CN115663049A

CN115663049A - Photovoltaic module

Info

Publication number: CN115663049A
Application number: CN202211275760.4A
Authority: CN
Inventors: 郝国晖; 郭志球; 黄世亮; 刘大娇; 张宁波
Original assignee: Zhejiang Jinko Solar Co Ltd; Jinko Solar Co Ltd
Current assignee: Zhejiang Jinko Solar Co Ltd; Jinko Solar Co Ltd
Priority date: 2022-10-18
Filing date: 2022-10-18
Publication date: 2023-01-31

Abstract

The embodiment of the application relates to the technical field of photovoltaic products and discloses a photovoltaic module. The photovoltaic module comprises a cell piece and a welding strip, wherein the surface of the cell piece is provided with a plurality of mutually spaced thin grid lines. The welding strip is positioned on the surface of the battery piece, an adhesive layer and an alloy layer are distributed between the welding strip and the surface of the battery piece, the welding strip is connected with the surface of the battery piece through the adhesive layer and is electrically connected with the fine grid line through the alloy layer, and the alloy layer comprises 20-40 wt% of tin, 20-50 wt% of bismuth, 20-40 wt% of lead and 1-3 wt% of silver. The photovoltaic module that this application embodiment provided can effectively ensure photovoltaic module inner structure's connection stability to ensure electrically conductive stability.

Description

Photovoltaic module

Technical Field

The embodiment of the application relates to the technical field of photovoltaic products, in particular to a photovoltaic module.

Background

With the continuous development of new energy technology, the utilization of clean energy is going deep into daily life. Among them, the solar energy utilization is more and more important in clean energy due to the continuous improvement of the photovoltaic power generation products in cost control and power generation efficiency. The photovoltaic module is used as the core of a photovoltaic power generation product, solar energy can be converted into electric energy, the battery string in the photovoltaic module has a photovoltaic effect, and the electric energy can be generated under the irradiation of sunlight and is output outwards through other parts of the photovoltaic module.

The connection reliability of the internal structure of the photovoltaic module affects the efficiency of photovoltaic power generation and affects the reliability of whether the generated electric energy can be stably output to the outside. Therefore, how to ensure the connection reliability of the internal structure of the photovoltaic module so as to ensure the conductive stability is an important issue.

Disclosure of Invention

An object of the embodiment of the application is to provide a photovoltaic module, can effectively ensure the connection stability of photovoltaic module inner structure to ensure electrically conductive stability.

In order to solve the technical problem, an embodiment of the present application provides a photovoltaic module, which includes a battery piece and a solder strip. The surface of the battery piece is provided with a plurality of thin grid lines which are mutually spaced. The welding strip is positioned on the surface of the battery piece, an adhesive layer and an alloy layer are distributed between the welding strip and the surface of the battery piece, the welding strip is connected with the surface of the battery piece through the adhesive layer and is electrically connected with the fine grid line through the alloy layer, and the alloy layer comprises 20-40 wt% of tin, 20-50 wt% of bismuth, 20-40 wt% of lead and 1-3 wt% of silver.

According to the photovoltaic module provided by the embodiment of the application, the bonding layer and the alloy layer are distributed between the solder strip and the surface of the cell piece. The bonding layer can bond the welding strip and the battery piece, so that the welding strip is fixed on the surface of the battery piece. And the alloy layer formed between the solder strip and the thin grid line on the surface of the battery piece can play a role in conducting electricity between the solder strip and the thin grid line on the surface of the battery piece. Meanwhile, the alloy layer can enable the welding strip and the thin grid lines on the surface of the battery piece to be of an integrated structure, namely the alloy layer and the bonding layer play a role in fixing the welding strip and the battery piece. Because the molecular structure in the alloy layer is stable, the connection failure phenomenon caused by cracking due to the influence of external temperature is not easy to occur. Therefore, the photovoltaic module provided by some embodiments of the present application can effectively ensure the connection reliability of the internal structure of the photovoltaic module, so as to ensure the conductive stability.

In addition, the formed alloy layer contains 20-40 wt% of metal tin, so that the formed alloy layer has good ductility between the solder strip and the fine grid lines on the surface of the battery piece. The formed alloy layer has 20-50 wt% of metal bismuth, so that the alloy layer has good wettability. The ductility of the alloy layer can be improved by 20-40 wt% of metallic lead in the formed alloy layer. The formed alloy layer contains 1-3 wt% of metal silver, so that the series resistance between the solder strip and the thin grid line on the surface of the battery piece can be reduced.

In some embodiments, the composition of the alloy layer includes 20 to 30wt% tin, 30 to 40wt% bismuth, 30 to 40wt% lead, 1.6 to 2.0wt% silver.

In some embodiments, the composition of the alloy layer further includes copper 1 to 3wt%. Therefore, the alloy layer formed between the welding spot and the thin grid line of the battery piece has good conductivity through the good conductivity of the copper metal, and the reduction of series resistance between the welding strip and the thin grid line on the surface of the battery piece is facilitated.

In some embodiments, the orthographic projection of the alloy layer on the surface of the battery piece completely covers the thin grid lines in the width direction of the thin grid lines. Therefore, the sufficient contact area and the fixed area can be ensured between the alloy layer and the thin grid lines on the surface of the battery piece, the current loss at the alloy layer is reduced, and the sufficient connection strength is ensured between the welding strip and the thin grid lines on the surface of the battery piece.

In some embodiments, the alloy layers are distributed at intervals along the length direction of the solder strip and correspond to the thin grid lines one to one. Therefore, the current led out by each thin grid line on the surface of the battery piece can be effectively conducted to the welding strip, so that the output of the photo-generated current of the battery piece is realized.

In some embodiments, at least one thin grid line is arranged between two adjacent bonding layers distributed along the length direction of the solder strip at intervals. Like this, through the distribution position of rational arrangement adhesive linkage, be favorable to ensureing to weld the fixed effect of taking on the battery piece surface for it can not separate from the battery piece surface easily to weld the area.

In some embodiments, the bonding layers distributed along the length of the solder strip are equally spaced. Therefore, the fixing function can be uniformly realized between the welding strip and the surface of the battery piece, and the phenomenon that the part position on the welding strip is easy to deform and shift due to lack of constraint is avoided.

In some embodiments, the adhesive layer is an adhesive covering the surface of the battery piece, and the adhesive contains conductive particles or does not contain the conductive particles. Therefore, when the welding strip is fixed on the surface of the battery piece, the adhesive is coated on the surface of the battery piece in advance, and the battery piece is convenient to be connected in series.

In some embodiments, the adhesive is transparent and the adhesive has a light transmittance of greater than or equal to 85%. Therefore, the light shading effect of the adhesive on the surface of the battery piece can be avoided, and light can penetrate through the adhesive to reach the surface of the battery piece.

In some embodiments, the adhesive layer has a thickness greater than or equal to 70 micrometers and less than or equal to 180 micrometers. Therefore, the phenomenon that the welding strip cannot be effectively fixed due to the fact that the bonding layer is too thin can be avoided, and cost rise due to the fact that the bonding layer is too thick is avoided.

In some embodiments, the alloy layer has a melting point greater than or equal to 130 ℃ and less than or equal to 165 ℃. Therefore, the formation of the alloy layer can be realized at a lower temperature, the fixation between the welding strip and the surface of the battery piece is enhanced, and the problems of hidden cracking and breakage of the battery piece due to high-temperature welding are avoided.

Drawings

One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the figures in which like reference numerals refer to similar elements and which are not to scale unless otherwise specified.

Fig. 1 is a schematic top view of a solder ribbon and cell tab connection structure in a photovoltaic module provided by some embodiments of the present application;

fig. 2 is a schematic front view of a connection structure of a solder strip and a cell in a photovoltaic module according to some embodiments of the present disclosure;

fig. 3 is a schematic front view of another bonding strip and cell connection structure in a photovoltaic module according to some embodiments of the present disclosure;

fig. 4 is a schematic structural view of a photovoltaic module provided in some embodiments of the present application;

fig. 5 is a schematic front view of a connection structure of a solder strip and a cell in a photovoltaic module according to the prior art.

Detailed Description

To make the objects, technical solutions and advantages of the embodiments of the present application clearer, embodiments of the present application will be described in detail below with reference to the accompanying drawings. However, it will be appreciated by those of ordinary skill in the art that numerous technical details are set forth in various embodiments of the present application in order to provide a better understanding of the present application. However, the technical solution claimed in the present application can be implemented without these technical details and various changes and modifications based on the following embodiments. The following embodiments are divided for convenience of description, and should not constitute any limitation to the specific implementation manner of the present application, and the embodiments may be mutually incorporated and referred to without contradiction.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "including" and "having," and any variations thereof in the description and claims of this application and the description of the figures above, are intended to cover non-exclusive inclusions.

In the description of the embodiments of the present application, unless otherwise explicitly specified or limited, the terms "mounted," "connected," "fixed," and the like are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrated; mechanical connection or electrical connection is also possible; they may be directly connected or indirectly connected through intervening media, or may be connected through the use of two elements or the interaction of two elements. Specific meanings of the above terms in the embodiments of the present application can be understood by those of ordinary skill in the art according to specific situations.

The photovoltaic module, also called a cell module, has a cell sheet as an important component of the photovoltaic module, and plays a role in converting solar energy into electric energy in the photovoltaic module. The PN junction formed in the cell has a photovoltaic effect, can generate current under the irradiation of sunlight, and can be further conveyed outwards through the welding strip connected with the cell. In the manufacturing process of the photovoltaic module, the series welding process of the battery pieces can be carried out, and the battery piece series welding connects a plurality of battery pieces together in series through the welding strips. That is to say, different battery pieces are interconnected through the solder strips, so that the photovoltaic module obtains the set voltage and power.

Because the current generated by the cell under the irradiation of sunlight needs to be transmitted through the solder strip, the connection reliability of the solder strip and the cell affects the power generation stability of the photovoltaic module. Usually, the connection between the solder strip and the battery plate is realized by welding. The typical welding temperature is above 220 ℃, and the welding strip is melted at high temperature and fused with the silver paste on the surface of the battery piece. Due to the adoption of a high-temperature process, the battery piece is easy to generate stress warping under the influence of high temperature, so that hidden cracks and even fragments are generated.

Due to adverse effects caused by high-temperature welding, in the prior art, the welding strip is directly adhered to the surface of the battery piece through the adhesion effect of an adhesive or a conductive adhesive. And then the welding strip is contacted with the thin grid lines of the battery slices through the laminating effect to realize circuit connection, so that the battery slices are connected into a battery string. That is to say, the solder strip and the battery piece are connected together by adhesive or conductive adhesive, and the solder strip is electrically connected with the fine grid lines on the surface of the battery piece through physical contact. However, in practical cases, this physical connection form has a disadvantage of low conductive stability. As the finished photovoltaic module has different expansion coefficients along with the change of temperature in the outdoor use process, the packaging adhesive film, the grid line electrode and the silicon wafer in the photovoltaic module expand to different degrees. This makes it very likely that the solder strip will separate from the grid line electrode, resulting in excessive power attenuation of the photovoltaic module.

In order to solve the problem that the conductive stability of the solder strip and the surface of the cell is insufficient due to physical contact, some embodiments of the present application provide a photovoltaic module. When a cell in the photovoltaic module is connected with the welding strip through an adhesive or a conductive adhesive, an alloy structure is formed at the contact part of the welding strip and the thin grid line on the surface of the cell, and the welding strip is electrically connected with the thin grid line on the surface of the cell through the alloy structure. The formation of the alloy structure can be realized by low-temperature welding or lamination of 112-180 ℃, and the temperature during lamination can be controlled to be 112-180 ℃. The solder strip can be SnBiPb series or SnBiAg series low-temperature solder strip.

The following describes a photovoltaic module structure provided by some embodiments of the present application with reference to fig. 1 to 3.

As shown in fig. 1 to 3, a photovoltaic module 10 according to some embodiments of the present disclosure includes a cell 111 and a solder ribbon 112, wherein the cell 111 has a plurality of fine grid lines 1111 spaced from each other on a surface thereof. The solder strip 112 is located on the surface of the battery piece 111, the adhesive layer 101 and the alloy layer 102 are distributed between the solder strip 112 and the surface of the battery piece 111, the solder strip 112 is connected with the surface of the battery piece 111 through the adhesive layer 101 and is electrically connected with the fine grid lines 1111 through the alloy layer 102, and the alloy layer 102 comprises 20-40 wt% of tin, 20-50 wt% of bismuth, 20-40 wt% of lead and 1-3 wt% of silver.

The cell sheet 111 is a portion of the photovoltaic module 10 that performs a photoelectric conversion function. The cell 111 generally includes a substrate, a PN junction and a passivation structure formed on the substrate, and a gate line electrode on the surface of the cell 111. The substrate is usually a silicon substrate, and a PN junction formed on the silicon substrate generates current under the action of light. The gate line electrode includes a fine gate line 1111 for leading out a current generated by the PN junction.

The solder ribbons 112 connect different cells 111 in series in the photovoltaic module 10 to serve as interconnects. The solder ribbon 112 generally includes a copper substrate and an alloy coating coated on the copper substrate, wherein the alloy coating melts and fuses with the fine grid 1111 of the battery piece 111 under a certain temperature condition. In order to reduce the conductive length of the solder strip 112 on the surface of the battery piece 111, the arrangement direction of the solder strip 112 on the surface of the battery piece 111 and the extending direction of the fine grid lines 1111 on the surface of the battery piece 111 can be kept perpendicular to each other, so as to reduce the current loss on the solder strip 112.

The adhesive layer 101 serves to adhere the solder strip 112 to the cell piece 111 in the photovoltaic module 10, and the adhesive layer 101 may use an adhesive or a conductive adhesive to fix the solder strip 112 on the surface of the cell piece 111 through the adhesion of the adhesive layer 101. The alloy layer 102 is formed between the solder strip 112 and the fine grid lines 1111 on the surface of the battery piece 111, and in the process of connecting the solder strip 112 and the battery piece 111, the alloy layer 102 enables the solder strip 112 and the fine grid lines 1111 on the surface of the battery piece 111 to form good electric connection effect and fixing effect.

The alloy layer 102 is formed in the lamination or low-temperature welding process of the solder strip 112 and the battery piece 111, and the composition of the alloy layer 102 is formed by the solder strip 112 and the fine grid lines 1111 of the battery piece 111, and may be mostly formed by the composition on the solder strip 112 or the composition on the fine grid lines 1111 of the battery piece 111. The alloy layer 102 comprises tin, bismuth, lead and silver, which are both conductive. The metal tin has a high melting point (above 230 ℃) and strong plasticity, and the formed alloy layer 102 contains 20-40 wt% of the metal tin, so that the metal tin has good ductility between the solder strip 112 and the fine grid lines 1111 on the surface of the battery piece 111. The bismuth metal can form eutectic with the tin metal, which can effectively reduce the melting point of the alloy layer 102 and also can effectively improve the wettability of the alloy layer 102 on the copper substrate of the solder strip 112, so that the formed alloy layer 102 has 20 to 50 weight percent of bismuth metal, which can enable the alloy layer to have better wettability. The metal lead can increase the spreading area of the alloy structure, and the 20-40 wt% of the metal lead in the formed alloy layer 102 can increase the ductility of the alloy layer 102 because the recrystallization temperature of the metal lead is lower than the room temperature and has better plasticity. The metal silver has good conductivity and is usually used as a raw material of the grid line electrode, so that the 1-3 wt% of the metal silver in the formed alloy layer 102 can reduce the series resistance between the solder strip 112 and the thin grid lines 1111 on the surface of the cell 111, which is beneficial to reducing the silver content in the slurry of the grid line electrode of the cell 111 and reducing the cost for manufacturing the grid line electrode of the cell 111. In practical cases, the metallic tin in the alloy layer 102 may account for 20 to 25wt%, 25 to 30wt%, 30 to 35wt%, or 35 to 40wt%, preferably 20 to 30wt%; the metal bismuth in the alloy layer 102 may account for 20-25 wt%, 25-30 wt%, 30-35 wt%, 35-40 wt%, 40-45 wt%, or 45-50 wt%, preferably 30-40 wt%; the metallic lead in the alloy layer 102 may account for 20-25 wt%, 25-30 wt%, 30-35 wt%, or 35-40 wt%, preferably 30-40 wt%; the content ratio of metallic silver in the alloy layer 102 is preferably 1.6 to 2.0wt%. In an alternative example, the composition of alloy layer 102 includes 24wt% tin, 36wt% bismuth, 38wt% lead, and 2wt% silver.

According to the photovoltaic module 10 provided by some embodiments of the present application, the adhesive layer 101 and the alloy layer 102 are distributed between the solder strip 112 and the surface of the cell 111. The adhesive layer 101 can perform an adhesive function between the solder strip 112 and the battery piece 111, so as to fix the solder strip 112 on the surface of the battery piece 111. The alloy layer 102 formed between the solder strip 112 and the fine grid lines 1111 on the surface of the battery piece 111 can conduct electricity between the solder strip 112 and the fine grid lines 1111 on the surface of the battery piece 111. Meanwhile, the alloy layer 102 can enable the solder strip 112 and the fine grid lines 1111 on the surface of the battery piece 111 to be integrated into a whole, namely, the solder strip 112 and the battery piece 111 are fixed together with the adhesive layer 101. Since the molecular structure in the alloy layer 102 is stable, the connection failure phenomenon caused by cracking due to the influence of the external temperature is not easy to occur. Therefore, the photovoltaic module 10 provided by some embodiments of the present application can effectively ensure the connection reliability of the internal structure of the photovoltaic module 10, so as to ensure the conductive stability.

The alloy layer 102 is composed of the solder strip 112 and the fine grid lines 1111 of the battery piece 111, and the alloy layer 102 is formed by fusing the solder strip 112 and the fine grid lines 1111 of the battery piece 111 by melting at a temperature of 112-180 ℃. The components of the solder strip 112 and the fine grid lines 1111 on the cell 111 together realize that the alloy layer 102 can be formed at a low temperature, so that the problem that the cell 111 is prone to crack and break due to high-temperature welding when the cell 111 is connected in series can be solved.

In some embodiments herein, the composition of alloy layer 102 also includes copper 1 to 3wt%, preferably 0.8 to 1.2wt%.

For example, in an alternative example, the composition of alloy layer 102 includes 23wt% tin, 36wt% bismuth, 38wt% lead, 2wt% silver, and 1wt% copper.

Because the metal copper has good conductive performance, the alloy layer 102 formed by the alloy layer has 1-3 wt% of the metal copper, which enables the alloy layer to have good conductive performance, and is beneficial to reducing the series resistance between the solder strip 112 and the fine grid line 1111 on the surface of the battery piece 111. Meanwhile, the metal copper can form eutectic with other metals to jointly form a low-melting-point quinary alloy structure, and can be formed under the condition of relatively high temperature welding and relatively low temperature, so that the thermal deformation stress of the grid line electrode, the cell piece 111 and the solder strip 112 is relatively small, and the reduction of the breakage rate of photovoltaic module welding is facilitated.

The following table records the alloy layer formation temperature and the pullout force results determined when preparing photovoltaic modules having different specific metal contents in the alloy layer. Wherein, the content of the single metal before the connection of the solder strip or the thin grid line is controlled to form the alloy layers with different contents of the specific metal.

After preparing and forming different photovoltaic module samples, measuring the content ratio of the specific metal of the alloy layer in the formed photovoltaic module, and simultaneously recording the temperature of the alloy layer formed during the preparation of the photovoltaic module. And sequentially carrying out the tensile force test of the alloy layer on each photovoltaic module sample. When the alloy layer formed in the photovoltaic assembly is subjected to a drawing force test, all photovoltaic assembly samples are sequentially placed on a test bench, a welding strip is drawn, and the drawing force when the formed alloy layer is separated from the thin grid line is recorded.

TABLE I, table for measuring welding temperature and drawing force of photovoltaic module sample when alloy layer has metals with different content ratio

As can be seen from table one, when the content of the metal tin in the alloy layer 102 is 20 to 40wt%, the content of the metal bismuth is 20 to 50wt%, the content of the metal lead is 20 to 40wt%, the content of the metal silver is 1.6 to 2.0wt%, and the content of the metal copper is 0.8 to 1.2wt%, the welding temperature condition for forming the alloy layer 102 is low, is within the range of 140 ℃ to 186 ℃, and is far lower than the temperature used in high temperature welding. Meanwhile, the formed alloy layer 102 connecting structure has a large drawing force which is more than 3.0N, and the connecting strength between the solder strip and the thin grid line can be well ensured.

Also, from table one it can be seen that:

1. as the amount of metallic tin in alloy layer 102 increases, the soldering temperature conditions under which alloy layer 102 is formed also need to be increased accordingly. That is, when the content of the metallic tin in the alloy layer 102 accounts for 20 to 30wt%, the soldering temperature for forming the alloy layer 102 is reduced compared with the content of the metallic tin accounting for 30 to 40wt%, which is beneficial to improving the hidden cracking and fragment problems caused by higher temperature during the preparation of the photovoltaic module. In practical cases, the content of metallic tin in the alloy layer 102 is preferably 23wt%.

2. As the content of bismuth metal in the alloy layer 102 increases, the welding temperature condition for forming the alloy layer 102 decreases, but as the content of bismuth metal exceeds a certain value, the drawing force of the formed connection structure of the alloy layer 102 decreases. That is, when the content of the metal bismuth in the alloy layer 102 is 30 to 40wt%, the drawing force of the connection structure of the formed alloy layer 102 can be made large while the welding temperature condition for forming the alloy layer 102 is kept in a low range, compared to the content of the metal bismuth of 20 to 30wt% and 40 to 50 wt%. In practical cases, the content of the metal bismuth in the alloy layer 102 is preferably 36wt%.

3. As the content of metallic lead in the alloy layer 102 increases, the welding temperature condition at the time of forming the alloy layer 102 decreases, and the drawing force of the formed alloy layer 102 connection structure is large. That is, when the content of metallic lead in the alloy layer 102 accounts for 30 to 40wt%, the welding temperature condition for forming the alloy layer 102 is lower than that for 20 to 30wt%, and at the same time, the drawing force of the connection structure of the formed alloy layer 102 can be improved. In practical cases, the content ratio of metallic lead in the alloy layer 102 is preferably 38wt%.

In some embodiments of the present application, an orthographic projection of the alloy layer 102 on the surface of the battery piece 111 completely covers the fine grid lines 1111 in the width direction of the fine grid lines 1111.

Thus, on one hand, the contact area of the alloy layer 102 on the fine grid lines 1111 on the surface of the battery piece 111 can be ensured, so that the solder strip 112 and the fine grid lines 1111 on the surface of the battery piece 111 have better conductivity. On the other hand, the fixed area between the alloy layer 102 and the fine grid lines 1111 on the surface of the battery piece 111 can be ensured, so that the solder strip 112 and the fine grid lines 1111 on the surface of the battery piece 111 have sufficient connection strength.

In the case where the conductivity and the connection strength between the solder ribbon 112 and the thin grid lines 1111 on the surface of the battery piece 111 can be ensured, the orthogonal projection of the alloy layer 102 on the surface of the battery piece 111 may partially cover the thin grid lines 1111 in the width direction of the thin grid lines 1111. In this way, the material usage of the alloy layer 102 can be reduced, reducing the manufacturing cost of the photovoltaic module 10.

In some embodiments of the present application, the alloy layer 102 is distributed at intervals along the length direction of the solder ribbon 112, and corresponds to the plurality of fine grid lines 1111 one to one.

That is to say, each thin grid line 1111 on the surface of the battery piece 111 is corresponding to the alloy layer 102 and is fixedly and electrically connected with the solder strip 112, so that the current led out from each thin grid line 1111 on the surface of the battery piece 111 can be stably transmitted to the solder strip 112 through the alloy layer 102.

In some embodiments of the present application, at least one thin grid line 1111 is spaced between two adjacent adhesive layers 101 distributed along the length direction of the solder ribbon 112.

In order to improve the stability of the solder ribbon 112 when it is fixed to the surface of the battery piece 111, the adhesive layer 101 adheres the solder ribbon 112 to the surface of the battery piece 111 at more than one position. Meanwhile, two adjacent bonding layers 101 distributed along the length direction of the solder strip 112 are separated by the thin grid line 1111, and one or more thin grid lines 1111 may be separated between two adjacent bonding layers 101. After the solder ribbon 112 and the surface of the battery piece 111 are fixed by the adhesive layer 101, the formation of the alloy layer 102 can be smoothly completed, so that the alloy layer 102 can be continuously formed to enhance the connection strength between the solder ribbon 112 and the battery piece 111 through the alloy layer 102 on the basis of the adhesive effect of the adhesive layer 101.

In practical applications, in order to ensure the stability of the solder ribbons 112 when they are fixed on the surface of the battery piece 111, the distribution position of the adhesive layer 101 may be increased. As shown in fig. 2, one thin gate line 1111 may serve as a boundary between two adjacent adhesive layers 101, or, as shown in fig. 3, two thin gate lines 1111 may serve as a boundary between two adjacent adhesive layers 101.

In some embodiments of the present application, the adhesive layers 101 distributed along the length of the solder ribbon 112 are equally spaced.

That is, the distance between any two adjacent adhesive layers 101 distributed along the length direction of the solder ribbon 112 is equal. The adhesive layers 101 are uniformly distributed on the surface of the cell 111 along the length direction of the solder strip 112. In this way, the bonding effect of the bonding layer 101 can be made uniform, and the solder strip 112 can be stably fixed on the surface of the battery piece 111 without bending due to lack of constraint at a part of the solder strip 112.

In some embodiments of the present application, the adhesive layer 101 is an adhesive covering the surface of the battery sheet 111, and the adhesive contains conductive particles or does not contain conductive particles.

When the solder strip 112 needs to be fixed on the surface of the battery piece 111, the adhesive can be coated on the surface of the battery piece 111, and then the solder strip 112 is bonded with the adhesive, so that the solder strip 112 is fixed on the surface of the battery piece 111. This facilitates the connection of the battery cells 111 in series, and simplifies the fixing process of the solder strips 112.

In addition, the adhesive may contain conductive particles, and in the case where the adhesive contains conductive particles, the solder ribbon 112 and the fine grid lines 1111 on the surface of the battery piece 111 may be electrically connected by the adhesive. In the case where the adhesive does not contain conductive particles, the adhesive can function to fix the solder ribbons 112 on the surface of the battery piece 111.

The adhesive may be transparent, and the light transmittance of the adhesive may be 85% or more.

The transparent adhesive does not affect the absorption efficiency of the solar cell 111 under the action of light. That is, light can smoothly pass through the adhesive and reach the surface of the cell 111 without having a light-shielding effect in the photovoltaic module 10.

In some embodiments of the present application, the adhesive layer 101 has a thickness greater than or equal to 70 micrometers and less than or equal to 180 micrometers.

In this way, by controlling the thickness of the adhesive layer 101 to be greater than or equal to 70 μm, the adhesive layer 101 can have a stable fixing effect, and the solder strip 112 can not be easily separated from the surface of the battery piece 111. By controlling the thickness of the adhesive layer 101 to be less than or equal to 180 micrometers, the use of adhesives can be saved, and the cost of manufacturing the photovoltaic module 10 can be reduced.

In some embodiments of the present application, the melting point of the alloy layer 102 is greater than or equal to 130 degrees celsius and less than or equal to 165 degrees celsius.

Thus, the temperature condition for forming the alloy layer 102 is much lower than that during high-temperature welding, and the battery piece 111 can be prevented from being hidden or broken due to high temperature. Meanwhile, the alloy layer 102 can be melted to fuse the solder strip 112 and the fine grid lines 1111 on the surface of the battery piece 111 by only controlling the laminating temperature of the battery piece 111 and the solder strip 112 to be 130 to 165 ℃.

In addition, when the photovoltaic module 10 provided by some embodiments of the present application is used for connecting the battery pieces 111 in series, an adhesive may be first applied on the surface of the battery piece 111, and then the solder strip 112 is positioned on the battery piece 111 according to the position of the adhesive, while the solder strip 112 is reserved with a certain length. The solder ribbons 112 exposed from the cell sheet 111 to which the solder ribbons 112 are bonded are transferred to the surface of another cell sheet 111, so that the plurality of cell sheets 111 are sequentially connected in series, and the solder ribbons 112 are fixed to the cell sheets 111 after the adhesive is cured, thereby forming the cell string 11. The cell sheet 111 may be a single-sided solar cell or a double-sided solar cell, and the solder ribbons 112 may be connected in series on only one side of the cell sheet 111 or may be connected in series on both sides of the cell sheet 111.

As shown in fig. 4, after the series connection of the battery pieces 111 is completed, the stack including the packaging adhesive film 12 and the cover sheet 13 is formed on the front and the back of the battery string 11, respectively, to form a laminate. The packaging adhesive film 12 may be an EVA adhesive film, a POE adhesive film, an EPE adhesive film, or a PVB adhesive film. The laminated member is then placed in a laminating cavity of the laminating machine, the laminated member is laminated at a certain temperature, the packaging adhesive film 12 is melted to fill the periphery of the battery string 11, and the components of the laminated member are fixed to form the photovoltaic module 10.

The alloy layer 102 is formed between the solder ribbon 112 and the surface of the battery piece 111 at a predetermined lamination temperature, and firmly fixes the solder ribbon 112 to the surface of the battery piece 111 together with the adhesive. Meanwhile, the alloy layer 102 forms a conductive channel between the solder strip 112 and the fine grid line 1111 on the surface of the battery piece 111, thereby playing a role of electrically connecting the solder strip 112 and the battery piece 111.

Compared with the photovoltaic module in the prior art shown in fig. 5 in which the bonding layer 101 directly realizes the fixed connection between the solder strip 112 and the cell 111, the photovoltaic module provided by some embodiments of the present application can achieve a better fixing effect on the solder strip 112 and the cell 111 by forming the alloy layer 102, so as to ensure good conductive stability between the solder strip 112 and the cell 111.

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples of implementations of the present application, and that various changes in form and details may be made therein without departing from the spirit and scope of the present application.

Claims

1. A photovoltaic module, comprising:

the surface of the battery piece is provided with a plurality of fine grid lines which are mutually spaced;

the welding strip is positioned on the surface of the battery piece, an adhesive layer and an alloy layer are distributed between the welding strip and the surface of the battery piece, the welding strip is connected with the surface of the battery piece through the adhesive layer and is electrically connected with the fine grid line through the alloy layer, and the alloy layer comprises 20-40 wt% of tin, 20-50 wt% of bismuth, 20-40 wt% of lead and 1-3 wt% of silver.

2. The photovoltaic module of claim 1, wherein:

the alloy layer comprises 20-30 wt% of tin, 30-40 wt% of bismuth, 30-40 wt% of lead and 1.6-2.0 wt% of silver.

3. The photovoltaic module of claim 1 or 2, wherein:

the composition of the alloy layer also comprises 1-3 wt% of copper.

4. The photovoltaic module of claim 1, wherein:

the orthographic projection of the alloy layer on the surface of the battery piece completely covers the thin grid lines in the width direction of the thin grid lines.

5. The photovoltaic module of claim 4, wherein:

the alloy layer is distributed at intervals along the length direction of the welding strip and corresponds to the thin grid lines one by one.

6. The photovoltaic module of claim 1, wherein:

at least one thin grid line is arranged between every two adjacent bonding layers distributed along the length direction of the solder strip at intervals.

7. The photovoltaic module of claim 6, wherein:

the bonding layers distributed along the length direction of the welding strip are arranged at equal intervals.

8. The photovoltaic module of claim 1, wherein:

the adhesive layer is an adhesive covering the surface of the battery piece, and the adhesive contains conductive particles or does not contain conductive particles.

9. The photovoltaic module of claim 8, wherein:

the adhesive is transparent, and the light transmittance of the adhesive is greater than or equal to 85%.

10. The photovoltaic module of claim 1, wherein:

the thickness of the bonding layer is greater than or equal to 70 micrometers and less than or equal to 180 micrometers.

11. The photovoltaic module of claim 1, wherein:

the melting point of the alloy layer is greater than or equal to 130 ℃ and less than or equal to 165 ℃.