresses and reduce damage in a single direction, thereby improving the overall connection reliability of the solder strip 200.

[0070] It should be clear that, compared to a case where all solder joint structures 130 are configured as second solder joints W2, the embodiment of this application can not only improve the reliability of the solder strip 200 but also reduce the consumption of metal paste, thereby controlling the manufacturing costs of the solar cell. Compared to a case where all solder joint structures 130 are configured as first solder joints W1a, the embodiment of this application can further improve the connection reliability of the solder strip 200 through the second solder joint W2, and the second solder joint W2 and the first solder joint W1a can form differentiated voltage resistances, further improving the connection reliability of the solder strip 200.

[0071] It should be noted that some embodiments of the first solder joint W1a, which are described above Fig. 2, Fig. 4 and Fig. 5 can be freely combined with the second solder point W2 to form different arrangements of the solder point structures 130, as shown in Fig. Figures 7 to 9 are shown, which is not specifically restricted here. Fig. Figure 8 is a schematic structural view of the solder joint structures 130 in the same target region according to other embodiments of this application, and Fig. Figure 9 is a schematic structural view of the solder joint structures in the same target region according to further embodiments of this application.

[0072] Reference is made to Fig. Figure 10, which represents a schematic structural view of the solder joint structures 130 in the same target region z0 according to further embodiments of this application. Several second solder joints W2 are provided on the target region z0. In the target region z0 provided with several second solder joints W2, the areas of the orthographic projections of the second solder joints W2 on the cell base 110 have at least two types. Such a device can be used for all target regions z0 or a section of the target regions z0, which is not specifically limited here.

[0073] In the example from Fig. In the same target region z0, the orthographic projections of the second solder joints W2 on the cell base 110 exhibit two types, and the orthographic projections of at least one group of two adjacent second solder joints W2 along the second direction F2 on the cell base 110 differ from these. Thus, by providing the differentiated second solder joints W2, the difference between the solder joint structures 130 is exploited to form different degrees of tensile strength with the solder strip 200, which is advantageous for withstanding stresses in different scenarios, thereby further improving the reliability of the solder strip 200 connection.

[0074] In the example from Fig. 10. The areas of the orthographic projections of any group of three adjacent second solder joints W2 along the second direction F2 on the cell base 110 in the same target region z0 are different. One of the second solder joints W2 is defined as a first-type solder joint W2a, and the other two second solder joints W2 are defined as second-type solder joints W2b. The area of ​​an orthographic projection of the first-type solder joint W2a on the cell base 110 is larger than the area of ​​an orthographic projection of the second-type solder joint W2b on the cell base 110.

[0075] It should be noted that the first solder joint W1a can be located between two adjacent second solder joints W2 along the second direction F2, but it does not have to be. In the example from Fig. 10, along the second direction F2, the first solder point W1a is provided between a group of two adjacent second solder points W2, and the first solder point W1a is also provided between another group of two adjacent second solder points W2. Alternatively, with reference to Fig. 7 to 10 the second solder point W2 between two adjacent first solder points W1a along the second direction F2 must be provided, however this is not required, which is not specifically restricted here.

[0076] When the same solder strip 200 is subjected to a thermal cycle or mechanical vibrations, stresses are transmitted between adjacent solder joint structures 130 along the longitudinal direction of the solder strip 200. If the areas of the orthographic projections of at least one group of two adjacent second solder joints W2 on the cell base 110 differ, the stress transmission path can be interrupted here, thereby reducing the risk of stress superposition in the region between adjacent solder joint structures 130, improving the mechanical shock resistance, and thus increasing the connection stability and reliability of the solder strip 200.

[0077] Reference is made to Fig. Figure 11 shows a schematic structural view of the solder joint structures 130 in the same target region z0 according to other embodiments of this application. The target region z0 comprises a central region and two boundary sections located on either side of the central region along the second direction F2. In the target region z0, the area of ​​the orthographic projection of the second solder joint W2 on the cell base 110 is gradually increased along the second direction F2 of the central region up to the boundary sections. Such a device can be used for all target regions z0 or a section of the target regions z0, which is not specifically limited here.

[0078] Gradual enlargement means that the area of ​​the orthographic projection can increase sequentially, that it initially increases and then remains unchanged, or that it initially remains unchanged and then increases, which is not specifically restricted here. In the example from Fig. In the same target region z0, the area of ​​the orthographic projection of the second solder joint W2 on cell base 110 increases sequentially along the second direction from the central region to the edge sections. The solder joint of the second type W2b is located in the center of the target region z0, and the solder joint of the first type W2a is located adjacent to the edge of the target region z0.

[0079] Thus, the welding tensile force between the section that is closer to the edge of the solder strip 200 and the solder joint structure 130 is greater, which reduces the risk of the edge of the solder strip 200 detaching from the cell base 110 due to stresses.

[0080] With reference to Fig. According to some embodiments of this application, 6 to 11, several second solder joints W2 are provided on the target region z0. In the target region z0, at least one first solder joint W1a is provided between at least one group of two adjacent second solder joints W2 along the second direction F2. As in Fig. As shown in Figure 6, such a facility can be used for all target regions z0 or a section of the target regions z0, which is not specifically restricted here.

[0081] Thus, if voltage is transmitted between two adjacent second solder joints W2 along the second direction F2, the transmission path of the voltage through the first solder joint W1a, which differs from the second solder joint W2, can be interrupted, thereby further reducing the risk of voltage superposition in the region between adjacent solder joint structures 130 and further improving the connection stability and reliability of the solder strip 200.

[0082] With reference to Fig. According to some embodiments of this application, in the target region z0, the first solder joints W1a are provided on both sides of the second solder joint W2 along the second direction F2. As in Fig. As shown in Figure 6, such a facility can be used for all target regions z0 or a section of the target regions z0, which is not specifically restricted here.

[0083] Since the first solder joints W1a are provided on both sides of the second solder joint W2 along the second direction F2, the difference between the first solder joint W1a and the second solder joint W2 can be utilized. If the same solder strip 200 is undergoing a thermal cycle or is subjected to mechanical vibrations, the voltage transmission path can be further interrupted, thereby reducing the risk of voltage superposition in the area between adjacent solder joint structures 130. In addition, the edge of the first solder joint W1a can interact with the first solder joint W1a to increase the solder tensile strength of the solder strip 200, thereby further improving the connection stability and reliability of the solder strip 200.

[0084] With reference to Fig. According to some embodiments of this application, 6 to 9, several second solder points W2 are provided on the target region z0. In the target region z0 provided with several second solder points W2, the areas of the orthographic projections of the second solder points W2 on the cell base 110 are identical. As in Fig. As shown in Figure 6, such a facility can be used for all target regions z0 or a section of the target regions z0, which is not specifically restricted here.

[0085] Since the areas of the orthographic projections of the second solder joints W2 on the cell base 110 are of the same size, the production of the second solder joints W2 is facilitated.

[0086] With reference to Fig. According to some embodiments of this application, 6 to 9 and 11, several second solder joints W2 are provided on at least one target region z0. In the target region z0 provided with several second solder joints W2, the several second solder joints W2 are symmetrical with respect to the center of the first region z1. As in Fig. As shown in Figure 6, such a facility can be used for all target regions z0 or a section of the target regions z0, which is not specifically restricted here.

[0087] Thus, the symmetrical arrangement of the second solder joints W2 allows the stresses to be absorbed almost synchronously during the thermal cycle. This reduces the risk of deformation of the solder strip 200 due to excessive stress on one side of the solder strip 200, and also reduces the stress superposition between the solder joint structures 130. Furthermore, the symmetrical arrangement of the second solder joints W2 creates a more balanced connection structure for the solder strip 200, thereby further improving its impact and displacement resistance.

[0088] Reference is made to Fig. Figure 12 shows a schematic structural view of the solder joint structures 130 in the same target region z0 according to other embodiments of this application. According to some embodiments of this application, a second solder joint W2 is provided at at least one target region z0, and the second solder joint W2 is located in a central region of the target region z0. Such a provision can be used for all target regions z0 or a section of the target regions z0, which is not specifically limited here.

[0089] This not only increases the welding tensile force between the central section W11 of the solder strip 200 and the solder joint structure 130, so that the overall expansion and contraction of the solder strip 200 can be suppressed by fixing the solder strip 200 in the middle, but also allows the edge sections W12 of the solder strip 200 to buffer and distribute local stresses from the first solder joint W1a. At the same time, such a structure also simplifies the fabrication of the solder joint structure 130.

[0090] Reference is made to Fig. 6 to 12 in conjunction with Fig. Figure 13 shows a schematic structural view of the second solder joint W2 in some embodiments of this application. According to some embodiments of this application, the shape of the orthographic projection of the second solder joint W2 on the cell base 110 is rectangular. According to other embodiments of this application, the size of the second solder joint W2 along the first direction F1 is less than or equal to the size of the central section W11 along the first direction F1. According to still further embodiments of this application, the size of the second solder joint W2 along the second direction F2 is larger than the size of the edge section W12 along the second direction F2.

[0091] In the example of Fig. 3 and Fig. In equation 13, the size of the second solder joint W2 along the first direction F1 is defined as the third size d3, the size of the middle section W11 along the first direction F1 as the fourth size d4, and d3 ≤ d4. The size of the second solder joint W2 along the second direction F2 is defined as a fifth size d5, the size of the edge section W12 along the second direction F2 is defined as a second size d2, and d5 > d2.

[0092] Since the shape of the orthographic projection of the second solder joint W2 on the cell base 110 is rectangular, this is not only advantageous for improving the fastening strength of the solder strip 200, but also facilitates the manufacture and joining of the solder strip 200. By controlling the size of the second solder joint W2 along the first direction F1 and / or the second direction F2, a solder joint structure 130 can be formed between two adjacent first solder joints W1a that differs from the first solder joint W1a, which is advantageous for controlling the size of the second solder joint W2, thereby increasing the solder tensile strength of the solder strip 200 and simultaneously reducing the consumption of metal paste.

[0093] With reference to Fig. According to some embodiments of this application, 1, 2, 6 to 12 is a direction of extension of a line that connects the centers of the solder joint structures 130 in at least one target region z0, parallel to the second direction F2. As in Fig. 1 and Fig. As shown in Figure 6, such a facility can be used for all target regions z0 or a section of the target regions z0, which is not specifically restricted here.

[0094] This not only reduces the risk of deformations and stress concentrations in the solder strip 200, but also facilitates the production of the solder joint structures 130.

[0095] With reference to Fig. 1, 2, 6 to 12, according to some embodiments of this application, in at least one target region z0, along the second direction F2, comprising several solder joint structures 130 and two third solder joints W3, which are placed at both ends of the target region z0. The area of ​​an orthographic projection of each third solder joint W3 on the cell base 110 is larger than the area of ​​the orthographic projection of the second solder joint W2 on the cell base 110. As in Fig. 1 and Fig. As shown in Figure 6, such a facility can be used for all target regions z0 or a section of the target regions z0, which is not specifically restricted here.

[0096] By arranging the third solder joints W3 with larger orthographic projection areas at positions corresponding to the two ends of the solder strip 200, the welding tensile force at both ends of the solder strip 200 can be further increased.

[0097] With reference to Fig. According to some embodiments of this application, the ratio of the area of ​​the orthographic projection of the second solder joint W2 on the cell base 110 to the area of ​​the orthographic projection of the third solder joint W3 on the cell base 110 is in the range of 0.35 to 0.5. According to other embodiments of this application, the size of the second solder joint W2 along the first direction F1 is smaller than the size of the third solder joint W3 along the first direction F1, and the size of the second solder joint W2 along the second direction F2 is smaller than the size of the third solder joint W3 along the second direction F2. According to further embodiments of this application, the shape of the orthographic projection of the third solder joint W3 on the cell base 110 is rectangular.

[0098] For example, the ratio of the area of ​​the orthographic projection of the second solder joint W2 on cell base 110 to the area of ​​the orthographic projection of the third solder joint W3 on cell base 110 can be 0.35, 0.4, 0.45, 0.48, or 0.5. Alternatively, the ratio can also be any value in the range of 0.35 to 0.5, which is not specifically limited here.

[0099] In the example of Fig. 13 is in connection with Fig. Figure 14 shows a schematic structural view of the third solder joint W3 in some embodiments of this application. The size of the third solder joint W3 along the first direction F1 is defined as the sixth size d6, the size of the third solder joint W3 along the second direction F2 is defined as the seventh size d7, d6 > d3 and d7 > d5.

[0100] Since the shape of the orthographic projection of the third solder joint W3 on the cell base 110 is rectangular, this is not only advantageous for improving the fastening strength of the solder strip 200, but also facilitates the production and joining of the solder strip 200. By controlling the size of the third solder joint W3 along the first direction F1 and / or the second direction F2, a solder joint structure 130 is formed that differs from the first solder joint W1a and the second solder joint W2, which is advantageous for controlling the size of the third solder joint W3, thereby increasing the solder tensile strength of the solder strip 200 and simultaneously reducing the consumption of metal paste.

[0101] With reference to Fig. 6 and Fig. 7 According to some embodiments of this application, two second solder points W2 are provided at at least one target region z0, and the two second solder points W2 are symmetrical with respect to the center of the target region z0. As in Fig. As shown in Figure 6, such a facility can be used for all target regions z0 or a section of the target regions z0, which is not specifically restricted here.

[0102] The second solder joint W2 and the third solder joint W3 further increase the soldering tensile force at both ends of the solder strip 200 and in the middle section of the solder strip 200, thereby improving the connection reliability of the solder strip 200. With this structure, the solder strip 200 is divided into sections and works in conjunction with the first solder joint W1a, which not only controls the shape of the solder strip 200 and improves the connection stability of the solder strip 200, but also contributes to improving the connection reliability of the solder strip 200.

[0103] With reference to Fig. According to some embodiments of this application, 3 is a direction in which an initial end of the middle section W11 points towards a final end of the middle section W11, parallel to the first direction F1. According to other embodiments of this application, the size of the middle section W11 along the second direction F2 is larger than the size of the finger 120 along the second direction F2.

[0104] In the example of Fig. 3 and Fig. 15 is Fig. Figure 15 shows a schematic structural view of a section of finger 120 according to some embodiments of this application. The size of finger 120 along the second direction F2 is defined as one-eighth of the size d8, and d1 > d8.

[0105] Thus, by controlling the approximate shape of the central section W11 and / or its size along the second direction F2, it is preferred to connect the central section W11 to the finger 120 and simultaneously facilitate the connection of the central section W11 to the solder strip 200. Furthermore, since the size of the edge section W12 along the second direction F2 is larger than the size of the central section W11 along the second direction F2, the reliability of the connection between the finger 120 and the first solder joint W1a can be improved by using the edge section W12, which facilitates the connection between the first solder joint W1a and the finger 120.

[0106] With reference to Fig. 3 and Fig. 15 According to some embodiments of this application, the ratio between the size of the middle section W11 F2 and the size of the finger 120 along the second direction F2 is in the range of 3 to 6. According to other embodiments of this application, the size of the middle section W11 along the second direction F2 is between 40 µm and 55 µm.

[0107] In the example of Fig. 3 and Fig. In 15, the ratio between the first quantity d1 and the eighth quantity d8 is 3, 3.5, 4, 4.5, 5, 5.5, or 6. Alternatively, the ratio between the first quantity d1 and the eighth quantity d8 can be any value in the range of 3 to 6, which is not specifically restricted here.

[0108] In the example of Fig. 3. The first dimension d1 can be, for example, 40 µm, 42 µm, 45 µm, 46 µm, 48 µm, 50 µm, 52 µm, 53 µm, or 55 µm. Alternatively, the first dimension d1 can be any value within the range of 40 µm to 55 µm, which is not specifically limited here.

[0109] By controlling the size ratio between the middle section W11 and the finger 120 and / or the size of the middle section W11 along the second direction F2, the connection with the finger 120 and the solder strip 200 is facilitated, while at the same time saving the metal paste.

[0110] With reference to Fig. 3 According to some embodiments of this application, the edge section W12 extends along the second direction F2. This improves the process window for producing the first solder joint W1a and the finger 120, which is advantageous both for the connection between the edge section W12 and the finger 120 and for the connection between the first solder joint W1a and the solder strip 200.

[0111] According to some embodiments of this application, a connection region is defined at a transition between the edge section W12 and the middle section W11, and the edge sections W12 are arranged symmetrically with respect to the connection region.

[0112] This allows the edge section W12 to be easily connected with the finger 120 and the edge section W12 to be produced.

[0113] With reference to Fig. 3 According to some embodiments of this application, the second dimension d2 of the edge section W12 lies between 0.1 mm and 0.3 mm along the second direction F2.

[0114] For example, the second dimension d2 could be 0.1 mm, 0.12 mm, 0.15 mm, 0.2 mm, 0.24 mm, 0.28 mm, or 0.3 mm. Alternatively, the second dimension d2 can be any value within the range of 0.1 mm to 0.3 mm, which is not specifically limited here.

[0115] By controlling the size of the edge section W12, the connection with the finger 120 and the solder strip 200 is facilitated, while at the same time saving the metal paste.

[0116] With reference to Fig. According to some embodiments of this application, the middle section W11 extends linearly from the beginning end to the end end, from 1 to 12.

[0117] Since the central section W11 extends in a straight line, this is not only advantageous for manufacturing, but also for improving the stability of the connection between the central section W11 and the solder strip 200 and facilitates a more even distribution of stress.

[0118] Reference is made to Fig. Figure 16, which shows a schematic structural view of the solder joint structures 130 in the same target region z0 according to a further embodiment of this application. According to some embodiments of this application, the middle section W11 extends from the start end to the end end in a curve. Thus, a first solder joint W1b is formed, which differs from the first solder joint W1a illustrated above. It is noted that the position of the middle section of the first solder joint W1b is related to the position of the middle section W11 of the first solder joint W1a in Fig. Figure 3 is shown to be clear. The difference is that the middle section of the first solder joint W1b and the middle section W11 of the first solder joint W1a have different shapes.

[0119] Since the middle section extends in a curved shape, not only can the contact area with the solder strip 200 be increased, but more stress relief spaces can also be formed by using the curved middle section, thereby further improving the connection stability and reliability of the solder strip 200.

[0120] Reference is made to Fig. Figure 17 shows a schematic structural view of the solder joint structures 130 in the same target region z0 according to further embodiments of this application. According to some embodiments of this application, the first solder joint W1c further comprises at least one reinforcement section W13, which is provided in the middle region of the middle section W11. It should be noted that the position of the middle section of the first solder joint W1c is determined with reference to the position of the middle section W11 of the first solder joint W1a in Fig. 3 is shown to be understood. The difference is that on the middle section W11 of the first solder joint W1a, which is in Fig. As shown in section 3, no reinforcement section is provided.

[0121] The structure and arrangement of reinforcement section W13 can be related to the boundary section W12 illustrated above and are not repeated here. The difference between reinforcement section W13 and boundary section W12 is that reinforcement section W13 is located in the central region of the central section W11. For example, in Fig. 17 the first solder joint W1c several reinforcement sections W13 spaced apart along the first direction F1.

[0122] It can be understood that the reinforcing section W13 can increase the contact area between the first solder joint W1c and the solder strip 200, thereby improving the connection performance between the first solder joint W1c and the solder strip 200. Thus, by providing the reinforcing section W13, the connection performance of the solder strip 200 can be further improved.

[0123] In some embodiments, the multiple reinforcement sections W13 of the first solder joint W1c can be arranged offset along the second direction F2 on the same target region z0. This allows the difference between the individual sections of the solder joint structure 130 to further improve the connection stability and reliability of the solder strip 200.

[0124] With reference to Fig. 18 and Fig. 19 is Fig. 18 a schematic structural view of a solar cell 100c according to further embodiments of this application, and Fig. Figure 19 is a schematic structural view of the solder joint structures 130 in the same target region z0 according to further embodiments of this application. According to some embodiments of this application, the solar cell 100c further comprises at least one connecting line 140a. In the target region z0, the at least one connecting line 140a is connected to at least one section of the solder joint structures 130. As in Fig. As shown in Figure 18, such a facility can be used for all target regions z0 or a section of the target regions z0, which is not specifically restricted here.

[0125] Fig. Figure 19 shows a case in which a connecting line 140a, which is connected to all solder joint structures 130, is provided in the same target region z0. In the example of Fig. 20 is Fig. 20 A schematic structural view of the solder joint structures 130 in the same target region z0 according to further embodiments of this application. According to some embodiments of this application, the solar cell 100c further comprises a connecting line 140b and a connecting line 140c, wherein the connecting line 140b is connected to one section of the solder joint structures 130 and the connecting line 140c is connected to the other section of the solder joint structures 130, which is not specifically limited herein.

[0126] In the example of Fig. 19 and Fig. 20. The connecting line 140a, the connecting line 140b and the connecting line 140c all extend linearly along the second direction F2. Alternatively, the connecting line 140a can also be arranged in a curved configuration, which is not specifically restricted here.

[0127] By providing the connecting leads, the welding tensile strength of the solder strip 200 and the reliability of the connection between each solder joint structure 130 and the solder strip 200 can be further improved, thereby further improving the reliability of the connection of the solder strip 200.

[0128] It should be noted that the number of connecting lines is related to the number of target regions z0. The number of target regions z0 can be from 10 to 20, and the number of connecting lines can also be from 10 to 20. Fig. Figure 21 is a schematic structural view of a solar cell 100d according to further embodiments of this application. In the example of Fig. In 21, the number of target regions z0 is 10, and the number of connecting lines 140a is also 10. Alternatively, the number of connecting lines 140a can also be greater than the number of target regions z0 if multiple connecting lines 140a are provided on one target region z0, which is not specifically restricted here. Furthermore, in some of the above embodiments where no connecting lines are shown, connecting lines can also be provided with reference to the illustrations above, which is not specifically restricted here.

[0129] Reference is made to Fig. Figure 22 shows a schematic structural view of a section structure of a solar cell according to a further embodiment of this application. According to some embodiments of this application, the finger 120 connected to the first solder joint W1a comprises several subfingers 121 spaced apart from one another along the first direction F1, and the solar cell further comprises several transition connection sections 150. Two adjacent subfingers 121 along the first direction F1 are each connected to both ends of the first solder joint W1a along the first direction F1 in a one-to-one correspondence by a transition connection section 150.

[0130] By setting up the finger 120 as several sub-fingers 121 and connecting the sub-fingers 121 and the corresponding first solder points W1a using the transition connection section 150, not only can the connection between the sub-fingers 121 and the corresponding first solder points W1a be realized, but the risk of grid breakage of the sub-fingers 121 can also be reduced.

[0131] In other embodiments, the multiple grid section lines encompassed in finger 120 can also be directly connected to each other, which is not specifically restricted here.

[0132] With reference to Fig. 22, according to some embodiments of this application, the size of the transition connecting section 150 decreases gradually along the second direction F2 in the direction in which one end of the transition connecting section 150, which is connected to the first solder joint W1a, points to the other end of the transition connecting section 150, which is connected to the lower finger 121.

[0133] Gradually decreasing means that the size first decreases and then remains unchanged, or decreases continuously, or remains unchanged first and then decreases. In the example of Fig. 22, along the direction in which one end of the transition connection section 150, which is connected to the first solder joint W1a, points to the other end of the transition connection section 150, which is connected to the lower finger 121, the size of the transition connection section 150 along the second direction F2 initially remains unchanged and then decreases. The size of the transition connection section 150 along the second direction F2 is defined as the ninth size d9, which is in Fig. 22 is shown.

[0134] By controlling the size of the transition connection section 150 along the second direction F2, the transition connection section 150 between the lower finger 121 and the first solder joint W1a is temporarily connected, thereby further reducing the risk of a grid break of the lower finger 121 and at the same time saving the metal paste for the manufacture of the transition connection section 150.

[0135] According to some embodiments of this application, the cell base 110 comprises a front and a back side that are opposite to each other, the fingers 120 are provided on both the front and back sides, and at least the back side is provided with the target region z0 and the solder joint structures 130.

[0136] Since the back of the cell base 110 poses a high reliability risk, providing the target region z0 and the solder joint structures 130 on the back side is advantageous for improving the connection reliability of the solder strip 200.

[0137] Therefore, the solder joint structure 130 in the embodiments of this application are described by way of example based on the situations illustrated in the above embodiments, but are not limited thereto.

[0138] In Example 1, the middle section W11 extends from Fig. 6 and Fig. The edge sections W12 extend longitudinally along the first direction F1 and along the second direction F2, and are arranged symmetrically with respect to the central section W11. The size of the edge sections W12 along the second direction F2 ranges from 0.1 mm to 0.3 mm, the size of the first central section W11a along the second direction F2 is 40 µm, and the size of the second central section W11b along the second direction F2 is 55 µm. The first central section W11a and the second central section W11b are arranged alternately along the second direction F2. The orthographic projection of the second solder point W2 on the cell base 110 is rectangular, and two second solder points W2 are provided.The two second solder points W2 are arranged symmetrically with respect to the center of the target region z0, and the first solder points W1a are provided on both sides of the second solder point W2 along the second direction F2. The distance between the two second solder points W2 along the second direction F2 is between 14 mm and 15 mm. The size of the second solder point W2 along the first direction F1 is 0.7 mm, and the size of the second solder point W2 along the second direction F2 is 0.3 mm. The orthographic projection of the third solder point W3 on cell base 110 is rectangular; the size of the third solder point W3 along the first direction F1 is 1 mm, and the size of the third solder point W3 along the second direction F2 is 0.6 mm.

[0139] Example 2 uses the example from Fig. 12. In contrast to Example 1, a second solder point W2 is provided, which is placed in the middle of the target region z0.

[0140] In example 3, using the example from Fig. 12, which differs from example 2, the size of the second middle section W11b along the second direction F2 is 50 µm.

[0141] In example 4, the solder joint structure is 130, as in Fig. 2 shown, provided on the target region z0 of the front of the cell base 110, and the solder joint structure 130, as in Fig. As shown in Figure 7, the target region z0 on the back side of cell base 110 is provided. The implementation of the in Fig. The solder joint structure shown in Figure 7 (130) may refer to Example 1.

[0142] Example 5 uses the example from Fig. 19 In contrast to Example 1, a connecting line 140a is provided which connects all solder joint structures 130 on the target region z0.

[0143] Example 6 uses the example from Fig. Example 1, which differs from example 2, does not provide a second solder point W2.

[0144] It is noted that in the embodiments of this application, the finger 120, the solder joint structure 130, the connecting line 140a, and the connecting section can all be formed on the cell base 110 by printing metal paste. The finger 120, the solder joint structure 130, the connecting line 140a, and the connecting section can be printed simultaneously over the same printing grid or separately over different printing grids, which is not specifically restricted here. It is understood that the grid structures on the printing grid are each adapted to the finger 120, the solder joint structure 130, the connecting line 140a, and the connecting section to be printed.

[0145] If multiple target regions z0 are provided, the solder joint structures 130 provided on the multiple target regions z0 can be the same or different. In embodiments such as in Fig. 1, Fig. 6, Fig. 18 and Fig. Figure 21 shows that the solder joint structures 130 are the same in all target regions z0. It is understood that if the solder joint structures 130 provided on the multiple target regions z0 are different, different solder joint structures 130 can be set up more flexibly according to different sections of the cell base 110, thereby improving the reliability of the overall structure.

[0146] Reference is made to Fig. Figure 23 shows a schematic structural view of a photovoltaic module 10 according to some embodiments of this application. One embodiment of this application provides a photovoltaic module 10 comprising the solar cell according to one of the above embodiments and a solder strip 200. The solder strip 200 is connected to the solder joint structures 130 and covers at least a section of the solder joint structure 130.

[0147] The photovoltaic module 10 comprises, for example, a cover plate 13, an encapsulation layer 12, and a cell string 11, wherein the cover plate 13 is connected to the cell string 11 via the encapsulation layer 12. The cell string 11 comprises several solar cells according to one of the above embodiments and a solder strip 200, and the several solar cells are connected by the solder strip 200. The encapsulation layer 12 is configured to cover an area of ​​the cell string 11. The cover plate 13 is configured to cover an area of ​​the encapsulation layer 12 facing away from the cell string 11.

[0148] The encapsulation layer 12 can, for example, be an organic encapsulation film such as an ethylene vinyl acetate copolymer film (EVA film), a polyethylene octene copolymer elastomer film (POE film) or a polyethylene terephthalate film (PET film).

[0149] For example, the cover plate 13 could be a glass cover plate, a plastic cover plate, or other cover plates with light transmission.

[0150] Each solar cell can be, for example, a whole cell or a split cell that is 1 / N of the whole cell; this is not specifically restricted here. If the solar cell is, for example, a split cell that makes up 1 / 4 of the whole cell, the above implementation with the third solder joint W3 is also advantageous for providing a bridging layer and reducing the risk of solder failures caused by the bridging layer.

[0151] The solar cell type is, for example, a zero-busbar cell (0BB cell). By completely removing the front busbar, the front of the solar cell can be fully exposed to sunlight, maximizing the light absorption area. This reduces optical losses and improves short-circuit current. At the same time, by retaining the finger and back electrode, the solar cell achieves high photoelectric conversion efficiency and low production costs.

[0152] The photovoltaic module 10 also exhibits the aforementioned advantages of solar cells, which will not be repeated here.

[0153] This invention relates to a solar cell. The solar cell comprises: a cell base with several first regions arranged along a first direction, wherein at least one of the several first regions is a target region; several fingers spaced apart along a second direction; and several solder joint structures connected to one of the several fingers, wherein the several solder joint structures are provided in the target region and arranged along the second direction; the several solder joint structures comprise a first solder joint, wherein the first solder joint comprises a central section and edge sections provided at both ends of the central section along the first direction; and the size of the central section along the second direction is smaller than the size of the edge section along the second direction.

Claims

[1] Solar cell, comprising: a cell base (110) defining several first regions (z1) arranged along a first direction (F1), wherein at least one of the several first regions (z1) is a target region (z0); several fingers (120) spaced apart along a second direction (F2); and several solder joint structures (130) connected to one of the several fingers (120), wherein the several solder joint structures (130) are placed in the target region (z0) and arranged along the second direction (F2), wherein the several solder joint structures (130) have a first solder joint (W1a), the first solder joint (W1a) has a middle section (W11) and edge sections (W12) provided at both ends of the middle section (W11) along the first direction (F1), and the size of the middle section (W11) along the second direction (F2) is smaller than the size of the edge section (W12) along the second direction (F2). [2] Solar cell according to claim 1, wherein the multiple solder joint structures (130) have multiple first solder joints (W1a) and in the target region (z0) have two middle sections (W11) of two adjacent first solder joints (W1a) of different sizes along the second direction (F2); or furthermore, have a connecting line (140a), wherein the connecting line (140a) connects at least one section of the multiple solder joint structures (130) in the target region (z0). [3] Solar cell according to claim 1 or 2, wherein the middle section (W11) extends linearly or in a curved manner from the initial end to the final end; or wherein a direction in which an initial end of the middle section (W11) points to a final end of the middle section (W11) is parallel to the first direction (F1); or the size of the middle section (W11) along the second direction (F2) is greater than a size of the finger (120) along the second direction (F2); where optionally along the second direction (F2) the ratio of the size of the middle section (W11) to the size of the finger (120) is in the range of 3 to 6; or the size of the middle section (W11) along the second direction (F2) is in the range of 40 µm to 55 µm. [4] Solar cell according to one of claims 1 to 3, wherein the edge section (W12) extends along the second direction (F2), a connection region is defined at a transition between the edge section (W12) and the middle section (W11), and the edge section (W12) is arranged symmetrically with respect to the connection region; wherein optionally the size of the edge section (W12) along the second direction (F2) is between 0.1 mm and 0.3 mm. [5] Solar cell according to one of claims 1 to 4, wherein the multiple solder joint structures (130) have a second solder joint (W2), a shape of the second solder joint (W2) differs from a shape of the first solder joint (W1a) and an area of ​​an orthographic projection of the first solder joint (W1a) on the cell base (110) is smaller than an area of ​​an orthographic projection of the second solder joint (W2) on the cell base (110). [6] Solar cell according to claim 5, wherein the multiple solder joint structures (130) have multiple second solder joints (W2) and the areas of two adjacent second solder joints (W2) differ along the second direction (F2); where optionally the target region (z0) has a central region and edge sections placed on both sides of the central region along the second direction (F2), wherein areas of orthographic projections of the multiple second solder joints (W2) on the cell base (110) are gradually increased from the central region to the edge sections; or wherein at least one first solder joint (W1a) is provided between two adjacent second solder joints (W2) along the second direction (F2), or the first solder joint (W1a) is provided on each of the two sides of the second solder joint (W2) along the second direction (F2). [7] Solar cell according to claim 5, wherein the multiple solder joint structures (130) have multiple second solder joints (W2) and the areas of the orthographic projections of the multiple second solder joints (W2) on the cell base (110) are the same; or wherein the multiple second solder joints (W2) are symmetrical with respect to a center of the target region (z0), or wherein the multiple second solder joints (W2) are placed in a central region of the target region (z0); or wherein the orthographic projection of the second solder joint (W2) on the cell base (110) is rectangular; or wherein a size of the second solder joint (W2) along the first direction (F1) is less than or equal to the size of the middle section (W11) along the first direction (F1); or wherein a size of the second solder joint (W2) along the first direction (F1) is greater than a size of the second solder joint (W2) along the second direction (F2). [8] Solar cell according to claim 5, wherein the multiple solder joint structures (130) have two third solder joints (W3) each located at both ends of the target region (z0) along the second direction (F2), wherein an area of ​​an orthographic projection of each third solder joint (W3) on the cell base (110) is larger than the area of ​​the orthographic projection of the second solder joint (W2) on the cell base (110); where optionally the ratio of the area of ​​the orthographic projection of the second solder joint (W2) on the cell base (110) to the area of ​​the orthographic projection of the third solder joint (W3) on the cell base (110) is in the range of 0.35 to 0.5; or wherein a size of the second solder joint (W2) along the first direction (F1) is smaller than a size of the third solder joint (W3) along the first direction (F1), and a size of the second solder joint (W2) along the second direction (F2) is smaller than a size of the third solder joint (W3) along the second direction (F2); or wherein a form of orthographic projection of the third solder joint (W3) on the cell base (110) is rectangular. [9] Solar cell according to one of claims 1 to 8, further comprising several transition connection sections (150), wherein the finger (120) connected to the first solder joint (W1a) has a plurality of subfingers (121) spaced apart along the first direction (F1), and two adjacent subfingers (121) along the first direction (F1) are each connected to both ends of the first solder joint (W1a) along the first direction (F1) in a one-to-one correspondence by two transition connection sections (150); where optionally, along the direction in which one end of the transition connecting section (150) connected to the first solder joint (W1a) points to another end of the transition connecting section (150) connected to the lower finger (121), the size of the transition connecting section (150) is gradually reduced along the second direction (F2). [10] Photovoltaic module (10) comprising the solar cell according to one of claims 1 to 9 and a solder strip (200), wherein the solder strip (200) is connected to several solder joint structures (130) and covers at least one section of the several solder joint structures (130).

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