光伏支架夹具与压块用什么改性尼龙?风载雪载,最怕组件脱落

应用领域 发布时间: 2026-09-13 1087 阅读

171 Photovoltaic mounting fixture and bridle

The operating conditions for the clamp are wind load plus ultraviolet exposure

The photovoltaic module clamp must press the module against the bracket and withstand wind loads (designed wind speed 30-45 m/s), snow load, temperature cycling (-40°C to 85°C), and ultraviolet exposure.

The failure of the fixture is module detachment, which is not a minor issue. Among these four operating conditions, the most easily underestimated is the temperature cycling—once a day-night cycle per day, which is 9,000 cycles over 25 years.

Division of Aluminum Alloy and Plastic Division

Aluminum alloy fixtures are the traditional mainstream: high strength, good weather resistance, and long lifespan, but high unit price, multiple processing steps, and require additional grounding for conductivity. PA66-GF30 weather-resistant fixtures have become mainstream in recent years: unit price 40% lower, one-time injection molding, built-in insulation without grounding, and 70% lightweight. Distributed rooftop projects almost exclusively use plastic fixtures, while large-span ground power stations still mainly use aluminum.

On-site reconstruction: counting after the typhoon passed

In mid-September 2024, a typhoon passed along the southeast coast, and the operations team at a photovoltaic power station in Zhejiang counted the losses: the modules were not broken, but rows of modules slipped out of the briquettes, and more than a dozen panels in the diagonal rows were displaced and misaligned. The EPC project manager called while flipping through photos: "The briquettes aren't broken, they're loose."

Not broken but loose—these five words point to creep and preload decay. We brought back two briquettes from the site: the universal PA66-GF30, which was not weather-resistant, and after two years of use, the surface had already become rough;

Measured hardness at room temperature remains, but compressive strength at 80°C drops by 40%—the back of the module can reach 70-80°C in summer, and the compressed blocks bear wind loads at this temperature every day.

replaced the photovoltaic-specific weather-resistant PA66-GF30 for the customer: strength and creep data at 80°C are fully reported, xenon lamp aging is complete, and the torque limit structure is made in the mold, so installers won't crack even if they turn the head.

The next year during the same typhoon season, the power station count resulted: displacement was zero.

The cruelty of photovoltaic components is: when problems don't occur, no one knows where the material difference lies; losses are calculated according to the plan. The compressed block is one of the lowest-priced components in the entire system, yet it is the hand that presses the entire module onto the bracket.

25-year lifespan depends on the weather-resistant system

Outdoor UV doses accumulate over 25 years; ordinary PA66 pulverizes after two years without weather resistance.

Photovoltaic-specific weather-resistant PA66-GF30 requires a three-piece set of UV absorber + hamper-resistant amine light stabilizer (HALS) + antioxidant;

also requires 3000 h xenon lamp aging verification—3000 hours corresponds to about 5 years outdoors.

Only after 3000 hours of tensile strength remains above 80% qualifies to be considered 25 years.

Creep resistance is the core indicator of the fixture

fixtures rely on friction to fix the assembly; if the bolt preload is reduced due to creep, the component will slide. The creep of the

PA66-GF30 under 25 years of continuous load is a key design —

At room temperature, 20 MPa stress yields about 1.5% creep strain for 100,000 hours, so sufficient margin must be left in the preload design.

This is why the fixture does not use PA6—PA6 has 1.5 times creep than PA66.

Deeper Layer: How to Convert Creep Numbers into Design Allowances

Talking About Photovoltaic Fixtures: The word creep appears most frequently, but many choices stop at the phrase 'must resist creep' and don't go further. Let's take a step and see.

Creep data looks like this: PA66-GF30 under 20 MPa stress and room temperature, creep strain of about 1.5% over 100,000 hours. How do you use this number?

The compression blocks press the module onto the bracket by bolt pretension. Assuming a material stress of 20 MPa for preload, creep strain will continue to accumulate over 8,760 hours per year and 220,000 hours over 25 years.

The result of strain accumulation is that the clamp is stretched a bit and the pressing surface is loosened, causing friction to decrease—below the critical value, and the module slips when wind load is on.

So the design allowance depends on three factors: creep strain margin (initial tension should leave room for 25 years of accumulated strain), high-temperature reduction (creep at 80°C is faster than at room temperature, data should be taken according to operating temperature), and damp heat aging reduction (after water absorption and plasticization, creep accelerates by another level).

After folding all three strips, many of the "room temperature data looks great" are exposed. This is also why we insist on showing customers 100,000 hours of data instead of thousands of hours of extrapolation: creep curves follow logarithmic coordinates, short-term extrapolations look similar, but when you add 100,000 hours of data, the high and low points become obvious.

Photovoltaics is a 25-year business, so material accounting must also be calculated based on 25 years.

Electrocouple corrosion is an advantage of plastics

Aluminum alloy fixtures and steel brackets will cause galvanic corrosion, requiring insulating gaskets or surface treatment.

Plastic fixtures are naturally insulated, so this problem does not exist, eliminating insulating gaskets and grounding steps. This is the implicit reason why plastic fixtures are rapidly penetrating distributed projects—not only is the material cheap, but the entire installation process is more economical.

Hidden Variable in Installation

Fixture installation relies on manual tightening, resulting in high torque dispersion. Plastic fixtures must be designed with torque limiting structures; overtightening will cause cracking directly.

Additionally, the back temperature of the photovoltaic panel can reach 70-80°C. For fixtures kept at this temperature for extended periods, strength must be checked at 80°C rather than room temperature—

PA66-GF30 has only 55% of its strength at 80°C.

Engineering Testing: 4 mandatory tests

Test 1: Xenon lamp aging for 3000 hours. Weather-resistant PA66-GF30 maintains tensile at 82%, while standard PA66-GF30 drops to 55%—outdoor materials must be specially used for weathering.

Test 2: Wind load resistance. At 45 m/s wind load, the PA66-GF30 fixture displacement is <1 mm, meeting IEC 61215 requirements.

Test 3: Creep. At 20 MPa for 100,000 hours, PA66-GF30 creep strain reaches 1.5%, PA6-GF30 reaches 3.8%—fixtures do not use PA6.

Test 4: 80°C strength. PA66-GF30 tensile strength at 80°C is 55% of room temperature—must be checked at high temperature.

Follow-up question, three questions: The three most frequently asked questions in procurement

First question: How do you distinguish between plastic fixtures and aluminum alloy? Simple version: For distributed roofs, use plastic (cost, insulation, installation efficiency take over), for large ground spans, use aluminum (strength and span requirements). For the middle zone, look at wind load calculations—it's not a matter of material, but of working conditions.

Second question: Is there a difference between compressed blocks and medium compressed blocks? Different force logic: edge compressed blocks press against the edges of components, medium compressed blocks press against adjacent edges. Medium compressed blocks have a narrow compression surface and strong unit pressure, making creep and embedding issues more prominent. The material selection grade is a notch higher than that of edge compressed blocks. This detail drawings often do not distinguish between these details, leaving it to the selector to control themselves.

Three Questions: The quotation sheet says weather resistance, how to verify it? Three reports to verify authenticity: xenon lamp for 3,000 hours (tensile retention above 80%), wet heat for 1,000 hours (tensile breaking force maintained above 80%), and 100,000 hours creep curve. Suppliers with matching data for all three can be counted on two hands in the industry—if any one is missing, even the lowest quote is questionable. ### Calculate the Material Account: LCOE Perspective for Compressed Blocks

The photovoltaic industry has a ready-made ledger tool called LCOE (Cost of Electricity per Kilowatt-Hour). Using it to calculate the material ledger for briquettes immediately changes the perspective.

Each briquette is 0.8 yuan more expensive, so a 100 MW power plant uses about 400,000 briquettes, with a material price difference of 320,000 yuan. This 320,000 yuan is spread over 2025 years of total power generation (about 3.5 billion kWh), which equals 0.00009 yuan per kWh — the fourth decimal place.

Module displacement, hot spots, and cleaning abnormalities caused by briquetting failures reduce generation efficiency by 1%, resulting in losses in the million-yuan range over 25 years. The ratio of material price difference to failure risk is over 1 to 30 yuan from this perspective.

This also explains why leading power plant operators increasingly ignore block unit prices in centralized procurement and look at verification reports: they have internally calculated this LCOE ledger. The lesson for suppliers is to get the reports right—3000-hour xenon lamp, damp heat, and creep reports in hand, even if bids 20% higher, they still win bids;

If the report is absent, no matter how low the quote is, it won't make the shortlist.

In the photovoltaic materials business, price wars are for those who don't know the goods; data wars are for operators. Competition over data thickness is more dignified and lasts longer than price competition. ### Boundary Statement

Operating ConditionsRecommended Materials
Distributed RoofPA66-GF30 Weather-Resistant Special Material
Large Span for Ground Power StationsAluminum Alloy
High UV RegionWeathering Grade + Carbon Black
Low temperature regionsToughening and weather-resistant PA66-GF30
Insulation required, no grounding requiredPlastic fixtures

Engineering memo

Photovoltaic fixtures: before mass production, three items must be performed: 3000 hours xenon lamp aging + wind load + creep. Verify strength at 80°C, not at room temperature.

Practical Case: Common pitfalls and correct answers

Pitfall 1: Using conventional PA66 to make outdoor photovoltaic fixtures without a weathering system, they will pulverize and crack after two years. Correct answer: Photovoltaic energy storage components have a design lifespan of 25 years and must use a dedicated weathering grade—UV absorber + HALS + antioxidant—a three-piece set that is indispensable, and must be tested with 3000 hours of xenon lamp aging. Pitfall 2: Only focus on strength at room temperature, not strength after damp heat aging. When installing photovoltaic fixtures outdoors, materials with strength retention below 70% after 1000 hours of damp heat aging cannot be used. Correct answer: Select materials based on damp heat aging data, not room temperature data. Pitfall 3: Temporary material replacement to pass certification, but no re-aging verification after replacement, resulting in mass installation and centralized failure. Correct answer: The replacement number must re-cycle the entire aging process; this is a basic rule in the photovoltaic industry.

Reverse case: Price difference of 0.8 yuan per unit

In March 2024, a distributed photovoltaic project centralized procurement briquette had two suppliers bidding: Company A's photovoltaic-specific weather-resistant brand was 3.6 yuan each; Company B's general enhancement brand with weathering agent was 2.8 yuan per unit. The core indicators on the physical property table were almost identical, but centralized procurement proceeded at a low price. B won the bid for 400,000 units.

was fine that winter. Starting in May of the following year, each project site began reporting module displacement. Before the rainy season in July, a concentrated inspection found over 3,000 displacement modules, with some edge pressure blocks showing creep cracking.

La B materials conducted comparative tests: at 80°C, the compression strength was only 70% of Company A's, and the extrapolated strain after 100,000 hours of creep exceeded the design margin by twice — the general-purpose brand weathering agent only solved pulverization, not high-temperature creep.

Rework cost calculation: Manual labor for high-altitude operations cost 4 yuan per compressed block, plus component reset and hazard inspection, total losses are five to six times the original 320,000 yuan saved.

EPC The procurement manager later said something we often quote: "A 20% price difference for photovoltaic components means someone missed two sets of aging." This applies to compressed blocks and the entire photovoltaic materials community. ### Extended judgment: Two easily confused concepts

In the material selection discussions for photovoltaic fixtures, two concepts have long been confused. The first is flame retardant and insulation.

Flame retardant solves the problem of non-fire, while insulation and anti-electric mark protection solve the problem of no creeping or breakdown. These are two different things.

One material can be flame-retardant with V-0, but CTI is only 250 V, so installing it on live parts can still cause problems.

The second is strength and toughness. Glass fiber reinforcement increases strength but reduces toughness; toughening increases toughness but reduces strength and rigidity.

For the same piece, structural parts need strength, fastening parts require toughness. Generally, two types of materials are used. For convenience, using one material results in either snap snaps or the body cracks.

Writing these three things into a sheet and sending it to suppliers is more effective than making ten phone calls—the cost of communication for photovoltaic fixture selection is basically spent on repeated confirmations of these items.

Final Q&A: Three Critical Moments of Judgment

Dilemma One: EPC clients only want low prices and are unwilling to wait for reports. Two options: wait three weeks to get the full report and go for standard price, or wait for the report to go for a "risk bearing" clause plus insurance coverage. Return the option to the customer, splitting the quotation into two columns—many clients see the risk clause in the second column and then return to the first column themselves.

Dilemma 2: After winning the bid, the client requests to switch to cheaper materials. Speaking with creep data: a page comparing the 100,000-hour strain of two types of materials at 80°C, along with a rework cost estimate. Photovoltaic industry clients are thoroughly educated by industry accidents; once the data is in place, most will give up—if you can't give up, write the boundary of responsibility into the supplementary agreement.

Dilemma 3: Should the briquettes follow the customer's "all-plastic power station" concept? Zone participation: Structural parts (pressure blocks, pads) can be plasticized maturely, but main load-bearing structures (purlins, columns) plasticization is too early to keep pace. The concept cycle in the photovoltaic industry is short; material suppliers and concepts must be "verified as closed-loop" parts. ### Additional note: Three on-site judgment signals

Signal One: Module displacement, compressed blocks not cracked. Creep plus pre-tightening attenuation, recalculate stress at 80°C; don't just replace bolts—no matter how tight the bolts are, the material cannot hold up or is loose.

Signal 2: Briquette surface is fuzzy and white. Insufficient weather resistance system, strength decay is accelerating; concentrated batch changes before the rainy season, don't delay until typhoon season.

Signal 3: Compressed blocks cracking during installation. No torque limiting or poor material toughness at low temperatures; investigate these two issues separately: structural limit ribs, material check -40°C impact data. ### Verification sequence: After completing three steps, place an order

Step one: For environment: determine the working condition package based on the project's UV intensity, extreme temperature, and wind load rating; each has a set of stricter items for plateau and coastal areas.

Step two: test three items: xenon lamp, humidity heat, creep. The report must include cycle base and attenuation data; dry state reports are not accepted.

Step three: inspect installation: torque limit and on-site assembly for small-batch trial installation. Parts twisted by workers will not appear on any physical property tables. After completing these three steps, the cheapest part for briquettes is the most expensive insurance.

Conclusion

About us, four sentences—the earlier you ask about material selection, the easier it is.

For material selection and mold trials for these types of pieces, you can chat together

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