EN IEC 62788-1-1 Measurement Procedures for Materials Used in Photovoltaic Modules - Part 1-1: Capsules - Polymeric Materials Used for Encapsulation

The main purposes of the encapsulant, defined in the standard “EN IEC 62788-1-1 Measurement procedures for materials used in photovoltaic modules - Part 1-1: Encapsulators - Polymeric materials used for encapsulation”, which is based on a European standard and later published by the International Electrotechnical Commission (IEC), are:

• Optically coupling the cell to external radiation
• Mechanically connecting module components and holding them in their relative positions
• Electrically isolating module components
• Thermally bonding module components
• Chemically protecting module components (for example, by limiting the concentration and transport of water or oxygen)

This part of the IEC 62788 standard defines test methods and reporting requirements for the properties (optical, mechanical, electrical, thermal and chemical) of non-rigid polymeric materials (e.g. polyethylene-co-vinyl acetate, EVA) intended for use as polymeric encapsulants in terrestrial photovoltaic (PV) modules.

Typically, encapsulants are considered functional insulators, meaning that they provide electrical insulation when present, but may not meet the requirements for reliable insulation.

The requirements for reliable insulation are defined in the standards IEC 61730-1 and IEC 62788-2-1.

The test methods described in this standard define how to characterize encapsulation materials in a way that is representative of how they will be used in the module. This includes combination with other components such as front sheets, back sheets, adhesives, edge seals or glass. The methods described in this standard support and complement the safety and performance related tests defined at the PV module level as defined in IEC 61730-2 and IEC 61215-2. This standard also defines test methods for the evaluation of the general material properties of polymeric encapsulation materials.

The test methods described in this standard can be used to:

• Data sheet reporting (aids module design or materials research and development).
• Process and production control (e.g. incoming or outgoing inspection).
• Implementation in module security and design type qualification protocols.
• Reliability and durability study/standards development.

For the purposes of this standard, the following terms and definitions apply:

• Adhesive failure is the dissolution of the bond between the adhesive and the substrate (distinct from cohesive failure within the adhesive material).
• Cohesive failure is failure that occurs when cracks propagate through the mass of a material.
• Encapsulant is the material used between the substrate and the top layer to provide environmental protection for photovoltaic cells in the photovoltaic module.
• Fickian is the descriptive term for a material in which the diffusion coefficient is constant, independent of the concentration of the permeant within experimental uncertainty.
• The module junction box is a combination of parts such as boxes, covers, cover plates, box extensions, accessories, etc. It provides adequate protection against external influences after assembly and installation on the photovoltaic module in normal use and defined protection against contact with enclosed live parts from any accessible direction.
• Polymeric materials are materials that are natural or synthetic. They consist primarily of chained monomers, monomer combinations, or conjugated polymers and may contain crosslinking agents, fillers, colorants, and other additives.
• A release layer is a 50 μm to 250 μm thick film material deposited onto a stack of layers prior to lamination to neutralize adhesion between interfaces. Examples of suitable release materials include fluoropolymer sheets and silicone-treated sheets.
• Reliable insulation is the system that provides protection against electric shock in the final application (with the requirements for thickness, thermal durability and resistance of the material to environmental stress factors).
• Required testing is the testing that must be performed, including module qualification.
• The storage module is the actual part of the complex module.
• The substrate is the combination of the outer layer of the PV module, which is located behind the PV module as the substrate and protects the internal components of the module from external stresses and weather conditions and provides electrical insulation between live parts and accessible surfaces.
• The top layer is the outer layer (joint) of the PV module, located as the top layer on the front side of the PV module and protects the internal components of the module from external stresses and weather conditions, as well as providing electrical insulation between live parts and accessible surfaces.

To comply in principle with this standard, the following test procedures are used to evaluate the optical, mechanical, electrical, thermal and chemical properties of polymeric materials designed for use in terrestrial PV modules as polymeric encapsulation materials.

The universal characterization form provides standardized comprehensive reporting of properties frequently considered for encapsulating agents, including those found in the data sheet.

Our organization has a strong staff that closely follows the developments in the world in the field of science and technology and constantly improves itself. Among the numerous test, measurement, analysis and evaluation studies provided for businesses in various sectors, there are also test services in accordance with the standard “EN IEC 62788-1-1 Measurement procedures for materials used in photovoltaic modules - Part 1-1: Capsules - Polymeric materials used for encapsulation”.