Flexible Module Encapsulation Opportunities
While near-term opportunities for BIPV encapsulation are centered mostly on rigid modules, NanoMarkets’ research indicates that flexible module encapsulation will be the long-term growth area for high margin opportunities for new materials in BIPV applications.
And although current flexible modules are mostly limited to a-Si modules with some CIGS-based modules now becoming more routinely available, flexible high efficiency CIGS module growth will drive the majority of growth for encapsulation in the foreseeable future in the flexible module area.
Flexible substrates and encapsulation have several inherent advantages compared to rigid substrates in BIPV applications.
• The biggest advantage of flexible modules is their ability to conform to curved façade surfaces.
• Another major advantage is module weight compared to rigid modules. Modern rigid modules weigh 10 to 30 kg/m2, while flexible modules are on the order of 3 to 5 kg/m2.
• Flexible modules also have an aesthetic advantage over rigid modules, which contain iconic but unattractive silicon wafers or polysilicon modules in rectangular framed modules. In contrast, the latest flexible BIPV products can be ordered in custom shapes for application to cover an entire façade with very inconspicuous seams and thin-film absorbers that present an attractive uniform exterior surface.
While flexible thin-film-based modules have many advantages over rigid modules for BIPV applications in theory, several practical issues have greatly limited flexible BIPV adoption to date. Reliability issues, high cost, and poor efficiency have limited the appeal and use of flexible BIPV to date.
The limitations of current encapsulation materials are at the heart of all of these concerns. From an efficiency perspective, until recently, flexible BIPV has been limited to a-Si, which has less stringent encapsulation needs for oxygen and moisture penetration than high efficiency CIGS modules. And because flexible BIPV has generally been limited to a-Si, the efficiency has been capped for these modules around 8-9 percent.