A soldering apparatus, soldering method and application for a gridless photovoltaic cell

Abstract

The present application relates to the field of photovoltaic cells, and more particularly to a welding device, a welding method and application of a main gridless photovoltaic cell. The welding device of the main gridless photovoltaic cell comprises: a first heating part and a second heating part; the first heating part and the second heating part can move up and down; a side surface of the first heating part is provided with a plurality of heating grooves; a side surface of the second heating part is provided with a plurality of heating grooves; the side surface of the first heating part provided with the heating grooves and the side surface of the second heating part provided with the heating grooves are oppositely arranged; and the heating grooves are used for accommodating welding wires on the cell. The welding device of the main gridless photovoltaic cell can easily realize welding operation and contact welding, has simple structure design, does not need to use a UV lamp related to glue curing, does not cause loss of cell efficiency, improves the reliability of welding, and reduces material cost.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cells, and more specifically, to a welding apparatus, welding method, and application for a gridless photovoltaic cell. Background Technology

[0002] In photovoltaic cells, the main grid is a metal conductive strip connecting the cells and used to collect current. OBB technology eliminates the main grid by replacing it with finer solder strips, thereby reducing silver loss, improving power generation efficiency, and helping to lower production costs. Specifically, the solder strips directly interconnect with the fine grid to collect the grid current and then conduct the current, achieving both current collection and transmission.

[0003] Currently, OBB technology, which combines tunnel oxide passivation contacts (TOPCon), heterojunction (HJT), BC, and other battery modules, has become a trend. It mainly uses two methods, namely dispensing (or superimposed welding) and film coating, to achieve the metallization connection between the solder strip and the battery.

[0004] Both methods have disadvantages. For example, dispensing requires UV curing, which can lead to HJT degradation. The adhesive used for dispensing is an insulator, which can easily cause high hot spot temperatures or damage to the module when hot spots occur. The cost of the coating material is high. Both methods use low-temperature solder ribbons and high-temperature lamination to metallize the solder ribbons to the cells, but the metallization effect is uncontrollable and undetectable, posing a high reliability risk.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a welding device, welding method and application for a gridless photovoltaic cell. The welding device for the gridless photovoltaic cell has the advantages of simple structural design, low welding cost and high welding reliability.

[0007] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0008] A welding apparatus for gridless photovoltaic cells includes: a first heating section and a second heating section;

[0009] The first heating element and the second heating element can move up and down;

[0010] A plurality of heating grooves are provided on one side surface of the first heating part; a plurality of heating grooves are provided on one side surface of the second heating part; the side surface of the first heating part with the heating grooves and the side surface of the second heating part with the heating grooves are arranged facing each other;

[0011] The heating groove is used to hold the welding wires on the battery cells.

[0012] The aforementioned welding device for gridless photovoltaic cells can easily perform welding operations and conduct contact welding. It has a simple structural design, does not require the use of UV lamps related to glue curing, does not cause loss of battery efficiency, improves welding reliability, and reduces material costs.

[0013] Preferably, the shape of the heating groove is adapted to the shape of the welding wire.

[0014] Preferably, the heating groove includes any one of a semi-circular groove, a trapezoidal groove, a rectangular groove, or a triangular groove.

[0015] Preferably, the diameter of the semi-circular groove is 0.02 to 0.1 mm.

[0016] A welding method for a grid-less photovoltaic cell, applicable to the welding apparatus for the grid-less photovoltaic cell, includes the following steps:

[0017] (a) Place welding wire in the heating tank of the first heating section and the heating tank of the second heating section;

[0018] (b) The first heating element and the second heating element are respectively attached to the two side surfaces of the battery cell;

[0019] (c) The first heating section and the second heating section are subjected to heating treatment.

[0020] The aforementioned welding method for gridless photovoltaic cells is simple and easy to operate, with low welding costs. It optimizes the welding method of the solder strip in OBB technology, adopts contact welding, improves welding reliability, and reduces material costs.

[0021] Preferably, the diameter of the welding wire is 0.16 to 0.32 mm.

[0022] Preferably, the shape of the welding wire includes any one of cylindrical, quadrangular prism, or triangular prism.

[0023] Preferably, the type of welding wire includes tin-plated welding wire.

[0024] Preferably, the temperature of the heat treatment is 150–230°C.

[0025] Preferably, the heating treatment time is 600–1500 ms.

[0026] A method for fabricating a grid-less photovoltaic cell includes a welding method for the grid-less photovoltaic cell.

[0027] A photovoltaic module includes a gridless photovoltaic cell prepared by the aforementioned method.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] (1) The welding device for gridless photovoltaic cells provided by the present invention can easily realize welding operation and perform contact welding by setting a heating groove on the heating part that is adapted to the shape of the welding wire. The structure design is simple, and there is no need to use UV lamps related to glue curing, which will not cause loss of battery efficiency, improve welding reliability, and reduce material costs.

[0030] (2) The welding method of the gridless photovoltaic cell provided by the present invention optimizes the welding method of the solder strip in the OBB technology, adopts contact welding, and replaces the dispensing and coating processes used in conventional OBB technology. It eliminates the need for thermosetting adhesives, UV adhesives and other glues, thereby reducing costs, improving welding reliability and reducing material costs. The use of solder strips with conventional welding temperatures greatly reduces the cost of solder strips. Attached Figure Description

[0031] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 Welding apparatus for gridless photovoltaic cells provided in embodiments of the present invention;

[0033] Figure 2 A welding apparatus for a gridless photovoltaic cell is provided in another embodiment of the present invention;

[0034] Figure 3 A schematic diagram of the welding method for a gridless photovoltaic cell provided in an embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of the trapezoidal groove structure provided in an embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram of a rectangular groove structure provided in an embodiment of the present invention;

[0037] Figure 6 This is a schematic diagram of the triangular groove structure provided in an embodiment of the present invention.

[0038] Figure label:

[0039] 1-First heating section, 2-Second heating section, 3-Heating groove, 4-Welding wire, 5-Battery cell, 6-Drive section, 7-Heating tube. Detailed Implementation

[0040] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0041] One aspect of the present invention relates to a welding apparatus for a gridless photovoltaic cell, comprising: a first heating part 1 and a second heating part 2;

[0042] The first heating part 1 and the second heating part 2 can move up and down;

[0043] A plurality of heating grooves 3 are provided on one side surface of the first heating part 1; a plurality of heating grooves 3 are provided on one side surface of the second heating part 2; the side surface of the first heating part 1 with the heating grooves 3 and the side surface of the second heating part 2 with the heating grooves 3 are arranged facing each other.

[0044] The heating groove 3 is used to accommodate the welding wire 4 on the battery cell 5.

[0045] The aforementioned welding device for gridless photovoltaic cells can easily achieve welding operations and perform contact welding by setting a heating groove 3 on the heating part that is adapted to the shape of the welding wire 4. The structure is simple, does not require the use of UV lamps related to glue curing, does not cause loss of battery efficiency, improves welding reliability, and reduces material costs.

[0046] The welding device for the gridless photovoltaic cell can be used for single-string welding or for simultaneous heating of the entire module (for example, photovoltaic modules are generally 12 strings / module, so 12 strings can be placed on the heating platform and welded together at the same time). In other words, a heating plate needs to be added, and a complete set of heating plates should be used.

[0047] Existing technologies suffer from uneven metallization due to welding methods, resulting in a mixture of different metal materials that is difficult to detect. The present invention can achieve uniform metallization by following the shape of the heating tank, making it convenient for instruments to detect.

[0048] A heating tank 3 is provided on the heating part. On the one hand, the heating tank 3 can be used for heating, and on the other hand, it can control the planning of the solder path during soldering, thereby optimizing the soldering effect.

[0049] Furthermore, the shape of the heating groove 3 is adapted to the shape of the welding wire 4, meaning that the shape and size of the heating groove 3 are sufficient to accommodate the welding wire 4, and it has a certain contact area or complete contact with the welding wire 4. During welding, the shape of the heating groove 3 is adapted to the shape of the welding wire 4, the welding wire 4 is in contact with the heating groove 3, and the heating groove 3 covers the surface of the welding wire 4 to a certain extent, increasing the heating area of ​​the welding wire 4, making it easier for the welding wire 4 to undergo tinning and metallize with the battery cell 5, thereby improving reliability.

[0050] Furthermore, the heating groove 3 includes, but is not limited to: a semi-circular groove, a trapezoidal groove (such as... Figure 4 As shown), rectangular groove (as shown) Figure 5 (as shown) or triangular groove (such as) Figure 6 Any one of the ones shown.

[0051] Furthermore, the diameter of the semi-circular groove is 0.02–0.1 mm. This diameter is slightly larger than the diameter of the welding wire 4, ensuring that the welding wire 4 can be smoothly placed in the heating tank 3 for welding.

[0052] Furthermore, the first heating section 1 and the second heating section 2 are equipped with a plurality of heating tubes 7. Through the arrangement of the heating tubes 7, the heating section can uniformly and quickly complete the heating of the entire plate.

[0053] Furthermore, the first heating unit 1 and the second heating unit 2 are controlled to move up and down by the drive unit 6, which includes, but is not limited to, a cylinder or a motor.

[0054] When welding is required, the first heating part 1 and the second heating part 2 move up and down together to heat the entire string of battery cells 5 simultaneously, heating both sides of the battery cells 5 to metallize the welding wire 4 to the battery cells 5. After welding is completed, the first heating part 1 and the second heating part 2 move up and down, moving away from the welded battery. In actual operation, the first heating part 1 and the second heating part 2 can be moved simultaneously to bring them together or separate, or either the first heating part 1 or the second heating part 2 can be moved individually to bring them together or separate them. Heating both sides simultaneously allows welding to be performed on both the front and back sides at the same time, improving welding efficiency; heating both sides simultaneously also makes the battery cells heat more evenly, improving thermal deformation of the battery cells and reducing the breakage rate of the battery cells.

[0055] In some specific implementation methods, such as Figure 2 As shown, the first heating part 1 (containing heating tube 7 inside) is a welding fixture for whole-string welding. During welding, the first heating part 1 is controlled by the drive part 6 to move up and down to perform welding. The first heating part 1 and the second heating part 2 are heated together to allow the round welding wire 4 to be tinned and metallized with the battery cell 5.

[0056] Another aspect of the present invention relates to a welding method for a grid-less photovoltaic cell, applicable to the welding apparatus for the grid-less photovoltaic cell, comprising the following steps:

[0057] (a) Welding wire 4 is placed in the heating groove 3 of the first heating section 1 and the heating groove 3 of the second heating section 2;

[0058] (b) The first heating part 1 and the second heating part 2 are respectively attached to the two side surfaces of the battery cell 5;

[0059] (c) The first heating part 1 and the second heating part 2 are subjected to heating treatment.

[0060] The welding method for the gridless photovoltaic cell optimizes the welding method of the solder strip in OBB technology, adopts contact welding, improves welding reliability and reduces material costs.

[0061] The aforementioned welding method for gridless photovoltaic cells employs a special welding technique that replaces the dispensing and coating processes used in conventional OBB technology. It eliminates the need for thermosetting adhesives, UV adhesives, and other glues, thereby reducing costs. Furthermore, it utilizes solder strips at conventional welding temperatures, significantly reducing the cost of the solder strips.

[0062] Furthermore, the diameter of the welding wire 4 is 0.16–0.32 mm, including but not limited to any one of 0.16 mm, 0.18 mm, 0.20 mm, 0.22 mm, 0.24 mm, 0.26 mm, 0.28 mm, 0.30 mm, or 0.32 mm, or a range between any two. Limiting the diameter of the welding wire 4 to a certain range allows it to match the heating groove 3 on the heating unit.

[0063] Furthermore, the shape of the welding wire 4 includes, but is not limited to, any one of cylindrical, quadrangular prism, or triangular prism.

[0064] The cylindrical welding wire 4, in conjunction with the semi-circular groove, can control the tin melting range of the welding wire 4 within the heating tank 3, thereby improving the accuracy and reliability of welding.

[0065] Furthermore, the type of welding wire 4 includes, but is not limited to, tin-plated welding wire. Existing technologies for metallizing the solder strip and battery all require the use of low-temperature solder strips, which are more expensive than conventional welding wire 4. This invention can complete the welding using conventional welding wire 4, resulting in lower welding costs compared to existing technologies. This invention can adjust the shape of the heating groove to match conventional welding wire. The battery cell itself is composed of silicon wafers and surface silver paste, and the material itself is heat-resistant. Heating only targets the surface silver paste of the battery cell for welding (conventional welding also involves heat and falls under the category of heating welding).

[0066] Furthermore, the type of welding wire 4 includes, but is not limited to, any one of tin-plated round welding wire, tin-plated rectangular welding wire, or tin-plated triangular welding wire.

[0067] Furthermore, the temperature of the heat treatment is 150 to 230°C, including but not limited to any one of 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C or 230°C, or a range between any two.

[0068] Furthermore, the heat treatment time is 600–1500 ms, including but not limited to any one of 600 ms, 650 ms, 700 ms, 750 ms, 800 ms, 850 ms, 900 ms, 950 ms, 1000 ms, 1050 ms, 1100 ms, 1150 ms, 1200 ms, 1250 ms, 1300 ms, 1350 ms, 1400 ms, 1450 ms, or 1500 ms, or a range between any two. The heat treatment time can be adjusted according to the welding effect.

[0069] By controlling the temperature and time of the heat treatment within a certain range, the welding wire 4 can complete the tinning and metallize with the battery cell 5.

[0070] In some specific embodiments, the welding method for the gridless photovoltaic cell includes the following steps:

[0071] like Figure 3 As shown, during welding, the round welding wire 4 is first placed in the heating groove 3 of the first heating part 1 and the heating groove 3 of the second heating part 2. During welding, the first heating part 1 and the second heating part 2 simultaneously perform upward or downward welding operations. After the heating part is heated, the tin layer on the surface of the round welding wire 4 will melt onto the surface of the battery cell 5, completing the metallization of the round welding wire 4 and the battery cell 5. After welding is completed, the heating part moves away from the battery cell 5.

[0072] Another aspect of the present invention relates to a method for preparing a gridless photovoltaic cell, including the welding method for the gridless photovoltaic cell.

[0073] Another aspect of the present invention relates to a photovoltaic module, comprising a gridless photovoltaic cell prepared by the aforementioned method for preparing a gridless photovoltaic cell.

[0074] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0075] Example 1

[0076] The welding apparatus for gridless photovoltaic cells provided in this embodiment, such as... Figure 1 and Figure 2 As shown, it includes: a first heating unit 1 and a second heating unit 2;

[0077] The first heating part 1 and the second heating part 2 can move up and down;

[0078] A plurality of heating grooves 3 are provided on one side surface of the first heating part 1; a plurality of heating grooves 3 are provided on one side surface of the second heating part 2.

[0079] The first heating part 1 has one side surface with the heating groove 3 and the second heating part 2 has one side surface with the heating groove 3 facing each other.

[0080] Heating groove 3 is used to accommodate welding wire 4 on battery cell 5;

[0081] The shape of the heating groove 3 is adapted to the shape of the welding wire 4; the heating groove 3 is a semi-circular groove with a diameter of 0.05mm.

[0082] Example 2

[0083] The welding device for gridless photovoltaic cells provided in this embodiment differs from that in Embodiment 1 only in that the diameter of the semi-circular groove is 0.02 mm.

[0084] Example 3

[0085] The welding device for gridless photovoltaic cells provided in this embodiment differs from that in Embodiment 1 only in that the diameter of the semi-circular groove is 0.1 mm.

[0086] Example 4

[0087] The welding method for grid-free photovoltaic cells provided in this embodiment uses the welding apparatus for grid-free photovoltaic cells provided in Embodiment 1, and includes the following steps:

[0088] 1. A welding wire 4 is placed in the heating groove 3 of the first heating section 1 and the heating groove 3 of the second heating section 2; the diameter of the welding wire 4 is 0.25mm; the shape of the welding wire 4 is cylindrical; the type of the welding wire 4 is tin-plated welding wire.

[0089] 2. The first heating part 1 and the second heating part 2 are respectively attached to the two side surfaces of the battery cell 5;

[0090] 3. The first heating section 1 and the second heating section 2 are heated; the heating temperature is 180℃ and the time is 1000ms.

[0091] Example 5

[0092] The welding method for gridless photovoltaic cells provided in this embodiment uses the welding device for gridless photovoltaic cells provided in Embodiment 2, and the rest is the same as in Embodiment 4. The diameter of the welding wire 4 is 0.16 mm, the heating temperature is 230°C, and the heating time is 600 ms.

[0093] Example 6

[0094] The welding method for gridless photovoltaic cells provided in this embodiment uses the welding device for gridless photovoltaic cells provided in Embodiment 3, and the rest is the same as in Embodiment 4. The diameter of the welding wire 4 is 0.32 mm, the heating temperature is 150°C, and the heating time is 1500 ms.

[0095] Comparative Example 1

[0096] The only difference between this comparative example and Example 4 is that the heat treatment temperature is 250°C.

[0097] Experimental Example

[0098] The gridless photovoltaic cells obtained by welding Examples 4-6 and Comparative Example 1 were subjected to conventional tensile tests. The specific test method was to use a tensile testing machine to test the peel force between the welding wire and the cell. The results are shown in Table 1.

[0099] Table 1

[0100]

[0101]

[0102] As shown in Table 1, Example 5 exhibits the highest tensile strength and the best welding effect. This indicates that welding temperature is the primary influencing factor, followed by welding time. By using a welding temperature of 230℃ and an appropriate welding time, the welding tensile strength can meet the requirements.

[0103] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A soldering apparatus for a gridless photovoltaic cell, characterized by, The application relates to a soldering method for a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell.

2. The apparatus for soldering of a gridless photovoltaic cell according to claim 1, characterized in that, The application relates to a main-grid-free photovoltaic cell.

3. The apparatus for soldering of a gridless photovoltaic cell according to claim 2, characterized in that, The application relates to a main-grid-free photovoltaic cell.

4. A soldering method for a gridless photovoltaic cell, suitable for use in the soldering apparatus according to any one of claims 1 to 3, characterized by, The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell.

5. The soldering method of a gridless photovoltaic cell according to claim 4, wherein The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell.

6. The soldering method of a gridless photovoltaic cell according to claim 4, wherein The application relates to a main-grid-free photovoltaic cell.

7. The soldering method of a gridless photovoltaic cell according to claim 4, wherein The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell.

8. A method of fabricating a gridless photovoltaic cell, characterized by, The application relates to a main-grid-free photovoltaic cell.

9. A photovoltaic module, characterized by The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The application relates to a main-grid-free photovoltaic cell. The

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