阅读说明：本技术 一种光伏组件用黑色汇流条及制备方法及光伏组件 (Black bus bar for photovoltaic module, preparation method of black bus bar and photovoltaic module ) 是由 陈斌 王樱 陈道远 于 2021-08-31 设计创作，主要内容包括：本发明公开了一种光伏组件用黑色汇流条及其制备方法及光伏组件,属于光伏组件技术领域,用以解决使用现有的黑色汇流条的光伏组件的输出功率衰减较快的问题。本发明的光伏组件用黑色汇流条包括依次设置的：锡层、铜基层、第一金属层和黑色树脂层,所述第一金属层的熔点高于所述锡层的熔点。本发明的光伏组件包括上述光伏组件用黑色汇流条。使用本发明的黑色汇流条的光伏组件的输出功率的衰减降低。(The invention discloses a black bus bar for a photovoltaic module, a preparation method of the black bus bar and the photovoltaic module, belongs to the technical field of photovoltaic modules, and aims to solve the problem that the output power of the photovoltaic module using the existing black bus bar is attenuated quickly. The black bus bar for the photovoltaic module comprises the following components in sequence: the tin-based composite material comprises a tin layer, a copper base layer, a first metal layer and a black resin layer, wherein the melting point of the first metal layer is higher than that of the tin layer. The photovoltaic module comprises the black bus bar for the photovoltaic module. The attenuation of the output power of the photovoltaic module using the black bus bar of the present invention is reduced.)

1. The utility model provides a black busbar for photovoltaic module which characterized in that, including setting gradually: the tin-based composite material comprises a tin layer (1), a copper base layer (2), a first metal layer (3) and a black resin layer (4), wherein the melting point of the first metal layer (3) is higher than that of the tin layer (1).

2. The black bus bar for photovoltaic modules according to claim 1, wherein the first metal layer (3) has a melting point higher than 400 ℃;

preferably, the first metal layer (3) is aluminum, an aluminum alloy, nickel or a nickel alloy;

preferably, the thickness of the first metal layer (3) is 40 to 800u ″.

3. The black bus bar for photovoltaic module according to claim 1, wherein the thickness of the tin layer (1) is 15 to 25 μm.

4. The black bus bar for photovoltaic module according to claim 1, wherein the thickness of the black resin layer (4) is 5 to 20 μm.

5. The black bus bar for photovoltaic module according to claim 1, wherein a second metal layer (5) is provided between the tin layer (1) and the copper base layer (2);

preferably, the second metal layer (5) and the first metal layer (3) are made of the same material.

6. The black bus bar for photovoltaic module according to claim 1, wherein the surface of the black resin layer (4) has an uneven structure.

7. The black bus bar for photovoltaic modules according to claim 1 or 6, wherein the dyne value of the surface of the black resin layer (4) is 40 or more.

8. A preparation method of a black bus bar for a photovoltaic module is characterized by comprising the following steps:

s1, preparing a copper base layer (2);

s2, arranging a first metal layer (3) on one side surface of the copper base layer (2);

s3, arranging a black resin layer (4) on the surface of the first metal layer (3);

s4, plating a tin layer (1) on the surface of the other side of the copper base layer (2) in a back-to-back mode;

s5, performing corona treatment on the black resin layer (4) to obtain a black bus bar;

the first metal layer (3) has a higher melting point than the tin layer (1).

9. A preparation method of a black bus bar for a photovoltaic module is characterized by comprising the following steps:

step 1, preparing a copper base layer (2);

step 2, respectively arranging a first metal layer (3) and a second metal layer (5) on the surfaces of the two sides of the copper base layer (2);

step 3, arranging a black resin layer (4) on the surface of the first metal layer (3);

step 4, plating a tin layer (1) on the surface of the second metal layer (5) in a back-to-back mode;

step 5, performing corona treatment on the black resin layer (4) to obtain a black bus bar;

the first metal layer (3) has a higher melting point than the tin layer (1).

10. A photovoltaic module comprising the black bus bar for photovoltaic modules described in claims 1 to 7 or the black bus bar for photovoltaic modules produced by the production method described in claim 8 or 9.

Technical Field

The invention belongs to the technical field of photovoltaic modules, and particularly relates to a black bus bar for a photovoltaic module, a preparation method of the black bus bar and the photovoltaic module.

Background

At present, the photovoltaic module is widely applied to distributed photovoltaic systems such as roofs, building outer walls and the like. For such distributed photovoltaic systems, the appearance of the photovoltaic module is required to be black. Therefore, a black bus bar needs to be employed.

The prior art provides a black bus bar, which comprises a copper base layer, a tin layer arranged on one surface of the copper base layer, and a black resin coating arranged on the other surface of the copper base layer.

However, the inventor finds that the photovoltaic module adopting the existing black bus bar has the problem of fast output power attenuation after long-term use. Therefore, it is desired to provide a black bus bar having good appearance, good stability and low cost.

Disclosure of Invention

In view of the above analysis, the present invention aims to provide a black bus bar for a photovoltaic module, a method for manufacturing the same, and a photovoltaic module, which can solve the following technical problems: the output power of a photovoltaic module using the existing black bus bar decays faster.

The purpose of the invention is mainly realized by the following technical scheme:

in one aspect, the present invention provides a black bus bar for a photovoltaic module, including sequentially disposed: the tin-based composite material comprises a tin layer, a copper base layer, a first metal layer and a black resin layer, wherein the melting point of the first metal layer is higher than that of the tin layer.

Further, the melting point of the first metal layer is higher than 400 ℃.

Further, the first metal layer is aluminum, an aluminum alloy, nickel or a nickel alloy.

Furthermore, the thickness of the first metal layer is 40-800 u'.

Furthermore, the thickness of the tin layer is 15-25 μm.

Furthermore, the thickness of the black resin layer is 5-20 μm.

Further, a second metal layer is arranged between the tin layer and the copper base layer.

Further, the second metal layer and the first metal layer are made of the same material.

Further, the surface of the black resin layer is of a concave-convex structure.

Further, the dyne value of the surface of the black resin layer is 40 or more.

In one aspect, the present invention provides a method for preparing a black bus bar for a photovoltaic module, including:

s1, preparing a copper base layer;

s2, arranging a first metal layer on one side surface of the copper base layer;

s3, arranging a black resin layer on the surface of the first metal layer;

s4, plating a tin layer on the surface of the other side of the copper base layer in a back-to-back mode;

s5, performing corona treatment on the black resin layer to obtain a black bus bar;

the first metal layer has a melting point higher than that of the tin layer.

In another aspect, the present invention provides a method for preparing a black bus bar for a photovoltaic module, including:

step 1, preparing a copper base layer;

step 2, respectively arranging a first metal layer and a second metal layer on the surfaces of the two sides of the copper base layer;

step 3, arranging a black resin layer on the surface of the first metal layer;

step 4, plating a tin layer on the surface of the second metal layer in a back-to-back mode;

step 5, performing corona treatment on the black resin layer to obtain a black bus bar;

the first metal layer has a melting point higher than that of the tin layer.

In another aspect, the invention provides a photovoltaic module, which comprises the black bus bar for the photovoltaic module.

Compared with the prior art, the invention can realize at least one of the following beneficial effects:

a) the first metal layer is arranged between the copper base layer and the black resin layer of the black bus bar for the photovoltaic module, and can play a role in blocking moisture and oxygen in the using process, so that the copper base layer is protected, the copper base layer is prevented from being oxidized, and the attenuation of the output power of the module is slowed down.

b) The melting point of the first metal layer is high, the first metal layer cannot be melted during welding, the bonding of the black resin layer and the adhesive film cannot be influenced, and the delaminating phenomenon during welding can be avoided.

c) According to the black bus bar for the photovoltaic module, the high-melting-point metal layer and the black resin layer are plated firstly, and then the tin layer is plated, so that the tin layer is prevented from being molten and incapable of being formed when the tin layer is plated firstly and then the high-melting-point metal layer is plated. According to the invention, the black resin layer is subjected to corona treatment, so that the binding force between the black resin layer and the photovoltaic module packaging adhesive film can be obviously improved.

d) The black bus bar provided by the invention is simple in preparation method, and the cost of the used black resin layer and the first metal layer is lower, so that the cost of the black bus bar provided by the embodiment of the invention is not obviously increased, the cost is lower, and the appearance of the black bus bar is better.

e) According to the black bus bar of the photovoltaic module, the first metal layer with the high melting point is arranged between the black resin layer and the copper base layer, so that the copper base layer is prevented from being corroded, and the output power attenuation of the photovoltaic module is reduced.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description.

Drawings

The drawings are only for purposes of illustrating the particular invention and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout the figures.

Fig. 1 is an overall structural schematic view of a black bus bar of embodiment 1 of the present invention;

fig. 2 is an overall structural schematic view of a black bus bar of embodiment 2 of the present invention;

fig. 3 is a schematic view of clamping two bus bars in a back-to-back manner in example 1 of the present invention;

fig. 4 is a front appearance photograph of a photovoltaic module including the bus bar of comparative example 1;

fig. 5 is a front appearance photograph of a photovoltaic module including the bus bar of example 1.

Reference numerals

1-tin layer, 2-copper base layer, 3-first metal layer, 4-black resin layer and 5-second metal layer.

Detailed Description

The following examples describe the invention in detail. The examples are illustrative and are intended to describe embodiments of the invention and not to limit the scope of the invention.

In the process of assembling the photovoltaic assembly, the photovoltaic assembly laminating piece is placed into a laminating machine for laminating; the photovoltaic module laminating piece comprises photovoltaic glass/an adhesive film/a battery array/an adhesive film/a photovoltaic back plate, and the battery array comprises a bus bar. The bus bars in the battery array need to be welded with the solder strips first.

The prior art provides a black bus bar, which comprises a copper base layer, a tin layer arranged on one surface of the copper base layer, and a black resin coating arranged on the other surface of the copper base layer. However, the inventors have found, through long-term use, that the output power of a photovoltaic module employing the existing black bus bar decays relatively quickly. The inventor finds out through intensive research that: photovoltaic module in the use, have moisture, inside oxygen gets into the subassembly, because the black resin coating is less strong to moisture, the separation effect of oxygen, moisture and oxygen can see through black resin coating and corrode the copper-based layer, and the copper-based layer is corroded the back, and the resistance grow for the decay of subassembly output power accelerates (normal photovoltaic module exports the back output all can have the decay, and the copper-based layer can make the decay accelerate after being corroded). If the copper base layer corrodes significantly, it may also cause the component to burn out. Therefore, it is desired to provide a black bus bar having good appearance, good stability and low cost.

Based on the discovery, research and analysis, the invention provides a black bus bar for a photovoltaic module, which comprises the following components in sequence: a tin layer 1, a copper base layer 2, a first metal layer 3 and a black resin layer 4; the melting point of the first metal layer 3 is higher than the melting point of the tin layer 1.

It should be noted that, considering that the black bus bar for the photovoltaic module needs to be welded with the adhesive film in the using process, the bus bar has fast heat conduction during welding, and if the melting point of the metal layer is low, the metal layer is easy to melt and flow during welding, so that the black resin layer is not firmly bonded with the adhesive film, and the delamination phenomenon is aggravated; therefore, the melting point of the first metal layer 3 is controlled to be higher than 400 ℃, and may be 450 ℃ or higher, 500 ℃ or higher, 550 ℃ or higher, 600 ℃ or higher, 650 ℃ or higher, or the like.

Specifically, the first metal layer 3 may be aluminum, an aluminum alloy, nickel, or a nickel alloy; in view of manufacturing cost, the first metal layer 3 may be a low-cost metal, and preferably, the first metal layer 3 may be aluminum.

Compared with the prior art, the first metal layer is arranged between the copper base layer and the black resin layer of the black bus bar for the photovoltaic module, and in the using process, the first metal layer can play a role in blocking moisture and oxygen, so that the copper base layer is protected, the copper base layer is prevented from being oxidized, and the attenuation of the output power of the module is slowed down; and the melting point of the first metal layer is high, so that the first metal layer is not melted during welding, and the delaminating phenomenon during welding can be avoided.

A second metal layer 5 may also be provided between the tin layer 1 and the copper base layer 2 in consideration of convenience in fabrication of the black bus bar. The second metal layer 5 is of the same material as the first metal layer 3.

Specifically, considering that the thickness of the first metal layer 3 is too large, the cost of the black bus bar is high, and the manufacturing difficulty is large; the thickness of the first metal layer 3 is too small, the resistivity of the black bus bar is high, and the output power of the component is influenced; accordingly, the thickness of the first metal layer 3 is controlled to be 40 to 800u "(1u ″ -0.0254 μm, the same applies hereinafter), for example, 50u ″, 100u ″, 150u ″, 200u ″, 250u ″, 300u ″, 350u ″, 400u ″, 420u ″, 440u ″, 450u ″, 460u ″, 480u ″, 500u ″, 520u ″, 540u ″, 550u ″, 560u ″, 580u ″, 600u ″, 620u ″, 640u ″, 650u ″, 660u ″, 680u ″, 700u ″, 720u ″, 740u ″, 750u ″, 760u ″, 780u ″, and the like. The thickness of the first metal layer can be selected based on the cost, resistivity and other factors, for example, the thickness of the first metal layer can be selected to be more than 400u 'for low-cost metal such as aluminum, and the thickness of the first metal layer can be selected to be 40-300 u' for high-cost metal.

The thickness of the second metal layer 5 may be the same as the thickness of the first metal layer 3.

Specifically, the copper base layer 2 is oxygen-free copper, and the content of copper is required to be more than or equal to 99.9%.

Specifically, the thickness of the tin layer 1 is too large, the cost of the black bus bar is high, and the manufacturing difficulty is large; if the resistance is too small, the resistivity of the black bus bar is high, and the output power of the assembly is influenced; therefore, the thickness of the tin layer 1 is controlled to be 15 to 25 μm, for example, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, etc.

Specifically, the thickness of the black resin layer 4 is too large, the cost of the black bus bar is high, and the manufacturing difficulty is large; if the resistance is too small, the resistivity of the black bus bar is high, and the output power of the assembly is influenced; therefore, the thickness of the black resin layer 4 is controlled to be 5 to 20 μm, for example, 6 μm, 8 μm, 10 μm, 12 μm, 14 μm, 15 μm, 16 μm, 18 μm, etc.

In the conventional module using the black bus bar, a large area of white air bubbles appears near the bent portion of the bus bar on the front surface of the module, and the appearance of the module is greatly affected (the position indicated by the circle in fig. 4). The inventor finds that the reason for the large-area white bubble group is poor adhesion between the black resin layer and the photovoltaic module packaging adhesive film and delamination between the black resin layer and the packaging adhesive film. Therefore, the problem of white bubble groups can be solved by improving the bonding strength of the black resin layer and the adhesive film.

Specifically, the adhesive strength can be improved by increasing the contact area of the black resin layer 4 and the adhesive film. The contact area can be increased by making the surface of the black resin layer 4 have an uneven structure. In a possible implementation manner, after the first metal layer 3 is formed, the concave-convex structure may be provided on the surface of the first metal layer 3 by etching or other means, and then the black resin layer 4 may be provided on the first metal layer 3, so that the surface of the black resin layer 4 is in the concave-convex structure.

Alternatively, the black resin layer 4 has protrusions in the shape of inverted pyramids on the surface.

Specifically, the adhesion strength with the adhesive film can be improved by increasing the dyne value of the surface of the black resin layer 4. The dyne value of the surface of the black resin layer 4 may be increased by corona treatment, for example.

The surface of the black resin layer 4 may be subjected to corona treatment in addition to the uneven structure on the surface of the black resin layer 4.

Specifically, the higher the dyne value of the black resin layer 4 is, the better the adhesion with the adhesive film is, on the contrary, the dyne value is too small, so that the black resin layer is easy to delaminate and generate bubbles; therefore, the dyne value of the black resin layer 4 is controlled to be 40 or more.

In the present invention, the composition of the black resin layer 4 is not particularly limited, and commercially available black ink and black paint used in the photovoltaic field may be used. For example, a composite resin in which two or more kinds of amino resin, acrylic resin, and epoxy resin are mixed in a ratio as main components can be used.

The invention also provides a preparation method of the black bus bar for the photovoltaic module, which comprises the following steps:

s1, preparing a copper base layer 2;

s2, arranging a first metal layer 3 on one side surface of the copper base layer 2;

s3, disposing black composite resin 4 on the surface of the first metal layer 3;

s4, plating a tin layer 1 on the other side surface of the copper base layer 2 in a back-to-back mode;

s5, the black composite resin 4 was subjected to corona treatment to obtain a black bus bar.

Specifically, in S4, the tin plating layer is formed by electroless plating.

Specifically, as shown in fig. 3, in the step S4, the step of plating the tin layer 1 on the other side surface of the copper base layer 2 in a back-to-back manner includes:

s401, aligning the black composite resin 4 sides of two bus bars plated with the copper base layer 2, the first metal layer 3 and the black composite resin 4, and clamping the two aligned bus bars by using a clamp 6;

s402, putting the clamped bus bar piece into chemical liquid for immersion plating of a tin layer.

Specifically, in S5 described above, it is necessary to separate the two bus bars clamped after the tin plating in S4 and then perform corona treatment on the black composite resin 4.

Note that if the black bus bar further includes the second metal layer 5, in S2, the first metal layer 3 and the second metal layer 5 are plated on both side surfaces of the copper base layer 2, respectively.

The method may further include providing a surface of the black resin layer with a concave-convex structure.

Compared with the prior art, the method of the invention firstly plates the high melting point metal layer and the black resin layer and then plates the tin layer, which can prevent the tin layer from melting and being incapable of forming when the tin layer is firstly plated and then the high melting point metal layer is plated. According to the invention, the black resin layer is subjected to corona treatment finally, so that the bonding force between the black resin layer and the photovoltaic module packaging adhesive film can be obviously improved, and a large-area white bubble group near the bending position of the bus bar on the front side of the module can be effectively prevented, thereby improving the appearance of the module.

The invention also provides a photovoltaic module which comprises the black bus bar for the photovoltaic module. According to the black bus bar of the photovoltaic module, the first metal layer with the high melting point is arranged between the black resin layer and the copper base layer, so that the copper base layer is prevented from being corroded, and the output power attenuation of the photovoltaic module is reduced. Furthermore, due to the fact that the black resin layer and the packaging adhesive film have strong adhesive force, white bubble groups are almost not formed near the bending position of the bus bar on the front face of the module, and appearance of the module is improved.

The black bus bar for photovoltaic modules and the method for manufacturing the same according to the present invention will be illustrated below by specific examples.

Example 1

This embodiment provides a black busbar for photovoltaic module, as shown in fig. 1, from top to bottom include set gradually: tin layer 1, copper base layer 2, first metal layer 3 and black resin layer 4. Wherein the tin layer 1 has a thickness of 20 μm, the first metal layer 3 has a thickness of 40u ″, the copper content in the copper base layer 2 is 99.95%, the black resin layer 4 has a thickness of 10 μm, and the dyne value of the black resin layer 4 is 50. The material of the first metal layer 3 is aluminum.

The preparation method of the black bus bar for the photovoltaic module comprises the following steps:

s1, preparing a copper base layer 2;

s2, arranging a first metal layer 3 on the surface of one side of the copper base layer 2;

s3, disposing the black resin layer 4 on the surface of the first metal layer 3;

s4, plating a tin layer 1 on the surface of the copper base layer 2 in a back-to-back mode;

s5, corona treatment was performed on the black composite resin coating 4 to obtain a black bus bar.

Example 2

The present embodiment provides a black bus bar for photovoltaic module, which has the same structure as embodiment 1 except that: the first metal layer 3 has a thickness of 400u ".

Example 3

This embodiment provides a black busbar for photovoltaic module, as shown in fig. 2, from top to bottom include set gradually: tin layer 1, second metal layer 5, copper base layer 2, first metal layer 3 and black resin layer 4. Wherein the thickness of the tin layer 1 is 20 μm, the thickness of the first metal layer 3 and the second metal layer 5 are both 40u ", the content of copper in the copper base layer 2 is 99.95%, and the thickness of the black resin layer 4 is 10 μm. The material of the first metal layer 3 and the second metal layer 5 is aluminum.

The preparation method of the black bus bar for the photovoltaic module comprises the following steps:

s1, preparing a copper base layer 2;

s2, respectively plating a first metal layer 3 and a second metal layer 5 on the surfaces of two sides of the copper base layer 2;

s3, disposing the black resin layer 4 on the surface of the first metal layer 3;

s4, plating a tin layer 1 on the surface of the second metal layer 5 in a back-to-back mode;

s5, the black resin layer 4 was subjected to corona treatment to obtain a black bus bar.

Example 4

The present embodiment provides a black bus bar for a photovoltaic module, which has the same structure as in embodiment 1 except that a concave-convex structure is provided on the surface of the black resin layer. The preparation method of the black bus bar further comprises the step of arranging a concave-convex structure on the surface of the black resin layer, wherein the black resin layer is not subjected to corona treatment.

Example 5

This example provides a black bus bar for photovoltaic modules, which has the same structure as example 3 except that the black resin layer is subjected to corona treatment.

Example 6

The present embodiment provides a photovoltaic module including the black bus bar for photovoltaic modules of embodiments 1 to 5. The preparation process of the photovoltaic module comprises the following steps:

(1) sequentially laying a front EVA (ethylene vinyl acetate) packaging adhesive film and a battery string on a glass cover plate, wherein a battery piece used in the battery string is a half 9-piece main grid double-sided PERC (polymer electrolyte resistance) battery;

(2) after the battery string was laid, the bus bars (i.e., the black bus bars in example 1 or 2) were welded to the solder ribbons of the battery string;

(3) after welding is finished, sequentially laying a rear EVA packaging adhesive film and a TPT back plate on the battery string, and enabling the leading-out end of the bus bar to penetrate out of the holes of the rear EVA packaging adhesive film and the TPT back plate to obtain a laminated piece;

(4) laminating the obtained laminated member to obtain a laminated member;

(5) and installing an aluminum frame around the laminated part, and then installing a junction box to obtain the photovoltaic module.

It should be noted that the above preparation method is the best solution obtained by long-term and intensive experimental study, and here, the inventors provide some solutions with poor effect in the study process as comparative examples.

Comparative example 1

This comparative example provides a black busbar for photovoltaic module, as shown in fig. 1, includes from last to down setting gradually: tin layer 1, copper base layer 2, first metal layer 3 and black resin layer 4. Wherein the thickness of the tin layer 1 is 20 μm, the thickness of the first metal layer 3 is 40u ", the content of copper in the copper base layer 2 is 99.95%, and the thickness of the black composite resin 4 is 10 μm. The material of the first metal layer 3 is aluminum.

The preparation method of the black bus bar for the photovoltaic module comprises the following steps:

s1, preparing a copper base layer 2;

s2, arranging a first metal layer 3 on the surface of one side of the copper base layer 2;

s3, disposing black composite resin 4 on the surface of the first metal layer 3;

s4, plating a tin layer 1 on the surface of the copper base layer 2 in a back-to-back mode; a black bus bar was obtained.

Comparative example 2

This comparative example provides a black busbar for photovoltaic module, includes setting gradually from last to including down: tin layer, copper base layer, metal layer and black resin layer. Wherein the thickness of the tin layer is 20 μm, the thickness of the metal layer is 40u ", the content of copper in the copper base layer is 99.95%, and the thickness of the black resin layer is 10 μm. The metal layer is made of tin.

The preparation method of the black bus bar for the photovoltaic module comprises the following steps:

s1, preparing a copper base layer;

s2, plating metal layers on the surfaces of the two sides of the copper base layer;

s3, the black resin layer 4 was formed on the surface of one metal layer, and a black bus bar was obtained.

Comparative example 3

This comparative example provides a black busbar for photovoltaic module, including tin layer 1, copper-based layer 2, black resin layer 4 that set gradually. Wherein the thickness of the tin layer 1 was 20 μm, the copper content in the copper base layer 2 was 99.95%, the thickness of the black resin layer 4 was 10 μm, and the material of the black resin layer was the same as that of example 1.

The bus bars of examples 1 to 5 and comparative examples 1 to 3 described above were applied to photovoltaic modules, which were prepared as follows:

(1) sequentially laying a front EVA (ethylene vinyl acetate) packaging adhesive film and a battery string on a glass cover plate, wherein a battery piece used in the battery string is a half 9-piece main grid double-sided PERC (polymer electrolyte resistance) battery;

(2) after the battery string was laid, the bus bars (i.e., the bus bars in examples 1 to 5 or comparative examples 1 to 3) were welded to the solder ribbons of the battery string;

(3) after welding is finished, sequentially laying a rear EVA packaging adhesive film and a TPT back plate on the battery string, and enabling the leading-out end of the bus bar to penetrate out of the holes of the rear EVA packaging adhesive film and the TPT back plate to obtain a laminated piece;

(4) laminating the obtained laminated member to obtain a laminated member;

(5) and installing an aluminum frame around the laminated part, and then installing a junction box to obtain the photovoltaic module.

As shown in fig. 4, which is a front appearance picture of a photovoltaic module including the bus bar of comparative example 1, a large area of white bubble groups are generated near the bending position of the bus bar (in the figure, the bubble groups are in the circles); through experiments, a large number of white bubble groups appear near the bending position of the bus bar of the photovoltaic module comprising the bus bar of the comparative example 2 or 3, and the bonding force between the black bus bar of the comparative examples 1-3 and the EVA adhesive film is low. It can be seen that comparative examples 1 and 3 are not subjected to corona treatment, and the adhesive force between the black resin layer and the photovoltaic module packaging adhesive film is low; the metal layer of comparative example 2 is a tin layer, and the tin layer is melted and flowed during soldering, so that the black resin layer is not firmly adhered to the adhesive film. The photovoltaic module products of comparative examples 1-3 did not meet the quality standards and were off-spec or degraded products.

As shown in fig. 5, which is a front view of a photovoltaic module including the black bus bar of example 1, it can be seen that there is almost no bubble generation near the bending position of the bus bar, and the black bus bar is transparent, and it can be seen that the black bus bar of example 1 has high adhesion to the EVA film. Through experiments, almost no bubbles are generated near the bus bar of the photovoltaic module comprising the black bus bar of the embodiment 2-5, and it can be seen that the black bus bar of the embodiment 2-5 has high adhesion with the EVA adhesive film, and the adhesion of the black bus bar with the EVA adhesive film can be improved through corona treatment or arrangement of the concave-convex structure on the black resin layer.

Adopting the photovoltaic module comprising the black bus bar of the embodiment 1 and the photovoltaic module adopting the black bus bar of the comparative example 3, respectively manufacturing 10 photovoltaic modules according to the steps, respectively testing the initial output power of each photovoltaic module, then placing the photovoltaic modules into an experimental box with the temperature of 85 ℃ and the humidity of 85%, placing for 1000 hours, testing the output power of each photovoltaic module, and calculating the power attenuation rate according to the following formula:

(initial output power-output power after test)/initial output power x 100%

Among them, 10 photovoltaic modules using the black bus bar of example 1 had power attenuation rates in the range of 0.8% to 1.5%, and 10 photovoltaic modules using the black bus bar of comparative example 3 had power attenuation rates in the range of 2.0% to 6.0%, and it can be seen that the black bus bar provided in the examples of the present invention prevents the copper base layer from being corroded and reduces the output power attenuation of the photovoltaic modules by providing the first metal layer having a high melting point between the black resin layer and the copper base layer.

In addition, the preparation method of the black bus bar provided by the embodiment of the invention is simple, and the cost of the used black resin layer and the first metal layer is lower, so that the cost of the black bus bar provided by the embodiment of the invention is not obviously increased.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.