Welding device, welding method and application of main-grid-free photovoltaic cell

Abstract

The invention relates to the field of photovoltaic cells, in particular to a welding device and method for a main-grid-free photovoltaic cell and application. The welding device for the main-grid-free 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 plurality of heating grooves are formed in the surface of one side of the first heating part; a plurality of heating grooves are formed in the surface of one side of the second heating part; the surface of the side, provided with the heating groove, of the first heating part and the surface of the side, provided with the heating groove, of the second heating part are oppositely arranged; and the heating groove is used for accommodating a welding wire on a battery piece. According to the welding device for the photovoltaic cell without the main grid, welding operation can be easily achieved, contact type welding can be carried out, the structural design is simple, a UV lamp related to glue solidification does not need to be used, the loss of the cell efficiency cannot be caused, the welding reliability is improved, and the material cost is reduced.

Description

Technical Field

[0001] The invention relates to the field of photovoltaic cells, and in particular to a welding device, a welding method and an application of a main grid-free photovoltaic cell. Background Art

[0002] In photovoltaic cells, the main grid is a metal conductive strip that connects the cells and is used to collect current. 0BB technology eliminates the main grid and replaces it with a thinner welding strip, thereby reducing silver consumption, improving power generation efficiency, and helping to reduce production costs. Specifically, the welding strip is directly interconnected with the fine grid to collect the fine grid current, and then the current is derived to achieve current collection and transmission.

[0003] At present, 0BB technology superimposed on tunneling oxide passivation contact (TOPCon), heterojunction (HJT), BC and other battery components has become a trend, mainly using dispensing (or superimposed welding) and lamination to achieve metallization connection between solder strips and batteries.

[0004] Both methods have disadvantages. For example, dispensing requires UV curing, which will cause HJT attenuation. The glue used for dispensing is an insulator, which can easily cause a high hot spot temperature or damage the component when a hot spot occurs. The cost of the coating material is relatively high. Both methods use low-temperature solder tape + lamination high temperature to connect the solder tape to the battery metallization, but the metallization effect is uncontrollable and undetectable, and there is a high reliability risk.

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

[0006] The object of the present invention is to provide a welding device, a welding method and an application of a busbar-free photovoltaic cell. The welding device of the busbar-free photovoltaic cell has the advantages of simple structural design, low welding cost and high welding reliability.

[0007] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0008] A welding device for a busbar-less photovoltaic cell comprises: a first heating part and a second heating part;

[0009] Wherein, the first heating part and the second heating part can move up and down;

[0010] A plurality of heating grooves are arranged on one side surface of the first heating part; a plurality of the heating grooves are arranged on one side surface of the second heating part; a side surface of the first heating part on which the heating grooves are arranged and a side surface of the second heating part on which the heating grooves are arranged face to face;

[0011] The heating tank is used to accommodate the welding wire on the battery cell.

[0012] The welding device for the main grid-free photovoltaic cell can easily realize welding operations and perform 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 cell efficiency, improves welding reliability, and reduces material costs.

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

[0014] Preferably, the heating groove comprises any one of a semicircular groove, a trapezoidal groove, a rectangular groove or a triangular groove.

[0015] Preferably, the diameter of the semicircular groove is 0.02-0.1 mm.

[0016] A method for welding a busbar-free photovoltaic cell, applicable to the welding device for the busbar-free photovoltaic cell, comprises the following steps:

[0017] (a) placing welding wire in the heating groove of the first heating unit and the heating groove of the second heating unit;

[0018] (b) attaching the first heating part and the second heating part to the two side surfaces of the battery cell respectively;

[0019] (c) The first heating unit and the second heating unit perform heating treatment.

[0020] The described welding method for busbar-free photovoltaic cells is simple and easy to operate, has low welding cost, optimizes the welding method of welding strips in 0BB technology, adopts contact welding, improves welding reliability, and reduces material cost.

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

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

[0023] Preferably, the type of welding wire includes: tinned welding wire.

[0024] Preferably, the temperature of the heating treatment is 150-230°C.

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

[0026] A method for preparing a busbar-free photovoltaic cell comprises the welding method of the busbar-free photovoltaic cell.

[0027] A photovoltaic assembly comprises a busbar-free photovoltaic cell prepared by the method for preparing a busbar-free photovoltaic cell.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

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

[0030] (2) The welding method of the main-grid-free photovoltaic cell provided by the present invention optimizes the welding method of the welding strip in the 0BB technology and adopts contact welding to replace the dispensing, laminating and other processes used in the conventional 0BB technology. There is no need to use glue such as thermosetting glue and UV glue, thereby reducing costs, improving welding reliability and reducing material costs. The welding strip with conventional welding temperature is used to greatly reduce the cost of the welding strip. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 A welding device for a busbar-free photovoltaic cell provided in an embodiment of the present invention;

[0033] Figure 2 A welding device for a busbar-free photovoltaic cell provided in another embodiment of the present invention;

[0034] Figure 3 A schematic flow chart of a welding method for a busbar-free photovoltaic cell provided in an embodiment of the present invention;

[0035] Figure 4 A schematic diagram of a trapezoidal groove structure provided by an embodiment of the present invention;

[0036] Figure 5 A schematic diagram of a rectangular groove structure provided by an embodiment of the present invention;

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

[0038] Reference numerals:

[0039] 1-first heating part, 2-second heating part, 3-heating tank, 4-welding wire, 5-battery cell, 6-driving part, 7-heating tube. DETAILED DESCRIPTION

[0040] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0041] One aspect of the present invention relates to a welding device for a busbar-less photovoltaic cell, comprising: a first heating unit 1 and a second heating unit 2;

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

[0043] A plurality of heating grooves 3 are arranged on one side surface of the first heating part 1; a plurality of heating grooves 3 are arranged on one side surface of the second heating part 2; a side surface of the first heating part 1 on which the heating grooves 3 are arranged faces a side surface of the second heating part 2 on which the heating grooves 3 are arranged;

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

[0045] The welding device for the main-grid-free photovoltaic cell can easily realize the welding operation and perform contact welding by setting a heating groove 3 that is adapted to the shape of the welding wire 4 on the heating part. It has a simple structural design and does not require the use of UV lamps related to glue curing, which will not cause loss of cell efficiency, improve welding reliability, and reduce material costs.

[0046] The welding device for the main-grid-free photovoltaic cell can use single-string welding or simultaneous whole-block component heating (for example, the current photovoltaic components generally have 12 strings / block, and 12 strings can be placed on the heating platform at the same time and welded simultaneously), that is, a heating plate needs to be added and a complete set of heating plates needs to be used.

[0047] The prior art has uneven metallization due to the welding method, and different metal materials are mixed together, which makes it difficult to detect. The metallization of the present invention can be carried out in accordance with the shape of the heating tank to achieve uniform metallization, which is convenient for instruments to detect.

[0048] A heating slot 3 is provided on the heating part. On the one hand, the heating slot 3 can be used for heating, and on the other hand, the path of tin is controlled during welding, so as to optimize the welding effect.

[0049] Furthermore, the shape of the heating groove 3 is adapted to the shape of the welding wire 4, that is, the shape and size of the heating groove 3 are sufficient to accommodate the welding wire 4, and have a certain contact area or full 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 is coated on the surface of the welding wire 4 to a certain extent, increasing the heated area of ​​the welding wire 4, making it easier for the welding wire 4 to be tinned and metallized with the battery cell 5, thereby improving reliability.

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

[0051] Furthermore, the diameter of the semicircular groove is 0.02-0.1 mm, which is slightly larger than the diameter of the welding wire 4, so as to ensure that the welding wire 4 can be smoothly placed in the heating tank 3 for welding.

[0052] Furthermore, a plurality of heating tubes 7 are disposed inside the first heating part 1 and the second heating part 2. By disposing the heating tubes 7, the heating part can heat the entire plate evenly and quickly.

[0053] Furthermore, the first heating part 1 and the second heating part 2 are controlled to move up and down by a driving part 6 , and the driving part 6 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 are combined by moving up and down to heat the battery cell 5 in a whole string, and heat both sides of the battery cell 5 at the same time, so that the welding wire 4 and the battery cell 5 are metallized. After welding is completed, the first heating part 1 and the second heating part 2 move up and down, away from the already welded battery. In the actual operation process, the first heating part 1 and the second heating part 2 can be moved at the same time to complete the bonding or separation of the two, or the first heating part 1 or the second heating part 2 can be moved alone to complete the bonding or separation of the two. Heating both sides at the same time can weld the front and back sides at the same time, improving the efficiency of welding; heating both sides at the same time can make the battery cell heated more evenly, improve the thermal deformation of the battery cell, and reduce the breakage rate of the battery cell.

[0055] In some specific embodiments, such as Figure 2 As shown, the first heating part 1 (containing a heating tube 7 inside) is a welding tool for welding a whole string. During welding, the driving part 6 controls the first heating part 1 to move up and down for welding. The first heating part 1 and the second heating part 2 are combined for heating to allow the round welding wire 4 to be tinned and metallized with the battery cell 5.

[0056] Another aspect of the present invention also relates to a welding method for a busbar-free photovoltaic cell, which is applicable to a welding device for the busbar-free photovoltaic cell, and comprises the following steps:

[0057] (a) placing welding wire 4 in heating groove 3 of first heating unit 1 and heating groove 3 of second heating unit 2;

[0058] (b) attaching the first heating unit 1 and the second heating unit 2 to the two side surfaces of the battery cell 5 respectively;

[0059] (c) The first heating unit 1 and the second heating unit 2 perform heating treatment.

[0060] The described welding method of busbar-free photovoltaic cells optimizes the welding method of welding strips in 0BB technology, adopts contact welding, improves welding reliability and reduces material costs.

[0061] The welding method of the main-grid-free photovoltaic cell adopts a special welding method to replace the dispensing, laminating and other processes used in conventional 0BB technology. It does not need to use glue such as thermosetting glue and UV glue, thereby reducing costs; and uses welding strips with conventional welding temperatures, greatly reducing the cost of welding strips.

[0062] Further, the diameter of the welding wire 4 is 0.16-0.32 mm, including but not limited to any point value 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 value between any two of them. The diameter of the welding wire 4 is limited to a certain range, which can match the heating slot 3 on the heating part.

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

[0064] The cylindrical welding wire 4 cooperates with the semicircular groove, so that the tinning range of the welding wire 4 can be controlled within the range of the heating tank 3, thereby improving the accuracy and reliability of welding.

[0065] Furthermore, the types of the welding wire 4 include but are not limited to: tinned welding wire. In the prior art, the metallization connection between the welding strip and the battery requires the use of a low-temperature welding strip, and the low-temperature welding strip has a higher cost than the conventional welding wire 4. The present invention uses a conventional welding wire 4 to complete welding, and the welding cost is lower than that of the prior art. The present invention can match conventional welding wires by adjusting the shape of the heating tank. The battery cell itself is composed of a silicon chip + surface silver paste, etc. The material itself is heat-resistant, and the heating is only for welding the silver paste on the surface of the battery cell (conventional welding also has heat, and it also belongs to the mode of heating welding).

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

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

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

[0069] By controlling the temperature and time of the heating treatment within a certain range, the solder wire 4 can be completely tinned and metallized with the battery cell 5 .

[0070] In some specific embodiments, the welding method of the busbar-free photovoltaic cell comprises 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 an upward or downward pressing welding operation. After the heating part is heated, the tin layer on the surface of the round welding wire 4 will melt on the surface of the battery cell 5, completing the metallization combination of the round welding wire 4 and the battery cell 5. After welding is completed, the heating part is away from the battery cell 5.

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

[0073] Another aspect of the present invention also relates to a photovoltaic module, including a busbar-free photovoltaic cell prepared by the method for preparing a busbar-free photovoltaic cell.

[0074] The embodiments of the present invention will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. If no specific conditions are specified in the examples, the conditions are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0075] Example 1

[0076] The welding device for the main grid-free photovoltaic cell provided in this embodiment is as follows: Figure 1 and Figure 2 As shown, it comprises: a first heating part 1 and a second heating part 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 is provided with a side surface of the heating groove 3 and the second heating part 2 is provided with a side surface of the heating groove 3 facing each other;

[0080] The heating tank 3 is used to accommodate the welding wire 4 on the 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 semicircular groove, and the diameter of the semicircular groove is 0.05 mm.

[0082] Example 2

[0083] The welding device for busbar-free photovoltaic cells provided in this embodiment is different from that in Embodiment 1 only in that the diameter of the semicircular groove is 0.02 mm.

[0084] Example 3

[0085] The welding device for busbar-free photovoltaic cells provided in this embodiment is different from that in Embodiment 1 only in that the diameter of the semicircular groove is 0.1 mm.

[0086] Example 4

[0087] The welding method of the busbar-free photovoltaic cell provided in this embodiment uses the busbar-free photovoltaic cell welding device provided in Example 1, and comprises the following steps:

[0088] 1. Place welding wire 4 in heating groove 3 of first heating part 1 and heating groove 3 of second heating part 2; the diameter of welding wire 4 is 0.25 mm; the shape of welding wire 4 is cylindrical; the type of welding wire 4 is tinned welding wire;

[0089] 2. Attach the first heating unit 1 and the second heating unit 2 to the two side surfaces of the battery cell 5 respectively;

[0090] 3. The first heating part 1 and the second heating part 2 are subjected to heating treatment; the heating treatment temperature is 180° C. and the time is 1000 ms.

[0091] Example 5

[0092] The welding method of the busbar-free photovoltaic cell provided in this embodiment uses the busbar-free photovoltaic cell welding device provided in Example 2, and the rest is the same as Example 4. The diameter of the welding wire 4 is 0.16 mm, the heating treatment temperature is 230° C., and the heating treatment time is 600 ms.

[0093] Example 6

[0094] The welding method of the busbar-free photovoltaic cell provided in this embodiment uses the busbar-free photovoltaic cell welding device provided in Example 3, and the rest is the same as Example 4. The diameter of the welding wire 4 is 0.32 mm, the heating treatment temperature is 150° C., and the heating treatment time is 1500 ms.

[0095] Comparative Example 1

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

[0097] Experimental example

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

[0099] Table 1

[0100]

[0101]

[0102] It can be seen from Table 1 that Example 5 has the largest tensile force and the best welding effect. It can be concluded that welding temperature is the main influencing factor, followed by welding time. Using a welding temperature of 230° C. and a proper welding time can make the welding tensile force meet the requirements.

[0103] Although the present invention has been illustrated and described with specific embodiments, it should be appreciated that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents without departing from the spirit and scope of the present invention. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications within the scope of the present invention are included in the appended claims.

Claims

1. A welding device for a busbar-free photovoltaic cell, characterized in that: include: a first heating unit and a second heating unit; Wherein, the first heating part and the second heating part can move up and down; A plurality of heating grooves are arranged on one side surface of the first heating part; a plurality of the heating grooves are arranged on one side surface of the second heating part; a side surface of the first heating part on which the heating grooves are arranged and a side surface of the second heating part on which the heating grooves are arranged face to face; The heating tank is used to accommodate the welding wire on the battery cell.

2. The welding device for busbar-free photovoltaic cells according to claim 1, characterized in that: The shape of the heating tank is adapted to the shape of the welding wire.

3. The welding device for busbar-free photovoltaic cells according to claim 1, characterized in that: The heating groove includes any one of a semicircular groove, a trapezoidal groove, a rectangular groove or a triangular groove.

4. The welding device for busbar-free photovoltaic cells according to claim 3, characterized in that: The diameter of the semicircular groove is 0.02-0.1 mm.

5. A method for welding a busbar-free photovoltaic cell, applicable to the welding device for a busbar-free photovoltaic cell according to any one of claims 1 to 4, characterized in that: The following steps are involved: (a) placing welding wire in the heating groove of the first heating unit and the heating groove of the second heating unit; (b) attaching the first heating part and the second heating part to the two side surfaces of the battery cell respectively; (c) The first heating unit and the second heating unit perform heating treatment.

6. The welding method of busbar-free photovoltaic cells according to claim 5, characterized in that: The diameter of the welding wire is 0.16-0.32 mm; And / or, the shape of the welding wire includes: any one of a cylindrical shape, a quadrangular prism shape or a triangular prism shape.

7. The welding method of busbar-free photovoltaic cells according to claim 5, characterized in that: The types of welding wire include: tinned welding wire.

8. The welding method of busbar-free photovoltaic cells according to claim 5, characterized in that: The temperature of the heating treatment is 150-230°C; And / or, the heating treatment time is 600 to 1500 ms.

9. A method for preparing a busbar-free photovoltaic cell, characterized in that: A welding method for a busbar-free photovoltaic cell comprising the method described in any one of claims 5 to 8.

10. A photovoltaic module, characterized in that: A busbar-free photovoltaic cell prepared by the method for preparing a busbar-free photovoltaic cell according to claim 9.

Images