Battery string, photovoltaic module and electric connection structure

Abstract

The utility model discloses a battery string, a photovoltaic assembly and an electric connection structure. The battery string can comprise a plurality of back contact battery pieces and electric connection structures, and every two adjacent back contact battery pieces are electrically connected through the electric connection structures; the electric connection structure comprises connection parts and bending buffer parts which are alternately arranged, and the bending direction of the bending buffer parts is parallel to the main surface of the back contact battery piece. And after the connecting part is welded and connected to the main grid line of the back contact battery piece, the connecting part stretches and bends the buffer part so as to eliminate the warping stress of the connecting part to the back contact battery piece. The battery string structure can prevent the back contact battery pieces in the battery string from warping so as to improve the reliability of the photovoltaic module comprising the battery string.

Description

Technical Field

[0001] This utility model relates to a battery string, a photovoltaic module, and an electrical connection structure. Background Technology

[0002] Back-contact solar cells, with their grids entirely on the back side, offer better photoelectric conversion efficiency and a more elegant appearance, giving them a strong competitive advantage in the photovoltaic market. However, this back-contact structure, where the grids are entirely on the back, can cause cell warping when connecting back-contact solar cells in series with solder ribbons or when cells are cut from back-contact solar cells. For example, as... Figure 1 As shown, after connecting the back contact solar cells 11 in series using existing solder ribbons 50 to form a solar cell string, the existing solder ribbons 50 cause the back contact solar cells 11 to warp towards the direction of the existing solder ribbons 50 (i.e., the back side of the back contact solar cell 11). This is because both the existing solder ribbons 50 and the back contact solar cells 11 will heat up and expand during the welding process, and then cool down and shrink after welding. Since the coefficients of expansion of the existing solder ribbons 50 and the back contact solar cells 11 are different, they will expand to different degrees during welding (the solder ribbons expand more). After welding, the existing solder ribbons 50 will cool down and shrink more, causing the back contact solar cells 11 to warp. Warped back contact solar cells 11 are prone to microcracks in subsequent lamination processes, leading to reduced reliability of the photovoltaic module. Utility Model Content

[0003] In view of this, the present invention provides a battery string, a photovoltaic module, and an electrical connection structure. For the battery string, after the connecting part of the electrical connection structure is welded to the main grid line of the back contact cell, the bending buffer part of the electrical connection structure will be stretched, which can eliminate the warping stress of the connecting part on the back contact cell, thereby avoiding warping of the back contact cell in the battery string and improving the reliability of the photovoltaic module containing the battery string.

[0004] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0005] In a first aspect, embodiments of the present invention provide a battery string, comprising: a plurality of back-contact battery cells and an electrical connection structure, wherein...

[0006] Each pair of adjacent back contact cells is electrically connected through the electrical connection structure.

[0007] The electrical connection structure includes: alternating connecting portions and bending buffer portions, wherein the bending direction of the bending buffer portions is parallel to the main surface of the back contact battery cell;

[0008] After the connecting part is welded to the main grid line of the back contact cell, the connecting part stretches the bending buffer part to eliminate the warping stress of the connecting part on the back contact cell.

[0009] Secondly, embodiments of the present invention provide a photovoltaic module, which may include:

[0010] Cover plate;

[0011] Encapsulating film;

[0012] Back panel;

[0013] And one or more battery strings provided in the first aspect embodiments described above.

[0014] Thirdly, embodiments of this utility model provide an electrical connection structure for electrically connecting every two adjacent back-contact battery cells in a battery string. The electrical connection structure includes alternating connecting portions and bending buffer portions, wherein...

[0015] The bending direction of the bending buffer is parallel to the main surface of the back contact battery cell of the electrical connection structure.

[0016] After the connecting part is welded to the main grid line of the back contact cell, the connecting part stretches the bending buffer part to eliminate the warping stress of the connecting part on the back contact cell.

[0017] The first aspect of the above-mentioned utility model has the following advantages or beneficial effects:

[0018] The battery string provided in this embodiment of the utility model has an alternating arrangement of connecting parts and bending buffer parts in its electrical connection structure. After the connecting parts are welded to the main grid line of the back contact cell, there is no connection between the bending buffer part and the main grid line. The connecting parts stretch and bend the buffer part, which can eliminate the warping stress on the back contact cell caused by the cooling and shrinkage of the connecting parts. This avoids the back contact cell in the battery string from warping, reduces the risk of back contact cell cracking, and improves the reliability of the photovoltaic module containing the battery string.

[0019] In addition, since the bending direction of the bending buffer is parallel to the main surface of the back contact cell, on the one hand, the precision requirements of the bending buffer can be reduced. Even if the bending buffer is still bent in the final cell string, the production process window of the cell string can be wider, reducing the process precision, difficulty and complexity of the cell string. On the other hand, in the subsequent process of assembling the cell string into a photovoltaic module, even if the bending buffer is still bent, it will not cause pressure or lamination stress on the back contact cell, reducing the risk of lamination cracking and improving the reliability of the photovoltaic module. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the main structure of a battery string with back contact cells, based on existing technology.

[0021] Figure 2 This is a partial structural schematic diagram of a battery string provided according to an embodiment of the present utility model;

[0022] Figure 3 This is a schematic diagram showing the relationship between the back contact battery cells, main grid lines and electrical connection structures in a battery string according to an embodiment of the present invention.

[0023] Figure 4 This is a schematic diagram of the electrical connection structure before welding to the back contact battery cell according to an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the electrical connection structure after welding and connecting with the back contact battery cell according to an embodiment of the present utility model;

[0025] Figure 6 This is a schematic diagram of the electrical connection structure formed by the punching plate according to the embodiments of the present utility model;

[0026] Figure 7 This is a schematic diagram of a first type of electrical connection structure formed by the first split structure and the second split structure according to the embodiments of the present utility model;

[0027] Figure 8 This is a schematic diagram of a second type of electrical connection structure formed by the first split structure and the second split structure provided in the embodiments of this utility model;

[0028] Figure 9 This is a cross-sectional structural schematic diagram of the electrical connection structure provided according to an embodiment of the present utility model;

[0029] Figure 10 This is a cross-sectional structural diagram of a photovoltaic module provided according to an embodiment of the present utility model.

[0030] The attached figures are labeled as follows:

[0031] 10-Battery string; 11-Back contact cell; 111-Main grid line; 1111-First conductive grid line segment; 1112-Second conductive grid line segment; 12-Electrical connection structure; 121-Connecting part; 122-Bending buffer part; 123-First split structure; 1231-First connector; 1232-First bending part; 124-Second split structure; 1241-Second connector; 1242-Second bending part; 125-Conductive substrate; 126-Tin plating film layer; 12'-Stamping plate; 20-Cover plate; 30-Encapsulating film; 40-Back plate; 50-Existing solder strip. Detailed Implementation

[0032] The battery string 10 involved in this embodiment generally refers to a string structure formed by connecting multiple back-contact battery cells 11 (which can be back-contact solar cells or cells cut from back-contact solar cells). The battery string 10 can be formed by connecting each back-contact battery cell 11 in series. Alternatively, the battery string 10 may also include multiple sub-battery strings, where each back-contact battery cell 11 within a sub-battery string is connected in series, and adjacent sub-battery strings are connected in parallel. For example, the battery string 10 includes two sub-battery strings, where each back-contact battery cell 11 is connected in series, and the two sub-battery strings are connected in parallel.

[0033] The back contact battery cell 11 addressed in this embodiment is generally a back contact battery cell 11 with a main grid line 111. The main grid line 111 is arranged perpendicularly to the fine grid lines of the back contact battery cell 11. One main grid line 111 is connected to multiple fine grid lines of the same polarity. That is, the extension direction of the connecting portion 121 of the electrical connection structure 12 is parallel to the main grid line 111 and perpendicular to the fine grid lines. Alternatively, for back contact battery cells without a main grid line 111, each fine grid line can also be connected through the electrical connection structure 12 provided by this invention, but the connecting portion 121 of the electrical connection structure 12 needs to be perpendicular to the fine grid lines.

[0034] The specific structure of the battery string connected to the main grid line 111 by the electrical connection structure 12 provided in this embodiment of the present invention will be described in detail below.

[0035] in, Figure 2 This is a partial structural schematic diagram of a battery string provided according to an embodiment of the present utility model; Figure 3 This is a schematic diagram showing the relationship between the back contact battery cells, main grid lines and electrical connection structures in a battery string according to an embodiment of the present invention. Figure 4 and Figure 5 These are schematic diagrams of the electrical connection structure before and after welding connection with the back contact battery cell, according to embodiments of the present invention. Figure 6This is a schematic diagram of the electrical connection structure formed by the punching plate according to the embodiments of the present utility model; Figure 7 and Figure 8 These are schematic diagrams of different electrical connection structures provided according to embodiments of the present utility model. Figure 9 This is a cross-sectional structural schematic diagram of the electrical connection structure provided according to an embodiment of the present utility model; Figure 10 This is a cross-sectional structural diagram of a photovoltaic module provided according to an embodiment of the present utility model.

[0036] Specifically, such as Figure 2 As shown, the battery string 10 provided in this embodiment of the present invention may include: a plurality of back contact battery cells 11 and an electrical connection structure 12, wherein each pair of adjacent back contact battery cells 11 are electrically connected through the electrical connection structure 12 to realize that adjacent back contact battery cells 11 are connected in series or adjacent back contact battery cells 11 are connected in parallel.

[0037] Among them, such as Figures 2 to 8 As shown, the electrical connection structure 12 may include alternating connecting portions 121 and bending buffer portions 122, the bending direction of which is parallel to the main surface of the back contact battery cell 11. By limiting the bending direction of the bending buffer portion 122 to be parallel to the main surface of the back contact battery cell 11, even if the bending buffer portion 122 remains bent, it will not generate stress that compresses the back contact battery cell 11, thus avoiding microcracks or cracks in the back contact battery cell 11.

[0038] More specifically, after the connecting portion 121 is welded to the main grid line 111 of the back contact cell 11, the connecting portion 121 is stretched and bent to create a buffer portion 122 to eliminate the warping stress of the connecting portion 121 on the back contact cell 11. For example, as... Figure 3 As shown, after the connecting portion 121 is welded to the main grid line 111 of the back contact cell 11, during the shrinkage process of the connecting portion 121, both ends of each connecting portion 121 shrink towards the middle. At this time, both ends of each connecting portion 121 will generate opposite forces F1 and F2 in the direction of extension of the connecting portion 121 to the bending buffer portion 122 to which it is connected. Therefore, for a bending buffer portion 122, it simultaneously bears two opposite forces F1 and F2. These opposite forces F1 and F2 will stretch the bending buffer portion 122 to compensate for the shrinkage defect caused by the shrinkage of the connecting portion 121, thereby avoiding the warping of the back contact cell 11 caused by the shrinkage of the connecting portion 121. For example, as Figure 4 The electrical connection structure 12 shown before welding is such that, after welding, the bending buffer portion 122 is less bent due to the stretching and bending of the connection portion 121, resulting in the following: Figure 5The electrical connection structure 12 after welding is shown. It is worth noting that after welding, the bending buffer portion 122 can be completely stretched into a line segment structure, so that the connecting portion 121 and the bending buffer portion 122 included in the electrical connection structure 12 after welding form a straight line.

[0039] Therefore, the battery string provided by this utility model has an alternating connection portion 121 and a bending buffer portion 122 in its electrical connection structure 12. After the connection portion 121 is welded to the main grid line 111 of the back contact cell 11, there is no connection between the bending buffer portion 122 and the main grid line 111. The connection portion stretches the bending buffer portion 122, which can eliminate the warping stress on the back contact cell 11 caused by the cooling and shrinkage of the connection portion 121. This avoids the back contact cell 11 in the battery string 10 from warping, reduces the risk of the back contact cell 11 cracking, and improves the reliability of the photovoltaic module containing the battery string 10.

[0040] Furthermore, since the bending direction of the bending buffer portion 122 is parallel to the main surface of the back contact cell 11, on the one hand, the precision requirements of the bending buffer portion 122 can be reduced. Even if the bending buffer portion 122 is still in a bent state in the final formed cell string, the production process window of the cell string 10 can be wider, reducing the process precision, difficulty and complexity of the cell string 10. On the other hand, in the subsequent process of assembling the cell string 10 into a photovoltaic module, even if the bending buffer portion 122 is still in a bent state, it will not cause pressure or lamination stress on the back contact cell 11, reducing the risk of lamination cracking and improving the reliability of the photovoltaic module.

[0041] Furthermore, such as Figure 3 As shown, the main grid line 111 of the back contact battery cell 11 in the battery string provided by this utility model generally includes alternating first conductive grid line segments 1111 and second conductive grid line segments 1112, with adjacent first conductive grid line segments 1111 and second conductive grid line segments 1112 connected together; the connecting part 121 corresponds to the first conductive grid line segment 1111, and the bending buffer part 122 corresponds to the second conductive grid line segment 1112; the connecting part 121 is welded to the first conductive grid line segment 1111.

[0042] The first conductive grid segment 1111 can be formed using a paste capable of withstanding high welding temperatures, while the second conductive grid segment 1112 can be formed using a paste that does not require high welding temperatures. For example, the first conductive grid segment 1111 can be formed using a silver-containing paste, and the second conductive grid segment 1112 can be formed using a copper-containing paste. Generally, pastes capable of withstanding high welding temperatures are often more expensive. By alternating the first conductive grid segment 1111 and the second conductive grid segment 1112, the cost of the back contact cell 11 can be effectively reduced, thereby effectively controlling the production cost of the cell string 10 and the photovoltaic module.

[0043] The first conductive grid segment 1111 and the second conductive grid segment 1112 are welded together through the connecting part 121. The first conductive grid segment 1111 and the second conductive grid segment 1112 collect current. The current collected by the first conductive grid segment 1111 is transmitted to the connecting part 121 through the first conductive grid segment 1111, and the current collected by the second conductive grid segment 1112 is transmitted to the connecting part 121 through the first conductive grid segment 1111, thereby realizing the transmission of the current generated by the back contact battery cell 11 through the electrical connection structure 12.

[0044] As can be seen from the above, in the battery string provided by this utility model, the structure of the electrical connection structure 12 directly affects the warping of the back contact battery cell 11. Therefore, the electrical connection structure 12 in the battery string of this utility model will be described in detail below.

[0045] Specifically, such as Figures 2 to 10 As shown, the connecting part 121 is a line segment structure that covers the main gate line 111 and is welded to the main gate line 111. The line segment structure and the bending buffer part 122 are an integral structure. Through this line segment structure, the welding connection between the connecting part 121 and the main gate line 111 or the first conductive gate line segment 1111 can be established relatively well, and the reliability of the welding connection can be improved.

[0046] Regarding the bending buffer section 122, in addition to... Figure 2 In addition to the curved line segments pointing in one direction shown, there can also be... Figures 3 to 8 As shown, the bending buffer section 122 is an axisymmetric frame structure, wherein the frame structure is parallel to the main surface of the back contact cell 11, and the projection of the axis of symmetry of the frame structure onto the back contact cell 11 overlaps with the main grid line 111. This frame structure can be any axisymmetric frame structure such as a circular frame, a rectangular frame, an isosceles trapezoidal frame, or a rhombus frame.

[0047] Studies have found that if the bending buffer portion 122 bends in one direction, resulting in an asymmetrical structure, the force exerted on the connecting portion 121 will be unbalanced, greatly increasing the risk of the connecting portion 121 detaching. The embodiment provided by this invention, by using an axisymmetric frame structure for the bending buffer portion 122, ensures that the bending buffer portion 122 provides a more balanced force to the connecting portion 121, reducing the risk of the connecting portion 121 detaching.

[0048] Furthermore, such as Figure 4 As shown, in the direction parallel to the main surface of the back contact cell 11, the frame width W2 of the frame structure is generally one-third to one-half of the width W1 of the connecting portion 121. Preferably, the frame width W2 of the frame structure is generally half the width W1 of the connecting portion 121. This frame width W2 can ensure a stable connection between the bending buffer portion 122 and the connecting portion 121 while reducing the material consumption of the bending buffer portion 122, thereby effectively controlling the cost of the electrical connection structure 12. In addition, by controlling the frame width W2 of the frame structure, the flexibility of the frame structure is increased, making it easier to stretch and deform, further reducing the risk of warping of the back contact cell 11.

[0049] Among them, the bending buffer portion 122 and the connecting portion 121 of the electrical connection structure 12, such as Figure 6 As shown, an electrical connection structure 12 can be formed by a punching plate 12'.

[0050] In addition, such as Figure 7 and Figure 8 As shown, the electrical connection structure 12 may include: a first split structure 123 and a second split structure 124 that are axially symmetrical; wherein the projection of the axis of symmetry of the first split structure 123 and the second split structure 124 onto the back contact cell 11 overlaps with the main busbar 111.

[0051] Furthermore, such as Figure 7 and Figure 8 As shown, the first split structure 123 may include: alternating first connectors 1231 and first bending members 1232; the second split structure 124 may include: alternating second connectors 1241 and second bending members 1242; the first connectors 1231 and the second connectors 1241 correspond to each other and are spliced ​​together to form a connecting part 121; the first bending members 1232 and the second bending members 1242 correspond to each other and are spliced ​​together to form a bending buffer part 122.

[0052] Since the width of the first split structure 123 and the second split structure 124 is smaller than the width of the electrical connection structure 12, the electrical connection structure 12 can be formed by splicing the first split structure 123 and the second split structure 124, which can reduce the restrictions on the specifications of raw materials and reduce the cost of the electrical connection structure 12.

[0053] Additionally, in the electrical connection structure 12, such as Figure 4 As shown, the spacing L2 between any two adjacent connecting portions 121 is generally 5mm to 20mm. For example, the spacing L2 between any two adjacent connecting portions 121 can be 5mm, 10mm, 15mm, or 20mm, etc. By controlling the spacing L2 between any two adjacent connecting portions 121, the reliability of the connection between the electrical connection structure 12 and the main grid line 111 can be ensured.

[0054] Furthermore, such as Figure 4 As shown, the length L1 of the connecting portion 121 in the main grid line extension direction is generally 5mm to 20mm. For example, the length L1 of the connecting portion 121 in the main grid line extension direction can be 5mm, 10mm, 15mm, or 20mm, etc. By controlling the length L1 of the connecting portion 121 in the main grid line extension direction, the reliability of the connection between the electrical connection structure 12 and the main grid line 111 can be further improved.

[0055] More specifically, such as Figure 4 As shown, the width W1 of the connecting portion 121 is generally 0.3mm to 1.0mm. For example, the width W1 of the connecting portion 121 can be 0.3mm, 0.6mm, or 1.0mm, etc. By controlling the width W1 of the connecting portion 121, the positioning between the connecting portion 121 and the main grid line 111 can be facilitated, and the current collection capability of the connecting portion 121 can be guaranteed.

[0056] Furthermore, such as Figure 3 As shown, the thickness T of the connection portion 121 is generally 0.1 mm to 0.3 mm. For example, the thickness T of the connection portion 121 can be 0.1 mm, 0.2 mm, or 0.3 mm, etc. By controlling the thickness T of the connection portion 121, the current collection capability of the connection portion 121 can be further improved.

[0057] In addition, such as Figure 9 As shown, the connection structure 12 may include a conductive substrate 125 and a tin-plated film layer 126 encapsulating the conductive substrate 125. This tin-plated film layer 126 can improve the reliability of the solder connection between the connection portion 121 and the main gate line 111. The substrate may be phosphor bronze, beryllium bronze, or oxygen-free copper, etc., and the tin layer may be tin-lead, tin-lead-bismuth, tin-bismuth-silver, or tin-silver-copper, etc.

[0058] The thickness of the tin-plated film layer 126 is generally 5μm to 25μm. For example, the thickness of the tin-plated film layer 126 can be 5μm, 8μm, 10μm, 12μm, 15μm, 17μm, 20μm, 22μm, or 25μm, etc. By controlling the thickness of the tin-plated film layer 126, the reliability of the solder connection between the connector 121 and the main gate line 111 can be further improved.

[0059] Furthermore, this embodiment of the invention also provides a photovoltaic module. For example... Figure 10 As shown, the photovoltaic module may include:

[0060] Cover plate 20;

[0061] 30mm encapsulating film;

[0062] Back panel 40;

[0063] And one or more battery strings 10 provided in any of the above embodiments.

[0064] Because the photovoltaic module uses the battery string 10 provided in any of the above embodiments, which does not have warping of the back contact cell 11, a balanced force is generated at each position of the back contact cell 11 during the photovoltaic module lamination process. The use of the battery string 10 effectively reduces the risk of microcracks or cracks in the back contact cell 11 during the lamination process, thereby improving the reliability and yield of the photovoltaic module.

[0065] Furthermore, this embodiment of the invention also provides an electrical connection structure 12. This electrical connection structure 12 is used to electrically connect every two adjacent back-contact battery cells 11 included in the battery string 10. Specifically, as... Figures 2 to 8 As shown, the electrical connection structure 12 may include: alternating connecting portions 121 and bending buffer portions 122, wherein the bending direction of the bending buffer portions 122 is parallel to the main surface of the back contact battery cell 11 to which the electrical connection structure 12 is electrically connected; after the connecting portions 121 are welded to the main grid lines 111 of the back contact battery cell 11, the connecting portions 121 stretch the bending buffer portions 122 to eliminate the warping stress of the connecting portions 121 on the back contact battery cell 11.

[0066] For example, such as Figure 3 As shown, after the connecting portion 121 is welded to the main grid line 111 of the back contact cell 11, during the shrinkage process of the connecting portion 121, both ends of each connecting portion 121 shrink towards the middle. At this time, both ends of each connecting portion 121 will generate opposite forces F1 and F2 in the direction of extension of the connecting portion 121 to the bending buffer portion 122 to which it is connected. Therefore, for a bending buffer portion 122, it simultaneously bears two opposite forces F1 and F2. These opposite forces F1 and F2 will stretch the bending buffer portion 122 to compensate for the shrinkage defect caused by the shrinkage of the connecting portion 121, thereby avoiding the warping of the back contact cell 11 caused by the shrinkage of the connecting portion 121. For example, as Figure 4 The electrical connection structure 12 shown before welding is such that, after welding, the bending buffer portion 122 is less bent due to the stretching and bending of the connection portion 121, resulting in the following: Figure 5The electrical connection structure 12 after welding is shown. It is worth noting that after welding, the bending buffer portion 122 can be completely stretched into a line segment structure, so that the connecting portion 121 and the bending buffer portion 122 included in the electrical connection structure 12 after welding form a straight line.

[0067] Regarding the bending buffer section 122, in addition to... Figure 2 In addition to the curved line segments pointing in one direction shown, there can also be... Figures 3 to 8 As shown, the bending buffer section 122 is an axisymmetric frame structure, wherein the frame structure is parallel to the main surface of the back contact cell 11, and the projection of the axis of symmetry of the frame structure onto the back contact cell 11 overlaps with the main grid line 111. This frame structure can be any axisymmetric frame structure such as a circular frame, a rectangular frame, an isosceles trapezoidal frame, or a rhombus frame.

[0068] Furthermore, such as Figure 4 As shown, in the direction parallel to the main surface of the back contact cell 11, the frame width W2 of the frame structure is generally one-third to one-half of the width W1 of the connecting portion 121. Preferably, the frame width W2 of the frame structure is generally half the width W1 of the connecting portion 121. This frame width W2 can ensure a stable connection between the bending buffer portion 122 and the connecting portion 121 while also reducing the amount of material used in the bending buffer portion 122, thereby effectively controlling the cost of the electrical connection structure 12.

[0069] Among them, the bending buffer portion 122 and the connecting portion 121 of the electrical connection structure 12, such as Figure 6 As shown, an electrical connection structure 12 can be formed by a punching plate 12'.

[0070] In addition, such as Figure 7 and Figure 8 As shown, the electrical connection structure 12 may include: a first split structure 123 and a second split structure 124 that are axially symmetrical; wherein the projection of the axis of symmetry of the first split structure 123 and the second split structure 124 onto the back contact cell 11 overlaps with the main busbar 111.

[0071] Furthermore, such as Figure 7 and Figure 8 As shown, the first split structure 123 may include: alternating first connectors 1231 and first bending members 1232; the second split structure 124 may include: alternating second connectors 1241 and second bending members 1242; the first connectors 1231 and the second connectors 1241 correspond to each other and are spliced ​​together to form a connecting part 121; the first bending members 1232 and the second bending members 1242 correspond to each other and are spliced ​​together to form a bending buffer part 122.

[0072] Since the width of the first split structure 123 and the second split structure 124 is smaller than the width of the electrical connection structure 12, the electrical connection structure 12 can be formed by splicing the first split structure 123 and the second split structure 124, which can reduce the restrictions on the specifications of raw materials and reduce the cost of the electrical connection structure 12.

[0073] Additionally, in the electrical connection structure 12, such as Figure 4 As shown, the spacing L2 between any two adjacent connecting portions 121 is generally 5mm to 20mm. For example, the spacing L2 between any two adjacent connecting portions 121 can be 5mm, 10mm, 15mm, or 20mm, etc. By controlling the spacing L2 between any two adjacent connecting portions 121, the reliability of the connection between the electrical connection structure 12 and the main grid line 111 can be ensured.

[0074] Furthermore, such as Figure 4 As shown, the length L1 of the connecting portion 121 in the main grid line extension direction is generally 5mm to 20mm. For example, the length L1 of the connecting portion 121 in the main grid line extension direction can be 5mm, 10mm, 15mm, or 20mm, etc. By controlling the length L1 of the connecting portion 121 in the main grid line extension direction, the reliability of the connection between the electrical connection structure 12 and the main grid line 111 can be further improved.

[0075] More specifically, such as Figure 4 As shown, the width W1 of the connecting portion 121 is generally 0.3mm to 1.0mm. For example, the width W1 of the connecting portion 121 can be 0.3mm, 0.6mm, or 1.0mm, etc. By controlling the width W1 of the connecting portion 121, the positioning between the connecting portion 121 and the main grid line 111 can be facilitated, and the current collection capability of the connecting portion 121 can be guaranteed.

[0076] Furthermore, such as Figure 3 As shown, the thickness T of the connection portion 121 is generally 0.1 mm to 0.3 mm. For example, the thickness T of the connection portion 121 can be 0.1 mm, 0.2 mm, or 0.3 mm, etc. By controlling the thickness T of the connection portion 121, the current collection capability of the connection portion 121 can be further improved.

[0077] In addition, such as Figure 9 As shown, the connection structure 12 may include a conductive substrate 125 and a tin-plated film layer 126 covering the conductive substrate 125. The tin-plated film layer 126 can improve the reliability of the solder connection between the connection portion 121 and the main gate line 111.

[0078] The thickness of the tin-plated film layer 126 is generally 5μm to 25μm. For example, the thickness of the tin-plated film layer 126 can be 5μm, 8μm, 10μm, 12μm, 15μm, 17μm, 20μm, 22μm, or 25μm, etc. By controlling the thickness of the tin-plated film layer 126, the reliability of the solder connection between the connector 121 and the main gate line 111 can be further improved.

[0079] In summary, this utility model provides the following technical solution:

[0080] Technical Solution 1: A battery string, comprising: multiple back-contact battery cells 11 and an electrical connection structure 12, wherein,

[0081] Each pair of adjacent back contact battery cells 11 are electrically connected through the electrical connection structure 12;

[0082] The electrical connection structure 12 includes: alternating connecting portions 121 and bending buffer portions 122, wherein the bending direction of the bending buffer portions 122 is parallel to the main surface of the back contact battery cell 11;

[0083] After the connecting part 121 is welded to the main grid line 111 of the back contact cell 11, the connecting part 121 stretches the bending buffer part 122 to eliminate the warping stress of the connecting part 121 on the back contact cell 11.

[0084] Technical Solution 2: The battery string as described in Technical Solution 1,

[0085] The bending buffer section 122 is an axisymmetric frame structure, wherein the frame structure is parallel to the main surface of the back contact battery cell 11, and the projection of the axis of symmetry of the frame structure onto the back contact battery cell 11 overlaps with the main grid line 111.

[0086] Technical solution 3: The battery string according to technical solution 1 or 2,

[0087] The connecting part 121 is a line segment structure that covers the main grid line 111 and is welded to the main grid line 111. The line segment structure and the bending buffer part 122 are an integral structure.

[0088] Technical solution 4: The battery string according to technical solution 2.

[0089] In a direction parallel to the main surface of the back contact cell 11, the frame width of the frame structure is one-third to one-half the width of the connecting portion 121.

[0090] Technical Solution 5: According to the battery string described in Technical Solution 2, the electrical connection structure 12 includes: a first split structure 123 and a second split structure 124 that are axially symmetrical; wherein,

[0091] The projections of the axes of symmetry of the first split structure 123 and the second split structure 124 onto the back contact cell 11 overlap with the main grid line 111.

[0092] Technical solution 6: The battery string according to technical solution 5,

[0093] The first split structure 123 includes: alternating first connectors 1231 and first bending members 1232;

[0094] The second split structure 124 includes: alternating second connectors 1241 and second bending members 1242;

[0095] The first connector 1231 corresponds to the second connector 1241 and is spliced ​​together to form the connecting part 121;

[0096] The first bending member 1232 corresponds to the second bending member 1242 and is spliced ​​together to form the bending buffer part 122.

[0097] Technical solution 7: The battery string according to any one of technical solutions 1, 2, and 4 to 6.

[0098] In the electrical connection structure 12, the spacing between any two adjacent connection portions 121 is 5mm to 20mm;

[0099] And / or,

[0100] The length of the connecting part 121 in the direction of extension of the main grid line is 5mm to 20mm;

[0101] And / or,

[0102] The width of the connecting portion 121 is 0.3mm to 1.0mm;

[0103] And / or,

[0104] The thickness of the connecting part 121 is 0.1mm to 0.3mm.

[0105] Technical Solution 8: According to any of Technical Solutions 1, 2, and 4 to 6, the main grid line 111 includes alternating first conductive grid line segments 1111 and second conductive grid line segments 1112.

[0106] The adjacent first conductive gate segment 1111 and the second conductive gate segment 1112 are connected;

[0107] The connecting portion 121 corresponds to the first conductive gate segment 1111, and the bending buffer portion 122 corresponds to the second conductive gate segment 1112;

[0108] The connecting part 121 is welded to the first conductive grid line segment 1111.

[0109] Technical solution 9: The battery string according to any one of technical solutions 1, 2, and 4 to 6.

[0110] The connection structure 12 includes: a conductive substrate 125 and a tin-plated film layer 126 that encapsulates the conductive substrate 125.

[0111] Technical solution 10: The battery string according to technical solution 9,

[0112] The thickness of the tin-plated film layer 126 is 5μm to 25μm.

[0113] Technical Solution 11: A photovoltaic module, comprising:

[0114] Cover plate 20;

[0115] 30mm encapsulating film;

[0116] Back panel 40;

[0117] And, the battery string 10 described in any one of the technical solutions 1 to 10.

[0118] Technical solution 12: An electrical connection structure 12 for electrically connecting every two adjacent back-contact battery cells 11 in a battery string 10, wherein the electrical connection structure 12 includes: alternately arranged connecting portions 121 and bending buffer portions 122, wherein...

[0119] The bending direction of the bending buffer portion 122 is parallel to the main surface of the back contact battery cell 11 electrically connected to the electrical connection structure 12.

[0120] After the connecting part 121 is welded to the main grid line 111 of the back contact cell 11, the connecting part 121 stretches the bending buffer part 122 to eliminate the warping stress of the connecting part 121 on the back contact cell 11.

[0121] The above steps are provided only to help understand the method, structure, and core idea of ​​this utility model. For those skilled in the art, various improvements and modifications can be made to this utility model without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of this utility model.

Claims

1. A battery string, characterized in that, include: Multiple back-contact battery cells (11) and an electrical connection structure (12), wherein, Each pair of adjacent back contact battery cells (11) are electrically connected through the electrical connection structure (12); The electrical connection structure (12) includes: alternating connecting portions (121) and bending buffer portions (122), wherein the bending direction of the bending buffer portions (122) is parallel to the main surface of the back contact battery cell (11); After the connecting part (121) is welded to the main grid line (111) of the back contact cell (11), the connecting part (121) stretches the bending buffer part (122) to eliminate the warping stress of the connecting part (121) on the back contact cell (11).

2. The battery string according to claim 1, characterized in that, The bending buffer section (122) is an axisymmetric frame structure, wherein the frame structure is parallel to the main surface of the back contact battery cell (11), and the projection of the axis of symmetry of the frame structure onto the back contact battery cell (11) overlaps with the main grid line (111).

3. The battery string according to claim 1 or 2, characterized in that, The connecting part (121) is a line segment structure that covers the main grid line (111) and is welded to the main grid line (111). The line segment structure and the bending buffer part (122) are an integral structure.

4. The battery string according to claim 2, characterized in that, In a direction parallel to the main surface of the back contact cell (11), the frame width of the frame structure is one-third to one-half the width of the connecting part (121).

5. The battery string according to claim 2, characterized in that, The electrical connection structure (12) includes: a first split structure (123) and a second split structure (124) that are axially symmetrical; wherein, The projection of the axis of symmetry of the first split structure (123) and the second split structure (124) onto the back contact cell (11) overlaps with the main grid line (111).

6. The battery string according to claim 5, characterized in that, The first split structure (123) includes: alternating first connecting members (1231) and first bending members (1232); The second split structure (124) includes: alternating second connectors (1241) and second bending members (1242); The first connector (1231) corresponds to the second connector (1241) and is spliced ​​together to form the connecting part (121); The first bending member (1232) corresponds to the second bending member (1242) and is spliced ​​together to form the bending buffer part (122).

7. The battery string according to any one of claims 1, 2, and 4 to 6, characterized in that, In the electrical connection structure (12), the spacing between any two adjacent connection portions (121) is 5 mm to 20 mm; And / or, The length of the connecting part (121) in the direction of extension of the main grid line is 5mm to 20mm; And / or, The width of the connecting part (121) is 0.3mm to 1.0mm; And / or, The thickness of the connecting part (121) is 0.1 mm to 0.3 mm.

8. The battery string according to any one of claims 1, 2, and 4 to 6, characterized in that, The main gate line (111) includes alternating first conductive gate line segments (1111) and second conductive gate line segments (1112). The adjacent first conductive gate segment (1111) and second conductive gate segment (1112) are connected; The connecting portion (121) corresponds to the first conductive gate segment (1111), and the bending buffer portion (122) corresponds to the second conductive gate segment (1112); The connecting part (121) is welded to the first conductive grid line segment (1111).

9. The battery string according to any one of claims 1, 2, and 4 to 6, characterized in that, The connection structure (12) includes a conductive substrate (125) and a tin-plated film layer (126) that encapsulates the conductive substrate (125).

10. The battery string according to claim 9, characterized in that, The thickness of the tin-plated film layer (126) is 5μm to 25μm.

11. A photovoltaic module, characterized in that, include: Cover plate (20); Encapsulating film (30); Back panel (40); And one or more battery strings (10) according to any one of claims 1 to 10.

12. An electrical connection structure (12), characterized in that, For electrically connecting each two adjacent back-contact battery cells (11) of the battery string (10), the electrical connection structure (12) includes: alternating connecting portions (121) and bending buffer portions (122), wherein, The bending direction of the bending buffer section (122) is parallel to the main surface of the back contact battery cell (11) electrically connected to the electrical connection structure (12); After the connecting part (121) is welded to the main grid line (111) of the back contact cell (11), the connecting part (121) stretches the bending buffer part (122) to eliminate the warping stress of the connecting part (121) on the back contact cell (11).

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