Battery string repair method, photovoltaic module and preparation method thereof

Abstract

The invention discloses a battery string repair method, a photovoltaic module and a preparation method thereof, the battery string repair method comprises the following steps: repair treatment: a repair material is placed at a to-be-welded position of a battery string, and the welding temperature of the repair material is 130-160 DEG C; pre-welding treatment is conducted, specifically, the repair material at the position to be welded is pre-welded for 3-10 s, the repair material is partially alloyed, and the heating temperature of pre-welding treatment is not lower than the welding temperature of the repair material; retesting: detecting whether the battery string is qualified or not; and laminating and welding: laminating the qualified battery strings at the temperature not lower than the welding temperature of the repair material, so that the repair material is further alloyed, and the unqualified battery strings are returned to the repair treatment step. According to the method, the risk of over-welding or unwelding generated by the welding wire in the repair process can be reduced, and meanwhile the repair difficulty is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of solar cells, in particular to a cell string repair method, a photovoltaic module and a preparation method thereof. BACKGROUND

[0002] A cell string is a component in which different cell pieces are connected by welding wires. When a cell string is determined to be unqualified through quality detection such as EL (Electroluminescence) detection, repair processing is needed. However, in the current cell string repair process, workers usually rely on manual operation to weld the welding wires using a soldering iron. This manual welding method has uncontrollable problems such as contact pressure of the soldering iron, which causes the welding wires around the repair position to be prone to overwelding or unwelding. Especially as the number of welding wires increases and the diameter of the welding wires decreases, the difficulty of repair increases significantly. SUMMARY

[0003] In order to reduce the risk of overwelding or unwelding of the welding wires during the repair process and reduce the repair difficulty, embodiments of the present application disclose a cell string repair method, a photovoltaic module and a preparation method thereof.

[0004] In a first aspect, embodiments of the present application provide a cell string repair method.

[0005] The cell string repair method comprises the following steps:

[0006] Repair processing: placing a repair material at a welding position of the cell string, and the welding temperature of the repair material is 130-160℃;

[0007] Pre-welding processing: pre-welding the repair material at the welding position for 3-10s to partially alloy the repair material, and the heating temperature of the pre-welding processing is not lower than the welding temperature of the repair material;

[0008] Re-inspection: detecting whether the cell string is qualified;

[0009] Laminated welding: performing laminated processing on the cell string that is qualified, and the temperature of the laminated processing is not lower than the welding temperature of the repair material to further alloy the repair material, and the cell string that is unqualified is returned to the repair processing step.

[0010] As an optional implementation, in embodiments of the present application, when the defect position of the cell string is a welding wire part of the cell string, the welding position is the welding wire part, and the repair material is a repair liquid;

[0011] The repair processing comprises the following steps:

[0012] covering the surface of the battery string with a diaphragm having a hollowed area, the to-be-welded position being opposite to the hollowed area;

[0013] applying the repair liquid to the hollowed area opposite to the to-be-welded position;

[0014] removing the diaphragm, the repair liquid covering the to-be-welded position.

[0015] As an optional embodiment, in the embodiment of the present application, the repair liquid comprises the following components by mass percentage:

[0016] welding alloy powder 50% to 70%

[0017] flux 10% to 20%

[0018] solvent 5% to 15%.

[0019] As an optional embodiment, in the embodiment of the present application, the particle size of the welding alloy powder is 5 μm to 15 μm, and the welding alloy powder comprises one or a combination of tin, lead or bismuth;

[0020] and / or,

[0021] the flux comprises rosin;

[0022] and / or,

[0023] the solvent comprises one or both of ethanol or isopropyl alcohol;

[0024] and / or,

[0025] the repair liquid further comprises one or more of an active agent, an antioxidant and a thickening agent;

[0026] and / or,

[0027] the repair liquid further comprises the following components by mass percentage:

[0028] active agent 1% to 5%

[0029] antioxidant 0.1% to 1%

[0030] thickening agent 0.1% to 3%.

[0031] As an optional embodiment, in the embodiment of the present application, the diaphragm is a silica gel material or a rubber material;

[0032] and / or, the width of the hollowed area is 1 to 1.5 times the width of the grid line of the battery piece, and the length of the hollowed area is 0.2 to 0.5 times the length of the battery piece.

[0033] As an optional implementation, in an embodiment of the present invention, when the defective location of the battery string is inside the battery cell in the battery string, the defective battery cell is designated as the first sub-battery cell, the welding wire on the battery cell adjacent to the first sub-battery cell is designated as the first sub-welding wire, the battery cell that replaces the first sub-battery cell in the battery string is designated as the second sub-battery cell, the second sub-battery cell is the battery cell with the second sub-welding wire pre-welded, the area between the first sub-welding wire and the second sub-welding wire that is close to each other is the position to be welded, and the rework material is a rework film tape;

[0034] The rework process includes the following steps:

[0035] Cut the welding wire between the first sub-cell and the adjacent cell;

[0036] Replace the first sub-cell in the battery string with the second sub-cell;

[0037] There is a gap between the surface near the end of the second sub-cell and the welding wire. When the rework film is inserted into the gap and placed at the welding position, the rework film simultaneously contacts the first sub-welding wire and the second sub-welding wire.

[0038] As an optional implementation, in an embodiment of the present invention, the repair film tape includes:

[0039] grassroots level;

[0040] A conductive layer is disposed on the base layer;

[0041] A welding alloy layer is disposed on the side of the conductive layer opposite to the base layer;

[0042] When the rework film is placed at the position to be welded, the welding alloy layer comes into contact with the welding wire.

[0043] As an optional implementation, in an embodiment of the present invention, the battery cell is a back-contact solar cell, and the base layer is an insulating thin film material;

[0044] And / or,

[0045] The material of the conductive layer includes sheet material composed of any one or more of copper, aluminum or silver;

[0046] And / or,

[0047] The material of the welding alloy layer comprises a welding alloy coating material consisting of one or more of tin, lead or bismuth;

[0048] And / or,

[0049] The thickness of the base layer is 0.01mm-0.1mm;

[0050] and / or,

[0051] The thickness of the conductive layer is 0.02mm-0.2mm;

[0052] and / or,

[0053] The thickness of the welding alloy layer is 0.01mm-0.2mm.

[0054] As an optional embodiment, in the embodiment of the present application, the surface structure of the base layer or the welding alloy layer is any one of corrugated structure, sawtooth structure or planar structure;

[0055] and / or,

[0056] After the repair film tape is inserted into the position to be welded, the position to be welded is also bonded with a tape, and the tape is located on the other side of the welding wire relative to the repair film tape.

[0057] As an optional embodiment, in the embodiment of the present application, in the pre-welding processing step, the heating mode is infrared heat treatment.

[0058] and / or,

[0059] In the retesting step, the way to detect whether the battery string is qualified is electroluminescence detection.

[0060] and / or,

[0061] In the laminated welding step, the temperature of the laminated treatment is 130℃-160℃, and the time is 15min-30min.

[0062] As an optional embodiment, in the embodiment of the present application, the diameter of the welding wire is 0.05mm-0.3mm.

[0063] In a second aspect, the embodiment of the present application provides a photovoltaic module.

[0064] A photovoltaic module comprises:

[0065] A front plate;

[0066] A glue film layer is arranged on the front plate;

[0067] The battery string processed by the battery string repair method of the first aspect is arranged in the glue film layer;

[0068] A back plate is arranged on the side of the glue film layer away from the front plate.

[0069] In a third aspect, the embodiments of the present application provide a preparation method of a photovoltaic module.

[0070] A preparation method of a photovoltaic module, the preparation method of the photovoltaic module as mentioned in the second aspect comprises the following steps:

[0071] coating a film material on the front plate, and placing the battery string with qualified retest result in the film material;

[0072] arranging the back plate on the side of the film material away from the front plate;

[0073] laminating at 130-160℃ for 15-30min, the film material is converted into the film layer, and the battery string completes the laminated welding, and the photovoltaic module is obtained.

[0074] Compared with the prior art, the present application has the following beneficial effects:

[0075] The battery string rework method provided by the embodiments of the present application uses a rework material with a welding temperature of 130-160℃ for rework processing. The welding temperature of the rework material is lower than the welding temperature (180-230℃) of the conventional welding wire, which can effectively reduce the risk of over-welding or de-welding of the welding wire during the rework process. In addition, during the rework process, the rework material is partially alloyed through a short pre-welding process (3-10s). This step not only ensures the connectivity of the battery string and meets the retest requirements, but also reduces the influence of welding heat on the welding wire, especially the welding wire with a smaller diameter, thereby further reducing the risk of new problems such as over-welding or de-welding of the battery string during the rework process.

[0076] After the pre-welding process, the battery string can be retested by an EL detection device or other quality detection device to timely find and solve potential problems and ensure the quality of the battery string. For the battery string with qualified detection, it enters the subsequent laminating process. The laminating process not only forms good contact between the rework material and the welding wire or the welding position on the surface of the battery piece, but also provides additional energy and sufficient welding time for the welding of the rework material, so that the rework material forms a better alloying effect. At the same time, since the laminating process is generally completed by a laminating device, the controllability is significantly improved compared with manual welding, which provides strong support for the quality control of the battery string and the photovoltaic module. BRIEF DESCRIPTION OF DRAWINGS

[0077] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0078] Figure 1 is a flowchart for illustrating a process of using a repair liquid as a repair material for repair processing according to an embodiment of the present application;

[0079] Figure 2 is a cross-sectional structure diagram of a battery string after repair of a repair liquid according to an embodiment of the present application;

[0080] Figure 3 is a structure diagram for illustrating a position of cutting off a solder wire between a first sub-cell and an adjacent cell according to an embodiment of the present application;

[0081] Figure 4 is a flowchart for illustrating a process of using a repair film tape as a repair material for repair processing according to an embodiment of the present application;

[0082] Figure 5 is a cross-sectional structure diagram for illustrating a position of inserting a repair film tape into a position to be welded according to an embodiment of the present application;

[0083] Figure 6 is a structure diagram for illustrating a repair film tape according to an embodiment of the present application;

[0084] Figure 7 is a structure diagram for illustrating a repair film tape used in a back contact solar cell according to an embodiment of the present application;

[0085] Figure 8 is a structure diagram of a photovoltaic module according to an embodiment of the present application;

[0086] Figure 9 is a structure diagram of a photovoltaic module according to another embodiment of the present application.

[0087] Legend: 1, battery string; 11, solder wire; 111, position to be welded; 11A, first sub-solder wire; 11B, second sub-solder wire; 12, cell; 121, current collecting layer; 1211, positive current collecting layer; 1212, negative current collecting layer; 122, gap; 12A, first sub-cell; 12B, second sub-cell; 13, separator; 131, hollowed area; 2, repair material; 21, repair liquid; 22, repair film tape; 221, base layer; 222, conductive layer; 223, solder alloy layer; 3, adhesive tape; 4, infrared heat treatment; 5, front plate; 6, adhesive film layer; 7, back plate. DETAILED DESCRIPTION

[0088] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0089] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", and the like indicate the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not intended to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0090] In addition, in addition to indicating the orientation or positional relationship, the above-mentioned partial terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. For a person of ordinary skill in the art, the specific meaning of these terms in the present application can be understood according to the specific situation.

[0091] In addition, the terms "mount", "set", "provided with", "connect", "connected" should be broadly understood. For example, it can be fixedly connected, detachably connected, or integrally constructed; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, or internal communication between two devices, elements or components. For a person of ordinary skill in the art, the specific meaning of the above-mentioned terms in the present application can be understood according to the specific situation.

[0092] In addition, the terms "first", "second", and the like are mainly used to distinguish different devices, elements or components (the specific types and structures can be the same or different), and are not intended to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, the meaning of "multiple" is two or more.

[0093] The technical solutions of the present application will be further described below with reference to the embodiments and the accompanying drawings.

[0094] In a first aspect, the embodiments of the present application provide a battery string repair method.

[0095] Referring to Figure 1 The repair method of the battery string 1 includes the following steps:

[0096] Repairing process: the repairing material 2 is placed at the welding position 111 of the battery string 1, and the welding temperature of the repairing material 2 is 130-160℃;

[0097] Pre-welding process: the repairing material 2 at the welding position 111 is pre-welded for 3-10 seconds, so that the repairing material 2 is partially alloyed, and the heating temperature of the pre-welding process is not lower than the welding temperature of the repairing material 2;

[0098] Rechecking: whether the battery string 1 is qualified is detected;

[0099] Laminating welding: the battery string 1 qualified in the detection is subjected to laminating treatment, the temperature of the laminating treatment is not lower than the welding temperature of the repairing material 2, so that the repairing material 2 is further alloyed, and the battery string 1 unqualified in the detection is returned to the repairing process.

[0100] It is found in the present application that the repairing material 2 with a welding temperature of 130-160℃ is used for the repairing process of the battery string 1, the welding temperature of the repairing material 2 is lower than the welding temperature (180-230℃) of the conventional welding wire 11, so that the risk of over-welding or off-welding of the welding wire 11 in the repairing process is effectively reduced. In the repairing process, the repairing material 2 is partially alloyed through the short pre-welding process (3-10 seconds). This step not only ensures the connectivity of the battery string 1 and meets the requirements of the rechecking, but also reduces the influence of the welding heat on the welding wire 11, especially the welding wire 11 with a small diameter, so that the risk of over-welding or off-welding and other new problems of the battery string 1 in the repairing process is further reduced.

[0101] After the pre-welding process, the rechecking of the battery string 1 is carried out through the quality detection equipment such as EL detection equipment, so that potential problems are found and solved in time, so as to ensure the quality of the battery string 1. The battery string 1 qualified in the detection enters the subsequent laminating treatment process. The laminating treatment not only makes the repairing material 2 form good contact with the welding position on the surface of the welding wire 11 or the battery sheet 12, but also provides additional energy and sufficient welding time for the welding of the repairing material 2, so that the repairing material 2 further forms a better alloying effect. At the same time, since the laminating treatment is generally completed through the laminating equipment, the controllability is significantly improved compared with manual welding, which provides strong support for the quality control of the battery string 1 and the photovoltaic module.

[0102] Exemplarily, the welding temperature of the repairing material 2 can be 130℃, 133℃, 140℃, 145℃, 152℃ or 160℃, and the time of the pre-welding process can be 3 seconds, 5 seconds, 7 seconds or 10 seconds.

[0103] The battery string is a component connected by welding wires. When the battery string is determined to be unqualified due to quality problems, it may be that the welding wire has problems, including but not limited to defects such as virtual welding (i.e., the welding is not firm, and there is a gap) or overwelding (excessive welding, which may cause the welding point to be too large or the grid to be broken), or it may be that the battery sheet itself has problems, such as (internal micro-cracks of the battery sheet), scratches (physical damage to the surface), short circuits (unwanted conductive connection inside or between the battery sheets), and contamination (surface or internal contamination by impurities). Of course, it is also possible that both the welding wire and the battery sheet have problems.

[0104] For welding wire problems, the defective part of the welding wire can be repaired by repairing the welding wire. For quality problems of the battery sheet itself, the old battery sheet with problems needs to be replaced with a new, qualified battery sheet to ensure the overall performance and safety of the battery string. The repair processing strategies for different types of battery string quality problems are discussed below.

[0105] In some embodiments, referring to Figure 1 , when the defect position of the battery string 1 is the welding wire 11 part of the battery string 1, the welding position 111 is the welding wire 11 part, and the defect position of the battery string 1 refers to Figure 1 (a), the repair material 2 is a repair liquid 21;

[0106] The repair processing includes the following steps:

[0107] The surface of the battery string 1 is covered with a diaphragm 13 having a hollow area 131, the welding position 111 is opposite to the hollow area 131, and the surface structure of the battery string 1 after covering the diaphragm 13 is shown in Figure 1 (b);

[0108] The repair liquid 21 is coated on the hollow area 131 opposite to the welding position 111, and the surface structure of the battery string 1 after coating the repair liquid 21 is shown in Figure 1 (c);

[0109] The diaphragm 13 is removed, the repair liquid 21 covers the welding position 111, and the battery string 1 obtained is shown in Figure 1 (d).

[0110] This scheme uses a repair liquid 21 as a repair material 2 for connecting the welding wires 11. The amount of the repair liquid 21 can be flexibly adjusted according to the width and length of the welding position 111, which has higher flexibility and adaptability compared to the traditional welding wire 11. Moreover, the repair liquid 21 has strong fluidity, and referring to Figure 2 , the repair liquid 21 can fill the breakpoints between the welding wire 11 and the current collecting layer 121 (as shown in Figure 2 (a)), and the breakpoints in the welding wire 11 (as shown in Figure 2(b) or the current collecting layer 121 (as shown in (c)), effectively reducing the occurrence of false soldering problems. In summary, the combination of the rework liquid 21 and the separator 13 takes into account the flexibility and accuracy of the rework process, thereby improving the reliability and stability of the soldering. Figure 2

[0111] Referring back to Figure 1 After the rework process is completed, a pre-soldering process is performed, as shown in (e), to make the rework material 2 partially alloyed by heating, and after the pre-soldering process is completed, the battery string 1 as shown in (f) is obtained. Figure 1 Figure 1

[0112] It should be noted that in a solar cell, the main function of the current collecting layer 121 is to effectively collect and conduct the current generated by the photoelectric effect, ensuring that these currents can be smoothly conducted from the light-absorbing layer (usually a semiconductor material) of the solar cell, and then used by the external circuit. As an important part of the current collecting layer 121, the electrode main grid assumes the role of forming good electrical contact with the solder wire 11 to ensure efficient transmission of the current, so the current collecting layer 121 connected to the solder wire 11 is the electrode main grid of the solar cell.

[0113] In some embodiments, the rework liquid 21 includes the following components in the following mass percentages:

[0114] Soldering alloy powder 50% to 70%

[0115] Soldering flux 10% to 20%

[0116] Solvent 5% to 15%.

[0117] The soldering alloy powder, as the main material in the rework liquid 21, assumes the role of forming contact with the solder wire 11 or the current collecting layer 121 located at the soldering position 111 during the rework process. The addition of the soldering flux can reduce the surface tension of the rework liquid 21, thereby wetting the soldering position 111 and allowing the soldering alloy powder to form good contact with the solder wire 11 or the current collecting layer 121 at the soldering position 111. The solvent serves the functions of dissolving, adjusting viscosity, and promoting evaporation.

[0118] During the rework process of the battery string 1, the rework liquid 21 containing the above components is applied to the soldering position 111, and the soldering alloy powder forms good contact with the solder wire 11 or the current collecting layer 121 located at the soldering position 111. After the pre-soldering process of the battery string 1, the solvent evaporates and the soldering alloy powder is partially alloyed, forming the rework material 2 with certain electrical conductivity and soldering strength.

[0119] ​​​Exemplarily, in the repair liquid 21, the mass percentage of the solder alloy powder can be 50%, 55%, 60%, or 70%, etc., the mass percentage of the flux can be 10%, 13%, 17%, or 20%, etc., and the mass percentage of the solvent can be 5%, 8%, 12%, or 15%, etc.

[0120] In some embodiments, the particle size of the solder alloy powder is 5-15 μm, and the solder alloy powder comprises at least two of tin, lead, or bismuth.

[0121] When the particle size of the solder alloy powder is in the range of 5-15 μm, the solder alloy powder is easily heated uniformly, which helps to ensure that the powder is heated sufficiently and partially alloyed during the pre-welding treatment. The solder alloy powder is selected to be a low-temperature solder alloy with a melting temperature of 130-160 ℃, which is conducive to low-temperature welding. The alloy formed from at least two of tin, lead, or bismuth has a relatively low melting temperature, and can be effectively welded at a relatively low temperature, which is compatible with the pre-welding treatment and the laminated welding treatment process described above, thereby well meeting the process requirements of the low-temperature welding described above.

[0122] Exemplarily, the particle size of the solder alloy powder can be 5 μm, 7 μm, 11 μm, or 15 μm, etc.

[0123] In some embodiments, the flux comprises rosin.

[0124] In addition to improving the wettability of the repair liquid 21, rosin can also remove the oxide film on the metal surface, which is conducive to forming a good welding connection. Moreover, during the welding process, the melted rosin will be dispersed on the surface of the repair liquid 21 to form an isolation layer, which can effectively prevent the welding surface from being oxidized again and ensure the welding quality.

[0125] In some embodiments, the solvent comprises one or both of ethanol or isopropyl alcohol.

[0126] The solvents such as ethanol and isopropyl alcohol are highly volatile and relatively environmentally friendly, and can not only play a role in dissolving, adjusting viscosity, and promoting evaporation in the repair liquid 21, but also better meet the environmental protection needs.

[0127] In some embodiments, the repair liquid 21 further comprises one or more of an active agent, an antioxidant, and a thickening agent. Further preferably, the repair liquid 21 further comprises the following components in the following mass percentages:

[0128] Active agent 1%-5%

[0129] Antioxidant 0.1%-1%

[0130] Thickening agent 0.1%-3%.

[0131] The addition of the active agent can improve the wettability of the repair solution 21, while enhancing the adhesion of the repair solution 21. The combination of the active agent and the flux can further improve the bonding strength between the welding alloy powder and the solder wire 11 or the current collection layer 121 at the to-be-welded position 111, thereby ensuring the reliability of the repair. In some embodiments, the active agent is an organic acid or an organic amine, etc. Exemplarily, the active agent can be adipic acid or citric acid, etc.

[0132] The addition of the antioxidant can improve the antioxidation effect of the repair solution 21 during storage and use, and ensure that the repair solution 21 maintains good performance during use. In some embodiments, the antioxidant is butylated hydroxyanisole (BHA) or butylated hydroxytoluene (BHT).

[0133] Exemplarily, in the repair solution 21, the mass percentage of the active agent can be 1%, 3%, or 5%, etc., the mass percentage of the antioxidant can be 0.1%, 0.5%, or 1%, etc., and the mass percentage of the thickening agent can be 0.1%, 1%, or 3%, etc.

[0134] The diaphragm is made of a material with corrosion resistance to reduce the corrosion of the diaphragm due to the contact with the repair solution, while having a certain flexibility to form a better adhesion effect with the surface of the solar cell. In some embodiments, the diaphragm 13 is made of a silicone material or a rubber material. These two materials well meet the requirements of corrosion resistance and flexibility, and ensure the safety and efficiency of the solar cell during the repair process.

[0135] In some embodiments, the width of the hollowed-out area 131 is 1-1.5 times the width of the grid line of the cell sheet 12, and the length of the hollowed-out area 131 is 0.2-0.5 times the length of the cell sheet 12.

[0136] By limiting the width of the hollowed-out area 131, the coating range of the repair solution 21 can be effectively limited, avoiding the problem of serious shading due to the excessive coating range of the repair solution 21. In addition, when the solar cell is a back contact solar cell, the adjacent grid lines are heteropolar grid lines. By limiting the width of the hollowed-out area 131, the short circuit caused by the overlapping of the adjacent grid lines by the repair solution 21 during the repair process can be avoided.

[0137] Limiting the length of the hollowed-out area 131 within the above range can not only ensure that the processing requirements of the to-be-welded position 111 in a single solder wire 11 are met, but also greatly promote the convenience and efficiency of the production operation. If the length of the hollowed-out area 131 is too long or too short, it will adversely affect the actual production operation.

[0138] In some embodiments, with reference to Figure 3 and Figure 4When the defect position of the battery string 1 is inside the battery piece 12 in the battery string 1, the battery piece 12 with the defect is recorded as a first sub battery piece 12A, the welding wire 11 on the battery piece 12 adjacent to the first sub battery piece 12A is a first sub welding wire 11A, the battery piece 12 replacing the position of the first sub battery piece 12A in the battery string 1 is recorded as a second sub battery piece 12B, the second sub battery piece 12B is a battery piece 12 with a first sub welding wire 11B welded in advance, the area close to each other between the first sub welding wire 11A and the first sub welding wire 11B is a to-be-welded position 111, and the repair material 2 is a repair film tape 22.

[0139] The repair process includes the following steps:

[0140] The welding wire 11 between the first sub battery piece 12A and the adjacent battery piece 12 is cut off, and the position of the cut-off welding wire 11 can be Figure 3 the position of the dashed line shown in the figure;

[0141] The second sub battery piece 12B replaces the first sub battery piece 12A in the position of the battery string 1, and after the replacement is completed, the position of the second sub battery piece 12B is as shown in Figure 4 (a);

[0142] Referring back Figure 3 , the surface close to the end of the second sub battery piece 12B has a gap 122 with the welding wire 11, the repair film tape 22 is inserted into the gap 122, and when the repair film tape 22 is placed in the to-be-welded position 111, the repair film tape 22 is in contact with the first sub welding wire 11A and the first sub welding wire 11B at the same time. The schematic diagram after the repair film tape 22 is inserted into the to-be-welded position 111 is as shown in Figure 4 (a) and Figure 5 .

[0143] When the defect inside the battery piece 12 needs to be replaced, the traditional method usually involves cutting off the welding wire 11 at the head and tail of the battery piece 12 to be replaced, removing the old piece, and then replacing it with a new battery piece 12 with welding wire 11 welded in advance, and then welding these welding wires 11 one by one. Another method is to heat and remove the welding wire 11 connected to the battery piece 12 to be replaced, and then weld the original welding wire 11 to the new battery piece 12 one by one. Both methods require welding of the welding wire 11 one by one, which is not only tedious, time-consuming and laborious, but also prone to errors. With the advancement of battery technology, the number of welding wires 11 in the current battery string 1 is increasing, and the diameter of the welding wire 11 is gradually decreasing. Currently, the diameter of the welding wire 11 has been reduced to below 0.3 mm, and some products even use 0.18 mm welding wire 11, which undoubtedly greatly increases the difficulty of welding one by one.

[0144] The scheme introduces a repair film strip 22. By adjusting the position of the repair film strip 22, the repair film strip 22 is in contact with the first sub-welding wire 11A and the first sub-welding wire 11B at the same time, thereby serving as the connecting material of the first sub-welding wire 11A and the first sub-welding wire 11B, avoiding the cumbersome process of welding one by one, significantly reducing the repair difficulty, and accelerating the repair process. In addition, the repair film strip 22 has strong universality and adaptability, and can be compatible with welding wires 11 of different sizes. Even if the welding wire 11 is small in diameter and large in number, it can also form a good connection, showing high repair efficiency and flexibility.

[0145] With reference to Figure 6 In some embodiments, the repair film strip 22 comprises:

[0146] a base layer 221;

[0147] a conductive layer 222 disposed on the base layer 221;

[0148] a welding alloy layer 223 disposed on the side of the conductive layer 222 away from the base layer 221;

[0149] When the repair film strip 22 is placed at the welding position 111, the welding alloy layer 223 is in contact with the welding wire 11.

[0150] In the repair film strip 22, the base layer 221 can serve as a support part for the repair film strip 22, providing support for the conductive layer 222 and the soldering layer. The conductive layer 222 mainly plays the role of current conduction, reducing the contact resistance. The soldering layer plays the role of auxiliary welding, which can realize partial alloying during the pre-welding process, and further alloying during the lamination process.

[0151] In some embodiments, the battery piece 12 is a back contact solar cell, and the base layer 221 is an insulating film material such as a PET film.

[0152] With reference to Figure 7 The positive current collecting layer 1211 and the negative current collecting layer 1212 of the back contact solar cell are located on the back light side and are distributed in an interdigital manner on the back light side. When the repair film strip 22 is placed at the welding position 111, the welding alloy layer 223 is close to the welding wire 11, and the base layer 221 is close to the surface of the battery piece 12, which makes the base layer 221 contact the surface of the back contact solar cell. By setting the base layer 221 with an insulating film material, the positive current collecting layer 1211 and the negative current collecting layer 1212 on the surface of the battery piece 12 can be prevented from being in contact and communication through the base layer 221, causing the battery piece 12 to short circuit.

[0153] If the repair film tape 22 is not arranged in the gap 122 between the welding wire 11 and the battery sheet 12, but is directly arranged on the surface of the welding wire 11 away from the battery sheet 12, the welding alloy layer 223 on the surface of the repair film tape 22 is easy to contact the positive current collecting layer 1211 and the negative current collecting layer 1212 on the surface of the battery sheet 12 at the same time when contacting the welding wire 11, resulting in a short circuit between the positive current collecting layer 1211 and the negative current collecting layer 1212 on the surface of the battery sheet 12.

[0154] In some embodiments, the material of the conductive layer 222 includes a sheet material composed of any one or more of copper, aluminum or silver; and the material of the welding alloy layer 223 includes a welding alloy coating material composed of at least two of tin, lead or bismuth.

[0155] Copper, aluminum or silver all have good electrical conductivity, which is conducive to forming good electrical conductivity and improving the electrical conductivity of the repair film tape 22. At least two of tin, lead or bismuth can form an alloy with a relatively low melting temperature, which can achieve effective welding at a relatively low temperature, and is matched with the above-mentioned pre-welding treatment and laminated welding treatment process, thereby well meeting the process requirements of the above-mentioned low-temperature welding.

[0156] In some embodiments, the thickness of the base layer 221 is 0.01mm-0.1mm; the thickness of the conductive layer 222 is 0.02mm-0.2mm; and the thickness of the welding alloy layer 223 is 0.01mm-0.2mm.

[0157] The above-mentioned thicknesses of the base layer 221, the conductive layer 222 and the welding alloy layer 223 can well balance the requirements of low-temperature welding stability and electrical conductivity improvement, while controlling the material cost of the repair film tape 22.

[0158] Referring back Figure 6 In some embodiments, the surface structure of the base layer 221 or the welding alloy layer 223 is any one of a corrugated structure, a sawtooth structure or a planar structure.

[0159] The base layer 221 or the welding alloy layer 223 is the surface of the repair film tape 22, and the structure of the surface can be various, which can be Figure 6 (a) a planar structure as shown in the figure, Figure 6 (b) or Figure 6 (c) a corrugated structure as shown in the figure or Figure 6 (d) a sawtooth structure as shown in the figure, etc., or Figure 6 (e), Figure 6 (f), Figure 6 (g), Figure 6(h) any combination of the corrugated structure, the sawtooth structure or the flat structure. The welding alloy layer 223 can select the corrugated structure and the sawtooth structure, both of which can increase the contact area to make the welding alloy layer 223 have a better contact effect with the welding wire 11.

[0160] Referring back Figure 4 (b), in some embodiments, after the repair film tape 22 is inserted into the to-be-welded position 111, the to-be-welded position 111 is also bonded with the adhesive tape 3, and the adhesive tape 3 is located on the other side of the welding wire 11 relative to the repair film tape 22.

[0161] By introducing the adhesive tape 3, on the one hand, the welding wire 11 can be pressed on the welding alloy layer 223 to make the welding wire 11 fully contact with the welding alloy layer 223, and on the other hand, the connection stability of the adjacent battery pieces 12 can be increased in cooperation with the repair film tape 22, the relative position change between the adjacent battery pieces 12 during the transfer process is reduced, and the risk of separation between the adjacent battery pieces 12 is reduced.

[0162] Referring back Figure 1 (e) and Figure 4 (c), in some embodiments, in the pre-welding processing step, the heating manner is infrared heat treatment 4.

[0163] The infrared heat treatment 4 is a heating treatment by the energy of infrared light. This heating manner can accurately control the heating area and the heating effect, improve the controllability of the pre-welding processing, and further reduce the risk of over-welding or poor partial alloying effect.

[0164] In some embodiments, in the re-measuring step, the way to detect whether the battery string 1 is qualified is electroluminescence detection; and / or,

[0165] The electroluminescence detection technology is mature, which can effectively detect the defects existing in the battery string 1 and effectively monitor the quality of the battery string 1.

[0166] In some embodiments, in the laminated welding step, the temperature of the laminated processing is 130℃-160℃, and the time is 15min-30min.

[0167] In the laminated welding processing step in the present application, the temperature of the laminated processing is the same as the laminated processing temperature in the assembling photovoltaic module step, which makes the laminated welding processing in the present application can be carried out in the laminated equipment for assembling photovoltaic modules. By utilizing the laminated equipment to effectively control the laminated processing conditions, the error caused by manual welding operation is reduced, and the process is simplified and the efficiency is improved.

[0168] In some embodiments, the diameter of the welding wire 11 is 0.05mm-0.3mm.

[0169] For the welding wire 11 with a diameter in the range of 0.05mm to 0.3mm, the traditional one-by-one welding method is not only difficult to operate, but also inefficient and prone to errors. In the above-mentioned battery string 1 repair process of the present application, the repair material 2 is used to realize high-quality and rapid connection between the welding wires 11, and this advantage is particularly significant when the diameter of the welding wire 11 is small. The repair material 2 can not only effectively connect these small welding wires 11, but also ensure the stability and reliability of the connection, thereby greatly improving the repair efficiency and welding quality.

[0170] In a second aspect, embodiments of the present application provide a photovoltaic module.

[0171] Referring to Figure 8 and Figure 9 , a photovoltaic module comprises:

[0172] a front plate 5;

[0173] a glue film layer 6 arranged on the front plate 5;

[0174] a battery string 1 processed by the battery string 1 repair method as mentioned in the first aspect is arranged in the glue film layer 6;

[0175] a back plate 7 arranged on the side of the glue film layer 6 away from the front plate 5.

[0176] Figure 8 In the photovoltaic module shown, the battery string 1 is subjected to the repair processing flow as shown in Figure 1 . These repaired battery strings 1, after being combined with the glue film layer 6, the front plate 5 and the back plate 7, are assembled into three different photovoltaic modules according to the different breakpoint repair positions:

[0177] The photovoltaic module assembled by the battery string 1 involving the breakpoint repair of the welding wire 11 is marked as Figure 8 (a);

[0178] The photovoltaic module assembled by the battery string 1 involving the breakpoint repair of the welding wire 11 is marked as Figure 8 (b);

[0179] The photovoltaic module assembled by the battery string 1 involving the breakpoint repair of the current collecting layer 121 is marked as Figure 8 (c).

[0180] In the photovoltaic module shown, the battery string 1 is subjected to the repair processing flow as shown in Figure 9 . These battery strings 1, after being combined with the glue film layer 6, the front plate 5 and the back plate 7, constitute the photovoltaic module structure shown in Figure 4 Figure 9

[0181] ​​In a third aspect, the embodiments of the present application provide a method for manufacturing a photovoltaic module.

[0182] A method for manufacturing a photovoltaic module, comprising the following steps:

[0183] Coating a film material on the front plate 5, and placing the battery string 1 with qualified retest results in the film material;

[0184] Setting a back plate 7 on the side of the film material away from the front plate 5;

[0185] Laminating at 130-160℃ for 15-30min, the film material is converted into a film layer 6, and the battery string 1 is completed laminated and welded, and the photovoltaic module is obtained.

[0186] The temperature setting of the laminating process in the step of assembling the photovoltaic module is the same as that of the laminated and welded process, so that the error caused by manual welding operation is reduced by effectively controlling the laminating process conditions by using laminating equipment, and the process is simplified and the efficiency is improved.

[0187] Taking the defect position of the battery string 1 as the part of the welding wire 11 of the battery string 1 as an example, the repair process of the battery string 1 and the application step relationship thereof in the preparation of the photovoltaic module are further described, and the repair process of the battery string 1 can be referred to Figure 1 :

[0188] As shown in Figure 1 (a), the welding position 111 is the part of the welding wire 11, and the surface of the battery string 1 is covered with a diaphragm 13 having a hollow area 131, so that the welding position 111 is opposite to the hollow area 131, forming the surface structure of the battery string as shown in Figure 1 (b);

[0189] The repair liquid 21 is coated on the hollow area 131 opposite to the welding position 111, forming the surface structure of the battery string as shown in Figure 1 (c);

[0190] The diaphragm 13 is removed, the repair liquid 21 covers the welding position 111, forming the surface structure of the battery string as shown in Figure 1 (d);

[0191] Pre-welding process: as shown in Figure 1 (e), the repair material 2 of the welding position 111 is pre-welded for 3-10s by using the infrared heat treatment 4, so that the repair material 2 is partially alloyed, and the heating temperature of the pre-welding process is not lower than the welding temperature of the repair material 2, and the surface structure of the battery string after the pre-welding process is as shown in Figure 1 (f);

[0192] Re-inspection: whether the battery string 1 is qualified is detected, the battery string 1 with qualified re-inspection result enters the assembling process, and the battery string 1 with unqualified detection result returns to the repair processing step;

[0193] Assembling: the adhesive film material is coated on the front plate 5, the battery string 1 with qualified re-inspection result is placed in the adhesive film material, the back plate 7 is arranged on the side of the adhesive film material away from the front plate 5, the 130-160 ℃ laminating treatment is performed for 15-30 min, the adhesive film material is converted into the adhesive film layer 6, and the battery string 1 is completed laminating welding, and the photovoltaic module as shown in Figure 8

[0194] The battery string repair method, the photovoltaic module and the preparation method thereof disclosed in the above embodiments of the present application are introduced in detail, the principle and the implementation mode of the present application are described by applying specific examples, the above embodiment is only used for helping to understand the battery string repair method, the photovoltaic module and the preparation method thereof and the core idea thereof; meanwhile, for the general technical personnel in the field, the specific implementation mode and the application range will be changed according to the idea of the present application, and the content of the specification should not be understood as the limitation of the present application.​

Claims

1. A method for repairing battery strings, characterized in that, The method comprises the following steps: The repair processing: placing the repair material at the welding position of the battery string, the welding temperature of the repair material is 130-160℃; The pre-welding processing: pre-welding the repair material at the welding position for 3-10s, so that the repair material is partially alloyed, and the heating temperature of the pre-welding processing is not lower than the welding temperature of the repair material; The re-inspection: detecting whether the battery string is qualified; The laminated welding: carrying out the laminated processing on the battery string qualified in the detection, the temperature of the laminated processing is not lower than the welding temperature of the repair material, so that the repair material is further alloyed, and the battery string unqualified in the detection is returned to the repair processing step.

2. The method of claim 1, wherein, When the defect position of the battery string is the welding wire part of the battery string, the welding position is the welding wire part, and the repair material is a repair liquid; The repair processing comprises the following steps: Covering a diaphragm with a hollow area on the surface of the battery string, and the welding position is opposite to the hollow area; Coating the repair liquid on the hollow area opposite to the welding position; Removing the diaphragm, and the repair liquid covers the welding position.

3. The method of claim 2, wherein, The repair liquid comprises the following components with the mass percentage: 50-70% of welding alloy powder 10-20% of flux 5-15% of solvent.

4. The method of claim 3, wherein, The particle size of the welding alloy powder is 5-15μm, and the welding alloy powder comprises one or a combination of tin, lead or bismuth; And / or, The flux comprises rosin; And / or, The solvent comprises one or both of ethanol or isopropyl alcohol; And / or, The repair liquid further comprises one or more of active agent, antioxidant and thickening agent; And / or, The repair liquid further comprises the following components with the mass percentage: 1-5% of active agent 0.1-1% of antioxidant 0.1-3% of thickening agent.

5. The method of claim 2, wherein, The diaphragm is a silica gel material or a rubber material; And / or, the width of the hollow area is 1-1.5 times of the grid line width distance of the battery piece in the battery string, and the length of the hollow area is 0.2-0.5 times of the length of the battery piece.

6. The method of claim 1, wherein, When the defect position of the battery string is inside the battery piece in the battery string, the battery piece with defects is recorded as a first sub-battery piece, the welding wire on the battery piece adjacent to the first sub-battery piece is a first sub-welding wire, the battery piece replacing the position of the first sub-battery piece in the battery string is a second sub-battery piece, the second sub-battery piece is the battery piece with a second sub-welding wire welded in advance, the area close to each other between the first sub-welding wire and the second sub-welding wire is the welding position, and the repair material is a repair film strip; The repair processing comprises the following steps: Cutting off the welding wire between the first sub-battery piece and the adjacent battery piece; Replacing the first sub-battery piece with the second sub-battery piece in the position of the battery string; A gap is formed between the surface close to the second sub-cell end and the solder wire, and the repair film tape is inserted into the gap, so that the repair film tape is in contact with the first sub-solder wire and the second sub-solder wire at the same time when the repair film tape is placed at the welding position.

7. The method of claim 6, wherein, The repair film tape comprises: a base layer; a conductive layer arranged on the base layer; a solder alloy layer arranged on the side of the conductive layer away from the base layer; The solder alloy layer is in contact with the solder wire when the repair film tape is placed at the welding position.

8. The method of claim 7, wherein, The base layer is an insulating film material; and / or, The material of the conductive layer comprises a sheet material composed of any one or more of copper, aluminum or silver; and / or, The material of the solder alloy layer comprises a solder alloy coating material composed of any one or more of tin, lead or bismuth; and / or, The thickness of the base layer is 0.01mm-0.1mm; and / or, The thickness of the conductive layer is 0.02mm-0.2mm; and / or, The thickness of the solder alloy layer is 0.01mm-0.2mm.

9. The method of claim 6, wherein, The surface structure of the base layer or the solder alloy layer is any one of a corrugated structure, a sawtooth structure or a flat structure; and / or, After the repair film tape is inserted into the welding position, an adhesive tape is also attached to the welding position, and the adhesive tape is located on the other side of the solder wire relative to the repair film tape.

10. The method of claim 1, wherein, In the pre-welding process, the heating method is infrared heat treatment; and / or, In the re-measuring step, the method for detecting whether the battery string is qualified is electroluminescence detection; and / or, In the laminated welding step, the temperature of the laminated treatment is 130℃-160℃, and the time is 15min-30min.

11. The method of claim 1-10, wherein, The diameter of the solder wire is 0.05mm-0.3mm.

12. A photovoltaic module, characterized by It comprises: a front plate; an adhesive film layer arranged on the front plate; a battery string processed by the battery string repair method according to any one of claims 1-11, which is placed in the adhesive film layer; a back plate arranged on the side of the adhesive film layer away from the front plate.

13. A method of manufacturing a photovoltaic module as defined in claim 12, characterized in that, An adhesive film material is coated on the front plate, and the battery string with a qualified re-measuring result is placed in the adhesive film material; The back plate is arranged on the side of the adhesive film material away from the front plate; After 130℃-160℃ laminated treatment for 15min-30min, the adhesive film material is converted into the adhesive film layer, and the battery string completes the laminated welding to obtain the photovoltaic module.

Images