Are your modules STR Protected - PHOTOCAP Solar Encapsulants · 2013. 3. 27. · PV Module Performance. No Two EVA Encapsulant Formulations are Alike. Accelerated xenon arc weather

www.strsolar.com

Are your modules STR Protected™

?

Specialized Technology Resources, Inc. (STR) is the global leader in encapsulant technology for the solar module industry. STR has been manufacturing encapsulants for more than 30 years with zero field failures. Our products offer distinct competitive advantages that increase the bankability of our customer’s modules.

Given the high capital investment required to build solar projects and a module lifetime expectancy of more than two decades, it is critical to select a module brand that is “Bankable” to increase project IRR. STR believes that its ability to cite performance data over a multi-decade time frame serves to remarkably improve a module manufacturers’ bankability.

Ethylene Vinyl Acetate (EVA) has been the primary material used in solar encapsulants for the last few decades. STR PHOTOCAP® EVA is the only encapsulant technology with a proven track record of maintaining durability, adhesion, stability and transparency after more than 25 years of field exposure.

STR not only offers encapsulant with proven superior performance, but we work directly with our customers to improve their lamination processes and in turn, improve the quality of their modules, increase yield and reduce costs.

STR has been at the technology forefront of the solar encapsulant business for three decades and has retained its dominance by continually increasing the value of its products. It is abundantly clear that STR offers a level of technical and customer service unmatched by the competition. STR not only sells a premium product but “it also sells its engineers and scientists.”

Photovoltaic Solar Module Reliability and

Durability

Choosing the right solar encapsulant to protect the longevity of the solar module is the single-most important decision a developer or project owner will make.

PHOTOCAP® is a registered trademark of Specialized Technology Resources

Are your modules STR Protected™?

What happens when a project owner buys solar modules from a supplier that uses an inexpensive encapsulant and the power generation significantly declines over the life of the product? Who covers the cost?

A. Specialized Technology Resources, Inc. has been developing and producing solar encapsulant for over 35 years (circa 1975); through advanced engineering and time-tested durability.

Q. How has STR upheld high quality standards to safeguard solar modules?

How will you know that solar module components will perform as intended?

The solar industry is

challenged with collecting

energy and collecting it in

a cost effective way.

The value of any PV module

is determined by durability,

life-cycle, interest rates, and

cost of the materials used in

that device.

Cost Performance[P(t=∞)]Must Be Minimized

Must Be Demonstrated

The Solar Industry is Embattled With Opposing Forces.

Project IRR increases with long-term module performance.

Must Be Maximized

Durability[P(t)]

“Lifetime” 25 years

INDUSTRY FORCES

• STR Has Been Making Quality Encapsulant Since 1975

• More Than 20 Gigawatts of STR Protected™ Modules in the Field

• No Reported Failures of STR Encapsulant in Fielded Modules

• Unsurpassed Long-term Optical Performance of STR Encapsulant Facilitates Maximum

Power Output

Encapsulant reliability

requires accurate,

repeatable formulation,

top quality raw materials

and strict process control.

*“Bankability” is a financial industry term defined as “preferential to a bank” and “dependable and reliable.”

Bankability in the solar energy industry is another word for “risk mitigation.”

Solar Module “Bankability”* is a Function of Reliability and Durability.Investors in the solar industry are gaining a better understanding of how to calculate actual returns on investments. Discussions regarding price are moving from a capacity basis, traditionally discussed in terms of cost per watt, to an energy generation basis, which is discussed in terms of cost per kilowatt-hour of energy produced and represented by estimated levelized cost of electricity (LCOE).

In today’s PV market, everyone from system owners to start up thin-film PV firms will tell you about their calculated LCOE. Many assumptions go into this calculation, one of those key assumptions being the system degradation rate, which is highly dependent on the stability of your encapsulant.

BANkABILITYSTR PROTECTED

Consider This… Module Components Impact Module Durability.

STR Encapsulant Touches Every Component of the Solar Module, Therefore it Must Be Chemically & Physically Compatible to Enhance Module Durability.

Encapsulants are critical to solar modules, as they protect cells from the elements, bond the multiple layers together, and provide electrical isolation. Encapsulants must have high optical transparency, stability at high operating temperatures, the ability to withstand high levels of ultraviolet radiation, good adhesion to different module materials, adequate mechanical compliance to accommodate stresses induced by differences in thermal expansion coefficients between glass and cells, and high dielectric strength (electrical isolation). Even a slight deterioration of any of the properties of the encapsulant over time will impair the electrical output of the module, which is of critical importance to providing a 20 to 25-year working life of a solar module.

During solar module assembly, the encapsulation process is typically accomplished by vacuum lamination, wherein a “pre-lam” stack (as depicted in the diagrams to the right) is fashioned into a singular part comprising multiple layers. Sheets of EVA are inserted over and under the PV cells. Heating the “sandwich” then causes the EVA to cure, thus bonding the module into one piece. This step occurs towards the end of the manufacturing process and is critical to the entire solar module, as there is only one opportunity to laminate correctly.

Function of the EVA Encapsulant

• Bond All Components Together• Weatherability of the PV Device (up to 25 years)• High Light Transparency for Cell Efficiency• Electrical Isolation of the PV Device• Increase Stress Load of Glass• Moisture Ingress Protection• Allow Expansion and Contraction

Typical Crystalline Silicon Solar Module Construction

Typical Thin Film Solar Module Construction

Glass

Top Side EVA Encapsulant

Cells

Back Side EVA Encapsulant

Back Sheet

Glass

EVA EncapsulantDeviceGlass

DURABILITYSTR PROTECTED

Solar Module Component

Function of STR PHOTOCAP® EVA Encapsulant Benefits of STR Protected™

Glass Mechanical Stress Load Management

STR encapsulant minimizes stress load to cells; provides a thermal expansion buffer and absorbs stress to prevent cell cracking as well as module deformation. Bonds cells to glass.

PV Cell

Electrical Isolation STR encapsulant has high volume resistivity to minimize current leakage; high dielectric strength.

High Light Transmission STR encapsulant maintains clarity and is optically designed to allow a broad band of light transmission.

Dimensional Stability STR encapsulant does not move or shrink during lamination preventing void formation over cells, movement of cell strings, and cell breakage.

Mechanical Protection STR encapsulant physically isolates the cells and can absorb stresses that lead to cell cracking.

PV Ribbon Electrical Isolation STR encapsulant is compatible with most surfaces to maintain high dielectric strength.

Backsheet

Strong Adhesion STR encapsulant helps to protect the backsheet from yellowing; bonds cells to backsheet.

Chemically Compatible With Tie-Layers STR encapsulant bonds well to the backsheet.

Physical Robustness STR encapsulant provides a level of cut/tear resistance along with high bond strength.

BENEFITSSTR PROTECTED

Probably the oldest and most widely discussed solar module differentiator is module efficiency. Maintaining high module efficiency over time means that project IRR can be maximized, because electricity generation remains at expected rates. STR PHOTOCAP® EVA encapsulant does not discolor and helps to maintain original cell efficiency while being a small part of the overall cost of the solar module.

Poorly Formulated EVA Encapsulant Can Stain Back Sheet After Weathering

Some EVA Encapsulants Contain Additives That React and Turn the Encapsulant Brown

Some EVA Encapsulants Weather Poorly, Turning Yellow

STR PHOTOCAP® EVA Encapsulant is Engineered to Remain Clear After Weathering

Left: A Poorly Formulated EVA Encapsulant will Discolor and turn Yellow or Brown from Outdoor Exposure. The result is a drastic reduction in cell efficiency

MODULE DELAMINATION is the loss of adhesion between the encapsulant and other module layers. Delamination in the field can occur in cases where the encapsulant was improperly cured or where chemical incompatibilities between the encapsulant and other module components exist. Most of the delamination observed in the field has occurred at the interface between the encapsulant and the front surface of the solar cells or back sheet in the module. Delamination is more frequent and more severe in hot and humid climates, sometimes occurring after less than five years of exposure. Delamination first causes a performance loss due to optical de-coupling of the encapsulant from the cells. Of greater concern, is the likelihood that the void resulting from the delamination will provide a preferential location for moisture accumulation, greatly increasing the possibility of corrosive failure in metallic contacts.

FOR HIGH EFFICIENCY

Not All Encapsulants Are Formulated the Same!

FORMULATION “MASTERY”STR PROTECTED

STR-Owned Test Tracker in Arizona Yields 22-Year* Weathering Exposure and Power Analysis.Should you wager the value of your installation only on module validation data? When you’re STR Protected™, you won’t have to!

Pictured below is STR’s two-axis tracker in Tempe, AZ, USA – one of the sunniest places on earth. STR Scientists fielded modules with our key platform encapsulant formulations on this tracker in 1996 to evaluate their effectiveness at maintaining power output under the harshest of real-time, actual outdoor conditions. Our confidence is data-driven. Accept no substitutes.

*Two-axis tracking acceleration factor of 1.6 yields 22 years (in equivalent years)

STR Ultra-Fast Cure Encapsulant

STR Ultra-Fast Cure Encapsulant

Time on Tracker (equivalent years)

Time on Tracker (equivalent years)Re

lativ

e Po

wer

Pm

ax (%

)Re

lativ

e Sh

ort C

ircui

t Cur

rent

, Isc

(%)

080

85

90

95

100

105

8 16 24

080

85

90

95

100

105

8 16 24

TIME-TESTEDSTR PROTECTED

STR PHOTOCAP® EVA Does Not Shrink During Lamination to Protect Cells from Breakage and Movement Before and During Lamination.

Our EVA Touches Everything in the Module.Another important aspect of the encapsulant is dimensional stability. Shrink or inadequate adhesion during the lamination process of the PV solar modules can occur, and may result in voids or holes in the encapsulant during module lamination, which are considered defects and cause for rejection of the entire panel. The encapsulant is susceptible to several performance failures that can jeopardize the integrity and performance of the entire solar module, and lead to significant warranty costs.

STR Protected includes “User-Friendly” No Shrink Technology during the manufacturing of its encapsulant. This means ZERO Shrink and NO adverse impact on adhesion to glass, cell or backsheet, which can harm your modules in the field.

STR User Friendly (UF) Technology results in zero Shrink.

Competitive materials shrink during lamination.

LEADING EDGE TECHNOLOGYSTR PROTECTED

High Technology Formulations to Protect EfficiencyXenon Arc Accelerated Aging

Time in XAW (years)

Yello

wne

ss In

dex 15455P/UF Mega-Fast

Cure Encapsulant15420P/UF Ultra-Fast Cure EncapsulantCompetitor 1Competitor 2

00 4 8 12 16 20 24 28

5101520253035

072 120 168 264 408

20

40

60

80

100High Temperature (130˚C Heat Soak)

Time in XAW (hours)

Yello

wne

ss In

dex

15420P/UF Ultra-FastCure EncapsulantCompetitor 1Competitor 2Competitor 3

STR encapsulant outperforms the competition in high temperature accelerated weathering.

Subtle Chemical Deviations Have a Profound Impact on PV Module Performance. No Two EVA Encapsulant Formulations are Alike.Accelerated xenon arc weather testing can give a good indication of the performance of the encapsulant. Several competitive encapsulants were evaluated by STR. The truth is that no two encapsulants behave the same.

Time in XAW (in equivalent years: 2 weeks = 1 year)

Yello

wne

ss In

dex

(AST

M D

-192

5)

0

0

2

4

6

8

10

12

14

16

18

5 10 15 20 25

15420P/UF Ultra-Fast Cure EncapsulantCompetitor 1Competitor 2Competitor 3Competitor 4Competitor 5

Xenon Arc Weatherometer ExposureYellowness Index

STR’s long-term accelerated aging studies, coupled with our field testing, show that two weeks in accelerated chambers approximates almost one year in the field. STR encapsulants maintain clarity and photothermal stability.

Encapsulant discoloration reduces module power output. Encapsulant yellowing will diminish cell efficiency.

Poorly Formulated Encapsulants Will Degrade More Rapidly in High Temperature Environments, Reducing Module Output.

00.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

5 10 15 20 25

% Transmission Loss vs. EVA Yellowing

∆ Yellowness Index

Loss

in S

olar

Inte

grat

edTr

ansm

issi

on (∆

%T)

ADVANCED ENGINEERINGSTR PROTECTED

It All Starts with World-Class Internal Quality.STR Quality Control sets the industry standard for perfection in EVA encapsulant manufacturing. STR’s goal is 100% customer satisfaction—full stop. We achieve our goal with ZERO module returns from the field using STR PHOTOCAP® EVA encapsulant.

There are rogue encapsulant manufacturers existing in the industry. These companies don’t offer the time-tested assurance that their product will not discolor and degrade cell efficiency when weathered outdoors. STR has the industry time-tested expertise.

All cost/benefit tests point to STR PHOTOCAP® EVA as the practical choice for solar encapsulants. STR has over 35 years of formulatory knowledge for PV applications.

STR knows that modules containing STR PHOTOCAP® EVA encapsulant will perform as expected over the service life of the module. There are non-STR modules in the field today that have been recalled due to yellowing and/or visible signs of discoloration. If left unattended these modules will continue to decline in power output over time.

• World Class Global Quality

• Dashboard Metrics of Key Performance Parameters

• On Time Delivery

• Supply Chain Quality

• In-process/Final Quality Checks

• Global CAPA System on Manufacturing Lines

• Timely Corrective Action Board

• Six Sigma Philosophy

• Six Sigma Certified Black Belt(s)

• FMEA - Control Analysis

• Quality Manager/Staff at Each Site

• All Sites ISO 9001 Certified

• All STR Sites are UL Listed

Please Make Sure that You Are STR Protected!

Make Sure That You Have Time-Tested STR PHOTOCAP® EVA Encapsulant Inside.

WORLD-CLASS QUALITYSTR PROTECTED

STR ESPAÑA, S.A.PARquE TEcnológico dE ASTuRiAS, PARcElA 3633428 – llAnERA, ASTuRiASSPAinPhonE: +34-985-73-23-33FAx: +34-985-73-36-62

STR MAnuFAcTuRing locATionS

1699 King STREET, SuiTE 400EnFiEld, cT 06082 uSAPhonE: +1-860-758-7300FAx: +1-860-758-7301

STR coRPoRATE hEAdquARTERS

STR, inc.18 cRAFTSMAn RoAdEAST WindSoR, cT 06088 uSAPhonE: +1-860-763-7014

STR MAlAySiA Sdn BhdPloT 20, JAlAn TAnJung A/3PoRT oF TAnJung PElEPAS81560 gElAng PATAh, JohoRMAlAySiAPhonE: +607-507-3186FAx: +607-507-3190

gloBAl REAch

www.strsolar.com

The information, statements and recommendations contained herein are based on information, data, reports or tests believed to be reliable. however, Specialized Technology Resources, inc. makes no warranty or guarantee of accuracy or completeness in connection therewith, nor, with respect to any Specialized Technology Resources, inc. products involved, any warranty or merchantability or fitness for a particular purpose or use.

www.ul.com Keyword: PhoTocAP

iSo certification iSo 9001: 2008 STR, uSiSo 9001: 2008 STR, SpainiSo 9001: 2008 STR, Malaysia

5871 5871