A connection structure of solar photovoltaic cell assembly

Abstract

The present invention discloses a connection structure of a solar photovoltaic cell assembly, comprising a plurality of cells electrically connected to each other. The cells are each provided with a metal wire structure, and the metal wire structures on two adjacent cells are connected in series through a conductive connector to form a current transmission loop. The metal wire structure comprises a front metal grid arranged on the front of the cell and a back metal grid arranged on the back of the cell, the front metal grid comprises at least one front connection main grid, and the back metal grid comprises at least one back connection main grid. One end of the conductive connector is electrically connected to the front connection main grid of one cell, and the other end is electrically connected to the back connection main grid of another cell. The connection structure of the present invention can effectively form a reliable electrical connection between solar photovoltaic cells, and simplifies the process, reduces production costs, and improves the production yield and product reliability of solar photovoltaic cell assemblies.

Description

Technical Field

[0001] The invention relates to the technical field of photovoltaic cell connection, and in particular to a connection structure of a solar photovoltaic cell assembly. Background Art

[0002] With the accelerated consumption of conventional fossil energy such as coal, oil, and natural gas, the ecological environment is deteriorating, and the greenhouse gas emissions are leading to increasingly severe global climate change. The sustainable development of human society has been seriously threatened. Countries around the world have formulated their own energy development strategies to deal with the limited resources of conventional fossil energy and the environmental problems derived from their development and utilization. Solar cell modules have become one of the most important renewable energy sources due to their reliability, safety, extensiveness, longevity, environmental protection, and sufficient resources, and are expected to become the main pillar of global power supply in the future.

[0003] However, the development of the photovoltaic industry still faces many problems and challenges, especially the conversion efficiency and reliability of solar cell modules are the biggest technical barriers to the development of the solar photovoltaic industry, while cost control and scale-up are economic constraints. Therefore, continuously improving the conversion efficiency and weather-resistant reliability of solar cell modules is an inevitable trend in the development of high-efficiency solar photovoltaic modules.

[0004] At present, a variety of high-efficiency solar photovoltaic modules have emerged in the market, such as shingled, half-cell, multi-busbar, bifacial modules, etc. As the application sites and application areas of solar photovoltaic modules become more and more extensive, the requirements for their reliability are also getting higher and higher, especially in some areas prone to severe or extreme weather, where high-efficiency and high-reliability solar photovoltaic modules are more needed.

[0005] In terms of the current technical development trend of solar photovoltaic cell modules, the traditional solar photovoltaic cell sheets made by silver paste printing and sintering, in order to reduce the high series resistance and large current loss caused by the silver paste printing wire, it is an industry trend to slice the solar photovoltaic cell sheets and make the components in a shingled manner. Shingled components use the electrical principle of low current and low loss (the power loss of photovoltaic components is proportional to the square of the working current) to greatly reduce the power loss of the components. However, because the shingled components use conductive adhesives with elastomeric properties to replace the photovoltaic metal welding strips used in conventional components, and the battery components connected by conductive adhesives are prone to empty points or virtual points in the process of executing the glue dispensing, after being encapsulated, they are subject to environmental erosion during actual outdoor use, such as the relative displacement between the conductive adhesives caused by the alternating thermal expansion and contraction of high and low temperatures, especially in the dynamic environment of alternating high and low temperatures (natural loads such as wind and snow), the most serious is the current virtual connection or even circuit breakage, the main reason is generally due to the weak connection ability between the materials after the combination. The weak connection ability is mainly manifested in the fact that the conductive glue operation in the process requires a process operation window. This window is relatively narrow in the actual production process and is very susceptible to environmental factors, such as the temperature and humidity of the workplace, the length of time it stays in the air after applying the glue, etc., which will make the conductive glue lose its activity. At the same time, the uneven application of glue is prone to occur due to changes in the glue's own characteristics under the dispensing, spraying or printing process, which will pose a great threat to product reliability. Secondly, the conductive glue is mainly composed of polymer resin and a large amount of precious metal powder, which is expensive and damages the ecological environment to a certain extent (the production and processing of precious metals pollute the environment). Furthermore, the conductive glue is a paste, which has a certain fluidity during the process of applying glue or laminating. It is very easy to overflow the glue and cause the positive and negative poles of the shingled interconnected battery string to short-circuit. Therefore, the weather resistance and reliability and stability of the shingled components encapsulated with crystalline silicon cell chips after cutting using an elastomer conductive adhesive are questionable. For most shingled components made by conductive adhesive bonding, there are common problems such as weak interconnection strength, high environmental requirements for the process, easy glue overflow and short circuit during use, high cost of use, and low production efficiency. Summary of the invention

[0006] In order to overcome the above-mentioned shortcomings, the purpose of the present invention is to provide a connection structure of a solar photovoltaic cell assembly, which can effectively form a reliable electrical connection between solar photovoltaic cells, simplify the process, reduce production costs, and thereby improve the production yield and product reliability of the solar photovoltaic cell assembly.

[0007] In order to achieve the above purpose, the technical solution adopted by the present invention is: a connection structure of a solar photovoltaic cell assembly, including a plurality of cells electrically connected to each other. The cells are each provided with a metal wire structure, and the metal wire structures on two adjacent cells are connected in series through a conductive connector to form a current transmission loop. The metal wire structure includes a front metal grid arranged on the front of the cell and a back metal grid arranged on the back of the cell, the front metal grid includes at least one front connection main grid, and the back metal grid includes at least one back connection main grid. One end of the conductive connector is electrically connected to the front connection main grid of one cell, and the other end is electrically connected to the back connection main grid of another cell.

[0008] The beneficial effects of the present invention are: through the arrangement of the metal wire structure and the conductive connector, a good electrical contact path between the batteries can be effectively formed, avoiding the need to slice the batteries due to the high series impedance and use the shingled dispensing method to make solar photovoltaic battery modules; at the same time, by connecting the front connection main grid and the back connection main grid with the conductive connector, the direct contact connection between the positive and negative electrodes of the two batteries can be achieved without relying on the conductivity of the adhesive. The connection structure of the present invention is conducive to simplifying the production process, reducing the loss of broken pieces caused by slicing the battery, saving the cost of silver glue dispensing materials, and thus improving the overall production yield and product reliability of the solar photovoltaic battery module.

[0009] Specifically, the front metal grid includes a front transverse fine grid and a front vertical fine grid arranged vertically, wherein the front transverse fine grid is composed of 3-30 grid lines, and the front transverse fine grid is one of a continuous fine grid, an intermittent continuous fine grid, and a non-continuous fine grid; and the front vertical fine grid is composed of 60-200 grid lines. Several grid intersections between the front transverse fine grid and the front vertical fine grid are used as electrical contact connection points, thereby ensuring uniform and good electrical contact on the front of the battery.

[0010] Specifically, the back metal grid includes a back transverse fine grid and a back vertical fine grid arranged vertically, wherein the back transverse fine grid is composed of 3-30 grid lines, and the back transverse fine grid is one of a continuous fine grid, an intermittent continuous fine grid, and a non-continuous fine grid; and the back vertical fine grid is composed of 120-300 grid lines. Several grid intersections between the back transverse fine grid and the back vertical fine grid are used as electrical contact connection points, thereby ensuring uniform and good electrical contact on the back of the battery.

[0011] Specifically, the line width of the gate line is between 10-50 um, and the line height is between 3-20 um.

[0012] Specifically, the front connecting main grid is parallel to the front vertical fine grid and is electrically connected to at least one grid line of the front horizontal fine grid. The back connecting main grid is parallel to the back vertical fine grid and is electrically connected to at least one grid line of the back horizontal fine grid. The front connecting main grid realizes electrical connection between the front vertical fine grid, the front horizontal fine grid and the conductive connecting member, and the back connecting main grid realizes electrical connection between the back vertical fine grid, the back horizontal fine grid and the conductive connecting member, thereby realizing the series connection of the front and back sides of two adjacent batteries.

[0013] Furthermore, the line widths of the front-side connecting main grid and the back-side connecting main grid are both between 200-700 um, and the line heights are both between 3-20 um.

[0014] Furthermore, the metal wire structure is electroplated on the front and back of the battery, and the electroplating materials are nickel-copper-tin or nickel-copper-silver. The electroplated nickel layer is used as the electroplating bottom layer, and after high-temperature sintering, it will form a silicon-nickel alloy with the battery substrate silicon, effectively reducing the contact resistance and enhancing the adhesion of the metal wire structure. At the same time, the nickel metal layer is also a good barrier layer, which can effectively isolate the copper migration and diffusion of the subsequent electroplated copper layer; the electroplated copper layer is used as a carrier for battery current collection and transmission, which can effectively reduce the series resistance, reduce losses and thus improve the current transmission efficiency; therefore, when the solar photovoltaic module is subsequently manufactured, there is no need to slice the battery cells, and the front connecting main grid and the back connecting main grid between the batteries can be directly connected in series through conductive connectors; after the electroplated copper layer is manufactured, the electroplated tin or silver layer is then electroplated to protect the surface of the electroplated copper layer from oxidation to form a copper oxide layer.

[0015] Furthermore, the conductive connector is made of any one of copper, copper-tin, and copper-silver, and the thickness of the conductive connector is between 3-20um. The conductive connector, which matches the material of the metal wire structure, can be quickly and tightly combined with the front main grid and the back main grid through a hot pressing process, thus realizing the series connection manufacturing process between batteries in a simple and fast manner.

[0016] Furthermore, the conductive connector includes a conductive plate, and the two ends of the conductive plate are respectively provided with a front connecting plate and a back connecting plate integrally formed therewith and forming a "Z"-shaped structure. The conductive plate is located between two adjacent batteries, and its height is between 70-220um. The front connecting plate is attached to the front connecting main grid of one battery, and its attachment width is between 200-700um. The back connecting plate is attached to the back connecting main grid of another battery, and its attachment width is between 200-700um.

[0017] Furthermore, the length of the conductive connecting member is between 150-220 mm, and the width is between 15-50 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of an embodiment of the present invention;

[0019] Figure 2 A schematic structural diagram of the front side of a battery according to an embodiment of the present invention;

[0020] Figure 3 A schematic structural diagram of the back side of a battery according to an embodiment of the present invention;

[0021] Figure 4 is a schematic structural diagram of a conductive connecting member according to an embodiment of the present invention;

[0022] Figure 5 It is a structural schematic diagram of a case where the front transverse fine grid of an embodiment of the present invention is a continuous fine grid;

[0023] Figure 6 It is a structural schematic diagram of the front transverse fine grid of the embodiment of the present invention when the fine grid is discontinuous and continuous;

[0024] Figure 7 It is a structural schematic diagram of the front transverse fine grid of the embodiment of the present invention when the fine grid is discontinuous and continuous;

[0025] Figure 8 It is a schematic structural diagram of a case where the front transverse fine grid is a discontinuous fine grid according to an embodiment of the present invention.

[0026] In the figure:

[0027] 1-battery; 21-front metal grid; 211-front main grid; 212-front horizontal fine grid; 213-front vertical fine grid; 22-back metal grid; 221-back main grid; 222-back horizontal fine grid; 223-back vertical fine grid; 3-conductive connector; 31-conductive plate; 32-front connecting plate; 33-back connecting plate; 41-continuous grid line; 42-intermittent grid line. DETAILED DESCRIPTION

[0028] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0029] Example

[0030] See attached Figure 1-4As shown, a connection structure of a solar photovoltaic cell assembly of the present invention includes a plurality of cells 1 electrically connected to each other. The cells 1 are all electroplated with metal wire structures, and the metal wire structures on two adjacent cells 1 are connected in series through a conductive connector 3 to form a current transmission loop. The metal wire structure includes a front metal grid 21 arranged on the front of the cell 1 and a back metal grid 22 arranged on the back of the cell 1. The front metal grid 21 includes at least one front connection main grid 211, and the back metal grid 22 includes at least one back connection main grid 221. One end of the conductive connector 3 is electrically connected to the front connection main grid 211 of one cell 1, and the other end is electrically connected to the back connection main grid 221 of another cell 1.

[0031] The arrangement of the metal wire structure and the conductive connector 3 can effectively form a good electrical contact path between the cells 1, avoiding the need to slice the cells 1 and use the shingle dispensing method to make solar photovoltaic cell modules due to the high series impedance; at the same time, the positive and negative electrodes of the two cells 1 can be directly connected by connecting the front connecting main grid 211 and the back connecting main grid 221 through the conductive connector 3, without relying on the conductivity of the adhesive. The connection structure of this embodiment is conducive to simplifying the production process, reducing the loss of broken pieces caused by slicing the cells, saving the cost of silver glue dispensing materials, and thus improving the overall production yield and product reliability of the solar photovoltaic cell module.

[0032] In this embodiment, see the attached Figure 2 As shown, the front metal grid 21 includes a front horizontal fine grid 212 and a front vertical fine grid 213 which are vertically arranged. The front horizontal fine grid 212 is composed of 3-30 grid lines, and the front horizontal fine grid 212 is one of a continuous fine grid, an intermittent continuous fine grid, and a non-continuous fine grid. The front vertical fine grid 213 is composed of 60-200 grid lines, and the front vertical fine grid 213 is a continuous fine grid. See the attached Figure 3 As shown, the back metal grid 22 includes a back horizontal fine grid 222 and a back vertical fine grid 223 which are vertically arranged. The back horizontal fine grid 222 is composed of 3-30 grid lines, and the back horizontal fine grid 222 is one of a continuous fine grid, an intermittent continuous fine grid, and a non-continuous fine grid. The back vertical fine grid 223 is composed of 120-300 grid lines, and the back vertical fine grid 223 is a continuous fine grid. Using several grid intersections between the front horizontal fine grid 212 and the front vertical fine grid 213 as electrical contact connection points ensures uniform and good electrical contact on the front side of the battery 1; using several grid intersections between the back horizontal fine grid 222 and the back vertical fine grid 223 as electrical contact connection points ensures uniform and good electrical contact on the back side of the battery 1.

[0033] like Figure 5As shown, the continuous fine grid is composed of a plurality of parallel continuous grid lines, which together with the front vertical fine grid 213 (or the back vertical fine grid 223) can form a grid structure. Figure 6-7 As shown, the discontinuous continuous fine grid is composed of a plurality of continuous grid lines 41 and a plurality of discontinuous grid lines 42, and the plurality of continuous grid lines 41 and the discontinuous grid lines 42 are arranged in parallel. It should be noted that in the discontinuous continuous fine grid, when two adjacent grid lines are discontinuous grid lines 42, the two discontinuous grid lines 42 need to be arranged in an interlaced manner to achieve electrical connection between the grid lines of the front vertical fine grid 213 (or the back vertical fine grid 223). Figure 8 As shown, the discontinuous fine grid is composed of a plurality of parallel discontinuous grid lines 42, and two adjacent discontinuous grid lines 42 need to be staggered.

[0034] Specifically, the line width of the gate line is between 10-50 um, and the line height is between 3-20 um.

[0035] In this embodiment, the front connecting main grid 211 is parallel to the front vertical fine grid 213, and is electrically connected to at least one grid line of the front horizontal fine grid 212. The back connecting main grid 221 is parallel to the back vertical fine grid 223, and is electrically connected to at least one grid line of the back horizontal fine grid 222. The front connecting main grid 211 realizes the electrical connection between the front vertical fine grid 213, the front horizontal fine grid 212 and the conductive connecting member 3, and the back connecting main grid 221 realizes the electrical connection between the back vertical fine grid 223, the back horizontal fine grid 222 and the conductive connecting member 3, thereby realizing the series connection of the front and back sides of two adjacent batteries 1.

[0036] Specifically, the line width of the front connecting main grid 211 and the back connecting main grid 221 is between 200-700 um, and the line height is between 3-20 um.

[0037] See attached Figure 4 As shown, the conductive connector 3 includes a conductive plate 31, and the two ends of the conductive plate 31 are respectively provided with a front connecting plate 32 and a back connecting plate 33 which are integrally formed therewith and form a "Z"-shaped structure. The conductive plate 31 is located between two adjacent batteries 1, and its height is between 70-220um. The front connecting plate 32 is attached to the front connecting main grid 211 of one battery 1, and its attachment width is between 200-700um. The back connecting plate 33 is attached to the back connecting main grid 221 of another battery 1, and its attachment width is between 200-700um.

[0038] In this embodiment, the electroplating material of the metal wire structure is nickel-copper-tin or nickel-copper-silver. The electroplated nickel layer is used as the electroplated bottom layer of the metal wire structure. After high-temperature sintering, it can form a silicon-nickel alloy with the battery substrate silicon, effectively reducing the contact resistance and enhancing the adhesion of the metal wire structure. At the same time, the nickel metal layer is also a good barrier layer, which can effectively isolate the copper migration and diffusion of the subsequent electroplated copper layer; the electroplated copper layer is used as a carrier for battery current collection and transmission, which can effectively reduce the series resistance, reduce the loss and thus improve the current transmission efficiency; therefore, when the batteries 1 are subsequently connected in series, it is not necessary to slice the batteries 1, and the front connection main grid 211 of one battery 1 can be directly connected in series with the back connection main grid 221 of another battery 1 through the conductive connector 3; and then tin or silver is electroplated on the surface of the electroplated copper layer to protect the surface of the electroplated copper layer from oxidation to form a copper oxide layer.

[0039] The conductive connector 3 is made of any one of copper, copper-tin, and copper-silver, and the thickness of the conductive connector 3 is between 3-20um. The length of the conductive connector 3 is between 150-220mm, and the width is between 15-50mm. The conductive connector 3, which is matched with the material of the metal wire structure, can be quickly and tightly combined with the front connection main grid 211 and the back connection main grid 221 through a hot pressing process, so that the series manufacturing process of the batteries 1 can be realized simply and quickly.

[0040] The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A connection structure of a solar photovoltaic cell assembly, comprising a plurality of cells (1) electrically connected to each other; characterized in that: The batteries (1) are each provided with a metal conductor structure, and the metal conductor structures on two adjacent batteries (1) are connected in series via a conductive connector (3) to form a current transmission loop; the metal conductor structure comprises a front metal grid (21) arranged on the front of the battery (1) and a back metal grid (22) arranged on the back of the battery (1); the front metal grid (21) comprises at least one front connection main grid (211), and the back metal grid (22) comprises at least one back connection main grid (221); one end of the conductive connector (3) is electrically connected to the front connection main grid (211) of one battery (1), and the other end is electrically connected to the back connection main grid (221) of another battery (1); The conductive connector (3) comprises a conductive plate (31), and two ends of the conductive plate (31) are respectively provided with a front connecting plate (32) and a back connecting plate (33) which are integrally formed therewith and form a "Z"-shaped structure; the conductive plate (31) is located between two adjacent batteries (1), the front connecting plate (32) is attached to the front connecting main grid (211) of one battery (1); and the back connecting plate (33) is attached to the back connecting main grid (221) of the other battery (1); The front metal grid (21) comprises a front transverse fine grid (212) and a front vertical fine grid (213) arranged vertically, wherein the front transverse fine grid (212) is composed of 3-30 grid lines, and the front vertical fine grid (213) is composed of 60-200 grid lines; the back metal grid (22) comprises a back transverse fine grid (222) and a back vertical fine grid (223) arranged vertically, wherein the back transverse fine grid (222) is composed of 3-30 grid lines, and the back vertical fine grid (223) is composed of 120-300 grid lines; the grid lines have a line width of between 10 and 50 μm, and a line height of between 3 and 20 μm; The line width of the front connection main grid (211) and the back connection main grid (221) are both between 200-700 um, and the line height is between 3-20 um.

2. The connection structure according to claim 1, characterized in that: The front transverse fine grid is one of a continuous fine grid, an intermittent continuous fine grid, and a non-continuous fine grid.

3. The connection structure according to claim 1, characterized in that: The back side transverse fine grid is one of a continuous fine grid, an intermittent continuous fine grid and a non-continuous fine grid.

4. The connection structure according to claim 1, characterized in that: The front connecting main grid (211) is parallel to the front vertical fine grid (213), and is electrically connected to at least one grid line of the front horizontal fine grid (212); the back connecting main grid (221) is parallel to the back vertical fine grid (223), and is electrically connected to at least one grid line of the back horizontal fine grid (222).

5. The connection structure according to claim 1, characterized in that: The metal wire structure is electroplated on the front and back of the battery (1), and the electroplating materials are nickel-copper-tin or nickel-copper-silver.

6. The connection structure according to claim 1, characterized in that: The material of the conductive connecting member (3) is any one of copper, copper-tin and copper-silver, and the thickness of the conductive connecting member (3) is between 3 and 20 μm.

7. The connection structure according to claim 1, characterized in that: The height of the conductive plate (31) is between 70-220 um; the bonding width of the front connecting plate (32) is between 200-700 um; and the bonding width of the back connecting plate (33) is between 200-700 um.

8. The connection structure according to claim 1, characterized in that: The length of the conductive connecting piece (3) is between 150-220 mm, and the width is between 15-50 mm.

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