A busbar hidden photovoltaic module

Abstract

The utility model discloses a kind of busbar hidden photovoltaic module, belong to solar cell technical field, including BC battery string and electrode busbar structure, the back of BC battery string is uniformly provided with mutually staggered anode main grid line and cathode main grid line, the electrode busbar structure includes busbar, the busbar is set to the back of BC battery string head and tail piece, the top of busbar is transversely extended and is provided with several mutually staggered anode connecting parts and several cathode connecting parts, anode connecting part is electrically connected anode main grid line respectively, cathode connecting part is electrically connected cathode main grid line respectively. By being arranged in the back of battery string head and tail piece, and connecting directly with the positive and negative grid line of battery back by anode and cathode connecting part, the "hidden" of busbar is realized, fundamentally solve the problem of layout space waste caused by traditional BC module due to busbar exposure, so that component structure is more compact, power density is higher.

Description

Technical Field

[0001] This utility model relates to the field of solar cell technology, and more specifically, to a photovoltaic module with concealed busbars. Background Technology

[0002] Against the backdrop of global warming and the increasing scarcity of non-renewable energy, solar energy, as a clean and renewable energy source, has attracted much attention for its technological development. Back-contact (BC) solar cell technology, because it places all positive and negative electrodes on the back of the cell, avoids the shading of light by the front grid lines, thereby improving photoelectric conversion efficiency and enhancing the aesthetics of the module, has become a current research hotspot.

[0003] Currently, mainstream BC modules use a half-cell layout, dividing the module into two sub-modules. The cells within each sub-module are connected in series, while the two sub-modules are connected in parallel via busbars on the outside of the cells. Encapsulating cells into modules not only ensures their voltage, current, and output power but also protects them from environmental and mechanical damage. However, after crystalline silicon solar cells are encapsulated into modules, some non-power-generating areas remain. The larger these areas are, the greater the power loss from module encapsulation. Furthermore, the exposed busbars at the cell edges result in low space utilization, a less compact structure, and negatively impact the module's aesthetics. Therefore, addressing the issues of wasted space and poor aesthetics caused by exposed busbars in existing technologies has become a major research focus. Utility Model Content

[0004] To address the above problems, this utility model provides a photovoltaic module with concealed busbars, the technical solution of which is as follows:

[0005] A photovoltaic module with concealed busbars includes a BC cell string and an electrode busbar structure. Each BC cell string has several interleaved positive main grid lines and several interleaved negative main grid lines on its back side. The electrode busbar structure is electrically connected to the BC cell string. The electrode busbar structure includes a busbar located on the back side of the first and second cells of the BC cell string. The top of the busbar extends laterally and has several interleaved positive connection portions and several interleaved negative connection portions. The positive connection portions are electrically connected to the positive main grid lines, and the negative connection portions are electrically connected to the negative main grid lines.

[0006] By placing the busbars on the back of the first and last cells of the battery string and directly connecting the positive and negative terminals to the positive and negative grid lines on the back of the BC battery string, the busbars are "hidden," fundamentally solving the problem of wasted layout space caused by exposed busbars in traditional BC modules, resulting in a more compact module structure and higher power density.

[0007] Preferably, the busbar is made of low-melting-point tin-plated copper strip, with a width of 10-15 mm and a thickness of 0.1-0.15 mm. The low-melting-point tin-plated copper strip material ensures good solderability and conductivity during the lamination process; this size range ensures that the busbar has sufficient current-carrying capacity while meeting the current transmission requirements, and avoids the risk of affecting the lamination process or causing microcracks due to excessive thickness and rigidity.

[0008] Preferably, the width of the positive electrode connection portion is 0.6~0.8mm and the thickness is 0.2~0.25mm.

[0009] Preferably, the width of the negative electrode connection portion is 0.6~0.8mm and the thickness is 0.2~0.25mm.

[0010] Preferably, the electrode busbar structure comprises, from bottom to top, an EVA adhesive layer, a first insulating support layer, a first adhesive layer, a busbar, a second adhesive layer, and a second insulating support layer. Through the cooperation of the insulating support layer and the adhesive layer, reliable insulation and fixation are achieved between the conductive busbar and the battery cells and other components. This not only effectively prevents safety hazards such as leakage and short circuits, but also enhances the bonding strength between the entire structure and the battery cells through the EVA adhesive layer, improving the mechanical stability and long-term durability of the module.

[0011] Preferably, the positive electrode connection portion and the negative electrode connection portion are integrally formed with the busbar, and the second adhesive bonding layer and the insulating support layer are respectively stacked on the side of the positive electrode connection portion and the negative electrode connection portion away from the busbar.

[0012] Preferably, the first insulating support layer and the second insulating support layer are made of PET and have a thickness of 50~100μm. PET material has good insulation, heat resistance and mechanical strength.

[0013] Preferably, the first adhesive layer and the second adhesive layer are thermosetting adhesive films.

[0014] Preferably, the thickness of the EVA adhesive layer is 50~100μm.

[0015] Preferably, the BC battery string comprises a plurality of BC battery cells connected in series, and the BC battery cells are connected in series by solder strips.

[0016] This utility model also provides a method for preparing the above-mentioned BC photovoltaic module, comprising the following steps:

[0017] Step 1: Prepare the busbar and electrode busbar structure in sequence. Use a suction cup to pick up the top of the electrode busbar structure and place the bottom of the electrode busbar structure on the back of the BC battery string, so that the EVA adhesive layer at the bottom of the electrode busbar structure contacts the back of the first and last sheets of the BC battery string.

[0018] Step 2: Electrically connect several positive terminal connections and several negative terminal connections of the busbar to the positive main grid line and the negative main grid line on the back of the BC battery string, respectively.

[0019] Step 3: The photovoltaic module prepared in Step 2 is pressed together using a metal heating plate, and the EVA adhesive layer at the bottom of the electrode busbar structure is melted to form a preliminary bond with the BC cell string;

[0020] Step 4: EVA film, backplate or glass are sequentially laid on the back of the BC battery string, and the tin on the top of the busbar is melted and connected to the silver paste of the main grid of the BC battery string using a laminator.

[0021] Preferably, the heating temperature for pressing the heating plate in step three is 80~120℃, and the time is 5~10s.

[0022] Preferably, in step four, the heating temperature of the laminator is 150~155℃, and the time is 10~15min.

[0023] The beneficial effects of adopting the technical solution of this utility model are as follows:

[0024] This invention achieves "hidden" busbars by placing them on the back of the first and last cells of the battery string and directly connecting the positive and negative terminals to the positive and negative grid lines on the back of the battery. This fundamentally solves the problem of wasted layout space caused by exposed busbars in traditional BC modules, resulting in a more compact module structure and higher power density. Furthermore, it eliminates any metal components such as solder strips or busbars from obstructing the front of the module, improving the utilization rate of module layout space. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the back structure of the photovoltaic module with concealed busbars according to this utility model;

[0027] Figure 2This is a schematic diagram of the busbar located between battery strings according to this utility model;

[0028] Figure 3 This is a schematic diagram of the busbar located at the edge of the battery string according to this utility model;

[0029] Figure 4 This is a schematic diagram of the layer structure of the BC photovoltaic module with concealed busbars according to this utility model.

[0030] Among them, 1. BC battery string; 2. EVA adhesive layer; 3. First insulating support layer; 4. First adhesive layer; 5. Busbar; 51. Positive electrode connection part; 52. Negative electrode connection part; 6. Second adhesive layer; 7. Second insulating support layer. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this utility model, not all of them. Therefore, the detailed description of the embodiments provided by this utility model below is not intended to limit the scope of the claimed utility model, but merely represents selected embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0032] This embodiment achieves "hidden" busbars by placing them on the back of the first and last cells of the battery string and directly connecting the positive and negative terminals to the positive and negative grid lines on the back of the battery. This fundamentally solves the problem of wasted layout space caused by exposed busbars in traditional BC modules, resulting in a more compact module structure and higher power density. The specific implementation method is as follows:

[0033] like Figures 1-4 As shown, a photovoltaic module with concealed busbars includes a BC cell string 1 and an electrode busbar structure. The back of each BC cell string 1 is provided with several interleaved positive main grid lines and several interleaved negative main grid lines. The electrode busbar structure is electrically connected to the BC cell string 1. The electrode busbar structure includes a busbar 5, which is disposed on the back of the first and last cells of the BC cell string 1. The top of the busbar 5 extends laterally and is provided with several interleaved positive connection portions 51 and several interleaved negative connection portions 52. The positive connection portions 51 are electrically connected to the positive main grid lines, and the negative connection portions 52 are electrically connected to the negative main grid lines.

[0034] By placing the busbar 5 on the back of the first and last cells of the BC battery string 1 and directly connecting the positive and negative terminals (51, 52) to the positive and negative grid lines on the back of the battery, the busbar is "hidden", which fundamentally solves the problem of wasted layout space caused by exposed busbars in traditional BC modules, making the module structure more compact and the power density higher.

[0035] In a preferred embodiment, the busbar 5 is made of low-melting-point tin-plated copper strip with a width of 10-15 mm and a thickness of 0.1-0.15 mm. The low-melting-point tin-plated copper strip material ensures good solderability and conductivity during the lamination process; this size range ensures that the busbar has sufficient current-carrying capacity while meeting the current transmission requirements, and avoids the risk of affecting the lamination process or causing microcracks due to excessive thickness and rigidity.

[0036] In a preferred embodiment, the width of the positive electrode connection portion 51 is 0.6~0.8mm and the thickness is 0.2~0.25mm.

[0037] In a preferred embodiment, the width of the negative electrode connection portion 52 is 0.6~0.8mm and the thickness is 0.2~0.25mm.

[0038] In a preferred embodiment, the electrode busbar structure comprises, from bottom to top, an EVA adhesive layer 2, a first insulating support layer 3, a first adhesive layer 4, a busbar 5, a second adhesive layer 6, and a second insulating support layer 7. The positive electrode connection 51 and the negative electrode connection 52 of the busbar 5 are electrically connected to the BC battery string 1. Through the cooperation of the insulating support layers (3, 7) and the adhesive layers (4, 6), reliable insulation and fixation are achieved between the conductive busbar 5 and the battery cells and other components. This not only effectively prevents safety hazards such as leakage and short circuits, but also enhances the bonding strength between the entire structure and the battery cells through the EVA adhesive layer 2, improving the mechanical stability and long-term durability of the module.

[0039] In a preferred embodiment, the positive electrode connection portion 51 and the negative electrode connection portion 52 are integrally formed with the busbar 5, and the second adhesive layer 6 and the second insulating support layer 7 are respectively stacked on the side of the positive electrode connection portion 51 and the negative electrode connection portion 52 away from the busbar 5.

[0040] Preferably, the thickness of the EVA adhesive layer is 50~100μm.

[0041] Preferably, the BC battery string comprises a plurality of BC battery cells connected in series, and the BC battery cells are connected in series by solder strips.

[0042] In a preferred embodiment, the first insulating support layer 3 and the second insulating support layer 7 are made of PET and have a thickness of 50~100μm. PET material has good insulation, heat resistance and mechanical strength.

[0043] In a preferred embodiment, the first adhesive layer 4 and the second adhesive layer 6 are thermosetting adhesive films.

[0044] In a preferred embodiment, the thickness of the EVA adhesive layer 2 is 50~100μm.

[0045] In a preferred embodiment, the BC battery string 1 includes a plurality of BC battery cells connected in series, the BC battery cells being connected in series by solder strips.

[0046] This utility model also provides a method for preparing the above-mentioned BC photovoltaic module, comprising the following steps:

[0047] Step 1: Prepare the busbar 5 and the electrode busbar structure in sequence. Use a suction cup to pick up the top of the electrode busbar structure and place the bottom of the electrode busbar structure on the back of the BC battery string 1, so that the EVA adhesive layer 2 at the bottom of the electrode busbar structure contacts the back of the BC battery string 1.

[0048] Step 2: Electrically connect the positive terminal connection 51 and the negative terminal connection 52 of the busbar 5 to the positive main grid line and the negative main grid line on the back of the BC battery string 1, respectively.

[0049] Step 3: The photovoltaic module prepared in Step 2 is pressed together using a metal heating plate, and the bottom EVA adhesive layer 2 of the electrode busbar structure is melted to form a preliminary bond with the BC cell string 1.

[0050] Step 4: Lay EVA film, backplate or glass on the back of BC battery string 1 in sequence, and use a laminator to melt the tin at the top of busbar 5 and connect it with the silver paste of the main grid of BC battery string 1.

[0051] In a preferred embodiment, the heating temperature for pressing the heating plate in step three is 80~120℃, and the time is 5~10s.

[0052] In a preferred embodiment, the heating temperature of the laminator in step four is 150~155℃, and the time is 10~15min.

[0053] The present invention will be further described in detail below with reference to specific embodiments:

[0054] Example 1

[0055] This embodiment 1 provides a photovoltaic module with a concealed busbar, comprising, in sequence, a BC cell string, an EVA adhesive layer, a first insulating support layer, a first adhesive layer, a busbar, a second adhesive layer, and a second insulating support layer, wherein the positive and negative electrode connections of the busbar are electrically connected to the cell string. The busbar is made of low-melting-point tin-plated copper strip, with a width of 10 mm and a thickness of 0.15 mm; the positive electrode connection has a width of 0.6 mm and a thickness of 0.2 mm; the negative electrode connection has a width of 0.6 mm and a thickness of 0.2 mm; the first and second insulating support layers are made of PET, with a thickness of 50 μm; the EVA adhesive layer has a thickness of 50 μm. The fabrication method of the BC photovoltaic module in this embodiment 1 is as follows:

[0056] Step 1: Prepare the busbar and the electrode busbar structure in sequence. Use a suction cup to pick up the top of the electrode busbar structure and place the bottom of the electrode busbar structure on the back of the BC cell, so that the EVA adhesive layer at the bottom of the electrode busbar structure contacts the back of the BC cell.

[0057] Step 2: Electrically connect several positive electrode connection parts and several negative electrode connection parts of the busbar to the positive electrode main grid line and the negative electrode main grid line on the back of the BC battery cell, respectively.

[0058] Step 3: Press the photovoltaic module prepared in Step 2 with a metal heating plate at a heating temperature of 80°C for 5 seconds to melt the bottom EVA of the electrode busbar structure and form a preliminary bond with the battery cell.

[0059] Step 4: Lay EVA film, backplate or glass on the back of the battery cell in sequence. Use a laminator to melt the tin on the top of the busbar and connect it with the silver paste of the battery cell main grid. The heating temperature is 150℃ and the time is 15min.

[0060] Example 2

[0061] This embodiment 2 provides a photovoltaic module with a concealed busbar, comprising, in sequence, a BC cell string, an EVA adhesive layer, a first insulating support layer, a first adhesive layer, a busbar, a second adhesive layer, and a second insulating support layer. The positive and negative electrode connections of the busbar are electrically connected to the cell string. The busbar is made of low-melting-point tin-plated copper strip, with a width of 11 mm and a thickness of 0.14 mm; the positive electrode connection has a width of 0.7 mm and a thickness of 0.2 mm; the negative electrode connection has a width of 0.7 mm and a thickness of 0.2 mm; the first and second insulating support layers are made of PET, with a thickness of 60 μm; the EVA adhesive layer has a thickness of 60 μm. The fabrication method of the BC photovoltaic module in this embodiment 2 is as follows:

[0062] Step 1: Prepare the busbar and the electrode busbar structure in sequence. Use a suction cup to pick up the top of the electrode busbar structure and place the bottom of the electrode busbar structure on the back of the BC cell, so that the EVA adhesive layer at the bottom of the electrode busbar structure contacts the back of the BC cell.

[0063] Step 2: Electrically connect several positive electrode connection parts and several negative electrode connection parts of the busbar to the positive electrode main grid line and the negative electrode main grid line on the back of the BC battery cell, respectively.

[0064] Step 3: Press the photovoltaic module prepared in Step 2 with a metal heating plate at a heating temperature of 90°C for 6 seconds to melt the bottom EVA of the electrode busbar structure and form a preliminary bond with the battery cell.

[0065] Step 4: Lay EVA film, backplate or glass on the back of the battery cell in sequence. Use a laminator to melt the tin on the top of the busbar and connect it with the silver paste of the battery cell main grid. The heating temperature is 151℃ and the time is 14min.

[0066] Example 3

[0067] This embodiment 3 provides a photovoltaic module with a concealed busbar, comprising, in sequence, a BC cell string, an EVA adhesive layer, a first insulating support layer, a first adhesive layer, a busbar, a second adhesive layer, and a second insulating support layer. The positive and negative electrode connections of the busbar are electrically connected to the cell string. The busbar is made of low-melting-point tin-plated copper strip, with a width of 12 mm and a thickness of 0.13 mm; the positive electrode connection has a width of 0.7 mm and a thickness of 0.25 mm; the negative electrode connection has a width of 0.7 mm and a thickness of 0.25 mm; the first and second insulating support layers are made of PET, with a thickness of 70 μm; the EVA adhesive layer has a thickness of 70 μm. The fabrication method of the BC photovoltaic module in this embodiment 3 is as follows:

[0068] Step 1: Prepare the busbar and the electrode busbar structure in sequence. Use a suction cup to pick up the top of the electrode busbar structure and place the bottom of the electrode busbar structure on the back of the BC cell, so that the EVA adhesive layer at the bottom of the electrode busbar structure contacts the back of the BC cell.

[0069] Step 2: Electrically connect several positive electrode connection parts and several negative electrode connection parts of the busbar to the positive electrode main grid line and the negative electrode main grid line on the back of the BC battery cell, respectively.

[0070] Step 3: Press the photovoltaic module prepared in Step 2 with a metal heating plate at a heating temperature of 100°C for 7 seconds to melt the bottom EVA of the electrode busbar structure and form a preliminary bond with the battery cell.

[0071] Step 4: Lay EVA film, backplate or glass on the back of the battery cell in sequence. Use a laminator to melt the tin on the top of the busbar and connect it with the silver paste of the battery cell main grid. The heating temperature is 152℃ and the time is 13min.

[0072] Example 4

[0073] This embodiment 4 provides a photovoltaic module with a concealed busbar, comprising, in sequence, a BC cell string, an EVA adhesive layer, a first insulating support layer, a first adhesive layer, a busbar, a second adhesive layer, and a second insulating support layer. The positive and negative electrode connections of the busbar are electrically connected to the cell string. The busbar is made of low-melting-point tin-plated copper strip, with a width of 13 mm and a thickness of 0.12 mm; the positive electrode connection has a width of 0.8 mm and a thickness of 0.2 mm; the negative electrode connection has a width of 0.8 mm and a thickness of 0.2 mm; the first and second insulating support layers are made of PET, with a thickness of 80 μm; the EVA adhesive layer has a thickness of 80 μm. The fabrication method of the BC photovoltaic module in this embodiment 4 is as follows:

[0074] Step 1: Prepare the busbar and the electrode busbar structure in sequence. Use a suction cup to pick up the top of the electrode busbar structure and place the bottom of the electrode busbar structure on the back of the BC cell, so that the EVA adhesive layer at the bottom of the electrode busbar structure contacts the back of the BC cell.

[0075] Step 2: Electrically connect several positive electrode connection parts and several negative electrode connection parts of the busbar to the positive electrode main grid line and the negative electrode main grid line on the back of the BC battery cell, respectively.

[0076] Step 3: Press the photovoltaic module prepared in step 2 with a metal heating plate at a heating temperature of 110°C for 8 seconds to melt the bottom EVA of the electrode busbar structure and form a preliminary bond with the battery cell.

[0077] Step 4: Lay EVA film, backplate or glass on the back of the battery cell in sequence. Use a laminator to melt the tin on the top of the busbar and connect it with the silver paste of the battery cell main grid. The heating temperature is 153℃ and the time is 12min.

[0078] Example 5

[0079] This embodiment 5 provides a photovoltaic module with a concealed busbar, comprising, in sequence, a BC cell string, an EVA adhesive layer, a first insulating support layer, a first adhesive layer, a busbar, a second adhesive layer, and a second insulating support layer. The positive and negative electrode connections of the busbar are electrically connected to the cell string. The busbar is made of low-melting-point tin-plated copper strip, with a width of 14 mm and a thickness of 0.11 mm; the positive electrode connection has a width of 0.8 mm and a thickness of 0.25 mm; the negative electrode connection has a width of 0.8 mm and a thickness of 0.25 mm; the first and second insulating support layers are made of PET, with a thickness of 90 μm; the EVA adhesive layer has a thickness of 90 μm. The fabrication method of the BC photovoltaic module in this embodiment 5 is as follows:

[0080] Step 1: Prepare the busbar and the electrode busbar structure in sequence. Use a suction cup to pick up the top of the electrode busbar structure and place the bottom of the electrode busbar structure on the back of the BC cell, so that the EVA adhesive layer at the bottom of the electrode busbar structure contacts the back of the BC cell.

[0081] Step 2: Electrically connect several positive electrode connection parts and several negative electrode connection parts of the busbar to the positive electrode main grid line and the negative electrode main grid line on the back of the BC battery cell, respectively.

[0082] Step 3: Press the photovoltaic module prepared in step 2 with a metal heating plate at a heating temperature of 120°C for 9 seconds to melt the bottom EVA of the electrode busbar structure and form a preliminary bond with the battery cell.

[0083] Step 4: Lay EVA film, backplate or glass on the back of the battery cell in sequence. Use a laminator to melt the tin on the top of the busbar and connect it with the silver paste of the battery cell main grid. The heating temperature is 154℃ and the time is 11min.

[0084] Example 6

[0085] This embodiment 6 provides a photovoltaic module with a concealed busbar, comprising, in sequence, a BC cell string, an EVA adhesive layer, a first insulating support layer, a first adhesive layer, a busbar, a second adhesive layer, and a second insulating support layer, wherein the positive and negative electrode connections of the busbar are electrically connected to the cell string. The busbar is made of low-melting-point tin-plated copper strip, with a width of 15 mm and a thickness of 0.1 mm; the positive electrode connection has a width of 0.8 mm and a thickness of 0.25 mm; the negative electrode connection has a width of 0.8 mm and a thickness of 0.25 mm; the first and second insulating support layers are made of PET, with a thickness of 100 μm; the EVA adhesive layer has a thickness of 100 μm. The fabrication method of the BC photovoltaic module in this embodiment 6 is as follows:

[0086] Step 1: Prepare the busbar and the electrode busbar structure in sequence. Use a suction cup to pick up the top of the electrode busbar structure and place the bottom of the electrode busbar structure on the back of the BC cell, so that the EVA adhesive layer at the bottom of the electrode busbar structure contacts the back of the BC cell.

[0087] Step 2: Electrically connect several positive electrode connection parts and several negative electrode connection parts of the busbar to the positive electrode main grid line and the negative electrode main grid line on the back of the BC battery cell, respectively.

[0088] Step 3: Press the photovoltaic module prepared in Step 2 with a metal heating plate at a heating temperature of 120°C for 10 seconds to melt the bottom EVA of the electrode busbar structure and form a preliminary bond with the battery cell.

[0089] Step 4: Lay EVA film, backplate or glass on the back of the battery cell in sequence. Use a laminator to melt the tin on the top of the busbar and connect it with the silver paste of the battery cell main grid. The heating temperature is 155℃ and the time is 10 minutes.

[0090] Comparative Example 1

[0091] Comparative Example 1 provides a photovoltaic module, comprising BC solar cells, solder strips, and busbars. The busbars are made of conventional tin-plated copper strip with a melting point of 4 mm and a thickness of 0.4 mm. The fabrication method of the photovoltaic module in Comparative Example 1 is as follows:

[0092] Step 1: Connect the positive and negative poles of the BC solar cells using solder ribbon to obtain a battery string;

[0093] Step 2: Place the busbar directly below the outer solder strip of the first and last pieces of the battery string, and use a soldering iron to solder the solder strip to the busbar for 1-2 seconds.

[0094] Step 3: Lay EVA film, backplate or glass on the back of the battery cell in sequence. Use a laminator to melt the tin on the top of the busbar and connect it with the silver paste of the battery cell main grid. The heating temperature is 150℃ and the time is 15min.

[0095] The performance of the solar cells obtained in the above embodiments and comparative examples is tested below, and the results are as follows:

[0096] Table 1 Performance test results of the back contact batteries prepared in the examples and comparative examples Example 1 0.03% 654 24.2% Example 2 0.028% 656 24.3% Example 3 0.025% 658 24.4% Example 4 0.002% 657 24.3% Example 5 0.018% 662 24.5% Example 6 0.01% 660 24.4% Comparative Example 1 0.06% 650 24.06%

[0097] Examples 1-6 illustrate the "concealed busbar" structure used in this invention, while Comparative Example 1 represents a conventional busbar structure. Table 1 shows that Examples 1-6 outperform Comparative Example 1 in terms of busbar solder joint failure rate, module power, and module efficiency. The failure rate of all examples is lower than 0.06% of Comparative Example 1, with Example 4 exhibiting the lowest failure rate at only 0.002%. Furthermore, the module power of Examples 1-6 is generally higher than the 650W of Comparative Example 1, and the module efficiency is higher than 24.06% of Comparative Example 1. Therefore, this invention not only achieves "concealment" of the busbar, improving the aesthetics and space utilization of the module, but also significantly improves welding reliability, output power, and conversion efficiency, demonstrating promising prospects for industrial application.

[0098] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A photovoltaic module with concealed busbars, comprising a BC cell string and an electrode busbar structure, wherein each BC cell string has a plurality of interleaved positive main grid lines and a plurality of negative main grid lines on its back side, and the electrode busbar structure is electrically connected to the BC cell string, characterized in that, The electrode busbar structure includes busbars, which are respectively disposed on the back of the first and last plates of the BC battery string. The top of the busbar extends laterally and is provided with several positive electrode connection portions and several negative electrode connection portions that are intersected with each other. The positive electrode connection portions are electrically connected to the positive electrode main grid line, and the negative electrode connection portions are electrically connected to the negative electrode main grid line.

2. The photovoltaic module according to claim 1, characterized in that, The busbar is made of low-melting-point tin-plated copper strip, with a width of 10~15mm and a thickness of 0.1~0.15mm.

3. The photovoltaic module according to claim 2, characterized in that, The width of the positive electrode connection is 0.6~0.8mm and the thickness is 0.2~0.25mm.

4. The photovoltaic module according to claim 2, characterized in that, The width of the negative electrode connection is 0.6~0.8mm and the thickness is 0.2~0.25mm.

5. The photovoltaic module according to claim 1, characterized in that, The electrode busbar structure, from bottom to top, includes an EVA adhesive layer, a first insulating support layer, a first adhesive layer, a busbar, a second adhesive layer, and a second insulating support layer.

6. The photovoltaic module according to claim 5, characterized in that, The positive electrode connection and the negative electrode connection are integrally formed with the busbar. The second adhesive layer and the insulating support layer are respectively stacked on the side of the positive electrode connection and the negative electrode connection away from the busbar.

7. The photovoltaic module according to claim 5, characterized in that, The first insulating support layer and the second insulating support layer are made of PET and have a thickness of 50~100μm.

8. The photovoltaic module according to claim 5, characterized in that, The first adhesive layer and the second adhesive layer are thermosetting adhesive films.

9. The photovoltaic module according to claim 5, characterized in that, The thickness of the EVA adhesive layer is 50~100μm.

10. The photovoltaic module according to claim 1, characterized in that, The BC battery string includes several BC battery cells connected in series, and the BC battery cells are connected in series by solder strips.

Images