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Encapsulant Films

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Properties and selection of EVA, POE, EPE and other encapsulants

Articles

• To Crosslink or Not? How Perovskites, Flexible Modules and Recycling Are Rewriting the Future of PV EncapsulantsThis is the final article of our PV encapsulant series. The first twelve covered the encapsulant of today; this one looks at tomorrow: crosslinking-free thermoplastic encapsulants, low-temperature encapsulation, the encapsulation challenges of perovskite and tandem cells, new applications in lightweight flexible modules and space PV, and the new demands that recycling places on encapsulants. Drawing on NREL and Dow's perovskite encapsulation research, an EPJ Photovoltaics recycling study and 2026 industry developments, we try to answer where encapsulants go next, which directions are already under way and which still need time.
• One Company Holds Half the Market While the Rest Shake Out Through Losses: The PV Encapsulant Industry LandscapeThe first eleven articles were about technology; this one is about the industry. In this twelfth article of our PV encapsulant series, we follow the chain from upstream resins to midstream encapsulants to downstream modules and use 2025 annual reports and the latest 2026 periodic reports to answer three questions: how the "one giant, several strong players" structure formed, who is losing money and who is recovering after this round of price war, and what domestic production of EVA and POE resins has changed for the industry.
• How Many Gates Does a New Encapsulant Have to Pass? Encapsulant Selection, Qualification and Incoming Inspection from the Buyer's ViewThe first ten articles were about the encapsulant itself; this one takes the module maker's seat: what gates must a new encapsulant pass between selection and volume use? In this eleventh article of our PV encapsulant series, we walk through four stages (selection, validation, certification and volume-production control), set out what to check and test at each, explain how material tests, module reliability tests and BOM certification relate, and what IEC TS 62915 requires for material changes, and finally sum up the five most common pitfalls when changing encapsulants.
• DH, TC, HF, UV, PID: What Do Module Reliability Tests Really Ask of the Encapsulant?Article 5 covered material-level ageing of encapsulants; this one covers module-level reliability testing, where the encapsulant is tested inside a complete module together with cells, ribbons, glass and backsheet. In this tenth article of our PV encapsulant series, we go through the damp heat, thermal cycling, humidity freeze, UV and PID tests of IEC 61215 and the encapsulant job each one examines, then use the encapsulant-related findings of the Kiwa PVEL 2026 Reliability Scorecard to discuss why passing certification does not mean reliable, and how to judge the encapsulant's share of blame after a test failure.
• Yellowing, Delamination, Snail Trails, Acetic Acid Corrosion and PID: A Complete Guide to Encapsulant-Related Module FailuresEncapsulant problems usually surface only after a plant has run for several years, and they can hardly be repaired. In this ninth article of our PV encapsulant series, we break down five typical encapsulant-related failures (yellowing, acetic acid corrosion, snail trails, delamination and bubbles, and PID) using a "symptom, mechanism, diagnosis, prevention" structure, and draw on work by IEA PVPS, Fraunhofer and Kiwa PVEL to set out a troubleshooting path from the field to the lab.
• With Modules Below RMB 0.7/W, How Should the Encapsulant Cost-and-Efficiency Sums Be Done?As module prices keep falling, encapsulant's share of module cost has risen by default. In this eighth article of our PV encapsulant series, we use 2026 public prices to work through three sums: what the encapsulant in a module is worth; how much reducing grammage, replacing POE with EPE and differentiating front and rear can each save; and how many watts of gain \"efficiency\" solutions such as white and down-converting films need to cover their premium. Finally, we flag the sum most easily overlooked: reliability.
• From PERC to TOPCon, HJT and BC: Every New Cell Technology Sets Encapsulant a New ExamAlmost every encapsulant upgrade has a change in cell or module technology behind it. In this seventh article of our PV encapsulant series, we follow the path from PERC through bifacial glass-glass, TOPCon, HJT and BC to see the new questions each generation put to encapsulant, from PID to UV, from water barrier to corrosion, and on to rear-side insulation, and draw on research from Kiwa PVEL, Fraunhofer ISE and UNSW to discuss what encapsulant can and cannot fix.
• Why Does the Same Roll of Encapsulant Behave Differently on Two Lines? Encapsulant and the Lamination ProcessAll five of the encapsulant's jobs are \"completed\" in the laminator, so the same good roll can give different results under a different lamination profile. In this sixth article of our PV encapsulant series, we start from how a laminator works, break down the evacuation, pressing and curing stages, use measured data to show why degree of cure is a function of \"time × temperature\", compare lamination of EVA, POE and glass-glass modules, and set out the causes of and fixes for common problems such as bubbles, cell shift, squeeze-out and under-cure.
• Is a "Passing" Degree of Cure Really Enough? Key PV Encapsulant Indicators and Test MethodsAn encapsulant technical agreement or test report often lists a dozen or more indicators. Which matter most? How are the numbers measured? And what does each pass line really mean? In this fifth article of our PV encapsulant series, we group the indicators by the "five jobs" and, drawing on the association standards T/CPIA 0004—2017 (EVA encapsulant) and T/CPIA 0071—2024 (co-extruded encapsulant), explain the test methods, pass lines and common pitfalls for degree of cure, peel strength, transmittance, volume resistivity, water vapour transmission and post-ageing performance.
• A Short Process Where Consistency Is Everything: How a Roll of PV Encapsulant Is MadeFormulation sets an encapsulant's ceiling; manufacturing decides whether it reaches that ceiling consistently. In this fourth article of our PV encapsulant series, we walk down an encapsulant line (compounding, low-temperature extrusion, embossing and cooling, haul-off and thickness gauging, winding and slitting, and packaging) and focus on pre-crosslinking, shrinkage, grammage uniformity and co-extrusion layer control, and what each looks like at the module plant when it goes out of control.
• Same Resin, Very Different Films: Inside the Resin and Additive Formulation of PV EncapsulantsTwo encapsulant makers can buy the same EVA or POE resin yet produce films that differ widely in crosslinking, adhesion and ageing resistance; the difference lies in the formulation. In this third article of our PV encapsulant series, we break a film down into \"resin base + four classes of additives\": the trade-offs in EVA's VA content and melt index, why POE resin has long been a bottleneck, what crosslinkers, silane coupling agents, anti-ageing additives and functional additives each do, and why formulation is an art of balance.
• Still Mixing Up EVA, POE and EPE? A Complete Guide to the PV Encapsulant FamilyTransparent EVA, white EVA, POE, co-extruded EPE and down-converting films, plus niche routes such as PVB, TPO and silicone: PV encapsulant has long since stopped being a single material. In this second article of our PV encapsulant series, we use two threads, "resin base + functionalisation", to sort out the family: which of the five jobs from the previous article each member does best, where its weaknesses lie, which modules it suits, and why the market has moved in recent years from EVA dominance to several routes side by side.
• Only 3%–4% of the Cost, Yet the Safety Net for 25 Years: What Does PV Encapsulant Actually Do?Encapsulant accounts for only about 3%–4% of module cost and all but disappears after lamination, yet it does five jobs at once (adhesion, light transmission, insulation, barrier and cushioning), and once it fails it can hardly be repaired. In this first article of our PV encapsulant series, we start from where encapsulant sits in the module and work through the principle behind each of the five jobs, the key indicators for each, and what goes wrong in the module when a job is not done.
• "China-Made Pellets" for POE Encapsulants: After Going from Zero to One, How Far Has Localisation Come?Three years ago the PV industry was scrambling for POE pellets; today China's nominal POE capacity is about 700 kt a year, imports are falling, and Sinopec Maoming has exported POE to North America for the first time. We review the three barriers behind the bottleneck, progress at each pellet plant, four sober facts about mass production, how film makers are \"swapping the core\", and a four-layer validation approach for introducing domestic pellets.