TWI782688B - Polymer, polymer composition, and solar cell module - Google Patents

Abstract

A polymer is formed by reacting 1 part by weight of diacrylate compound and 8 to 200 parts by weight of ethylene vinyl acetate copolymer. The diacrylate compound has a chemical structure of

, wherein R ¹is a single bond, -O-,

,

,

,

,

, or -C=C-; each of R ²is independently H or CH ₃; and each of R ³is independently H or CH ₃.

Description

Polymers, polymer compositions, and solar cell modules

This disclosure relates to polymers, and more particularly to the use of polymers in solar cell modules.

Materials for the buffer layer in some known solar cell modules include maleimide and high olefin radical copolymers, modified or unmodified polyethylene vinyl acetate, modified or unmodified polyethylene Butyral, modified or unmodified polyolefin elastomer, modified or unmodified polyurethane, modified or unmodified ionic polymer, modified or unmodified silicone, Or a combination of the above materials. However, the above-mentioned buffer layer materials still cause the solar cell to have a certain degree of fragmentation problem. In order to overcome the fragmentation problem of solar cells, new buffer layer materials are urgently needed for the solar modules.

，其中R ¹為單鍵、-O-、

、

、

、

、

、或-C=C-；每一R ²獨立地為H或CH ₃；以及每一R ³獨立地為H或CH ₃。 The polymer provided in an embodiment of the present disclosure is formed by reacting 1 part by weight of a diacrylate-based compound with 8 to 200 parts by weight of ethylene-vinyl acetate copolymer, wherein the structure of the diacrylate-based compound is:

, where R ¹ is a single bond, -O-,

,

,

,

,

, or -C=C-; each R ² is independently H or CH ₃ ; and each R ³ is independently H or CH ₃ .

。 In some embodiments, the diacrylate-based compound has the structure

.

，其中x=200至300000，以及y=1000至250000。 In some embodiments, the ethylene-vinyl acetate copolymer has the structure

, where x=200 to 300000, and y=1000 to 250000.

，其中R ¹為單鍵、-O-、

、

、

、

、

、或-C=C-；每一R ²獨立地為H或CH ₃；以及每一R ³獨立地為H或CH ₃。 The polymer composition provided by an embodiment of the present disclosure includes: 1 part by weight of a diacrylate-based compound; and 8 to 200 parts by weight of an ethylene-vinyl acetate copolymer, wherein the structure of the diacrylate-based compound is:

, where R ¹ is a single bond, -O-,

,

,

,

,

, or -C=C-; each R ² is independently H or CH ₃ ; and each R ³ is independently H or CH ₃ .

。 In some embodiments, the diacrylate-based compound has the structure

.

，其中x=200至300000，以及y=1000至250000。 In some embodiments, the ethylene-vinyl acetate copolymer has the structure

, where x=200 to 300000, and y=1000 to 250000.

In some embodiments, the polymer composition further includes 0.1 to 2000 parts by weight of a solvent, and the solvent includes propylene glycol methyl ether acetate, toluene, xylene, dimethylformamide, N-methylpyrrolidone, cyclopentanone , or a combination of the above.

，其中R ¹為單鍵、-O-、

、

、

、

、

、或-C=C-；每一R ²獨立地為H或CH ₃；以及每一R ³獨立地為H或CH ₃。 A solar cell module provided by an embodiment of the present disclosure includes: a plurality of solar cells stacked on each other, and each solar cell has a first surface and a second surface opposite to the first surface; a plurality of conductive connectors, respectively Located on the first surface of any one of the solar cells and the second surface of the adjacent solar cells to connect the solar cells in series; and a plurality of buffer layers respectively located on the first surfaces of the adjacent sides of the adjacent solar cells On the surface and the second surface, wherein the extension direction of the buffer layer is perpendicular to the extension direction of the conductive connector, wherein the buffer layer includes a polymer, and the polymer is composed of 1 weight part of a diacrylate-based compound and 8 to 200 weight parts of Ethylene-vinyl acetate copolymer is reacted, and the structure of the diacrylate-based compound is:

, where R ¹ is a single bond, -O-,

,

,

,

,

, or -C=C-; each R ² is independently H or CH ₃ ; and each R ³ is independently H or CH ₃ .

。 In some embodiments, the diacrylate-based compound has the structure

.

，其中x=200至300000，以及y=1000至250000。 In some embodiments, the ethylene-vinyl acetate copolymer has the structure

, where x=200 to 300000, and y=1000 to 250000.

In some embodiments, the width of the buffer layer is between 0.5 mm and 10 mm, and the thickness of the buffer layer is between 0.1 mm and 1.2 mm.

，其中R ¹為單鍵、-O-、

、

、

、

、

、或-C=C-；每一R ²獨立地為H或CH ₃；以及每一R ³獨立地為H或CH ₃。舉例來說，二丙烯酸酯基化合物的結構可為

。 The polymer provided in an embodiment of the present disclosure is formed by reacting 1 part by weight of a diacrylate-based compound with 8 to 200 parts by weight of ethylene-vinyl acetate copolymer (EVA). If the ratio of the ethylene-vinyl acetate copolymer is too low or too high, the solar cell will be broken when applied to the solar cell module. The structure of the diacrylate-based compound is:

, where R ¹ is a single bond, -O-,

,

,

,

,

, or -C=C-; each R ² is independently H or CH ₃ ; and each R ³ is independently H or CH ₃ . For example, the structure of a diacrylate-based compound can be

.

，其中x=200至300000，以及y=1000至250000。在一些實施例中，可視情況挑選合適之乙烯-乙酸乙烯酯共聚物，例如x=300至100000，以及y=1500至200000。在一些實施例中，可視情況挑選合適之乙烯-乙酸乙烯酯共聚物，例如熔融指數(Melt Index) (測試方式ASTM D1238)為100 g/10 min至2000 g/10 min (190℃下)之乙烯-乙酸乙烯酯共聚物。 In some embodiments, the ethylene-vinyl acetate copolymer has the structure

, where x=200 to 300000, and y=1000 to 250000. In some embodiments, a suitable ethylene-vinyl acetate copolymer can be selected according to the situation, for example, x=300 to 100000, and y=1500 to 200000. In some embodiments, a suitable ethylene-vinyl acetate copolymer can be selected depending on the situation, for example, one with a melt index (Melt Index) (test method ASTM D1238) of 100 g/10 min to 2000 g/10 min (at 190° C.) Ethylene-vinyl acetate copolymer.

In some embodiments, the polymer is formed by reacting 1 part by weight of a diacrylate-based compound with 8 to 150 parts by weight of ethylene-vinyl acetate copolymer (EVA).

To form the above polymer, 1 part by weight of a diacrylate compound; and 8 to 200 parts by weight or 8 to 150 parts by weight of ethylene-vinyl acetate copolymer can be mixed to form a polymer composition. The diacrylate-based compound and the ethylene-vinyl acetate copolymer are as described above and will not be repeated here.

In some embodiments, the polymer composition further includes 0.1 to 2000 parts by weight or 10 to 500 parts by weight of a solvent, and the solvent includes propylene glycol methyl ether acetate, toluene, xylene, dimethylformamide, N-formaldehyde pyrrolidone, cyclopentanone, or a combination of the above. In this embodiment, the diacrylate-based compound and ethylene-vinyl acetate copolymer can be dispersed in a solvent to facilitate subsequent processes. For example, the above polymer composition can be heated to react the diacrylate-based compound and ethylene-vinyl acetate copolymer to form a polymer, which is then coated on a substrate, laminated and then heated and pressed to obtain a buffer layer. The above polymer composition can be stored at room temperature for a long time before use, as long as the polymer composition is heated to form a polymer before use.

The above-mentioned polymers can be used in solar cell modules, such as the Taiwan patent TWI686053B obtained by the applicant earlier. FIG. 1A is a cross-sectional view of the structure of a solar cell module according to an embodiment of the present disclosure. Fig. 1B is a cross-sectional view of line I-I' in Fig. 1A. The solar cell module 100 includes a plurality of stacked solar cells 102, a plurality of conductive connectors 104, and a plurality of buffer layers 106a and 106b, wherein the solar cells 102 can be silicon solar cells or other types of solar cells. In one embodiment, the silicon solar cell may include but not limited to 1/2, 1/3, 1/4, 1/5, 1/6, 1 /7 or 1/8 battery cut pieces. Each solar cell 102 has a first surface 102a and a second surface 102b opposite to the first surface 102a. The solar cells 102 in this embodiment are stacked to form a laminated solar cell module 100. Compared with the traditional tiled solar cell module, since there is no gap between the solar cells 102, it is expected that within the same area More solar cells 102 can be installed, thereby improving the efficiency of the solar cell module 100 .

In FIG. 1A , the conductive connectors 104 are respectively welded on the first surface 102 a of one solar cell 102 and the second surface 102 b of another adjacent solar cell 102 to connect several solar cells 102 in series. Since the electrodes of the general solar cell 102 are designed on the front side of the solar cell 102 (such as the first surface 102a), it is distributed with many finger electrodes (not shown) as front electrodes, and then at least one bus bar (not shown) shown) to connect the finger electrodes. A back electrode (not shown) is provided on the back side of the solar cell 102 (such as the second surface 102b) to collect the electricity generated by the solar cell 102, so the conductive connector 104 (which may be called a ribbon, ribbon) can be directly welded On the bus bar and the back electrode, and respectively electrically connected to the front electrode of one solar cell 102 and the back electrode of another adjacent solar cell 102, so that the solar cell module 100 can be integrated into the existing solar panel without additional renewal of materials with equipment. In addition, if a 6-inch solar panel is taken as an example, the solar cell 102 of the embodiment can be a "half-cut cell" in which the 6-inch cell is cut in half, and then the wires (conductive connectors 104) are used to connect two adjacent solar cells 102. welding. Therefore, compared with the general laminated module (using 6-inch cell cutting sheets with an area of 1/4~1/6 cut), the half-cut solar cell module 100 of this embodiment has fewer cutting places, so the carrier pairs The probability of recombination is also lower than that of general laminated modules. On the other hand, if the solar cell 102 of this embodiment is a 1/3-1/8 cut 6-inch cut sheet, the ohmic loss is lower because the generated current is lower than that of the half-cut cell.

In addition, the buffer layers 106a and 106b in the solar cell module 100 of this embodiment are respectively disposed on the first surface 102a and the second surface 102b of the adjacent side of the adjacent solar cell 102, and the extension of the buffer layers 106a and 106b The direction is perpendicular to the extending direction of the conductive connector 104, so when the module lamination process or thermal cycle test is performed, the buffer layers 106a and 106b can reduce the chance of silicon wafer cracks appearing at the intersection of the conductive connector 104 and the side edge of the solar cell 102 . In one embodiment, the heat-distortion temperature of the buffer layers 106a and 106b may be greater than or equal to 250°C, so as to withstand the high temperature when the conductive connector 104 is soldered to the battery bus bar. In addition, the glass transition temperature (Tg) of the buffer layers 106a and 106b may be -20°C to -80°C. For example, the buffer layers 106 a and 106 b of this embodiment include the above-mentioned polymers, such as polymers formed from polymer compositions.

In FIG. 1B, the buffer layer 106a is a continuous structure, and the buffer layer 106b is also a continuous structure to cover adjacent sides of the solar cell 102, but the present disclosure is not limited thereto; the above-mentioned buffer layers 106a and 106b can also be a discontinuous structure ( not shown), which cover part of the adjacent side of the solar cell 102 corresponding to the position of the conductive connecting member 104 . That is to say, buffer layers 106a and 106b must be provided on the side edges of the solar cell 102 through which the conductive connectors 104 pass, so that the conductive connectors 104 at the side edges are disposed between the buffer layers 106a and 106b, thus buffering Whether the layers 106a and 106b are continuous or discontinuous, the effect of preventing cracks in the silicon wafer can be achieved.

FIG. 1C is an enlarged view of site 110 of FIG. 1A . 1C shows the situation where the conductive connector 104 is welded to a solar cell 102, wherein the buffer layer 106b that has not been laminated can have a width w of 0.5 mm to 10 mm and a thickness t of 0.1 mm to 1.2 mm, but The present disclosure is not limited thereto. If the width w is too large, the contact area between the conductive connector 104 and the battery bus bar will be reduced, resulting in an increase in the series resistance of the solar cell module 100; if the thickness t is too small, it will cause the solar cell 102 to fail in the module lamination process or thermal cycle test. cracks occur. After the lamination process, the thickness t of the buffer layer 106b is reduced due to compression. In addition, if the thermal deformation temperature of the buffer layer 106b is relatively low, the distance d between the soldering portion of the conductive connector 104 and the buffer layer 106b can be set to be greater than 2 mm. If the thermal deformation temperature of the buffer layer 106b is relatively high, the distance d between the soldering portion of the conductive connector 104 and the buffer layer 106b may be less than 2mm.

The above-mentioned polymers do not contain halogen and phosphorus compounds, and do not need to add toxic polymers to comply with solar cell module tests. The above-mentioned polymers have high temperature resistant elastic cushioning properties, their surface resistance≧10 ¹² Ω, flexural modulus≦400 MPa, phase change temperature≦150℃, Td≧330℃, floating soldering time≧ 20 seconds (288°C). The above-mentioned polymers have been evaluated by tin oven, and they pass the lead-free process temperature requirements and can reduce the missing soldering.

The above-mentioned polymers have both environmental protection and high heat resistance characteristics, and are suitable for high-temperature lead-free material process applications. It is worth noting that, in addition to being used as the buffer layer of the above-mentioned solar cell module, the polymer formed by the reaction of the above-mentioned polymer composition with it can be used in other environment-friendly and highly heat-resistant lead-free material process applications.

In order to make the above content and other purposes, features, and advantages of this disclosure more comprehensible, the preferred embodiments are listed below, together with the accompanying drawings, and are described in detail as follows: [ Embodiment ]

Synthetic example Take 136 g of 4-hydroxyacetophenone (1 mol), 185 g of methacrylic anhydride (1.2 mol), and 8.4 g of sodium bicarbonate (0.1 mol), and mix and react at 80 ° C under nitrogen protection 2 hours. After the reaction was complete, 700 mL of aqueous sodium hydroxide solution (2 M) was added, stirred overnight, and the product was filtered, washed with water, and dried. 198 g of product was obtained (yield 97%). The above reaction looks like this:

Take the above product and add 64 g of hydrazine sulfate (0.49 mol), 49 g of triethylamine (0.49 mol), and 200 g of ethanol, and react under reflux for 5 hours. After the reaction was completed, the temperature was lowered to room temperature, and after the product was precipitated, the product was washed with ethanol and deionized water and dried to obtain 120 g of the product. The hydrogen spectrum of the above product is as follows: ¹ H NMR (400 MHz, d ₆ -DMSO): 7.97 (d, 4H, J=8.0 Hz ), 7.26 (d, 4H, J=8.0 Hz), 6.30 (s, 2H) , 5.91 (s, 2H), 2.29 (s, 6H), 2.01 (s, 6H). The above reaction is as follows:

Example 1 Take 2 g of the product of the synthesis example, 198 g of ethylene-vinyl acetate copolymer (EVA, UE647 purchased from USI Co.), and 600 g of cyclopentanone (cyclopentanone), and mix to form a polymer Composition. The polymer composition was heated to 80° C. and stirred for 120 minutes to form a polymer. After the reaction, wait until the temperature drops to room temperature to obtain the glue. Glue is coated on the sides of the solar cells, and conductive connectors are formed to connect the solar cells in series. After stacking, heat and press at 150° C. for 1 hour to make the glue form a buffer layer to obtain a solar cell module. After the solar cell module is tested by the thermal cycle (50 cycles) of the standard test method IEC61215-2016, electroluminescence is used to detect whether the solar cell is broken, and the broken rate is 0%. The thermal conductivity of the above-mentioned buffer layer is 0.31 W/m*°C (the measurement standard is ASTM D5470), the phase change temperature is 85°C (the measurement standard is the rheometer temperature rise: 5°C/min), and the thermal decomposition temperature (Td _{5 %} ) is 334°C (the measurement standard is TGA temperature rise: 20°C/min), the float soldering time is 25 seconds (288°C, the measurement standard is IPC TM-650-2.4.13), and the melt index at 190°C is 795 g/10 minutes (the measurement standard is ASTM D1238).

Example 2 Take 20 g of the product of the synthesis example, 180 g of ethylene-vinyl acetate copolymer (EVA, UE647 purchased from USI Co.), and 600 g of cyclopentanone (cyclopentanone), and mix to form a polymer Composition. The polymer composition was heated to 80° C. and stirred for 120 minutes to form a polymer. After the reaction, wait until the temperature drops to room temperature to obtain the glue. Glue is coated on the sides of the solar cells, and conductive connectors are formed to connect the solar cells in series. After stacking, heat and press at 150° C. for 1 hour to make the glue form a buffer layer to obtain a solar cell module. After the solar cell module is tested by the thermal cycle (50 cycles) of the standard test method IEC61215-2016, electroluminescence is used to detect whether the solar cell is broken, and the broken rate is 0%. The thermal conductivity of the above buffer layer is 0.35 W/m*°C, the phase change temperature is 75°C, the thermal decomposition temperature (Td _5% ) is 343°C, the float soldering time is 28 seconds (288°C), and the melt index is 190°C It is 710 g/10 minutes. The above measurement standard is the same as that of Example 1.

Example 3 Take 10 g of the product of the synthesis example, 190 g of ethylene-vinyl acetate copolymer (EVA, UE647 purchased from USI Co.), and 600 g of cyclopentanone (cyclopentanone), and mix to form a polymer Composition. The polymer composition was heated to 80° C. and stirred for 120 minutes to form a polymer. After the reaction, wait until the temperature drops to room temperature to obtain the glue. Glue is coated on the sides of the solar cells, and conductive connectors are formed to connect the solar cells in series. After stacking, heat and press at 150° C. for 1 hour to make the glue form a buffer layer to obtain a solar cell module. After the solar cell module is tested by the thermal cycle (50 cycles) of the standard test method IEC61215-2016, electroluminescence is used to detect whether the solar cell is broken, and the broken rate is 0%. The thermal conductivity of the above buffer layer is 0.32 W/m*°C, the phase change temperature is 62°C, the thermal decomposition temperature (Td _5% ) is 352°C, the float soldering time is 28 seconds (288°C), and the melt index is 190°C It is 730 g/10 minutes. The above measurement standard is the same as that of Example 1.

Comparative Example 1 200 g of ethylene-vinyl acetate copolymer (EVA, UE647 available from USI Co.) and 600 g of cyclopentanone (cyclopentanone) were mixed to form a polymer composition. Heat the polymer composition to 80°C and stir for 120 minutes, and wait until the temperature drops to room temperature to obtain the glue. Glue is coated on the sides of the solar cells, and conductive connectors are formed to connect the solar cells in series. After stacking, heat and press at 150° C. for 1 hour to make the glue form a buffer layer to obtain a solar cell module. After the solar cell module is tested by the thermal cycle (50 cycles) of the standard test method IEC61215-2016, electroluminescence is used to detect whether the solar cell is broken, and the broken rate is 0.2%. The thermal conductivity of the above buffer layer is 0.21 W/m*°C, the phase change temperature is 77°C, the thermal decomposition temperature (Td _5% ) is 312°C, the float soldering time is 21 seconds (288°C), and the melt index is 190°C It is 795 g/10 minutes. The above measurement standard is the same as that of Example 1. It can be seen from Comparative Example 1 that the product of the non-synthetic example reacts with EVA to form a polymer, and the buffer layer formed by the glue will cause the solar cell to break.

Comparative Example 2 Take 25 g of the product of the synthesis example, 175 g of ethylene-vinyl acetate copolymer (EVA, UE647 purchased from USI Co.), and 600 g of cyclopentanone (cyclopentanone), and mix to form a polymer Composition. The polymer composition was heated to 80° C. and stirred for 120 minutes to form a polymer. After the reaction, wait until the temperature drops to room temperature to obtain the glue. Glue is coated on the sides of the solar cells, and conductive connectors are formed to connect the solar cells in series. After stacking, heat and press at 150° C. for 1 hour to make the glue form a buffer layer to obtain a solar cell module. After the solar cell module is tested by the thermal cycle (50 cycles) of the standard test method IEC61215-2016, electroluminescence is used to detect whether the solar cell is broken, and the broken rate is 1.5%. The thermal conductivity of the above buffer layer is 0.35 W/m*°C, the phase change temperature is 76°C, the thermal decomposition temperature (Td _5% ) is 328°C, the float soldering time is 15 seconds (288°C), and the melt index is 190°C It is 590 g/10 minutes. The above measurement standard is the same as that of Example 1. It can be known from Comparative Example 2 that if the ratio of the product in the synthesis example is too high, the buffer layer formed by the glue will cause the solar cell to break.

Comparative Example 3 Take 10 g of the product of the synthesis example, 190 g of ethylene-vinyl acetate copolymer (EVA, UE647 purchased from USI Co.), and 600 g of cyclopentanone (cyclopentanone), and mix to form a polymer Composition. The polymer composition was stirred at room temperature for 120 minutes to obtain a glue. Glue is coated on the sides of the solar cells, and conductive connectors are formed to connect the solar cells in series. After stacking, heat and press at 150° C. for 1 hour to make the glue form a buffer layer to obtain a solar cell module. After the solar cell module is tested by the thermal cycle (50 cycles) of the standard test method IEC61215-2016, electroluminescence is used to detect whether the solar cell is broken, and the broken rate is 0.3%. The thermal conductivity of the above buffer layer is 0.26 W/m*°C, the phase change temperature is 70°C, the thermal decomposition temperature (Td _5% ) is 331°C, the float soldering time is 23 seconds (288°C), and the melt index is 190°C It is 735 g/10 minutes. The above measurement standard is the same as that of Example 1. It can be known from Comparative Example 3 that if the product of the synthesis example is only mixed with EVA without reacting to form a polymer, it cannot be used as a buffer layer.

Although the disclosure has been disclosed above with several preferred embodiments, it is not intended to limit the disclosure. Anyone with ordinary knowledge in the technical field can make any changes without departing from the spirit and scope of the disclosure. and retouching, so the scope of protection of this disclosure should be defined by the scope of the appended patent application.

d: distance t: thickness w: width I-I': section line 100:Solar battery module 102: Solar cell 102a: first surface 102b: second surface 104: Conductive connector 106a, 106b: buffer layer 110: parts

FIG. 1A is a structural cross-sectional view of a solar cell module according to an embodiment of the present disclosure. Fig. 1B is a cross-sectional view taken along line I-I' of Fig. 1A. FIG. 1C is an enlarged view of the part of FIG. 1A .

I-I': section line

100:Solar battery module

102: Solar cell

102a: first surface

102b: second surface

104: Conductive connector

106a, 106b: buffer layer

110: parts

Claims (7)

A polymer formed by reacting 1 part by weight of a diacrylate-based compound with 8 to 200 parts by weight of ethylene-vinyl acetate copolymer, wherein the structure of the diacrylate-based compound is:

As the polymer of claim 1, wherein the structure of ethylene-vinyl acetate copolymer is

, where x=200 to 300000, and y=1000 to 250000. A polymer composition, comprising: 1 part by weight of a diacrylate-based compound; and 8 to 200 parts by weight of an ethylene-vinyl acetate copolymer, wherein the structure of the diacrylate-based compound is:

As the polymer composition of claim 3, wherein the structure of ethylene-vinyl acetate copolymer is

, where x=200 to 300000, and y=1000 to 250000. Such as the polymer composition of claim 3, further comprising 0.1 to 2000 parts by weight of a solvent, and the solvent includes propylene glycol methyl ether acetate, toluene, xylene, dimethylformamide, N-methylpyrrolidone, cyclopentanone , or a combination of the above. A solar cell module, comprising: a plurality of solar cells stacked on each other, and each of the solar cells has a first surface and a second surface opposite to the first surface; a plurality of conductive connectors are located on the On the first surface of any one of the solar cells and the second surface of the solar cell adjacent to it, so as to connect the solar cells in series; and a plurality of buffer layers, respectively located on the adjacent solar cells On the first surface and the second surface of the adjacent side of the battery, wherein the extension direction of the buffer layers is perpendicular to the extension direction of the conductive connector, wherein the buffer layer includes a polymer, and the polymer is made of It is formed by reacting 1 part by weight of a diacrylate-based compound with 8 to 200 parts by weight of ethylene-vinyl acetate copolymer, wherein the structure of the diacrylate-based compound is:

Such as the solar cell module of claim 6, wherein the structure of the ethylene-vinyl acetate copolymer is

, where x=200 to 300000, and y=1000 to 250000.

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