Back contact cell string and photovoltaic module

Abstract

The utility model discloses a back contact cell string and a photovoltaic assembly, the back contact cell string comprises a back contact cell sheet, and the back surface of the back contact cell sheet is provided with first fine grids and second fine grids which are sequentially and alternately arranged; a first solder strip and a second solder strip, the first solder strip covers or partially covers the first fine grid, and the second solder strip covers or partially covers the second fine grid; welding layers are arranged at the positions, making contact with the first welding strips, of the first fine grids and the positions, making contact with the second welding strips, of the second fine grids. The welding layer comprises a conductive connecting layer and an adhesive layer, and the adhesive layer covers the conductive connecting layer. According to the utility model, the welding strip has better welding tension, and the welding quality of the welding strip is good.

Description

TECHNICAL FIELD

[0001] The utility model relates to solar cell technical field especially relates to a back contact cell string and photovoltaic module. BACKGROUND

[0002] The photoelectric current of the back contact cell string is generally collected from the cell piece base to the fine grid, is transmitted to the main grid through the fine grid horizontally, is transmitted to the solder strip vertically, and is finally transmitted out of the cell piece through the solder strip, the current path is complex, and loss is increased. SUMMARY

[0003] The utility model provides a back contact cell string, and the solder strip has good welding tension.

[0004] The utility model also provides a photovoltaic module, and the yield is high.

[0005] In order to solve the above problem, the utility model discloses a back contact cell string, including back contact cell piece, the back surface of back contact cell piece has the first fine grid and second fine grid along the first direction alternately arranged;

[0006] First solder strip and second solder strip, the first solder strip and second solder strip along the first direction alternately arranged, the first solder strip covers or partially covers the first fine grid, and the second solder strip covers or partially covers the second fine grid;

[0007] Wherein, the position of the first fine grid and the second solder strip contact, the position of the second fine grid and the first solder strip contact are all equipped with welding layer;The welding layer includes conductive connection layer and adhesive layer, and the adhesive layer covers the conductive connection layer.

[0008] As the improvement of the above technical scheme, the width of the adhesive layer is greater than or equal to the width of the first solder strip and / or second solder strip.

[0009] As the improvement of the above technical scheme, the conductive connection layer is one or more of conductive adhesive layer, conductive paste layer and tin paste layer.

[0010] As the improvement of the above technical scheme, the insulating layer is arranged between the adjacent first fine grid and second fine grid, and the first solder strip and the second solder strip are insulated and isolated through the insulating layer.

[0011] As the improvement of the above technical scheme, the height of the insulation layer is D1, the height of the welding layer is D2, and D1>D2.

[0012] As the improvement of the above technical scheme, the D1 is 10-150 μm, and the D2 is 10-80 μm.

[0013] As the improvement of the above technical scheme, the width of the insulation layer is L1, and the distance between the adjacent first and second solder strips is L2, and L1

[0014] As the improvement of the above technical scheme, the L1 and L2 satisfy the following relationship: 0.2*L2≤L1≤0.8*L2.

[0015] As the improvement of the above technical scheme, the insulation layer is continuously or discontinuously arranged between the adjacent first and second gate lines.

[0016] As the improvement of the above technical scheme, the insulation layer comprises a straight portion and a bending portion, the bending portion is arranged at one end of the straight portion, and the bending portion covers one end of the first or second fine gate.

[0017] As the improvement of the above technical scheme, the conductive connection layer is continuously or discontinuously arranged on the first or second fine gate.

[0018] As the improvement of the above technical scheme, the adhesive layer is continuously or discontinuously arranged on the conductive connection layer.

[0019] As the improvement of the above technical scheme, the cross-sectional shape of the first and second solder strips is one of a circle, a triangle, a rectangle and a trapezoid.

[0020] Correspondingly, the utility model discloses a photovoltaic module, including above-mentioned back contact cell string.

[0021] The utility model discloses a back contact cell string, which has the following beneficial effects: the solder strip of the back contact cell string covers the corresponding fine gate, the photo-generated current vertically reaches the solder strip from the inside of the cell sheet, there is no horizontal transmission process, and the resistance loss is small; the solder strip is connected with the fine gate through the welding layer, the welding layer comprises a conductive connection layer and an adhesive layer, the adhesive layer assists in improving the welding tensile force of the solder strip and the cell sheet, ensures the welding reliability of the solder strip, reduces the occurrence of welding quality problems such as false welding and delamination, and further improves the long-term reliability of the photovoltaic module. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is the cross-sectional structure schematic view of a back contact cell piece in the back contact cell string provided by the utility model;

[0023] Figure 2It is the back structure schematic view of one back contact battery piece in the back contact battery string provided by the embodiment 1 of the utility model;

[0024] Figure 3 It is the back structure schematic view of one back contact battery piece in the back contact battery string provided by the embodiment 2 of the utility model;

[0025] Figure 4 It is Figure 1 The enlarged view of A part of it;

[0026] Figure 5 It is the back structure schematic view of the back contact battery string provided by the embodiment 1 of the utility model;

[0027] Figure 6 It is the back structure schematic view of the back contact battery string provided by the embodiment 3 of the utility model;

[0028] Figure 7 It is the insulating glue setting schematic view of one back contact battery piece in the back contact battery string provided by the embodiment 3 of the utility model. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantage of the utility model more clear, the utility model is described further in detail below.

[0030] As Figure 1 And Figure 2 The utility model embodiment provides a back contact battery string, including back contact battery 1, the back of back contact battery 1 has the first thin grid 11 and second thin grid 12 that are arranged alternately and interval in proper order,

[0031] First solder strip 21 and second solder strip 22, first solder strip 21 covers or partially covers first thin grid 11, and second solder strip 22 covers or partially covers second thin grid 12,

[0032] Wherein, the position of first thin grid 11 and second solder strip 22 contact, the position of second thin grid 12 and first solder strip 21 contact are all equipped with welding layer 3, and welding layer 3 includes conductive connection layer 31 and adhesive layer 32, and adhesive layer 32 covers conductive connection layer 31.Adhesive layer covers conductive connection layer, and adhesive layer can provide tensile force in each direction to solder strip, improves the welding tensile force of solder strip, and guarantees the welding stability of solder strip.

[0033] The soldering ribbons of the back-contact cell strings of this utility model are overlaid on the corresponding fine grids. Photogenerated current flows vertically from the interior of the cell to the soldering ribbons, eliminating any lateral transmission process and minimizing resistance losses. Furthermore, the soldering ribbons are connected to the fine grids via a soldering layer, which includes a conductive connection layer and an adhesive layer. The adhesive layer helps increase the tensile strength of the soldering ribbon to the cell, ensuring soldering reliability and reducing the occurrence of welding quality issues such as cold joints and desoldering, thereby improving the long-term reliability of the photovoltaic module.

[0034] like Figures 2 to 4 As shown, in a preferred embodiment, the width of the adhesive layer 32 is greater than or equal to the width of the first soldering ribbon 21 and / or the second soldering ribbon 22, further improving the soldering tension of the soldering ribbons. Specifically, the conductive connection layer is one or more of a conductive adhesive layer, a conductive paste layer, and a solder paste layer. Specifically, the conductive adhesive layer can be made of a colloid material filled with conductive particles, the conductive paste layer can be made of silver paste, and the solder paste layer can be made of a tin-lead alloy, a tin-lead-silver alloy, or a tin-lead-bismuth-silicon alloy. The adhesive layer can be an insulating thermosetting adhesive layer and / or a UV adhesive layer.

[0035] To ensure electrical isolation between the fine grids of different polarities, prevent current leakage and short circuits, and guarantee battery safety and reliability, an insulating layer 4 is provided between the adjacent first fine grids 11 and second fine grids 12. The first welding ribbon 21 and the second welding ribbon 22 are insulated and isolated by the insulating layer 4. Specifically, the height of the insulating layer 4 is greater than the height of the welding layer 3. If the height of the insulating layer 4 is less than or equal to the height of the welding layer 3, the welding layer 3 may melt and flow due to heat during welding, potentially causing the welding layer 3 on the first fine grid 11 to contact the welding layer 3 on the second fine grid 12, thereby resulting in a short circuit.

[0036] In a preferred embodiment, the height H1 of the insulating layer is 10 μm to 150 μm, and is exemplarily, but not limited to, 20 μm, 40 μm, 60 μm, 100 μm, or 140 μm. If the height of the insulating layer is too small, good insulation performance cannot be achieved; if the thickness of the insulating layer is too large, costs increase. The height H2 of the solder layer is 10 μm to 80 μm, and is exemplarily, but not limited to, 20 μm, 40 μm, 50 μm, 60 μm, or 70 μm.

[0037] It is understood that the insulating layer does not contact the first welding strip 21 and the second welding strip 22. That is, the width of the insulating layer 4 is L1, and the distance between adjacent first welding strips 21 and second welding strips 22 is L2, where L1<L2. In a preferred embodiment, L1 and L2 satisfy the following relationship: 0.2*L2≤L1≤0.8*L2.

[0038] It can be understood that the shape of the insulating layer is not limited, such as Figure 2 and Figure 3 The insulating layer can be continuously or discontinuously arranged between adjacent first and second fine grids, as shown. If the insulating layer is continuously arranged, the insulating layer can be a strip-shaped insulating layer arranged parallel to the fine grid, or an irregularly shaped insulating layer. If the insulating layer is discontinuously arranged, the insulating layer can include a plurality of discontinuously arranged insulating blocks, and the shape of the insulating block can be rectangular, circular, etc.

[0039] In the production process of photovoltaic modules, it is necessary to connect a plurality of back contact cells, as shown in Figure 5 Two adjacent back contact cells can be directly connected by a solder strip. Specifically, in a back contact cell string, a plurality of back contact cells 1 are arranged in a first direction. It can be understood that the two adjacent back contact cells 1 can be arranged with a spacing, abutting or with an edge portion overlapping, and the specific arrangement mode is selected according to the actual situation. In an embodiment, the first direction can be the transverse direction or the longitudinal direction of the back contact cell 1. In the back contact cell string, a first solder strip 21 and a second solder strip 22 are placed on the two adjacent back contact cells 1, the first solder strip 21 and the second solder strip 22 are arranged alternately in the first direction, one end of the first solder strip 21 is in contact with the first fine grid 11 of one back contact cell 1 through the soldering layer 3, and the other end is in contact with the second fine grid 12 of the adjacent other back contact cell 1 through the soldering layer 3. Correspondingly, one end of the second solder strip 22 is in contact with the second fine grid 12 of one back contact cell 1 through the soldering layer 3, and the other end is in contact with the first fine grid 11 of the adjacent other back contact cell 1 through the soldering layer 3.

[0040] In another embodiment, as shown in Figure 6 Two adjacent back contact cells are connected by a bus bar on the basis of the solder strip connection, which improves the current collection efficiency. Specifically, a first solder strip 21 and a second solder strip 22 are placed on the two adjacent back contact cells 1, respectively, the first solder strip 21 and the second solder strip 22 are arranged alternately in the first direction, the first solder strip 21 is in contact with the first fine grid 11 of the back contact cell 1 through the soldering layer 3, and the second solder strip 22 is in contact with the second fine grid 12 of the back contact cell 1 through the soldering layer 3. The bus bar 5 is arranged between the two adjacent back contact cells 1, and the bus bar 5 is connected to the end of the first solder strip 21 of one back contact cell 1 and the end of the second solder strip 22 of the other back contact cell 1, respectively. In a preferred embodiment, as shown in Figure 7As shown, the insulating layer 4 includes a straight portion 41 and a bending portion 42, the bending portion 42 is arranged at one end of the straight portion 41, the insulating layer 4 is L-shaped, and the bending portion 42 covers one end of the first fine grid 11 or the second fine grid 12. The L-shaped insulating layer can ensure that the fine grid of one polarity is in contact with the bus bar, and the fine grid of the other polarity is well insulated from the bus bar 5, thereby improving the reliability of the battery.

[0041] Correspondingly, the conductive connection layer 31 can be continuously or discontinuously arranged on the first fine grid 11 or the second fine grid 12. The adhesive layer 32 is continuously or discontinuously arranged on the conductive connection layer 31. Continuous arrangement can ensure the stability of welding, and discontinuous arrangement can save materials. Specifically, the arrangement mode of the conductive connection layer and the adhesive layer is selected according to the actual situation.

[0042] In a preferred embodiment, the first solder strip or the second solder strip completely covers the first grid line or the second grid line, ensuring the transfer of the carrier collected by the fine grid to the solder strip, and improving the carrier collection effect.

[0043] In addition, the cross-sectional shape of the first solder strip 21 and the second solder strip 22 is one of a circle, a triangle, a rectangle, and a trapezoid. Preferably, the cross-sectional shape of the first solder strip 21 and the second solder strip 22 is a circle. The circular solder strip is more uniform in pressure on the adhesive layer to both sides under pressure, so that the solder strip can fully contact the conductive connection layer and complete welding, and has better welding effect.

[0044] Correspondingly, the utility model embodiment further discloses a photovoltaic module, which comprises a first cover plate, a first adhesive film, at least one above-mentioned back contact battery string, a second adhesive film and a second cover plate which are sequentially stacked.

[0045] Specifically, the first cover plate is usually made of a material with high light transmittance and strong weather resistance, including but not limited to glass, composite front plate. The first cover plate can protect the sensitive elements inside the battery assembly from the external environment, and at the same time provide the necessary mechanical support to ensure the structural integrity of the battery assembly.

[0046] The first adhesive film is located between the first cover plate and the back contact battery string, mainly plays a role of bonding and sealing, so as to ensure that the battery assembly will not have problems such as delamination or water vapor penetration during long-term use. The material of the first adhesive film includes but is not limited to EVA, POE, EPE and PVB. The EVA adhesive film is low in price and high in light transmittance. The POE adhesive film has good water vapor barrier effect and PID resistance. The EPE adhesive film has the advantages of the EVA adhesive film and the POE adhesive film, is beneficial to sealing the assembly, improves the quality of the assembly, and can also reduce the cost. The PVB adhesive film has higher penetration resistance, and meets the performance requirements of glass curtain wall interlayer safety glass.

[0047] The back contact battery string is the back contact battery string described above or prepared according to the method described above.

[0048] The second adhesive film is located between the back contact battery string and the second cover plate, and has a similar effect to the first adhesive film, which is beneficial to sealing the assembly and improving the quality of the assembly.

[0049] The second cover plate is usually made of a material with strong weather resistance, including but not limited to an aluminum plate, a back plate film and glass. The main function of the second cover plate is to protect the back of the battery assembly from the external environment and provide additional mechanical support, and the second cover plate can also serve as an insulation layer of the battery assembly to ensure safety in use.

[0050] The second cover plate, the first adhesive film, the second adhesive film, the insulation layer and the adhesive layer can adopt the same color system, such as white, black, transparent and the like, to realize the appearance consistency of the assembly. The adhesive layer can also be fluorescent or the like.

[0051] The utility model will be further described in the specific embodiments as follows:

[0052] Embodiment 1

[0053] The embodiment provides a back contact battery string, including a back contact battery, and the back of the back contact battery has first fine grids and second fine grids arranged alternately.

[0054] The first fine grids and the second fine grids are covered by first solder strips and second solder strips respectively.

[0055] The first fine grids and the second fine grids are covered by first solder strips and second solder strips respectively.

[0056] The adhesive layer covers the conductive connection layer. The adhesive layer is a thermosetting adhesive, and the conductive connection layer is a tin paste.

[0057] An insulating layer is arranged between the adjacent first fine grids and the second fine grids, the insulating layer is continuously arranged between the adjacent first fine grids and the second fine grids, and the first solder strip and the second solder strip are insulated and separated by the insulating layer. The height of the insulating layer is 20 μm, and the ratio of the width of the insulating layer to the distance between the adjacent first solder strip and the second solder strip is 0.2.

[0058] Embodiment 2

[0059] The embodiment provides a back contact battery string, which comprises a back contact battery, and the back surface of the back contact battery has first fine grids and second fine grids arranged alternately and spaced.

[0060] The first solder strip covers the first fine grids, and the second solder strip covers the second fine grids.

[0061] The position of the first fine grid in contact with the first solder strip and the position of the second fine grid in contact with the second solder strip are both provided with a soldering layer, the soldering layer comprises a conductive connecting layer and an adhesive layer, and the height of the soldering layer is 50 μm. The conductive connecting layer is discontinuously arranged on the first fine grid or the second fine grid, and the adhesive layer is continuously arranged on the conductive connecting layer.

[0062] The adhesive layer covers the conductive connecting layer. The adhesive layer is a thermosetting adhesive, and the conductive connecting layer is a tin paste.

[0063] An insulating layer is arranged between the adjacent first fine grids and the second fine grids, the insulating layer is continuously arranged between the adjacent first fine grids and the second fine grids, and the first solder strip and the second solder strip are insulated and separated by the insulating layer. The height of the insulating layer is 80 μm, and the ratio of the width of the insulating layer to the distance between the adjacent first solder strip and the second solder strip is 0.6.

[0064] Embodiment 3

[0065] The embodiment provides a back contact battery string, which comprises a back contact battery, and the back surface of the back contact battery has first fine grids and second fine grids arranged alternately and spaced.

[0066] The first solder strip covers the first fine grids, and the second solder strip covers the second fine grids.

[0067] The position of the first fine grid in contact with the first solder strip and the position of the second fine grid in contact with the second solder strip are both provided with a soldering layer, the soldering layer comprises a conductive connecting layer and an adhesive layer, and the height of the soldering layer is 50 μm. The conductive connecting layer is discontinuously arranged on the first fine grid or the second fine grid, and the adhesive layer is continuously arranged on the conductive connecting layer.

[0068] The adhesive layer covers the conductive connecting layer. The adhesive layer is a thermosetting adhesive, and the conductive connecting layer is a tin paste.

[0069] An insulating layer is provided between adjacent first and second fine grids. The insulating layer is continuously disposed between adjacent first and second fine grids, and the first and second welding strips are insulated and isolated by the insulating layer. The insulating layer includes a straight portion and a bent portion, with the bent portion disposed at one end of the straight portion. The insulating layer is L-shaped, and the bent portion covers one end of the first or second fine grid. The insulating layer is 80 μm in height, and the ratio of the width of the straight portion of the insulating layer to the distance between adjacent first and second welding strips is 0.6.

[0070] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A back contact cell string, characterized in that, The back contact cell string comprises back contact cell pieces, the back surface of the back contact cell pieces having first fine grids and second fine grids arranged alternately along a first direction; The first solder strip and the second solder strip are arranged alternately along the first direction, the first solder strip covering or partially covering the first fine grid, and the second solder strip covering or partially covering the second fine grid; The first fine grid and the second fine grid are provided with a welding layer at positions where the first fine grid and the second fine grid are in contact with the first solder strip and the second solder strip respectively; the welding layer comprises a conductive connection layer and an adhesive layer, and the adhesive layer covers the conductive connection layer.

2. The back contact cell string of claim 1, wherein, The width of the adhesive layer is greater than or equal to the width of the first solder strip and / or the second solder strip.

3. The back contact cell string of claim 1, wherein, The conductive connection layer is one or more of a conductive adhesive layer, a conductive paste layer and a tin paste layer.

4. The back contact cell string of claim 1, wherein, An insulating layer is arranged between adjacent first fine grids and second fine grids, and the first solder strip and the second solder strip are insulated and separated by the insulating layer.

5. The back contact cell string of claim 4, wherein, The height of the insulating layer is H1, and the height of the welding layer is H2, H1>H2.

6. The back contact cell string of claim 5, wherein, H1 is 10 μm to 150 μm, and H2 is 10 μm to 80 μm.

7. The back contact cell string of claim 4, wherein, The width of the insulating layer is L1, and the distance between adjacent first solder strips and second solder strips is L2, L1 8. The back contact cell string of claim 7, wherein, The L1 and L2 satisfy the following relationship: 0.2*L2≤L1≤0.8*L2.

9. The back contact cell string of claim 4, wherein, The insulating layer is continuously or intermittently arranged between adjacent first fine grids and second fine grids.

10. The back contact cell string of claim 9, wherein, The insulating layer comprises a straight portion and a bending portion, the bending portion being arranged at one end of the straight portion, and the bending portion covering one end of the first fine grid or the second fine grid.

11. The back contact cell string of claim 10, wherein, The conductive connection layer is continuously or intermittently arranged on the first fine grid or the second fine grid.

12. The back contact cell string of claim 11, wherein, The adhesive layer is continuously or intermittently arranged on the conductive connection layer.

13. The back contact cell string of claim 1, wherein, The cross-sectional shape of the first solder strip and the second solder strip is one of a circle, a triangle, a rectangle and a trapezoid.

14. A photovoltaic module, characterized by The back contact cell string comprises the back contact cell string according to any one of claims 1 to 13.

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