Battery string and photovoltaic module

Abstract

The invention provides a battery string and a photovoltaic module, and belongs to the technical field of solar cells, the battery string comprises a battery piece, and at least one surface of the battery piece is provided with at least two joint parts which are arranged at intervals along a first direction; and an electrical connection line extending in a first direction; wherein a bonding layer is arranged on the surface, facing the battery piece, of the electric connecting wire, and the bonding part is electrically connected with the electric connecting wire through the bonding layer; a first spreading width of the bonding layer in a second direction perpendicular to the first direction on each bonding portion is larger than a second spreading width in the second direction at a gap between two adjacent bonding portions. The photovoltaic module includes at least one cell string.

Description

[0001] This application claims an application date of April 8, 2024, an application number of 2024207162580, and an invention name of priority for battery strings and photovoltaic modules. All the contents recorded in the prior application are cited in this application by reference. Technical Field

[0002] At least one embodiment of the present application relates to the field of photovoltaic technology, and in particular to a battery string and a photovoltaic module. Background Art

[0003] A secondary grid is formed on the surface of the solar cell, and part of the secondary grid is arranged into a multi-segment structure with gaps to accommodate electrical connection wires or electrical connection wires and the main grid to pass through the gaps and be connected to at least part of the secondary grid.

[0004] When solar cells are interconnected, the electrical connection wires are welded to the joints through the welding points formed by the bonding layer, so that different cells are connected in series to form a battery string. Since the cells will deform to a certain extent during welding, layout and lamination are required in subsequent processes to flatten the cells.

[0005] The lamination bonding layer will spread outwards under pressure. The larger the spreading range of the bonding layer forming the solder joint, the more conducive it is to maintaining the electrical connection between the electrical connection line and the bonding part and the reliability of anti-pullout. However, if the spreading width of the bonding layer located in the gap formed by the auxiliary grid, especially the spreading width along the gap direction, is too large, it may cause the electrical connection line to be connected to the auxiliary grids on both sides, thereby causing a short circuit or damage to the auxiliary grids on both sides. Summary of the invention

[0006] In view of this, in order to at least partially solve the above-mentioned technical problems, the present application provides a battery string and a photovoltaic module.

[0007] In order to achieve the above purpose, the technical solution of this application is as follows:

[0008] According to an embodiment of one aspect of the present application, a battery string is provided, comprising: a battery cell, at least one surface of the battery cell having at least two joints arranged at intervals along a first direction; and an electrical connection line extending along the first direction; wherein a surface of the electrical connection line facing the battery cell is provided with a bonding layer, and the bonding portion is electrically connected to the electrical connection line through the bonding layer; a first spreading width of the bonding layer along a second direction perpendicular to the first direction located on each bonding portion is greater than a second spreading width along the second direction located at the interval between two adjacent bonding portions.

[0009] According to an embodiment of another aspect of the present application, a photovoltaic assembly is provided, including at least one battery string.

[0010] According to the battery string and photovoltaic module provided by the above-mentioned embodiments of the present application, different parts of the bonding layer arranged on the electrical connection line are configured to have different spreading widths. The part of the bonding layer located between the electrical connection line and the bonding part is configured to have a first spreading width, and the part located between two adjacent bonding parts is configured to have a second spreading width. The larger first spreading width can make the electrical connection line and the bonding part have a greater tensile resistance to maintain the conductivity and stability between the electrical connection line and the bonding part. The smaller second spreading width can isolate the bonding layer from the electrodes on both sides of the battery cell to prevent the occurrence of short circuits or reduce damage to the electrodes on both sides. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present application, rather than limiting the present application.

[0012] Figure 1 A schematic top view of a cell string formed by back-contact solar cells provided in an embodiment of the present application;

[0013] Figure 2 for Figure 1 A schematic diagram of a partial structure of a battery string of the embodiment shown;

[0014] Figure 3A for Figure 2 A partial cross-sectional view of the embodiment shown along the line A1-A2;

[0015] Figure 3B for Figure 2 A partial cross-sectional view of the embodiment shown along the line B1-B2;

[0016] Figure 4 A schematic top view of a cell string formed by back-contact solar cells provided in another embodiment of the present application;

[0017] Figure 5 for Figure 4 A schematic diagram of a partial structure of a battery string of the embodiment shown;

[0018] Figure 6 for Figure 5 A partial cross-sectional view of the embodiment shown along the line B1-B2;

[0019] Figure 7 A partial cross-sectional view of a cross section of a battery string along a second direction provided in yet another embodiment of the present application;

[0020] Figure 8 A schematic top view of a cell string formed by a double-sided solar cell provided in an embodiment of the present application;

[0021] Fig. 9 for Figure 8 A schematic diagram of a partial structure of a battery string of the embodiment shown;

[0022] Fig. 10A for Fig. 9 A partial cross-sectional view of the embodiment shown along the line A1-A2;

[0023] Fig. 10B for Fig. 9 A partial cross-sectional view of the embodiment shown along the line B1-B2;

[0024] Fig.11 A schematic top view of a cell string formed by bifacial solar cells provided in another embodiment of the present application;

[0025] Fig.12 for Fig.11 A schematic diagram of a partial structure of a battery string of the embodiment shown;

[0026] Fig.13 for Fig.12 A partial cross-sectional view of the embodiment shown along the line B1-B2;

[0027] Fig.14 is a partial cross-sectional schematic diagram of a solar cell before packaging according to an embodiment of the present application; and

[0028] Fig.15 It is a partial cross-sectional schematic diagram of a solar cell after packaging according to an embodiment of the present application.

[0029] Description of reference numerals:

[0030] 1-Battery cell;

[0031] 2-Electrical connection wire;

[0032] 3- first electrode;

[0033] 4- second electrode;

[0034] 5-joining part;

[0035] 51- first joint portion;

[0036] 52- second joint portion;

[0037] 6-Connection part;

[0038] 7- third electrode;

[0039] 8-bonding layer;

[0040] 81-Part I;

[0041] 82-Part II;

[0042] 9- Frame; and

[0043] 91- protrusion;

[0044] 11- a first adhesive film;

[0045] 12- second adhesive film;

[0046] 13- first adhesive film;

[0047] 14- second adhesive film;

[0048] 15-cover plate;

[0049] 16- back plate;

[0050] 21- copper substrate;

[0051] 22- Solder. DETAILED DESCRIPTION

[0052] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0053] In the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present application. However, it is apparent that one or more embodiments may be implemented without these specific details. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concepts of the present application.

[0054] The terms used herein are only for describing specific embodiments and are not intended to limit the present application. The term "comprising" used herein indicates the existence of features, steps, operations, but does not exclude the existence or addition of one or more other features.

[0055] In the case of using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted in accordance with the meaning of the expression generally understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.). In the case of using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted in accordance with the meaning of the expression generally understood by those skilled in the art (for example, "a system having at least one of A, B, or C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0056] The relative position between two components (such as film layers or regions) mentioned in this application, such as "above", "upper" or "above", may refer to the direct contact between the two components, or may refer to the indirect contact between the two components. Similarly, the relative position between two components mentioned in this application, such as "below", "lower" or "below", may refer to the direct contact between the two components, or may refer to the indirect contact between the two components. For example, when one of the components (such as film layers or regions) is referred to as "on another component", it can be directly on the other component, or there may be other components between the two. On the other hand, when a component is referred to as "directly on another component", there is no component between the two. In addition, when one of the components is referred to as "on another component", the two have an up-and-down relationship in the top-view direction, and this component can be above or below the other component, so this up-and-down relationship depends on the orientation of the device.

[0057] In a back-contact solar cell, the positive electrode (also called the first electrode or the first auxiliary grid) and the negative electrode (also called the second electrode or the second auxiliary grid) are both arranged on the back of the cell. To this end, auxiliary grids of different polarities need to be arranged on different doping regions of the cell, and the auxiliary grids are arranged into a multi-segment structure with gaps to accommodate electrical connection wires or electrical connection wires and main grids passing through the gaps and connected to the auxiliary grids of corresponding polarities to collect the current collected by the auxiliary grids. The electrical connection wires are then welded to the joints (such as pads) of different back-contact solar cells to connect different back-contact solar cells in series, thereby forming a battery string.

[0058] In a bifacial solar cell, the first electrode and the second electrode are respectively arranged on the first surface and the second surface of the cell. The main grid is connected to the secondary grid of the same polarity to collect the current collected by the electrode. Then, the electrical connection wire is welded to the joints (such as pads) of different bifacial solar cells to connect different bifacial solar cells in series, thereby forming a battery string.

[0059] At present, the bonding layer (including but not limited to solder) used for welding the electrical connection wires and pads is often set point by point along the extension direction of the electrical connection wires according to the welding position through a welding gun or other welding equipment, waiting for welding. During welding, the battery cell will undergo a certain deformation. Therefore, the battery cell needs to be flattened through subsequent layout and lamination processes, and the bonding layer will spread out in all directions under the pressure.

[0060] Among them, the spreading width of the bonding layer along the gap formed by the auxiliary grid needs to be paid special attention to. If the width is too small, it will affect the conductivity and reliability between the bonding part and the electrical connection line; if the width is too large, it will cause the bonding layer located in the gap formed by the auxiliary grid to contact the auxiliary grids on both sides, thereby affecting the auxiliary grids on both sides.

[0061] Therefore, based on the same inventive concept, how to provide a battery string and a photovoltaic module that can maintain the electrical connection and pull-out reliability of the electrical connection wire and the joint while avoiding connection with the auxiliary grids on both sides has become a technical problem that needs to be solved urgently.

[0062] According to an exemplary embodiment of the present application, the present application provides a battery string and a photovoltaic module, the battery string comprising:

[0063] A battery cell, wherein at least one surface of the battery cell has at least two joints spaced apart along a first direction; and

[0064] An electrical connection line extending along a first direction;

[0065] In which, a bonding layer is provided on the surface of the electrical connection line facing the battery cell, and the bonding part is electrically connected to the electrical connection line through the bonding layer; the bonding layer is located on each bonding part, and the first spreading width along the second direction perpendicular to the first direction is greater than the second spreading width along the second direction at the interval between two adjacent bonding parts.

[0066] According to an embodiment of the present application, the type of solar cell may be a back contact solar cell, and the back contact solar cell includes but is not limited to any one of an interdigitated back contact solar cell (Interdigitated Back Contact, IBC), a hybrid BC (combined passivated BC), a low-temperature interdigitated back contact heterojunction solar cell (heterojunction back contact, HBC), a tunneling oxide passivated contact back contact solar cell (tunneling oxide passivated contact back contact, TBC), and a polycrystalline silicon oxide interdigitated back contact solar cell (polycrystalline silicon onoxide interdigitated back contact, POLO-IBC); it may also be a bifacial solar cell, for example, it may be a bifacial heterojunction (Heterojunction with Intrinsic Thin-layer, referred to as HJT) cell.

[0067] Figure 1 A schematic top view of a cell string formed by back-contact solar cells provided in an embodiment of the present application.

[0068] Figure 2 for Figure 1 A schematic diagram of the partial structure of a battery string of the embodiment shown.

[0069] According to an exemplary embodiment of the present application, the present application provides a cell string formed by a back contact solar cell, referring to Figure 1 , Figure 2 As shown, it includes a battery cell 1 and an electrical connection line 2. The battery cell 1 has a first surface and a second surface relative to each other, and the second surface of the battery cell 1 has at least two bonding portions 5 arranged at intervals along the first direction. The electrical connection line 2 extends along the first direction, is bonded to the surface of the battery cell 1, and is electrically connected to the at least two bonding portions 5. Among them, the surface of the electrical connection line 2 facing the battery cell 1 is provided with a bonding layer 8, and the bonding portion 5 is electrically connected to the electrical connection line 2 through the bonding layer 8; the first spreading width of the bonding layer 8 between the electrical connection line 2 and the bonding portion 5 along the second direction is greater than the second spreading width between two adjacent bonding portions 5 along the second direction, and the first direction is orthogonal to the second direction.

[0070] That is, a first spreading width of the bonding layer 8 on each bonding portion 5 along a second direction perpendicular to the first direction is greater than a second spreading width along the second direction at a space between two adjacent bonding portions 5 .

[0071] In an exemplary embodiment, the battery cell 1 includes but is not limited to a substantially rectangular structure ( Figure 2 Only a part of the battery cell 1 is shown in FIG. 1 ), including a first direction (such as Figure 2 The first side extending in the up-down direction shown in FIG. 1 and the second side extending in the up-down direction shown in FIG. Figure 2 The first side may be used as the long side of the battery cell 1, and the corresponding second side may be used as the short side of the battery cell. It should be understood that the embodiments of the present application are not limited thereto.

[0072] For example, the joint portion 5 includes but is not limited to being configured as a substantially rectangular shape with chamfers, a polygon, a circle, an ellipse, a racetrack shape, or any other shape suitable for connecting with the electrical connection line 2 (ie, the welding strip). For example, the joint portion 5 includes but is not limited to being a pad.

[0073] In an illustrative embodiment, Figure 1 to Figure 2 As shown, a plurality of joints 5 ( Figure 2 Further, the plurality of joints 5 are arranged along the first direction (eg Figure 2 The plurality of joints 5 may be arranged at equal intervals along the first direction; or at least a portion of the joints 5 may have different intervals from other joints 5 (for example, the joints 5 arranged in the middle of the battery cell 1 are arranged at equal intervals, while the joints 5 located at the edge of the battery cell 1 are arranged at different intervals from the adjacent joints 5).

[0074] Figure 3A for Figure 2 A partial cross-sectional view along line A1-A2 of the illustrated embodiment.

[0075] Figure 3B for Figure 2 A partial cross-sectional view taken along line B1 - B2 of the illustrated embodiment.

[0076] In an illustrative embodiment, Figure 3A and Figure 3B As shown, the surface of the electrical connection wire 2 (i.e., the welding strip) facing the battery cell 1 (i.e., Figure 3A and Figure 3B The lower surface shown in FIG. 1 is provided with a bonding layer 8. In detail, the bonding layer 8 includes but is not limited to solder (such as solder and / or other bonding materials).

[0077] In an illustrative embodiment, Figure 3A and Figure 3B As shown, the bonding layer 8 includes a first portion 81 disposed between the electrical connection line 2 (i.e., the welding strip) and the bonding portion 5, and a second portion 82 disposed between the electrical connection line 2 (i.e., the welding strip) and the battery cell 1. In detail, the first portion 81 extends along the second direction (i.e., Figure 3A The first spreading width (ie, d1) of the second portion 82 (ie, the left-right direction as shown) is configured to be greater than the second spreading width (ie, d3) of the second portion 82, ie, d1>d3.

[0078] In such an embodiment, by setting the first part 81 and the second part 82 of the bonding layer 8 to have different spreading widths, the bonding layer 8 can be adapted to the spreading width requirements of different positions on the battery cell 1. The first part 81 is used as a welding point for connecting the electrical connection line 2 (i.e., welding strip) to the bonding portion 5. The first spreading width is configured to be greater than the second spreading width. On the basis of providing good weldability, the larger spreading area of ​​the first part 81 can provide a greater pulling resistance for the electrical connection line 2 (i.e., welding strip), which is beneficial to improving the conductivity and stability between the electrical connection line 2 (i.e., welding strip) and the bonding portion 5; and the second part 82 with a smaller second spreading width is beneficial to isolating the electrical connection line 2 from the electrodes of different polarities of the battery cell 1 to avoid the occurrence of a short circuit.

[0079] According to the embodiments of the present application, Figure 3A and Figure 3B As shown, the ratio of the second spreading width to the first spreading width is configured to be 0.2 / 0.8~0.6 / 0.8, for example, it can be 0.2 / 0.8, 0.3 / 0.8, 0.4 / 0.8, 0.5 / 0.8, 0.6 / 0.8, but is not limited to the listed values.

[0080] In an illustrative embodiment, Figure 3A and Figure 3BAs shown, d3 / d1 includes but is not limited to being configured as 0.2 / 0.8 to 0.6 / 0.8. Further, the bonding layer 8 along the second direction (such as Figure 3A and Figure 3B The spreading width (including the first spreading width and the second spreading width) spread in the left and right directions (shown in FIG. 1 ) is positively correlated with the thickness of the configured bonding layer 8, that is, the thicker the bonding layer 8 is, the larger the spreading width after bonding. For this reason, the thickness of the bonding layer 8 needs to be limited.

[0081] For example, for an electrical connection line 2 configured with a width of 0.3mm~0.6mm, the thickness of the bonding layer 8 before bonding includes but is not limited to being configured as 0.01mm~0.05mm; based on the above thickness of the bonding layer 8, the thickness of the first part 81 of the bonding layer 8 after bonding can be maintained at 0.005mm~0.03mm.

[0082] According to the embodiments of the present application, Figure 1 to Figure 2 , Figure 3A~Figure 3B As shown, the battery cell 1 also includes a plurality of first electrodes 3 and a second electrode 4 extending along the second direction on the second surface. The plurality of first electrodes 3 and the plurality of second electrodes 4 are alternately arranged in sequence along the first direction, and the first electrode 3 is connected to the joint 5 or the electrical connection line 2.

[0083] According to the embodiments of the present application, Figure 1 to Figure 2 , Figure 3B As shown, at least a portion of the second electrodes 4 is discontinuous in the second direction and a disconnection portion is formed at the discontinuous position. The electrical connection line 2 passes through the disconnection portion, and the joint portion 5 extends into a portion of the disconnection portion.

[0084] According to the embodiments of the present application, Figure 1 to Figure 2 As shown, a part of the disconnected portion forms a first gap, another part of the disconnected portion forms a second gap, and the joint 5 is arranged in the disconnected portion forming the first gap. The width of the first gap is configured to be greater than the width of the second gap.

[0085] In an illustrative embodiment, Figure 1 and Figure 2 As shown, the first electrode 3 (i.e., the auxiliary grid having the same polarity as the joint 5) and the second electrode 4 (i.e., the auxiliary grid having a different polarity from the joint 5) are arranged on the back side of the battery cell 1 (i.e., Figure 1 In detail, the plurality of first electrodes 3 and the plurality of second electrodes 4 are arranged along a first direction (such as Figure 2 In the up and down directions shown in the figure, the doped regions are alternately arranged in sequence to form an interdigitated structure to adapt to the different doped regions (such as p+ doped regions and n+ doped regions) arranged in parallel and at intervals on the back side of the battery cell 1.

[0086] According to the embodiments of the present application, Figure 2 As shown, the battery string further includes a connecting portion 6 extending along the second direction, and the connecting portion 6 connects the joining portion 5 and a portion of the first electrode 3 .

[0087] In an illustrative embodiment, Figure 2 As shown, the distal end of the connecting portion 6 away from the joint portion 5 (i.e. Figure 2 The width of the left end of the connecting portion 6 located on the left side, and the right end of the connecting portion 6 located on the right end) is configured to be smaller than the width of the proximal end near the joint 5 (the right end of the connecting portion located on the left side, and the left end of the connecting portion located on the right end) (i.e. Figure 2 The distance between the upper end and the lower end of the connecting portion 6 shown).

[0088] For example, the connection portion 6 may be arranged in a substantially triangular structure;

[0089] For example, the shape of the connection portion 6 is a triangle whose cross section gradually decreases from an end close to the joint portion 5 to an end far from the joint portion 5 .

[0090] For another example, the connecting portion 6 may be configured to be a substantially trapezoidal structure.

[0091] For example, the shape of the connection portion 6 is a trapezoid whose cross section gradually decreases from an end close to the joint portion 5 to an end far from the joint portion 5 .

[0092] In such an embodiment, the proximal end of the connecting portion 6 is arranged to be wider, which increases the width of the connecting portion between the first electrode 3 and the joint 5, which can prevent the connecting portion between the first electrode 3 and the joint 5 from being melted and prevent current concentration, which is beneficial to improving the current collection effect.

[0093] In an illustrative embodiment, Figure 1 and Figure 2 As shown, each second electrode 4 (ie, a secondary grid having a different polarity from the junction 5) has a second direction (eg Figure 2 In detail, a disconnection portion is formed between two adjacent electrode segments.

[0094] According to the embodiments of the present application, Figure 2 , Figure 3B As shown, the battery string further includes a third electrode 7 extending along the first direction on the second surface, the third electrode 7 passes through part of the disconnected portion and connects at least two adjacent joints 5. The portion of the joint layer 8 located between the third electrode 7 and the electrical connection line 2 is configured to have a second spreading width.

[0095] In an illustrative embodiment, Figure 2 As shown, the third electrode 7 (i.e., the main grid) is connected along the first direction (such as Figure 2A plurality of joints 5 are evenly spaced apart in the vertical direction (shown in FIG. 1 ). In detail, the joint 5 includes but is not limited to a structure configured to be substantially strip-shaped.

[0096] In an illustrative embodiment, Figure 2 and Figure 3B As shown, the third electrode 7 (i.e., the main grid) is arranged along the first direction (eg Figure 2 In detail, the third electrode 7 (i.e., the main grid) passes through the disconnected portion formed by the second electrode 4 of different polarity and is connected to the first electrode 3 of the same polarity. Further, the bonding layer 8 covers the third electrode 7 (i.e., the main grid).

[0097] In an illustrative embodiment, Figure 3A and Figure 3B As shown, the first spreading width (i.e., d1) of the first portion 81 is configured to be smaller than the width (i.e., d2) of the joint portion 5, and the width (i.e., d3) of the second portion 82 is configured to be smaller than the width (i.e., d4) of the disconnection portion formed by the second electrode 4. That is, d2>d1, d4>d3, and d1>d3.

[0098] In an illustrative embodiment, the electrode segments of the second electrode 4 located on both sides of the joint 5 form a first gap, and the second electrode 4 located on both sides of the third electrode 7 forms a second gap. The width of the first gap (i.e., L1) is configured to be greater than the width of the joint 5, the width of the second gap (i.e., L2) is configured to be greater than the width of the electrical connection line 2, and the width of the first gap is configured to be greater than the width of the second gap (i.e., L1>L2).

[0099] In such an embodiment, the disconnecting portion provided on the second electrode 4 is adapted to the width of the third electrode 7 and the joint portion 5 to configure gaps of different widths (i.e., the first gap and the second gap), which can more effectively maintain the isolation between the second electrode 4 and the third electrode 7 and / or the joint portion 5 of different polarities to avoid the occurrence of a short circuit.

[0100] In an illustrative embodiment, Figure 3A As shown, the width of the joint 5 (ie, d2) includes, but is not limited to, being configured to be 1.2 mm to 1.3 mm. Accordingly, the width of the third electrode 7 (ie, the main grid) includes, but is not limited to, being configured to be 50 μm to 90 μm.

[0101] Due to the precision limitation of the welding gun and / or other welding equipment, it is inevitable that the bonding layer 8 will be offset from the center line of the electrical connection line 2 (that is, in the orthographic projection in the thickness direction of the battery cell 1, the center line of the bonding layer 8 is offset from the center line of the electrical connection line 2 along the first direction), so that at least a part of the bonding layer 8 contacts the passivation layer on the surface of the battery cell 1 (for example, the bonding layer 8 is offset relative to the electrical connection line 2 in the first direction). Figure 3AThe left side offset shown in the figure results in the left end of the bonding layer 8 being located on the passivation layer). The passivation layer includes an oxide layer formed on the surface of the cell 1 to prevent the surface of the cell 1 from being corroded and damaged by the external environment. The passivation material forming the passivation layer includes but is not limited to Al2O3.

[0102] Based on the above-mentioned size configuration, the deviation of the bonding layer 8 caused by the equipment accuracy can be compensated, that is, when the bonding layer 8 is offset relative to the center line of the electrical connection line 2 (i.e., the welding strip), the bonding layer 8 is also prevented from contacting the second electrode 4 in the offset direction.

[0103] Figure 4 A schematic top view of a cell string formed by back-contact solar cells provided in accordance with another embodiment of the present application shows a back-contact solar cell without a main grid.

[0104] Figure 5 for Figure 4 A schematic diagram of the partial structure of a battery string of the embodiment shown.

[0105] Figure 6 for Figure 5 A partial cross-sectional view taken along line B1 - B2 of the illustrated embodiment.

[0106] In another exemplary embodiment, Figure 4-Figure 6 As shown, the first electrode 3 is directly connected to the electrical connection line 2, so that the current collected by the first electrode 3 is directly collected through the electrical connection line 2. In this way, the screen design of the printed electrode is simplified, and the paste (such as silver) used for printing the third electrode 7 (i.e., the main grid) is omitted.

[0107] According to an embodiment of the present application, the bonding portion 5 includes a first bonding portion 51 and a second bonding portion 52 , wherein along the first direction, the first bonding portion 51 is distributed near the edge of the battery cell 1 , and the size of the first bonding portion 51 is larger than that of the second bonding portion 52 .

[0108] According to the embodiment of the present application, the area of ​​the first joint portion 51 is larger than the area of ​​the second joint portion 52. The first joint portion 51 is distributed near the edge of the battery cell 1. The edge of the silicon wafer is the starting point and the end point of welding and is subjected to the greatest pull-out force. By setting the area of ​​the first joint portion 51 larger, a greater pull-out resistance is provided between the electrical connection line 2 and the first joint portion 51 to maintain the stability of the electrical connection line 2 and the first joint portion 51.

[0109] According to the embodiment of the present application, the width of the first joint portion 51 along the first direction is greater than the width of the second joint portion 52 along the first direction, and the length of the first joint portion 51 along the second direction is equal to or slightly less than the length of the second joint portion 52 along the second direction. The second joint portion 53 has a smaller width, which can ensure electrical interconnection with electrical connection wires at multiple positions and reduce the contact resistance between the joint portion and the electrical connection wire.

[0110] For example, refer to Figure 4 As shown, the bonding portion 5 includes a first bonding portion (i.e., a large pad) 51 located at the edge of the battery cell and a second bonding portion (i.e., a small pad) 52 located inside the battery cell, and the width of the second bonding portion 52 along the second direction is smaller than the width of the first bonding portion 51 along the second direction.

[0111] Figure 7 A partial cross-sectional view of a battery string along a second direction provided in yet another embodiment of the present application.

[0112] According to the embodiments of the present application, Figure 7 As shown, the battery string also includes a frame 9, which is arranged on the portion of the battery cell 1 located outside the joint 5, and a protrusion 91 is formed on the side of the frame 9 facing the joint 5, and the protrusion 91 is crimped to the first surface of the joint 5 facing away from the battery cell 1.

[0113] According to the embodiments of the present application, Figure 7 As shown, the distance between two protrusions 91 of the surrounding frame 9 facing each other along the second direction is greater than the width of the electrical connection line 2 .

[0114] According to the embodiments of the present application, Figure 7 As shown, the bonding layer (not shown in the figure) and the tin layer of the electrical connection line 2 are melted into one.

[0115] In an illustrative embodiment, Figure 7 As shown in FIG. 1 , the frame 9 is arranged on the battery cell 1 outside the joint 5 in response to the shape of the joint 5. In detail, the frame 9 is as follows: Figure 7 The upper portion shown in the figure is formed with a protruding portion 91 protruding toward one side of the joint portion 5 so that the surrounding frame 9 Figure 7 The cross section shown in FIG. 1 forms a cross-sectional structure similar to an "L-shape". Further, the protrusion 91 presses against the first surface of the joint 5 (ie, Figure 7 The upper surface shown in FIG. 1 ) is formed on the outer surface of the battery cell 1, thereby limiting the joint 5 between the frame 9 and the battery cell 1. The frame 9 includes but is not limited to being made of aluminum.

[0116] In an illustrative embodiment, the surrounding frame 9 of the joint portion 5 adapted to be configured as a rectangle is also configured as a substantially rectangular frame structure. It should be understood that the embodiments of the present application are not limited thereto.

[0117] The surrounding frame 9 may also be configured as a frame structure having a shape different from the outer shape of the joint portion 5. For example, the surrounding frame 9 may form an intermittent structure that half surrounds or abuts against a portion of the edge of the joint portion 5.

[0118] Figure 8 A schematic top view of a cell string formed by double-sided solar cells provided in an embodiment of the present application.

[0119] Fig. 9 for Figure 8 A schematic diagram of the partial structure of a battery string of the embodiment shown.

[0120] Fig. 10A for Fig. 9 A partial cross-sectional view along line A1-A2 of the illustrated embodiment.

[0121] Fig. 10B for Fig. 9 A partial cross-sectional view taken along line B1 - B2 of the illustrated embodiment.

[0122] According to an exemplary embodiment of the present application, the present application provides a battery string formed by a double-sided solar cell, such as Figure 8 , Fig. 9 As shown, it includes a battery cell 1 and an electrical connection line 2. The battery cell 1 has a first surface and a second surface relative to each other, and the first surface and / or the second surface has at least two bonding portions 5 arranged at intervals along the first direction. The electrical connection line 2 extends along the first direction, is bonded to the surface of the battery cell 1, and is electrically connected to the at least two bonding portions 5. Among them, the surface of the electrical connection line 2 facing the battery cell 1 is provided with a bonding layer 8, and the bonding portion 5 is electrically connected to the electrical connection line 2 through the bonding layer 8; the first spreading width of the bonding layer 8 between the electrical connection line 2 and the bonding portion 5 along the second direction perpendicular to the first direction is greater than the second spreading width between two adjacent bonding portions 5 along the second direction.

[0123] According to the embodiments of the present application, Fig. 10A , Fig. 10B As shown, the ratio of the second spreading width to the first spreading width is configured to be 0.2 / 0.8~0.6 / 0.8, for example, it can be 0.2 / 0.8, 0.3 / 0.8, 0.4 / 0.8, 0.5 / 0.8, 0.6 / 0.8, but is not limited to the listed values.

[0124] According to an embodiment of the present application, the battery cell 1 also includes a plurality of first electrodes 3 extending along the second direction on the first surface, the first electrodes 3 being connected to the joining portion 5 or the electrical connection line 2; and a plurality of second electrodes 4 extending along the second direction on the second surface, wherein the second electrodes 4 are connected to the joining portion 5 or the electrical connection line 2.

[0125] According to the embodiments of the present application, Figure 8 , Fig. 9 As shown, the cell string formed by the bifacial solar cells also includes a third electrode 7 extending along the first direction and located on the first surface and / or the second surface of the cell 1, and the third electrode 7 connects at least two adjacent joints 5; the portion of the bonding layer 8 located between the third electrode 7 and the electrical connection line 2 is configured to have a second spreading width.

[0126] According to an embodiment of the present application, in a bifacial solar cell, the portion of the bonding layer between the electrical connection line and the bonding portion is configured as a first spreading width, and the portion between two adjacent bonding portions is configured as a second spreading width. A larger first spreading width can provide a larger tensile strength between the electrical connection line and the bonding portion to maintain the conductivity and stability between the electrical connection line and the bonding portion; a smaller second spreading width can reduce the contact resistance between the electrical connection line and the electrodes on both sides, and can reduce damage to the electrodes on both sides.

[0127] Fig.11 A schematic top view of a cell string formed by bifacial solar cells provided in another embodiment of the present application.

[0128] Fig.12 for Fig.11 A schematic diagram of the partial structure of a battery string of the embodiment shown.

[0129] Fig.13 for Fig.12 A partial cross-sectional view taken along line B1 - B2 of the illustrated embodiment.

[0130] In another exemplary embodiment, Figure 11-13 As shown, the first electrode 3 and / or the second electrode 4 are directly connected to the electrical connection line 2, so that the current collected by the first electrode 3 and / or the second electrode 4 is directly collected through the electrical connection line 2. In this way, the screen design of the printed electrode is simplified, and the paste (such as silver) used for printing the third electrode 7 (i.e., the main grid) is omitted.

[0131] According to an embodiment of the present application, the battery string further comprises at least one adhesive film, which is suitable for covering the electrical connection wire 2 and at least a portion of the battery cell 1. The electrical connection wire 2 is fixed to the battery cell 1 by covering the adhesive film on the electrical connection wire 2.

[0132] Fig.14 It is a partial cross-sectional schematic diagram of a solar cell before packaging according to an embodiment of the present application.

[0133] Fig.15 It is a partial cross-sectional schematic diagram of a solar cell after packaging according to an embodiment of the present application.

[0134] like Fig.14As shown, electrical connection lines 2 are formed on the first surface and the second surface of the battery cell 1, respectively. The electrical connection lines 2 on the first surface are covered with a first adhesive film 11, and the electrical connection lines 2 on the second surface are covered with a second adhesive film 12. The first adhesive film 13 is covered on the cover plate 15, and the second adhesive film 14 is covered on the back plate 16.

[0135] like Fig.14 , Fig.15 As shown, the first adhesive film 11 and the first adhesive film 13 are bonded together, the second adhesive film 12 and the second adhesive film 14 are bonded together, and are placed in a heating chamber for lamination. The electrical connection line 2 is composed of a copper substrate 21 and a solder 22. The solder 22 is melted in the heating chamber to interconnect the secondary grid on the surface of the battery cell 1 with the electrical connection line 2; the first adhesive film 11 and the first adhesive film 13 are bonded together to connect the battery cell 1 and the cover plate 15, and the second adhesive film 12 and the second adhesive film 14 are bonded together to connect the battery cell 1 and the back plate 16.

[0136] A photovoltaic assembly provided in the present application, which is not shown in the figure, includes at least one battery string.

[0137] In an illustrative embodiment, not shown in the figure, the photovoltaic module includes a plurality of battery strings. Specifically, the plurality of battery strings are arranged at intervals. Further, the plurality of back-contact batteries in each battery string are arranged along a column. The electrical connection wires interconnect the battery cells in the same battery string.

[0138] The ordinal numbers used in the specification and claims, such as "first", "second", "third", etc., to modify the corresponding elements, do not themselves mean that the elements have any ordinal numbers, nor do they represent the order of one element and another element, or the order in the manufacturing method. The use of these ordinal numbers is only used to clearly distinguish a component with a certain name from another component with the same name.

[0139] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A battery string, characterized in that: include: A battery cell (1), wherein at least one surface of the battery cell (1) has at least two joint portions (5) arranged at intervals along a first direction; as well as An electrical connection line (2) extending along the first direction; Wherein, a bonding layer (8) is provided on a surface of the electrical connection line (2) facing the battery cell (1), and the bonding portion (5) is electrically connected to the electrical connection line (2) via the bonding layer (8); A first spreading width of the bonding layer (8) located on each bonding portion (5) along a second direction perpendicular to the first direction is greater than a second spreading width located at a gap between two adjacent bonding portions (5) along the second direction.

2. The battery string according to claim 1, characterized in that: The ratio of the second spreading width to the first spreading width is configured to be 0.2 / 0.8~0.6 / 0.

8.

3. The battery string according to claim 1, characterized in that: The battery cell (1) has a first surface and a second surface opposite to each other. The battery cell further comprises a plurality of first electrodes (3) and second electrodes (4) extending along the second direction on the second surface, the plurality of first electrodes (3) and the plurality of second electrodes (4) being arranged alternately and spaced in sequence along the first direction, and the first electrodes (3) being connected to the joint portion (5) or the electrical connection line (2).

4. The battery string according to claim 3, characterized in that: At least a portion of the second electrode (4) forms a disconnection portion in the second direction; The electrical connection line (2) passes through the disconnected portion, and the joint portion (5) extends into part of the disconnected portion.

5. The battery string according to claim 4, characterized in that: It also includes a third electrode (7) extending along the first direction, the third electrode (7) passing through part of the disconnected portion and connecting at least two adjacent joined portions (5); The portion of the bonding layer (8) located between the third electrode (7) and the electrical connection line (2) is configured to have the second spreading width.

6. The battery string according to claim 1, characterized in that: The battery cell (1) has a first surface and a second surface that are opposite to each other; The battery cell further comprises a plurality of first electrodes (3) extending along the second direction on the first surface, the first electrodes (3) being electrically connected to the joint portion (5) or the electrical connection line (2); as well as A plurality of second electrodes (4) extending along the second direction on the second surface, wherein the second electrodes (4) are electrically connected to the joining portion (5) or the electrical connection line (2).

7. The battery string according to claim 6, characterized in that: It also includes a third electrode (7) located on the first surface and / or the second surface and extending along the first direction, the third electrode (7) connecting at least two adjacent joining portions (5); The portion of the bonding layer (8) located between the third electrode (7) and the electrical connection line (2) is configured to have the second spreading width.

8. The battery string according to claim 1, characterized in that: The joining portion (5) comprises a first joining portion (51) and a second joining portion (52), Wherein, along the first direction, the first joining portion (51) is distributed close to the edge of the battery cell (1), and the size of the first joining portion (51) is larger than the size of the second joining portion (52).

9. The battery string according to claim 1, characterized in that: Also includes: At least one adhesive film is suitable for covering the electrical connection line (2) and at least a portion of the battery cell (1).

10. A photovoltaic module, characterized in that: Comprising at least one battery string as claimed in any one of claims 1 to 9.

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