Single-component heat-curing insulating adhesive for photovoltaic BC cell and preparation method thereof

Abstract

The application relates to the technical field of solar cells, and particularly discloses a single-component thermal curing insulating glue for photovoltaic BC cells and a preparation method thereof. The single-component thermal curing insulating glue comprises the following components: multifunctional acrylate resin 70-95 wt%, adsorbing filler 1-3 wt%, acid-absorbing filler 1-3 wt%, reaction acid filler 1-4 wt%, leveling and defoaming auxiliary agent 0.5-2 wt%, initiator 0.1-1 wt%, light protection agent 0-2 wt%, and pigment 0-10 wt%. The insulating glue for photovoltaic BC cells uses the pigment, the adsorbing filler, the acid-absorbing filler, the reaction acid filler and the light protection agent as fillers, and the cured film is a micro-nano coating. Compared with the commonly used insulating glue, the insulating glue has the functions of high-efficiency adsorption, fixation and reaction of acetic acid generated in the glue film, not only prevents the contact between the positive and negative electrodes in the BC cell, but also has the function of adsorbing and reacting acetic acid, and further improves the service life of the module.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of solar cells, and particularly discloses a single-component heat-curable insulating glue for a photovoltaic BC cell and a preparation method thereof. BACKGROUND

[0002] In current photovoltaic modules, the BC cell needs to be isolated by insulating glue to avoid short circuit due to structural characteristics, and the insulating glue is crucial in the BC cell module.

[0003] Nowadays, in order to reduce the cost of modules, EVA glue film is inevitably used in the packaging process. It is well known that EVA glue film inevitably produces acetic acid in the long-term use process, which causes corrosion of the solder strip, further shortens the service life of the photovoltaic module, although some manufacturers choose acid-resistant glue film, the corrosion of the solder strip by acetic acid is still inevitable. The solder strip of the BC cell is more prone to electrochemical corrosion caused by local acetic acid aggregation due to the small distance between the positive and negative electrodes and the thin insulating layer, and finally leads to the formation of ion migration channels between the positive and negative electrodes, and the failure rate of the module is significantly higher than that of the conventional structure. The traditional insulating glue is mainly single epoxy resin or silicone, which has insulation but lacks active acid absorption mechanism and cannot cope with the dynamic acid corrosion environment generated by the long-term aging of the glue film, resulting in a 10%-15% reduction in the service life of the module.

[0004] Some single-component heat-curable adhesives known at present cannot be directly applied to the BC cell, such as a single-component heat-curable acrylate adhesive precursor and a preparation method thereof proposed in patent 201880046490.5, the curing temperature is 120 DEG C and the time is 30 minutes, which seriously restricts the production efficiency of the existing module. In addition, if it is applied to the insulating glue of the BC cell in the photovoltaic module, the methyl methacrylate (the pKa of methyl methacrylate is 4.44, between the acetic acid (4.76) and the acrylic acid (4.26), and belongs to a medium-strength organic acid) in the adhesive is more acidic and will seriously corrode the solder strip.

[0005] Therefore, the application aims to develop an insulating glue with high weather resistance and high efficiency in absorbing acetic acid for application in the BC cell, which can efficiently absorb acetic acid near the positive and negative electrodes to avoid corrosion of the solder strip and improve the service life of the BC cell module. SUMMARY

[0006] The application aims to overcome the deficiencies of the prior art and provide a single-component heat-curable insulating glue for a photovoltaic BC cell and a preparation method thereof.

[0007] In one aspect, the application discloses a single-component heat-curable insulating glue for a photovoltaic BC cell, which adopts the following technical scheme:

[0008] The single-component heat-curable insulating glue for the photovoltaic BC cell comprises the following components in percentage by mass:

[0009] Multifunctional acrylate resins 70~95wt%

[0010] Adsorption filler 1~3wt%

[0011] Acid-absorbing filler 1~3wt%

[0012] 1~4wt% of reactive acid filler

[0013] Leveling and defoaming agent 0.5~2wt%

[0014] Initiator 0.1~1wt%

[0015] Photoprotectant 0~2wt%

[0016] Pigment 0~10wt%.

[0017] Preferably, the adsorption filler is one or more of zeolite molecular sieves, kaolin molecular sieves, zirconium powder, nano silica, and graphene carbon molecular sieves.

[0018] Preferably, the acid-absorbing filler is a metal-organic framework material.

[0019] Preferably, the reactive acid filler is one or more of magnesium hydroxide, calcium hydroxide, magnesium oxide, zinc oxide, calcium oxide, and metal-organic framework materials.

[0020] Preferably, the mass ratio of the adsorption packing, the acid adsorption packing, and the reactive acid packing is (1~2):(1~2):3.

[0021] Preferably, the functionality of the multifunctional acrylate resin is 2 to 6; the multifunctional acrylate resin is one or more of 1,9-nonanediol diacrylate, neopentyl glycol diacrylate, tricyclodecane methanol diacrylate, trimethylolpropane triacrylate, epoxidized trimethylolpropane triacrylate, pentaerythritol acrylate, dimeric pentaerythritol polyacrylate, and epoxidized dimeric pentaerythritol polyacrylate.

[0022] Preferably, the leveling and defoaming agent includes one or two of the following: a leveling agent or a defoamer; the leveling agent accounts for 0.25-1 wt% of the total weight of the insulating adhesive, and the defoamer accounts for 0.25-1.5 wt% of the total weight of the insulating adhesive; the leveling agent is one or two of the following: a silicone-modified polyether leveling agent or a silicone leveling agent; the defoamer is one or two of the following: a polyether defoamer or a silicone defoamer.

[0023] Preferably, the initiator is one or more of benzoyl peroxide (BPO), dicumyl peroxide (DCP), tert-butyl peroxide (TBPB), and tert-butyl percarbonate-2-ethylhexyl (TBEC).

[0024] Preferably, the photoprotective agent includes one or two of ultraviolet light absorbers or light stabilizers; the ultraviolet light absorber accounts for 0-0.75 wt% of the total weight of the insulating adhesive, and the light stabilizer accounts for 0-1.35 wt% of the total weight of the insulating adhesive; the ultraviolet light absorber is one or more of benzophenone, benzotriazole, triazine, zinc oxide, and nano titanium dioxide; and the light stabilizer is a hindered amine light stabilizer.

[0025] Preferably, the pigment is one or more of the following: titanium dioxide, barium sulfate, cadmium red, iron oxide red, 3132 scarlet, carbon black, copper chromium black, iron chromium black, cobalt chromium blue, phthalocyanine blue, malachite green, and phthalocyanine green.

[0026] On the other hand, this invention discloses a method for preparing a single-component thermosetting insulating adhesive for photovoltaic BC cells, employing the following technical solution:

[0027] A method for preparing a single-component thermosetting insulating adhesive for photovoltaic BC cells includes the following steps:

[0028] S1. Take 0-10 parts of pigment, 1-3 parts of adsorption filler, 1-3 parts of acid-absorbing filler, 1-3 parts of reactive acid filler, 0-2 parts of photoprotectant, 30-50 parts of multifunctional acrylate resin, and 1-2 parts of dispersant. Put them into a ball mill, mix them evenly, and grind them to a fineness of 5-15μm to make a color paste.

[0029] S2. Take 0.1-1 parts of color paste and initiator, 25-65 parts of multifunctional acrylate resin and 0.5-2 parts of leveling and defoaming agent from step S1, mix them evenly to make an insulating adhesive.

[0030] S3. Take the insulating adhesive from step S2, select a screen with different mesh counts according to the size of the battery cell, print it on the surface of the battery cell, and cure it at 150~180℃ for 2~5 minutes. The cured film thickness is 10~100μm.

[0031] Compared with the prior art, the present invention has at least the following beneficial effects:

[0032] The insulating adhesive for photovoltaic BC cells of this invention uses pigments, adsorbent fillers, acid-absorbing fillers, reactive acid fillers, and photoprotective agents as fillers. After curing, it forms a micro-nano-scale coating. Compared to conventional insulating adhesives, it has the function of efficiently adsorbing, fixing, and reacting with acetic acid generated in the adhesive film. The photoprotective agent primarily absorbs ultraviolet light, protecting the insulating adhesive structure and improving its weather resistance. The adsorbent fillers primarily adsorb acetic acid near the solder joints at the positive and negative electrode contact points. The acid-absorbing fillers primarily fix acetic acid molecules near the solder joints through coordination reactions. The reactive acid fillers primarily react with acetic acid molecules, reducing the acetic acid content near the solder joints and protecting them. The resulting insulating adhesive not only prevents contact between the positive and negative electrodes in the BC cell but also adsorbs reactive acetic acid, further extending the module's lifespan. Detailed Implementation

[0033] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to specific embodiments.

[0034] Example 1

[0035] A single-component thermosetting insulating adhesive for photovoltaic BC cells is prepared as follows:

[0036] S1. Pigment preparation: Take 5 parts of pigment titanium dioxide, 2 parts of adsorption filler ZSM-5 molecular sieve, 1 part of acid-absorbing filler metal-organic framework material (MOF-801), 3 parts of reactive acid filler magnesium hydroxide, 0.4 parts of ultraviolet light absorber nano titanium dioxide, 0.6 parts of light stabilizer (Tinuvin 770), 10 parts of difunctional acrylic resin (A-DCP Shin-Nakamura Chemical Industry Co., Ltd.), 20 parts of quadrifunctional acrylic resin (A-TMMT Shin-Nakamura Chemical Industry Co., Ltd.), 10 parts of hexafunctional acrylic resin (A-DPH-12E Shin-Nakamura Chemical Industry Co., Ltd.), and 1 part of BYK-W9010 dispersant. Grind the mixture using a ball mill for 6 passes. The grinding fineness is tested using a scraper fineness tester and found to be 8 μm. Place the pigment at room temperature for later use.

[0037] S2. Preparation of insulating adhesive: Take the color paste from step 1, 0.5 parts of benzoyl peroxide (BPO) initiator, 20 parts of 4-functional acrylate resin (A-TMMT Shin-Nakamura Chemical Industry Co., Ltd.), 25 parts of 6-functional acrylate resin (A-DPH-12E Shin-Nakamura Chemical Industry Co., Ltd.), 0.75 parts of silicone-modified polyether BYK330 leveling agent, and 0.75 parts of polyether BD3-3016 defoamer. Disperse them at high speed using a disperser, and place the uniformly dispersed insulating adhesive at room temperature for later use.

[0038] S3. Take the insulating adhesive from step 2, select a screen with a different mesh count according to the size of the battery cell, print it on the surface of the battery cell, and cure it at 160℃ for 5 minutes.

[0039] S4. The solar cells prepared in step 3 are used to prepare photovoltaic modules using ordinary EVA film and labeled as module 1. At the same time, commonly used insulating adhesive (without added adsorbent filler, acid absorbent filler, or reactive acid filler) is used to treat the solar cells using the method in step 3 and the solar cells are used to prepare photovoltaic modules using ordinary EVA film and labeled as module 2.

[0040] S5. Place the components 1 and 2 prepared in step 4 under a damp heat aging test and observe the appearance of the solder strips of the two groups of components. After DH1000h, there was no significant difference in appearance. After DH2000h, it was clearly observed that there was no significant change in the solder strips at the locations where insulating adhesive was applied in component 1, while slight blackening and corrosion appeared at the locations where insulating adhesive was not applied. The corrosion area of ​​the solder strips in component 1 was 0.8mm. 2 In component 2, both the areas coated with insulating adhesive and those without it showed the same degree of blackening corrosion, with the corrosion area of ​​the solder strips in component 2 being 15.7 mm. 2 After DH2000h, the power degradation of module 1 was reduced to -0.5% of the original value, and the power degradation of module 2 was reduced to -2.63% of the original value.

[0041] Example 2

[0042] A single-component thermosetting insulating adhesive for photovoltaic BC cells is prepared as follows:

[0043] S1. Pigment preparation: Take 5 parts of pigment iron chromium black, 1.5 parts of adsorption filler ZSM-5 molecular sieve, 1.5 parts of acid-absorbing filler metal-organic framework material (MOF-801), 3 parts of reactive acid filler calcium hydroxide, 0.4 parts of ultraviolet light absorber nano titanium dioxide, 0.6 parts of light stabilizer (Tinuvin 770), 10 parts of difunctional acrylic resin (A-DCP Shin-Nakamura Chemical Industry Co., Ltd.), 10 parts of trifunctional acrylic resin (A-TMM-3 Shin-Nakamura Chemical Industry Co., Ltd.), 10 parts of quadrifunctional acrylic resin (A-TMMT Shin-Nakamura Chemical Industry Co., Ltd.), 10 parts of hexafunctional acrylic resin (A-DPH-12E Shin-Nakamura Chemical Industry Co., Ltd.), and 1 part of BYK-W9010 dispersant. Grind the mixture using a ball mill for 6 passes. The grinding fineness is tested using a scraper fineness tester and found to be 9 μm. Place the pigment at room temperature for later use.

[0044] S2. Preparation of insulating adhesive: Take the color paste from step 1, 0.5 parts of benzoyl peroxide (BPO) initiator, 20 parts of 4-functional acrylate resin (A-TMMT Shin-Nakamura Chemical Industry Co., Ltd.), 25 parts of 6-functional acrylate resin (A-DPH-12E Shin-Nakamura Chemical Industry Co., Ltd.), 0.75 parts of silicone-modified polyether BYK330 leveling agent, and 0.75 parts of polyether BD3-3016 defoamer. Disperse them at high speed using a disperser, and place the uniformly dispersed insulating adhesive at room temperature for later use.

[0045] S3. Take the insulating adhesive from step 2, select a screen with a different mesh count according to the size of the battery cell, print it on the surface of the battery cell, and cure it at 160℃ for 5 minutes.

[0046] S4. The solar cells prepared in step 3 are used to prepare photovoltaic modules using ordinary EVA film and labeled as module 3. At the same time, commonly used insulating adhesive (without added adsorbent filler, acid absorbent filler, or reactive acid filler) is used to treat the solar cells using the method in step 3. The solar cells are then used to prepare photovoltaic modules using ordinary EVA film and labeled as module 4.

[0047] S5. Place components 3 and 4 prepared in step 4 under a damp heat aging test and observe the appearance of the solder strips of the two groups of components. After DH1000h, there was no significant difference in appearance. After DH2000h, it was clearly observed that there was no significant change in the solder strips at the locations where insulating adhesive was applied in component 3, while slight blackening and corrosion appeared at the locations where insulating adhesive was not applied. The corrosion area of ​​the solder strips in component 3 was 1.5mm. 2 In component 4, both the areas coated with insulating adhesive and those without showed the same degree of blackening corrosion, with the corrosion area of ​​the solder strips in component 4 being 15.7 mm. 2 After DH2000h, the power degradation of module 3 was reduced to -0.8% of its original value, and the power degradation of module 4 was reduced to -2.8% of its original value.

[0048] Example 3

[0049] A single-component thermosetting insulating adhesive for photovoltaic BC cells is prepared as follows:

[0050] S1. Pigment preparation: Take 5 parts of pigment titanium dioxide, 3 parts of adsorption filler ZSM-5 molecular sieve, 1 part of acid-absorbing filler metal-organic framework material (MOF-801), 1 part of reactive acid filler magnesium hydroxide, 0.4 parts of ultraviolet light absorber nano titanium dioxide, 0.6 parts of light stabilizer (Tinuvin 770), 10 parts of difunctional acrylic resin (A-DCP Shin-Nakamura Chemical Industry Co., Ltd.), 20 parts of quadrifunctional acrylic resin (A-TMMT Shin-Nakamura Chemical Industry Co., Ltd.), 10 parts of hexafunctional acrylic resin (A-DPH-12E Shin-Nakamura Chemical Industry Co., Ltd.), and 1 part of BYK-W9010 dispersant. Grind the mixture using a ball mill for 6 passes. The grinding fineness is tested using a scraper fineness tester and found to be 8 μm. Place the pigment at room temperature for later use.

[0051] S2. Preparation of insulating adhesive: Take the color paste from step 1, 0.5 parts of benzoyl peroxide (BPO) initiator, 20 parts of 4-functional acrylate resin (A-TMMT Shin-Nakamura Chemical Industry Co., Ltd.), 25 parts of 6-functional acrylate resin (A-DPH-12E Shin-Nakamura Chemical Industry Co., Ltd.), 0.75 parts of silicone-modified polyether BYK330 leveling agent, and 0.75 parts of polyether BD3-3016 defoamer. Disperse them at high speed using a disperser, and place the uniformly dispersed insulating adhesive at room temperature for later use.

[0052] S3. Take the insulating adhesive from step 2, select a screen with a different mesh count according to the size of the battery cell, print it on the surface of the battery cell, and cure it at 160℃ for 5 minutes.

[0053] S4. The solar cells prepared in step 3 are used to prepare a photovoltaic module using ordinary EVA film and labeled as module 5.

[0054] S5. The component 5 prepared in step 4 was placed under a damp heat aging test. The appearance of the component's solder strips was observed. After DH1000h, there was no significant difference in appearance. After DH2000h, it was clearly observed that there was no significant change in the solder strips at the location where the insulating adhesive was applied in component 5. The corrosion area of ​​the solder strips in component 5 was 3.1mm. 2 After DH2000h, the power attenuation of component 5 was reduced to -0.58% of its original value.

[0055] Example 4

[0056] A single-component thermosetting insulating adhesive for photovoltaic BC cells is prepared as follows:

[0057] S1. Pigment preparation: Take 5 parts of pigment titanium dioxide, 2 parts of adsorption filler ZSM-5 molecular sieve, 1 part of acid-absorbing filler metal-organic framework material (MOF-801), 4 parts of reactive acid filler magnesium hydroxide, 0.4 parts of ultraviolet light absorber nano titanium dioxide, 0.6 parts of light stabilizer (Tinuvin 770), 10 parts of difunctional acrylic resin (A-DCP Shin-Nakamura Chemical Industry Co., Ltd.), 20 parts of quadrifunctional acrylic resin (A-TMMT Shin-Nakamura Chemical Industry Co., Ltd.), 10 parts of hexafunctional acrylic resin (A-DPH-12E Shin-Nakamura Chemical Industry Co., Ltd.), and 1 part of BYK-W9010 dispersant. Grind the mixture using a ball mill for 6 passes. The grinding fineness is tested using a scraper fineness tester and found to be 8 μm. Place the pigment at room temperature for later use.

[0058] S2. Preparation of insulating adhesive: Take the color paste from step 1, 0.5 parts of benzoyl peroxide (BPO) initiator, 20 parts of 4-functional acrylate resin (A-TMMT Shin-Nakamura Chemical Industry Co., Ltd.), 25 parts of 6-functional acrylate resin (A-DPH-12E Shin-Nakamura Chemical Industry Co., Ltd.), 0.75 parts of silicone-modified polyether BYK330 leveling agent, and 0.75 parts of polyether BD3-3016 defoamer. Disperse them at high speed using a disperser, and place the uniformly dispersed insulating adhesive at room temperature for later use.

[0059] S3. Take the insulating adhesive from step 2, select a screen with a different mesh count according to the size of the battery cell, print it on the surface of the battery cell, and cure it at 160℃ for 5 minutes.

[0060] S4. The solar cells prepared in step 3 are used to prepare a photovoltaic module using ordinary EVA film and labeled as module 6.

[0061] S5. Place the component 6 prepared in step 4 under a damp heat aging test and observe the appearance of the solder strips. After DH1000h, there was no significant difference in appearance. After DH2000h, it was clearly observed that there was no significant change in the solder strips at the location where the insulating adhesive was applied in component 6, and the corrosion area of ​​the solder strips in component 6 was 0.83mm. 2 After DH2000h, the power attenuation of component 5 was reduced to -0.52% of the original value.

[0062] Therefore, it can be seen that the single-component thermosetting insulating adhesive for photovoltaic BC cells of the present invention can significantly reduce the corrosion area of ​​the solder ribbon and improve the life of BC cell modules compared with the insulating adhesives on the market.

[0063] To verify the effects of the adsorbent filler, acid absorbent filler, and reactive acid filler in the insulating adhesive, and the influence of the preparation method of this scheme on the performance of the insulating adhesive, the following comparative performance tests were conducted:

[0064] Comparative Examples 1-4

[0065] S1. Pigment preparation: Take 5 parts of pigment titanium dioxide, ZSM-5 molecular sieve with different proportions of adsorption filler in Table 1, metal-organic framework material (MOF-801) for acid absorption and magnesium hydroxide for reaction acid, 0.4 parts of ultraviolet light absorber nano titanium dioxide, 0.6 parts of light stabilizer (Tinuvin 770), 10 parts of difunctional acrylic resin (A-DCP Shin-Nakamura Chemical Industry Co., Ltd.), 20 parts of quadrifunctional acrylate resin (A-TMMT Shin-Nakamura Chemical Industry Co., Ltd.), 10 parts of hexafunctional acrylate resin (A-DPH-12E Shin-Nakamura Chemical Industry Co., Ltd.), and 1 part of BYK-W9010 dispersant. Grind the pigment using a ball mill for 6 passes. The grinding fineness is tested using a scraper fineness tester and found to be 8 μm. Place the pigment at room temperature for later use.

[0066] S2. Preparation of insulating adhesive: Take the color paste from step 1, 0.5 parts of benzoyl peroxide (BPO) initiator, 20 parts of 4-functional acrylate resin (A-TMMT Shin-Nakamura Chemical Industry Co., Ltd.), 25 parts of 6-functional acrylate resin (A-DPH-12E Shin-Nakamura Chemical Industry Co., Ltd.), 0.75 parts of BYK330 leveling agent, and 0.75 parts of polyether BD3-3016 defoamer. Disperse them at high speed using a disperser, and place the uniformly dispersed insulating adhesive at room temperature for later use.

[0067] S3. Take the insulating adhesive from step 2, select a screen with a different mesh count according to the size of the battery cell, print it on the surface of the battery cell, and cure it at 160℃ for 5 minutes.

[0068] S4. The solar cells prepared in step 3 were used to prepare photovoltaic modules using ordinary EVA film, labeled as comparative examples 1 / 2 / 3 / 4.

[0069] S5. Place the comparative component prepared in step 4 under a damp heat aging test for 1000h / 2000h, and observe the appearance of the solder strips of the two groups of components. The results are shown in Table 1.

[0070] Table 1

[0071]

[0072] Note: 1. The transmittance of the film was measured by ultraviolet spectrophotometry. The prepared insulating adhesive was coated onto the release film with a thickness of 10 micrometers using a scraper. After drying at 160°C for 5 minutes, the insulating film was peeled off and placed on a LAMBDA750 PerkinElmer UV-Vis spectrophotometer for measurement.

[0073] 2. The power attenuation of the damp heat aging test is tested according to the IEC61215 standard. The IEC61215 test is conducted for 1000 hours, while the market generally requires a more stringent test of 2000 hours.

[0074] 3. The corrosion area of ​​the weld strip follows the IEC61215 standard as the damp heat aging environment. The results measurement supplementary explanation is as follows: After the weld strip has undergone DH2000h test, high-definition images are taken. Under uniform lighting, clear photos of the weld strip are taken using a high-definition camera or microscope. A ruler must be placed in the photo so that the software can convert pixels to actual size. Using the "polygon selection" or "free lasso" tool in the software, the outline of all corrosion areas is manually and accurately delineated. The software automatically calculates the area of ​​the delineated area according to the set scale.

[0075] As can be seen from the test results in Table 1, adding only two of the adsorbent filler, acid-absorbing filler, and reactive acid filler (Comparative Examples 1-3) only slightly improved the anti-corrosion effect of the insulating adhesive on the weld strip compared to Comparative Example 4, which did not add any of the three fillers. However, Example 1, which added all three fillers simultaneously (adsorbent, acid-absorbing, and reactive acid filler), showed a significant performance improvement compared to Comparative Example 4, reducing the weld strip corrosion area from 14.3 mm. 2 Decreased to 0.8mm 2 The power attenuation decreased from -2.35% to -0.5%, which shows that the adsorption filler, acid absorber, and reactive acid filler are all indispensable and have a synergistic effect on significantly improving the electrochemical corrosion of the weld strip.

[0076] Furthermore, a comparison of Examples 1-4 shows that the light transmittance of the film is affected to some extent when the ratio of adsorbent filler, acid absorbent filler, and reactive acid filler changes. For example, after the three fillers in Examples 3-4 are compounded, the refractive index of the filler differs significantly from that of the main resin, affecting the light transmittance of the film. The decrease in light transmittance will undoubtedly reduce the absorption of light by the solar cell and affect its power generation efficiency. However, a comparison of Examples 1-2 shows that when the mass ratio of adsorbent filler, acid absorbent filler, and reactive acid filler is (1~2):(1~2):3, the resulting insulating adhesive not only maintains good anti-corrosion properties of the solder strip, but also has higher light transmittance, which is more conducive to the power generation efficiency of the photovoltaic module.

[0077] Comparative Example 5

[0078] S1. Preparation of insulating adhesive: Take 5 parts of pigment titanium dioxide, 2 parts of adsorption filler ZSM-5 molecular sieve, 1 part of acid-absorbing filler metal-organic framework material (MOF-801), 3 parts of reactive acid filler magnesium hydroxide, 0.4 parts of ultraviolet light absorber nano titanium dioxide, 0.6 parts of light stabilizer (Tinuvin 770), 10 parts of difunctional acrylic resin (A-DCP Shin-Nakamura Chemical Industry Co., Ltd.), 40 parts of difunctional acrylate resin (A-TMMT Shin-Nakamura Chemical Industry Co., Ltd.), 35 parts of hexafunctional acrylate resin (A-DPH-12E Shin-Nakamura Chemical Industry Co., Ltd.), 1 part of BYK-W9010 dispersant, 0.5 parts of benzoyl peroxide (BPO) initiator, 0.75 parts of polyether BYK330 leveling agent, and 0.75 parts of polyether BD3-3016 defoamer. Disperse the mixture at high speed using a disperser and place the uniformly dispersed insulating adhesive at room temperature for later use.

[0079] S2. Take the insulating adhesive from step 1, select different mesh screens according to the size of the battery cell, print it on the surface of the battery cell, and cure it at 160℃ for 5 minutes.

[0080] S3. The battery cells prepared in step 2 are laminated into a module using ordinary EVA film.

[0081] Comparative Example 5 uses a traditional insulating adhesive preparation process. Because the grinding process generates heat and reaches high temperatures, polymerization occurs during grinding, affecting the insulating adhesive's performance and causing clumping that hinders printing. Therefore, Comparative Example 5 cannot undergo grinding in step 1. Testing revealed that the coating obtained in step 1 has a fineness of 50 μm. Compared to the insulating adhesive prepared in Example 1, the insulating adhesive in Comparative Example 5 showed pigment sedimentation after the same storage time, failing to meet the shelf life requirement. Due to the larger particle size of the insulating adhesive, a grainy and uneven printing surface appeared during step 2. Furthermore, during step 3 lamination, printing problems with the insulating adhesive caused microcracks in some battery cells, resulting in appearance issues that did not meet requirements.

[0082] Therefore, the present invention adopts a two-step method. First, a portion of the acrylic resin is mixed with pigments, fillers, photoprotective agents and other additives and ground to obtain a fine color paste. Then, the remaining acrylic resin is mixed and dispersed with initiator, leveling and defoaming agent and color paste. The coating obtained in this way has stable properties and uniform pigment distribution. The insulating adhesive formed after heat curing has a smooth and delicate surface, which can better protect the battery cells.

[0083] The technical solution provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A single-component thermosetting insulating adhesive for photovoltaic BC cells, characterized in that, By mass percentage, it includes the following components: Multifunctional acrylate resins 70~95wt% Adsorption filler 1~3wt% Acid-absorbing filler 1~3wt% 1~4wt% of reactive acid filler Leveling and defoaming agent 0.5~2wt% Initiator 0.1~1wt% Photoprotectant 0~2wt% Pigment 0~10wt%; The acid-absorbing filler is MOF-801 metal-organic framework material; The reactive acid filler is one or more of magnesium hydroxide, calcium hydroxide, magnesium oxide, zinc oxide, and calcium oxide.

2. The single-component thermosetting insulating adhesive for photovoltaic BC cells according to claim 1, characterized in that, The adsorption packing material is one or more of zeolite molecular sieves, kaolin molecular sieves, nano-silica, and graphene carbon molecular sieves.

3. The single-component thermosetting insulating adhesive for photovoltaic BC cells according to claim 1, characterized in that, The mass ratio of the adsorption packing, acid adsorption packing, and reactive acid packing is (1~2):(1~2):

3.

4. The single-component thermosetting insulating adhesive for photovoltaic BC cells according to claim 1, characterized in that, The functionality of the multifunctional acrylate resin is 2 to 6; the multifunctional acrylate resin is one or more of 1,9-nonanediol diacrylate, neopentyl glycol diacrylate, tricyclodecane methanol diacrylate, trimethylolpropane triacrylate, epoxidized trimethylolpropane triacrylate, pentaerythritol acrylate, dipolypentaerythritol polyacrylate, and epoxidized dipolypentaerythritol polyacrylate.

5. The single-component thermosetting insulating adhesive for photovoltaic BC cells according to claim 1, characterized in that, The leveling and defoaming agent includes one or two of the following: a leveling agent or a defoamer; the leveling agent accounts for 0.25~1wt% of the total weight of the insulating adhesive, and the defoamer accounts for 0.25~1.5wt% of the total weight of the insulating adhesive; the leveling agent is one or two of the following: a silicone-modified polyether leveling agent or a silicone leveling agent; the defoamer is one or two of the following: a polyether defoamer or a silicone defoamer.

6. The single-component thermosetting insulating adhesive for photovoltaic BC cells according to claim 1, characterized in that, The initiator is one or more of benzoyl peroxide (BPO), dicumyl peroxide (DCP), tert-butyl peroxide (TBPB), and tert-butyl percarbonate-2-ethylhexyl (TBEC).

7. The single-component thermosetting insulating adhesive for photovoltaic BC cells according to claim 1, characterized in that, The photoprotective agent includes one or two of ultraviolet light absorbers or light stabilizers; the ultraviolet light absorber accounts for 0-0.75 wt% of the total weight of the insulating adhesive, and the light stabilizer accounts for 0-1.35 wt% of the total weight of the insulating adhesive; the ultraviolet light absorber is one or more of benzophenone, benzotriazole, triazine, zinc oxide, and nano titanium dioxide; the light stabilizer is a hindered amine light stabilizer.

8. A method for preparing a single-component thermosetting insulating adhesive for photovoltaic BC cells as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Take 0-10 parts of pigment, 1-3 parts of adsorption filler, 1-3 parts of acid-absorbing filler, 1-3 parts of reactive acid filler, 0-2 parts of photoprotectant, and 30-50 parts of multifunctional acrylate resin, put them into a ball mill, mix them evenly, and grind them to a fineness of 5-15μm to make a color paste. S2. Take 0.1-1 parts of color paste and initiator, 25-65 parts of multifunctional acrylate resin and 0.5-2 parts of leveling and defoaming agent from step S1, mix them evenly to make an insulating adhesive. S3. Take the insulating adhesive from step S2, select a screen with different mesh counts according to the size of the battery cell, print it on the surface of the battery cell, and cure it at 150~180℃ for 2~5 minutes. The cured film thickness is 10~100μm.

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