WO2015172457A1

WO2015172457A1 - Highly-weldable high-efficiency photovoltaic welding strip

Info

Publication number: WO2015172457A1
Application number: PCT/CN2014/085113
Authority: WO
Inventors: 钱海鹏
Original assignee: 凡登（江苏）新型材料有限公司
Priority date: 2014-05-14
Filing date: 2014-08-25
Publication date: 2015-11-19

Abstract

A highly-weldable high-efficiency photovoltaic welding strip comprises a conductive base strip (1). The conductive base strip (1) is made of metal elementary substances or alloy materials and has an upper wide surface and a lower wide surface. A plurality of groove assemblies (2) is distributed on at least one wide surface of the conductive base strip (1). Each groove assembly (2) is composed of a plurality of continuous grooves (3). Coupling platforms (4) are left between different groove assemblies (2). The height of the coupling platforms (4) is not smaller than the highest point of the grooves (3), and the diameter of the maximum inscribed circle of the coupling platforms (4) is not smaller than 0.1 mm. According to the welding strip, the coupling platforms of a certain area are left between the groove assemblies (2) on the surface, and therefore, requirements of a binding force of the welding strip and a battery sheet can be satisfied, and the proportion of the area of the grooves (3) to the area of the welding strip can be increased maximally, and the power of a whole battery component can be improved.

Description

High weldable high efficiency photovoltaic welding strip

Technical field

The invention belongs to the technical field of photovoltaic welding strip processing, and particularly relates to a high weldable high-efficiency photovoltaic welding strip.

Background technique

With the rapid development of the world economy, energy consumption is increasing, and countries all over the world are demanding the application and popularization of new energy. The demand for clean renewable energy is particularly strong in countries around the world due to the effects of greenhouse gases caused by carbon dioxide emissions that contribute to global warming and natural disasters. Since the global crisis caused by the 2007 subprime crisis in the United States has spread and expanded, countries have adopted more active measures to encourage the use of renewable energy in order to stimulate economic growth. The US Obama administration has proposed to invest 150 billion U.S. dollars in clean energy in the next 10 years; the EU has set a goal to increase the proportion of renewable energy in energy use to 20% by 2020; Japan proposes to build more than 70% of new homes by 2030. Install solar panels (about 70 GW). In order to alleviate the insufficient domestic demand for photovoltaic products, on March 26, 2009, the Ministry of Finance of China announced that it will promote the implementation of the “Solar Roof Plan” demonstration project. The "Implementation Opinions on Accelerating the Application of Solar Photovoltaic Buildings" jointly issued by the Ministry of Finance and the Ministry of Housing and Urban-Rural Development clearly stated that the implementation of the "Solar Roof Plan" will provide financial subsidies for photovoltaic building application demonstration projects, encourage technological progress and technological innovation. We will encourage local governments to introduce relevant financial support policies and strengthen policy support in the construction sector. At this stage, in large and medium-sized cities with developed economies and good industrial bases, we will actively promote the integration of photovoltaic roofs and photovoltaic curtain walls, and actively support the development of off-grid power generation in rural and remote areas, and implement regulations on power transmission to the countryside. It is also the direction for the application of solar technology. Taking the integration of photovoltaic roofs and photovoltaic curtain walls as a breakthrough, it is possible to let people see the many benefits of applying solar energy in the short term, and it is also conducive to large-scale promotion in the future, and stimulate the enthusiasm of industrial capital to invest in solar energy. The new energy policies of various countries may become the next important factor affecting our world development in the next 15 years. One of the policies. The 2009 Copenhagen Climate Conference reawakened and reinforces awareness of clean energy. With the application and popularization of new energy sources, the rapid growth of the photovoltaic industry has been further strengthened and valued.

Solder ribbons (including interconnecting strips and busbars) are important raw materials in the soldering process of photovoltaic modules. Solder ribbons are usually connected to each other by means of soldering or conductive adhesive bonding, and the quality of the soldering strips will be good. Directly affecting the collection efficiency of photovoltaic module currents has a great impact on the power of photovoltaic modules. How to increase the conversion rate of the battery sheet and reduce the fragmentation rate by isomerization of the solder ribbon has always been one of the research topics in the solder ribbon industry.

Chinese patent CN101789452A provides a tin-coated solder ribbon comprising a copper strip and a tin-coated layer on its surface, the tin-coated layer having a uniformly distributed pit-like body. This kind of solder band causes the sunlight to diffusely reflect in the pit, which improves the energy of receiving sunlight. However, the pit-like body only diffusely reflects, the proportion of sunlight reflected back to the cell sheet is small, and the conversion rate is limited; in addition, the pit is prepared during the tin-coating process, which generates an uneven solder layer, and There will be a phenomenon that the welding of the battery piece is not strong, and a virtual welding occurs.

Chinese patent CN102569470A provides a V-groove that is prepared perpendicular to the length of the strip on the surface of the strip to reduce the crack and chip rate of the cell. However, the V-shaped groove of the patented welding tape is perpendicular to the longitudinal direction and there is no significant spacing between the V-shaped grooves, so the welding tape is unstable when welded to the battery sheet, and the welding is not strong.

Chinese patents ZL201320071240.1, ZL201320071182.2, ZL201320110484.6, ZL201320463993.7, ZL201320466223.8, etc., proposed to achieve partial multiplexing of reflected light on the surface of the solder ribbon by performing different forms of heterogeneity on the conductive base strip of the solder ribbon. Adjust the soldering fastness between the solder ribbon and the cell sheet, reduce the sinking electric loss caused by the solder ribbon, and reduce the yield stress of the solder ribbon to improve the weathering safety of the component and the fragmentation rate during the production process. Practice has confirmed that there is still a common deficiency in the above patent groups: That is, when using the automatic cross-stack welding machine currently on the market, unless the total area of the baseband plane on the heterogeneous wide surface is greatly increased, the ratio of the heterogeneous wide surface to the back silver is contacted. There is a higher risk of solder joints. However, the consequence of greatly increasing the ratio of the total area of the baseband plane on the heterogeneous wide surface to the total area of the heterogeneous wide surface is the reason for the significant decrease in the reflectance of the reflected light on the surface of the positive silver strip, which is contrary to the main intention of product design. .

Summary of the invention

The technical problem to be solved by the present invention is to solve the problem of heterogeneous solder ribbon and battery in the environment of automatic stringer, in order to reasonably ensure the reflective multiplexing/stress reduction of the interconnecting strip through the surface heterogeneity of the conductive strip of the interconnecting strip. The reduction in solder fastness/increased risk of soldering increases, and the present invention provides a highly solderable high efficiency solder ribbon for photovoltaic modules.

The technical solution adopted by the present invention to solve the technical problem thereof is: a high solderable high-efficiency photovoltaic welding tape comprising a conductive base tape, the conductive base tape being a metal elemental or alloy material having two upper and lower wide surfaces, The conductive base tape has at least one wide surface distributed with a plurality of groove sets, each groove set is composed of a plurality of continuous grooves, and a coupling platform is left between the different groove sets, and the coupling platform is not height A platform that is lower than the highest point of the groove and whose largest inscribed circle has a diameter of not less than 0.1 mm. Due to the presence of the coupling platform, the grooves in the groove set are continuously distributed, that is, the adjacent grooves no longer need to reserve a welding platform/coupling platform with each other.

The above technical solution realizes the multiplexing of the reflected light on the surface of the partial solder ribbon by forming a groove set on the surface of the conductive base tape so that part of the surface reflected light can be re-reflected to the surface of the battery through the glass/air surface of the component. On the other hand, there is a coupling platform between the adjacent groove sets to ensure the bonding fastness of the solder ribbon to the battery sheet. A large number of experiments confirmed the use of mainstream automatic strings on the current market. In the welding machine, to ensure that the solder has sufficient welding fastness to the back silver surface of the battery during the welding process, the diameter of the largest inscribed circle of the coupling platform is not less than 0.1 mm, on the other hand, in order to put as many welding strips as possible The surface is left to construct a set of reflective grooves to enhance the reflective optical multiplexing capability of the solder strip surface, and generally the maximum length of the coupling platform along the length of the conductive base strip is less than 20 mm.

The diameter of the largest inscribed circle of the coupling platform is less than the width of the wide surface on which it is located. Under the condition that the welding strip can be welded or bonded and the stripping tension of the strip is satisfied, the length of the coupling platform on the width of the conductive base width is reduced as much as possible to increase the groove to obtain the best coupling platform and reflection. The proportion of the groove.

Further experimental demonstrations show that, in the current mainstream automatic stringer environment on the market, and from the cost-effectiveness of industrially stable production of high weldable strips, the diameter of the largest inscribed circle of the coupling platform is greater than 0.25 mm. And the maximum length of the coupling platform along the length direction of the conductive base tape is less than 2.5 mm.

The area ratio m of the surface area of the coupling platform to the surface of the conductive layer is 5% ≤ m < 95%.

The surface area ratio of the surface area of the coupling platform to the surface of the conductive base is 25% ≤ m < 75%.

The shape of the coupling platform is a parallelogram or a trapezoid.

The shape of the coupling platform is a rectangular, square or isosceles trapezoid.

The depth of the groove is less than 75% of the thickness of the conductive base tape.

The depth of the groove is uniform.

The depth of the groove is not uniform.

After the solder ribbon is soldered, the solder layer on the surface will naturally flow, so that the angle of the actual light-emitting groove after the soldering is completed becomes larger. The above problems do not occur with a non-welded method (typically, such as bonding a battery to a tie strip with a conductive adhesive). According to the specific application method, the groove is generally selected as a V-shaped groove with an angle between 75° and 138° to ensure that the surface of the preferred welding tape is reflected back to the battery through the glass/air surface. Surface efficiency.

The groove is parallel to the length direction of the conductive base tape.

The V-shaped groove and the length direction of the conductive base tape may also have an angle of less than 90°. When the angle is close to or equal to 90°, the reflection of the V-shaped groove will be mostly reflected back to the surface of the ribbon after being re-reflected by the glass/air surface, and will not be reused by the battery.

The coupling platform is higher than the highest point of the groove.

The outer surface of the solder ribbon is coated or plated with a tin-based solder layer so that it can be soldered directly; and a protective layer can be prepared between the conductive base tape and the tin-based solder layer to prevent aging of the solder ribbon and reliable performance.

The outer surface of the ribbon can also be coated or plated with a conductive reflective layer, which is suitable for bonding between the ribbon and the cell by non-welding (such as conductive adhesive bonding).

A transition layer is also prepared between the solder layer or the conductive light reflecting layer and the conductive base tape.

The invention discloses a high solderable high-efficiency photovoltaic welding strip, which has a coupling platform which leaves a certain area between the surface groove sets, and the soldering strip has a glass air interface which reflects the surface reflected light through the component and is reflected back to the battery surface. The ability and perfect solution to the problem of high risk of insufficient silver surface soldering on the automatic string welding device with insufficient groove/welding force on the grooved surface.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view showing the structure of a high-weld high-efficiency photovoltaic ribbon of the present invention.

2 is a schematic structural view of Embodiment 2 of the high solderable high efficiency photovoltaic ribbon of the present invention.

3 is a schematic view showing the structure of Embodiment 3 of the high solderable high efficiency photovoltaic ribbon of the present invention.

4 is a perspective view showing the structure of a high-weld high-efficiency photovoltaic ribbon of the present invention.

Figure 5 is a cross-sectional view showing a groove set of Embodiment 3 of the present invention.

Figure 6 is a cross-sectional view showing a coupling platform of a third embodiment of the present invention.

Figure 7 is a cross-sectional view showing a coupling platform in another embodiment of Embodiment 3 of the present invention.

Figure 8 is a schematic view showing the structure of a high-weld high-efficiency photovoltaic ribbon of the present invention.

Figure 9 is a schematic view showing the structure of a high-weld high-efficiency photovoltaic ribbon of the present invention.

Figure 10 is a schematic view showing the structure of a high-weld high-efficiency photovoltaic ribbon of the present invention.

detailed description

The invention will now be described in further detail with reference to the drawings. The drawings are simplified schematic diagrams, and only the basic structure of the present invention is illustrated in a schematic manner, and thus only the configurations related to the present invention are shown.

Example 1

TU1 oxygen-free copper is selected as the conductive base tape 1, as shown in FIG. 1, having a groove set 2 along the length direction of the conductive base tape 1 on one wide surface thereof, and two groove sets 2 are respectively disposed on both sides of the wide surface Each groove set 2 is composed of a plurality of continuous grooves 3 with a rectangular coupling platform 4 extending along the length of the conductive base strip 1 between the two groove sets 2, the coupling platform 4 The height is equal to the highest point of the groove 3, and the maximum inscribed circle of the coupling platform 4 has a diameter of 0.1 mm, which is smaller than the width of the wide surface thereof; each groove 3 is a V-shaped groove, and the V-clip The angle is 138°, the grooves 3 are all parallel to the length direction of the conductive base strip 1; the depth of the groove 3 is 50% of the thickness of the conductive base strip, and the depth is uniform; the surface area of the coupling platform 4 occupies a wide surface of the conductive base strip 1 The area ratio m is 5%.

The conductive light-reflecting layer is uniformly prepared by coating or electroplating onto the above-mentioned conductive base tape to prepare a high-weld high-efficiency photovoltaic welding ribbon.

Using 60 156*156 polycrystalline silicon wafers, the power of a set of battery components using this photovoltaic ribbon is 6W higher than that of components prepared using conventional solder ribbons, an increase of 2.4%.

The welding force of the welding strip is pulled by the force gauge along the direction of the battery sheet 45 degrees until the ribbon is removed from the battery. The tensile force required for peeling of the sheet is generally greater than 3N. The welding force of the strip in this embodiment is greater than 3N, which satisfies the requirements.

Example 2

TU1 oxygen-free copper is selected as the conductive base tape 1, as shown in FIG. 2, having a groove set 2 on one wide surface thereof, and each groove set 2 is composed of a plurality of continuous grooves 3, between different groove sets 2 A parallelogram-shaped coupling platform 4 is left, the height of the coupling platform 4 is equal to the highest point of the groove 3, and the diameter of the largest inscribed circle of the coupling platform 4 is 0.5 mm, which is smaller than the width of the wide surface thereof. The maximum length along the length direction of the conductive base tape 1 is 2.0 mm; the groove 3 is present around the coupling platform 4; each groove 3 is a V-shaped groove, and the V-shaped angle is 75°, and the groove 3 is The length of the conductive base strip 1 is 30 degrees, and the sides of the parallelogram have two sides parallel to the direction of the groove 3; the depth of the groove 3 is 35% of the thickness of the conductive base strip 1 and the depth is uneven; the coupling platform 4 The area ratio m of the surface area to the wide surface of the conductive base tape 1 is 75%.

A tin-lead solder is uniformly prepared by coating or electroplating onto the above-mentioned conductive base tape to prepare a high-weld high-efficiency photovoltaic ribbon.

Using 60 156*156 polycrystalline silicon wafers, the power of a set of battery components using this photovoltaic ribbon is 1.5W higher than that of components prepared using conventional solder ribbons, an increase of 0.6%.

The welding force of the welding strip is the tensile force required to pull the welding strip along the 45-degree direction of the battery sheet until the strip is peeled off from the battery sheet by a tensile force meter. Generally, the welding force requirement is greater than 3N, and the welding strip welding force of the embodiment is greater than 5N. fulfil requirements.

Example 3

TU1 oxygen-free copper is selected as the conductive base tape 1, as shown in FIGS. 3 and 4, having a groove set 2 spaced apart along the length direction of the wide surface on one of its wide surfaces, each groove set 2 being composed of a plurality of continuous concaves Slot 3 Composition, a rectangular coupling platform 4 is left between the different groove sets 2, the length of the coupling platform 4 in the width direction of the wide surface is equal to the width of the wide surface, the width is 1.6 mm, and the diameter of the largest inscribed circle is 0.5 mm, smaller than the width of the wide surface thereof, the maximum length along the length of the conductive base tape 1 is 0.5 mm; the height of the coupling platform 4 is equal to the highest point of the groove 3; each groove 3 is a V-shaped groove The V-shaped angle is 120°, the groove 3 is at an angle of 30 degrees with the length of the conductive base tape 1; the depth of the groove 3 is 35% of the thickness of the conductive base tape 1, and the depth is uniform; the surface area of the coupling platform 4 The area ratio m of the wide surface of the conductive base tape 1 is 95%. As shown in FIG. 5 and FIG. 6, which are respectively a schematic cross-sectional view of the groove set 2 and the coupling platform 4, the outer surface of the conductive base tape 1 is coated or plated with a tin-based solder layer 5. It is also possible to have a structure as shown in FIG. 7. The outer surface of the solder ribbon has no solder layer 5, the conductive light reflecting layer 6 is coated or plated, and a transition layer 7 is further prepared between the conductive light reflecting layer 6 and the conductive base tape 1.

Using 60 156*156 polycrystalline silicon wafers, the power of a set of battery components using this photovoltaic ribbon was 0.8 W higher than that of a component prepared using a conventional solder ribbon, an increase of 0.32%.

Example 4

TU1 oxygen-free copper is selected as the conductive base tape 1, as shown in FIG. 8, having a groove set 2 on one wide surface thereof, and each groove set 2 is composed of a plurality of continuous grooves 3, between different groove sets 2 A parallelogram-shaped coupling platform 4 is left, the height of the coupling platform 4 is equal to the highest point of the groove 3, and the diameter of the largest inscribed circle of the coupling platform 4 is 0.3 mm, which is smaller than the width of the wide surface thereof. There are grooves 3 on the upper and lower sides of the coupling platform 4, and there are no grooves 3 on the left and right sides, that is, the left and right sides of the coupling platform 4 extend to both side edges of the wide surface; each groove 3 is a V-shaped groove, and its V The angle of the type is 110°, the groove 3 and the conductive The length direction of the base tape 1 is 30 degrees, and the parallelogram has two sides parallel to the direction of the groove 3; the depth of the groove 3 is 35% of the thickness of the conductive base tape 1, and the depth is uneven; the surface area of the coupling platform 4 The area ratio m of the wide surface of the conductive base tape 1 is 55%.

Using 60 156*156 polycrystalline silicon wafers, the power of a set of battery components using this photovoltaic ribbon is 2W higher than that of components prepared using conventional solder ribbons, an increase of 0.8%.

The welding force of the welding strip is the tensile force required to pull the welding strip along the 45-degree direction of the battery sheet until the strip is peeled off from the battery sheet by a tensile force meter. Generally, the welding force requirement is greater than 3N, and the welding strip welding force of the embodiment is greater than 4N. fulfil requirements.

Example 5

TU1 oxygen-free copper is selected as the conductive base tape 1, as shown in FIG. 9, having a groove set 2 along the length direction of the conductive base tape 1 on one wide surface thereof, and two groove sets 2 are respectively disposed on both sides of the wide surface Each groove set 2 is composed of a plurality of continuous grooves 3 with a rectangular coupling platform 4 extending along the length of the conductive base strip 1 between the two groove sets 2, the coupling platform 4 The height is higher than the highest point of the groove 3, and the diameter of the largest inscribed circle of the coupling platform 4 is 0.6 mm, which is smaller than the width of the wide surface where it is located; each groove 3 is a V-shaped groove, and its V-shaped angle 135°, the grooves 3 are all parallel to the length direction of the conductive base tape 1; the depth of the groove 3 is 50% of the thickness of the conductive base tape, and the depth is uniform; the surface area of the coupling platform 4 occupies the wide surface of the conductive base tape 1 The area ratio m is 25%.

Using 60 pieces of 156*156 polycrystalline silicon wafers, the power ratio of a set of battery components is prepared using the photovoltaic ribbon Components made with conventional solder ribbons have a power of 4.2W, an increase of 1.68%.

Example 6

TU1 oxygen-free copper is selected as the conductive base tape 1, as shown in FIG. 10, having two groove sets 2 along the length direction of the conductive base tape 1 on one wide surface thereof, and two groove sets 2 are respectively disposed on both sides of the wide surface Each groove set 2 is composed of a plurality of continuous grooves 3 with a rectangular coupling platform 4 extending along the length of the conductive base strip 1 between the two groove sets 2, the coupling platform 4 The height is equal to the highest point of the groove 3, and the diameter of the largest inscribed circle of the coupling platform 4 is 1.6 mm, which is equal to the width of the wide surface thereof, and the maximum length along the length of the conductive base tape 1 is 18 mm; The groove 3 is a V-shaped groove having a V-shaped angle of 135°, and the grooves 3 are all parallel to the longitudinal direction of the conductive base tape 1; the depth of the groove 3 is 50% of the thickness of the conductive base tape, and the depth is uniform; The surface area of the platform 4 accounts for 50% of the area m of the wide surface of the conductive base tape 1.

Using 60 156*156 polycrystalline silicon wafers, the power of a set of battery components using this photovoltaic ribbon is 1.8 W higher than that of components prepared using conventional solder ribbons, an increase of 0.72%.

Claims

A high solderable high-efficiency photovoltaic ribbon characterized by comprising a conductive base tape (1), which is a metal elemental or alloy material having two upper and lower wide surfaces, said conductive base tape (1) At least one wide surface is distributed with a plurality of groove sets (2), each groove set (2) consisting of a plurality of continuous grooves (3), leaving between different groove sets (2) The coupling platform (4) is a platform having a height not lower than the highest point of the groove and a diameter of the largest inscribed circle of not less than 0.1 mm.
A photovoltaic ribbon according to claim 1, characterized in that the diameter of the largest inscribed circle of the coupling platform (4) is smaller than the width of the wide surface on which it is located.
The photovoltaic ribbon according to claim 1 or 2, characterized in that the maximum length of the coupling platform (4) along the length of the conductive base strip (1) is less than 20 mm.
The photovoltaic ribbon according to claim 3, wherein the diameter of the largest inscribed circle of the coupling platform (4) is greater than 0.25 mm, and the coupling platform (4) is along the length of the conductive base tape (1) The maximum length of the direction is less than 2.5mm.
The photovoltaic ribbon according to claim 1, characterized in that the surface area of the coupling platform (4) occupies 5% ≤ m < 95% of the area of the wide surface of the conductive base tape (1).
The photovoltaic ribbon according to claim 5, characterized in that the surface area ratio of the surface area of the coupling platform (4) to the wide surface of the conductive base tape (1) is 25% ≤ m < 75%.
A photovoltaic ribbon according to claim 1 or 2, characterized in that the coupling platform (4) is in the shape of a parallelogram or a trapezoid.
The photovoltaic ribbon according to claim 7, characterized in that the coupling platform (4) has a rectangular or isosceles trapezoidal shape.
The photovoltaic ribbon of claim 1 wherein said recess (3) has a depth less than 75% of the thickness of the conductive base strip (1).
A photovoltaic ribbon according to claim 9, characterized in that the depth of the groove (3) is uniform.
A photovoltaic ribbon according to claim 9, characterized in that the depth of the grooves (3) is not uniform.
A photovoltaic ribbon according to claim 1 wherein said recess (3) is a V-shaped groove having an angle between 75 and 138.
The photovoltaic ribbon according to claim 1 or 12, characterized in that the groove (3) is parallel to the longitudinal direction of the conductive base tape (1).
The photovoltaic ribbon according to claim 1 or 12, characterized in that the groove (3) and the length of the conductive base tape (1) have an angle of less than 90°.
A photovoltaic ribbon according to claim 1, characterized in that said coupling platform (4) is higher than the highest point of said groove (3).
The photovoltaic ribbon according to claim 1, characterized in that the surface of the conductive base tape (1) is coated or plated with a solder layer (5).
The photovoltaic ribbon according to claim 1, characterized in that the surface of the conductive base tape (1) is coated or plated with a conductive light reflecting layer (6).
The photovoltaic ribbon according to claim 16, characterized in that a transition layer (7) is further prepared between the solder layer (5) and the conductive base tape (1).
The photovoltaic ribbon according to claim 17, characterized in that a transition layer (7) is further prepared between the electrically conductive light-reflecting layer (6) and the electrically conductive base tape (1).