Encapsulation Technologies

Encapsulation technology is used to protect the solar cells from environmental influences such as moisture, dirt and mechanical stress and to improve the optical and thermal performance as well as the reliability of the PV module. For this purpose, the cells are encapsulated in a transparent polymer between two glass plates or between a glass plate and a backsheet in the lamination process. The polymer melts under vacuum and high temperature and forms a stable bond with the cells. 

There are various encapsulation technologies that can be used depending on the application and module type, such as glass-glass and glass-foil encapsulation, lightweight modules or 3D lamination. The choice of encapsulation materials and the optimization of the lamination process have an impact on lamination time, process costs, long-term stability and module performance. Fraunhofer ISE offers various services and research projects for the development and improvement of encapsulation technology.

Our R&D-Activities on the Topic "Encapsulation Technologies" Include:

• Bill-of-Material (BOM)-Development
• Process Development
• Lightweight Module Technology
• Dimensional Modules
• Material Characterization

In the bill-of-materials (BOM) development of PV modules, the material combinations and module design are tailored to the requirements and application of the solar module. Aspects such as performance, reliability, costs and processability are taken into account. BOM development includes the selection and testing of different materials for the encapsulation, the interconnection, the front and rear of the PV module and the cell interconnection. BOM development can be supported by software tools for performance prediction and optimization, costing and business models as well as comprehensive characterization methods in accredited laboratories.

Our Services

• Development of optimized BOMs for new and sensitive cell technologies such as HJT or perovskite silicon tandem solar cells
• Production of small samples and large modules up to 2.2 m x 1.2 m 
• Testing of samples in accredited laboratories up to certification preparation 
• Customer and material-specific process adaptations 
• Large material database and material recommendations for the respective application 
• Development of BOMs with new material concepts (metals, fiber composites, ...) 
• Detailed characterization of materials and modules

Process development for the production of PV modules includes the adaptation and optimization of encapsulation processes for solar cells in the lamination or autoclave process. Aspects such as process speed, process temperature, process pressure, process time and throughput are taken into account. The aim is to produce defect-free and reliable PV modules in a process that is optimized in terms of costs, throughput or material usage. Process development is supported by industrial equipment, simulation tools and digital models that enable rapid adjustment and testing of various parameters. Process development aims to increase the quality and reliability of PV modules and reduce manufacturing costs.

Our Services

• Development of processes for new materials, material classes and module structures 
•  In-house test days to evaluate materials and processes 
•  Lamination process adaptation to industrial laminators for high throughput 
•  Process development for autoclave processes 
•  Development of processes and materials for the production of 3D curved modules 
•  Cost and LCA evaluation of process adaptations

In lightweight solar module technology, we focus on particularly lightweight yet robust and efficient solar modules. Lightweight solar modules use special materials and construction techniques that make it possible to reduce the weight of the modules without compromising on durability or performance. This increases the range of possible uses in various applications and simplifies installations. Through continuous research and development, new materials and technologies are explored to improve the efficiency of solar modules and extend their lifespan.  

Our Services

• Use of thin and flexible materials such as films or fiber-reinforced materials 
•  Adaptation of interconnection and integration technology 
• Development of hail-resistant lightweight modules
  
•  Optimization of ultra-light module structures with a weight < 600 g

Integrated photovoltaics often require specially shaped solar modules that can, for example, be a special architectural feature for buildings or adapt to the aerodynamics and design of vehicles. These curved or 3D-shaped modules require special manufacturing processes in order to be aesthetically pleasing but also durable. In our laboratories, we develop the technologies to be able to produce such shaped modules with high throughput. We use various processes, from PV module lamination adapted for shaped modules, to classic glass autoclave processes and new encapsulation processes with shaped fiber components. These processes open up new possibilities for the integration of solar energy in architecture, vehicles and other areas where flat modules are not suitable.

Our Services

• Shape-bound and shaping processes in the lamination process 
• Shape-free processes in the autoclave process 
• Development of material structures and interconnection designs

In the material characterization of materials for the production of solar modules, comprehensive investigations are carried out into the physical, chemical and electrical properties of the materials used. An important aspect is the determination of optical properties, such as absorption and transparency. This makes it possible to understand the behaviour of the light in the solar modules and to take measures to optimize the light yield. In addition, the structural properties of the materials are also examined in order to assess their mechanical stability and durability. This includes analyzing the material composition, crystal structure and defects in the material.  

Our material characterization includes a variety of analytical methods, including spectroscopic techniques, electrical measurement methods, X-ray diffraction, microscopy and chemical analysis methods. This comprehensive characterization enables us to gain important insights to drive the development and optimization of materials for the production of solar modules. 

Our Services

• Soxhlet for absolute determination of the degree of cross-linking of various common encapsulation materials such as EVA and POE 
• Dynamic mechanical analysis (DMA) to determine the storage modulus and the loss factor of the encapsulation materials as a function of temperature 
• Tensile test to determine the tensile strength, elongation and fracture energy of the encapsulation materials and the adhesion to different materials 
• And further tests to investigate damage to PV modules