CN112151631B - Preparation method of welding strip - Google Patents

Abstract

The embodiment of the present invention relates to the field of photovoltaic technology, and discloses a welding tape, comprising: a conductive welding tape body, and the conductive welding tape body includes: a first outer surface; a silver film layer on the first outer surface, the The silver film layer is composed of nano silver particles. The welding tape, the photovoltaic module and the preparation method of the welding tape provided in the present invention take into account high conductivity and high reliability while realizing the coloring of the welding tape.

Description

Preparation method of welding strip

technical field

Embodiments of the present invention relate to the field of photovoltaic technology, and in particular, to a method for preparing a solder ribbon.

Background technique

Welding ribbon is an important raw material in the welding process of photovoltaic modules. Solar modules are connected to solar cells through the welding ribbon. Due to the good conductivity of the welding ribbon, each solar cell forms a complete electrical path after welding, thereby making the solar fiber The current and voltage generated under irradiation can be transmitted in the ribbon, providing a reliable basis for utilizing solar energy. According to different functions, welding strips can be further divided into two types: interconnecting strips and bus strips. However, the traditional welding strips are mainly bright silver, and the bright silver welding strips have light pollution, which is easy to form strong light reflection, which is not conducive to safe driving, and has great restrictions on the application scenarios of photovoltaic modules.

In view of the above problems, in the related art, the preparation of the black welding strip is realized by coating a layer of black paint on the surface of the welding strip. However, the black welding strip prepared by this method not only has the problem that the coating is easy to fall off, but also the welding strip is easy to fall off. Resistivity, solderability, etc. have been greatly affected. Therefore, there is an urgent need in the art for a technical solution, which can make the ribbons colored while taking into account the properties such as resistivity and reliability of the ribbons.

SUMMARY OF THE INVENTION

The purpose of the embodiments of the present invention is to provide a method for preparing a solder ribbon, which can achieve high electrical conductivity and high reliability while realizing the colorization of the solder ribbon.

In order to solve the above-mentioned technical problems, an embodiment of the present invention provides a welding ribbon, comprising: a conductive welding ribbon body, and the conductive welding ribbon body includes: a first outer surface; a silver film layer on the first outer surface , the silver film layer is composed of nano-silver particles.

An embodiment of the present invention also provides a photovoltaic module, comprising a plurality of solar cell strings composed of a plurality of solar cells, and at least one of the above-mentioned welding strips; the welding strips electrically connect two adjacent solar cell strings , or electrically connect two adjacent solar cells.

An embodiment of the present invention also provides a method for preparing a welding ribbon, comprising: placing a conductive welding ribbon body and an alloy solder in a heating container, the alloy solder being located on a first outer surface of the conductive welding ribbon body; Wherein, the alloy solder is a ternary alloy, and the ternary alloy includes: tin, silver and another metal; the heating vessel is heated and kept warm to obtain a molten alloy solder; the molten alloy is cooled alloy solder to obtain a silver film layer on the first outer surface, and an alloy layer between the conductive ribbon body and the silver film layer; wherein, the silver film layer is composed of nano-silver particles.

Compared with the related art, the embodiment of the present invention provides a welding ribbon, which includes a conductive welding ribbon body, and the conductive welding ribbon body includes: a first outer surface; a silver film layer on the first outer surface, the silver film layer is composed of nanometer Composition of silver particles. Since the first outer surface of the conductive ribbon body is provided with a silver film layer composed of nano-silver particles, and the color of the silver film layer composed of nano-silver particles is colored, so that a ribbon with a colored surface can be formed, avoiding the need for The problem of light pollution in the bright silver ribbon; and because the silver film layer is used to realize the colorization of the ribbon in this scheme, the silver film layer itself has high conductivity, and the silver film layer and the conductive ribbon body have good adhesion. , Not easy to fall off, so that the ribbon can take into account both high conductivity and high reliability.

In addition, the size of the nano-silver particles ranges from 10 nanometers to 80 nanometers.

In addition, the desired size of the nano-silver particles in the silver film layer is 22 nanometers, 30 nanometers, 32 nanometers or 45 nanometers.

In addition, in a direction perpendicular to the first outer surface, the thickness of the silver film layer ranges from 10 nanometers to 200 nanometers.

In addition, the conductive ribbon body further includes a second outer surface opposite to the first outer surface, and the silver film layer is also located on the second outer surface. A silver film layer is attached to the entire surface of the conductive ribbon body, so that the second outer surface of the conductive ribbon body attached to the object (such as a solar cell) and the first outer surface exposed to the outside are colored, which further reduces the Potential light pollution risk from the ribbon.

In addition, it also includes: an alloy layer located between the conductive ribbon body and the silver film layer, the alloy layer is a ternary alloy, and the ternary alloy includes: tin, silver and another metal. Since the ternary alloy contains metallic silver, the adhesion between the silver film layer and the alloy layer is stronger, and it is more difficult to fall off, which further improves the adhesion reliability of the silver film layer.

Additionally, the another metal includes copper, lead or bismuth.

In addition, the material of the conductive ribbon body includes any one of the following: copper, gold, silver, iron and tin.

In addition, in different preparation processes, the molten alloy solder is cooled at different cooling rates to obtain silver film layers with different desired sizes of nano-silver particles in different preparation processes; wherein, the faster the cooling rate is , the smaller the expected size value of the nano-silver particles in the silver film layer is. The size of the nano-silver particles can be effectively controlled by changing the cooling rate, and the corresponding colors of the nano-silver particles of different sizes can be used to make the welding strip show different colors, and the colored welding strip can be obtained, and the process is simple and controllable.

In addition, when the cooling rate is decreased by 1°C to 100°C per minute, the size of the nano-silver particles ranges from 10 nanometers to 80 nanometers.

In addition, the desired size of the nano-silver particles in the silver film layer is 22 nanometers, 30 nanometers, 32 nanometers or 45 nanometers.

Additionally, the another metal includes copper, lead or bismuth.

In addition, the silver accounts for 0.01% to 10% of the total mass of the alloy solder, the tin accounts for 5% to 90% of the total mass of the alloy solder, and the other metal accounts for 5% to 90% of the total mass of the alloy solder. 5%~90%.

Description of drawings

One or more embodiments are exemplified by the pictures in the corresponding drawings, and these exemplifications do not constitute limitations of the embodiments, and elements with the same reference numerals in the drawings are denoted as similar elements, Unless otherwise stated, the figures in the accompanying drawings do not constitute a scale limitation.

1 is a schematic cross-sectional view of a welding ribbon according to a first embodiment of the present invention;

2 is another schematic cross-sectional view of the welding ribbon according to the first embodiment of the present invention;

3 is a top view of a photovoltaic module according to a second embodiment of the present invention;

FIG. 4 is a schematic flowchart of a method for manufacturing a welding ribbon according to a third embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, each embodiment of the present invention will be described in detail below with reference to the accompanying drawings. However, those of ordinary skill in the art can appreciate that, in the various embodiments of the present invention, many technical details are set forth in order for the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present application can be realized.

The first embodiment of the present invention relates to a welding tape. The core of this embodiment is that the welding tape includes a conductive welding tape body, and the conductive welding tape body includes: a first outer surface; a silver film layer on the first outer surface, silver The film layer is composed of nano-silver particles. Since the first outer surface of the conductive ribbon body is provided with a silver film layer composed of nano-silver particles, and the color of the silver film layer composed of nano-silver particles is colored, so that a ribbon with a colored surface can be formed, avoiding the need for The problem of light pollution in the bright silver solder ribbon; and because the silver film layer is used to realize the colorization of the ribbon in this scheme, and the silver film layer itself has high conductivity, and the silver film layer has good adhesion to the conductive ribbon body. It is not easy to fall off, so that the ribbon can take into account high conductivity and high reliability at the same time.

The implementation details of the welding ribbon in this embodiment will be specifically described below, and the following content is only provided for the convenience of understanding, and is not necessary for implementing this solution.

The schematic structural diagram of the soldering ribbon 1 in this embodiment is shown in FIG. 1 : it includes a conductive soldering ribbon body 11 , and the material of the conductive soldering ribbon body 11 includes any one of the following: copper, gold, silver, iron and tin. In this embodiment, in order to achieve both high conductivity and low cost, copper is used as the material of the conductive ribbon body 11 .

The conductive ribbon body 11 includes a first outer surface 111 , and further includes: a silver film layer 13 located on the first outer surface 111 , and the silver film layer 13 is composed of nano-silver particles. As the size of the nano-silver particles changes, the corresponding range of the optical absorption of the nano-silver particles also changes accordingly, thereby showing various colors. The silver film layer 13 can obtain the solder ribbon 1 with a colored surface, which avoids the problem of light pollution existing in the bright silver solder ribbon 1 . In this embodiment, the silver film layer 13 is used to realize the colorization of the welding tape 1, and the silver film layer 13 itself has high conductivity, and the silver film layer 13 and the conductive welding tape body 11 belong to the same metal material, and have good adhesion, It is not easy to fall off, so that the welding tape 1 can take into account high conductivity and high reliability at the same time. Wherein, the surface shape of the welding strip 1 may be a circle, a triangle, a square or other shapes.

It is worth noting that the conductive ribbon body 11 is generally sheet-shaped. Since one surface of the conductive ribbon body 11 will be attached to an object (such as the solar cell 120 ) during use, in this embodiment, only the conductive ribbon The silver film layer 13 is formed on the first outer surface 111 of the main body 11 , and the silver film layer 13 is not formed on the other surface for adhering to the object, which further reduces the cost of the welding tape 1 .

Realizable, as shown in FIG. 2 , the conductive ribbon body 11 further includes a second outer surface 112 opposite to the first outer surface 111 , and the silver film layer 13 is also located on the second outer surface 112 . That is to say, the silver film layer 13 is attached to the entire surface of the conductive ribbon body 11 , so that the conductive ribbon body 11 is attached to the second outer surface 112 of the object (such as the solar cell 120 ) and the first surface exposed to the outside. The outer surfaces 111 are all colored, which further reduces the risk of light pollution that may exist in the welding tape 1 .

In some embodiments, an alloy layer 12 is further disposed between the conductive ribbon body 11 and the silver film layer 13 , the alloy layer 12 is a ternary alloy, and the ternary alloy includes: tin, silver and another metal. Since the ternary alloy contains metallic silver, the adhesion between the silver film layer 13 and the alloy layer 12 is stronger and less likely to fall off, which further improves the adhesion reliability of the silver film layer 13 .

Among them, another metal of the ternary alloy includes: copper, lead or bismuth. In this embodiment, in order to further improve the adhesion between the alloy layer 12 and the conductive ribbon body 11 , copper can be used for both the conductive ribbon body 11 and the other metal of the ternary alloy.

The size of the nano-silver particles in the silver film layer 13 in this embodiment ranges from 10 nanometers to 80 nanometers, and in the direction perpendicular to the first outer surface 111 , the thickness of the silver film layer 13 ranges from 10 nanometers to 200 nanometers.

Further, the desired size of the nano-silver particles in the silver film layer 13 is 22 nanometers, 30 nanometers, 32 nanometers or 45 nanometers.

Specifically, the expected size value means that the size of most of the silver nanoparticles in all the silver nanoparticles in the silver film layer 13 falls near this value. When the expected size value of the nano-silver particles in the silver film layer 13 is different, the color of the film layer is also different. For example: when the expected size value of the nano-silver particles is 22 nanometers, the silver film layer 13 is yellow-green. At this time, The size of the nano-silver particles in the silver film layer 13 is between 10 nanometers and 50 nanometers; when the expected size value of the nano-silver particles is 30 nanometers, the silver film layer 13 is brown, and at this time, the nano-silver particles in the silver film layer 13 are The size of the silver nanoparticles is between 20 nm and 50 nm; when the expected size of the silver nanoparticles is 32 nm, the silver film layer 13 is gray-green. At this time, the size of the silver nanoparticles in the silver film layer 13 is between 10 nm and 80 nm. between nanometers; when the expected size of the silver nanoparticle is 45 nanometers, the silver film layer 13 is brownish gray, and at this time, the size of the silver nanoparticle in the silver film layer 13 is between 20 nanometers and 80 nanometers.

It should be noted that the expected dimension values in this embodiment are only for illustration. In practical applications, the silver film layer 13 may be in other colors, such as red, yellow, etc. At this time, the expected size values of the corresponding nano-silver particles in the silver film layer 13 are also different, which are not exhaustive in this embodiment. , but it can be understood that the expected size values corresponding to the nano-silver particles in the silver film layer 13 of other colors are also within the protection scope of this embodiment.

The welding ribbon 1 in this embodiment is not only colored in appearance, but also can be applied to various occasions where the color of the welding ribbon 1 is different in practical applications; and since the welding ribbon 1 also has high conductivity and high reliability, In addition to being applied to the solar cell 120 to achieve electrical connection, the welding ribbon 1 in this embodiment can also be applied to various occasions requiring electrical conductivity, such as: welding of some light-emitting devices, which is not limited in this embodiment. .

Compared with the related art, an embodiment of the present invention provides a soldering ribbon 1 , which includes a conductive soldering ribbon body 11 , and the conductive soldering ribbon body 11 includes: a first outer surface 111 ; a silver film layer 13 located on the first outer surface 111 , the silver film layer 13 is composed of nano-silver particles. Since the first outer surface 111 of the conductive ribbon body 11 is provided with a silver film layer 13 composed of nano-silver particles, and the color of the silver film layer 13 composed of nano-silver particles is colored, it is possible to form a solder with a colored surface. Belt 1 avoids the problem of light pollution existing in bright silver solder ribbon 1; and because silver film layer 13 is used to achieve colorization of solder ribbon 1 in this scheme, and silver film layer 13 itself has high conductivity, and silver film layer 13 and The conductive ribbon body 11 has good adhesion and is not easy to fall off, so that the ribbon 1 can take both high conductivity and high reliability into consideration.

3 , the second embodiment of the present invention relates to a photovoltaic module, comprising: a plurality of solar cell strings 121 composed of a plurality of solar cells 120 , at least one welding ribbon 1 as in the first embodiment; a welding ribbon 1. Electrically connect two adjacent solar cell strings 121, or electrically connect two adjacent solar cells 120.

Wherein, the solar cell strings 121 can be electrically connected to each other via the solder ribbons 1 (conductive bus bars), and the solar cells 120 can be electrically connected to each other via the solder ribbons 1 (conductive interconnect bars). Ribbons 1 (eg, conductive bus bars and conductive interconnects) are designed to carry the electrical output generated by solar cells 120 from one solar cell 120 to another adjacent solar cell 120 and/or from a solar cell string 121 to Additional adjacent solar cell strings 121 . The ribbons 1 (eg, conductive bus bars and conductive interconnects) can be secured to the solar cells 120 or solar cell strings 121 by any suitable method known in relation to each other, including but not limited to the use of conductive adhesives (EAC) and/or or use solder.

In this embodiment, there is no specific limitation on the location of the welding ribbon 1 between the solar cells 120 and the solar battery string 121 , as long as the electrical connection between the solar cells 120 or between the solar battery strings 121 can be achieved, the welding ribbon 1 can be set Any position between the solar cell 120 and the solar cell string 121 should not be limited to the position of the welding tape 1 shown in FIG. 3 .

Referring to FIG. 4 , the third embodiment of the present invention relates to a method for preparing a welding ribbon. A schematic flowchart of the method for preparing a welding ribbon in this embodiment is shown in FIG. 4 , which specifically includes:

Step 101: Place the conductive solder ribbon body and the alloy solder in the heating container, and the alloy solder is located on the first outer surface of the conductive solder ribbon body; wherein, the alloy solder is a ternary alloy, and the ternary alloy includes: tin, silver and another metal.

Specifically, the material of the conductive ribbon body includes any one of the following: copper, gold, silver, iron and tin. In this embodiment, in order to achieve both high conductivity and low cost, copper is used as the material of the conductive ribbon body. The alloy solder is placed on the first outer surface of the conductive ribbon body. The alloy solder is separated from the copper before melting, and only adheres to the copper sheet after the solder is completely melted.

Among them, the alloy solder is a ternary alloy, and the ternary alloy includes: tin, silver and another metal. Among them, the other metal includes: copper, lead or bismuth. The composition of the equilibrium phase of the ternary alloy Sn(M)Ag is different for different components, and through the control of the composition, M can be a variety of elements, such as copper Cu, lead Pb, or bismuth Bi and so on. If the composition of the three metal materials in the ternary alloy is controlled and the composition of the ternary alloy Sn(M)Ag falls in the silver-rich phase region, the molten ternary alloy Sn(M)Ag cools down At room temperature, a certain amount of nano-silver will be precipitated.

In view of this, in this embodiment, the composition of the three metal materials can be controlled to make the composition of the welding strip fall in the silver-rich region, and the nano-silver particles can be precipitated on the surface of the ternary alloy by the melting recrystallization method. In this embodiment, the sum of the components of the three materials in the ternary alloy is 100%, wherein, when the composition of the ternary alloy Sn(M)Ag falls in the silver-rich phase region, the silver accounts for 0.01% of the total mass of the alloy solder. %~10%, tin accounts for 5%~90% of the total mass of the alloy solder, and another metal accounts for 5%~90% of the total mass of the alloy solder.

Step 102: Heating and maintaining the heating container to obtain molten alloy solder.

In this embodiment, a crucible can be used as a heating vessel. Since metals are prone to oxidation when heated, they should usually be heated in a controlled atmosphere, protective atmosphere, molten salt or vacuum, and can also be protected by coating or packaging methods. For example, in this embodiment, the heating container is vacuum-sealed by using a quartz glass tube. In this way, on the one hand, the oxidation of the conductive ribbon body or the alloy solder can be avoided during the heating process, and on the other hand, it can be avoided that the conductive ribbon body is located in the first place of the conductive ribbon body. The molten alloy solder on an outer surface flows.

Since the alloy solder begins to melt after the alloy solder is heated to the melting point, but it takes a certain amount of time for the alloy solder to completely transform into a molten state. Only when the internal and external temperatures of the alloy solder are consistent and the alloy solder is completely transformed can the equilibrium molten alloy solder be obtained.

In this embodiment, the heating and melting temperature may be 200-1000° C., and the holding time is longer than 15 minutes. Among them, the heating and melting temperature can be comprehensively selected according to the material of the conductive ribbon body and the material of the alloy solder. The heating and melting temperature should be higher than the melting point of the alloy solder, but should be lower than the melting point of the conductive ribbon body to avoid the conductive ribbon body. The shape changes after melting. The holding time can be set according to the quality and shape of the alloy solder to ensure that the alloy solder is completely transformed into a molten state within the holding time. For example: when the alloy solder is SnBiAg and the material of the conductive ribbon body is copper, the heating and melting temperature is 900°C, and the heat preservation is 4 hours, the equilibrium molten alloy solder can be obtained.

Step 103 : cooling the molten alloy solder to obtain a silver film layer on the first outer surface and an alloy layer between the conductive ribbon body and the silver film layer; wherein the silver film layer is composed of nano-silver particles.

Specifically, after obtaining the molten alloy solder, by controlling the cooling rate of cooling the molten alloy solder, the size of the nano-silver on the surface of the solder ribbon can be effectively regulated, thereby making the solder ribbon show different colors.

In this embodiment, by cooling the molten alloy solder at different cooling rates in different preparation processes, silver films with different desired sizes of nano-silver particles can be obtained in different preparation processes; Faster, the smaller the expected size value of the nano-silver particles in the silver film layer. The expected size value means that the size of most of the silver nanoparticles in the silver film layer falls near this value. When the expected size value of the silver nanoparticles in the silver film layer is different, the color of the film layer is also different. Are not the same.

Overall, the nano-silver particles ranged in size from 10 nm to 80 nm when the cooling rate was reduced by 1°C to 100°C per minute. Further, when the cooling rate is between 100 and 50°C/min, and the preferred cooling rate is 50°C/min, the desired size of the silver nanoparticles is between 10 nm and 20 nm, and the silver film layer is yellow-green; when When the cooling rate is between 50 and 25°C/min, and the preferred cooling rate is 25°C/min, the desired size of the silver nanoparticles is 30 nanometers, and the silver film layer is brown; when the cooling rate is between 25 and 10°C/min. When the cooling rate is preferably 10°C/min, the desired size of the nano-silver particles is 40 nm, and the silver film layer is gray-green; when the cooling rate is between 10 and 1°C/min, the preferred cooling rate is 5°C /min, the desired size of nano-silver particles is 50 nanometers, and the silver film layer is brown-gray.

The desired size of the nano-silver particles in the silver film layer in this embodiment is 22 nanometers, 30 nanometers, 32 nanometers or 45 nanometers. Among them, for example: when the expected size of the silver nanoparticles is 22 nanometers, the silver film layer is yellow-green, and at this time, the size of the silver nanoparticles in the silver film layer is between 10 nanometers and 50 nanometers; When the expected size value is 30 nanometers, the silver film layer is brown. At this time, the size of the nano-silver particles in the silver film layer is between 20 nanometers and 50 nanometers; when the expected size value of the nano-silver particles is 32 nanometers, the silver film layer is The layer is gray-green. At this time, the size of the nano-silver particles in the silver film layer is between 10 nanometers and 80 nanometers; when the expected size of the nano-silver particles is 45 nanometers, the silver film layer is brown-gray. At this time, the silver The size of the nano-silver particles in the film layer is between 20 nanometers and 80 nanometers.

Compared with the related art, the embodiment of the present invention provides a preparation method of a welding ribbon, which adopts the recrystallization method to separate silver, effectively regulates the size of the silver nanoparticles by changing the cooling speed, and uses the corresponding silver nanoparticles of different sizes. Different colors can make the welding strip show different colors, and obtain a colored welding strip. The process is simple and controllable, and the problems of resistivity reduction and reliability caused by the conventional method for preparing the colored welding strip can be effectively avoided.

The steps of the above various methods are divided only for the purpose of describing clearly. During implementation, they can be combined into one step or some steps can be split and decomposed into multiple steps. As long as the same logical relationship is included, they are all within the protection scope of this patent. ;Adding insignificant modifications to the algorithm or process or introducing insignificant designs, but not changing the core design of the algorithm and process are all within the scope of protection of this patent.

Those skilled in the art can understand that the above-mentioned embodiments are specific examples for realizing the present invention, and in practical applications, various changes in form and details can be made without departing from the spirit and the spirit of the present invention. scope.

Claims (5)

1. a preparation method of welding strip, is characterized in that, comprises: The conductive solder ribbon body and the alloy solder are placed in a heating container, and the alloy solder is located on the first outer surface of the conductive solder ribbon body; wherein, the alloy solder is a ternary alloy, and the ternary alloy includes : tin, silver and another metal; The heating vessel is heated and kept warm to obtain molten alloy solder; Cooling the molten alloy solder to obtain a silver film layer on the first outer surface, and an alloy layer between the conductive ribbon body and the silver film layer; wherein the silver film layer Composed of nano silver particles; In different preparation processes, the molten alloy solder is cooled at different cooling rates to obtain silver film layers with different desired sizes of nano-silver particles in different preparation processes; Wherein, the faster the cooling speed is, the smaller the expected size value of the nano-silver particles in the silver film layer is. 2 . The method for preparing a solder ribbon according to claim 1 , wherein when the cooling rate is decreased by 1° C. to 100° C. per minute, the size of the nano-silver particles ranges from 10 nanometers to 80 nanometers. 3 . 3 . The method for preparing a solder ribbon according to claim 2 , wherein the desired size of the nano-silver particles in the silver film layer is 22 nanometers, 30 nanometers, 32 nanometers or 45 nanometers. 4 . 4 . The method for preparing a solder ribbon according to claim 3 , wherein the other metal comprises: copper, lead or bismuth. 5 . 5. The method for preparing a solder ribbon according to claim 1 or 4, wherein the silver accounts for 0.01% to 10% of the total mass of the alloy solder, and the tin accounts for 5% of the total mass of the alloy solder. %~90%, the other metal accounts for 5%~90% of the total mass of the alloy solder.

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