EN IEC 62787 pdf download

EN IEC 62787 pdf download.CONCENTRATOR PHOTOVOLTAIC (CPV) SOLAR CELLS AND CELL ON CARRIER (CoC) ASSEMBLIES – QUALIFICATION
1 Scope
This document specifies the minimum requirements for the qualification of concentrator photovoltaic (CPV) cells and Cell on Carrier (CoC) assemblies for incorporation into CPV receivers, modules and systems. The object of this qualification standard is to determine the optoelectronic, mechanical, thermal, and processing characteristics of CPV cells and CoCs to show that they are capable of withstanding assembly processes and CPV application environments. The qualification tests of this document are designed to demonstrate that cells or CoCs are suitable for typical assembly processes, and when properly assembled, are capable of passing IEC 621 08. This document defines qualification testing for two levels of concentrator photovoltaic device assembly: a) cell, or bare cell; and b) cell on carrier (CoC). NOTE Note that a variety of alternate names are used within the industry, such as solar cell assembly, receiver, etc.
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC TS 61 836 and IEC 621 08 apply, as well as the following. ISO and IEC maintain terminological databases for use in standardization at the following addresses: • IEC Electropedia: available at http://www.electropedia.org/ • ISO Online browsing platform: available at http://www.iso.org/obp 3.1 bare cell refers to a semiconductor die level. The physical form during a commercial transaction may be a separated solar cell, a diced wafer on tape, or even a processed wafer. The one common denominator is that the qualified configuration is completely unprotected and not ready for interconnection with the rest of a CPV module Note 1 to entry: For this qualified configuration, the customer is responsible for all integration and assembly. Note 2 to entry: For some qualification tests, bare cells are mounted on a substrate, heatsink, or other type of carrier (see Figure 1 c). This provides mechanical stability, robust electrical contacts, and appropriate thermal management, but it is not considered in the bare solar cell qualification. 3.2 Cell on Carrier CoC cell bonded and interconnected with a cell carrier, at a minimum (see Figure 1 b). This is a relatively small, assembled unit in a relatively complete and rugged package
4 Operating environment
CPV systems are typically designed to be operated in the “open-air climates” defined in IEC 60721 -2-1 except the Polar one. Depending on the details of the system design, the bare solar cells and CoCs may or may not be protected from exposure to damp heat, freezing, condensation, and other elements of the CPV application environment. Figure 2 shows schematics of two CPV system designs.Regardless of the specific design approach taken, the high incident irradiance impinging on the solar cells in CPV systems will cause them to operate at (local) temperatures that can be significantly higher than the maximum ambient temperature specified for the system as a whole.
5 Sampling
Device samples used in qualification testing shall be selected randomly in accordance with IEC 61 1 93-2 from a minimum of two manufacturing batches and subjected to the defined Process Identification Document (PID) manufacturing and screening steps.The number of devices to be tested in each qualification test shall not be less than the sample sizes specified in Clause 8. In order to provide statistical meaning to the number of devices, IEC 61 1 93-2 has been used since it assigns a defect probability as a function of number of samples. The samples for each test of Table 1 and Table 2 shall be chosen randomly from the qualification lot. The qualification lot shall be a production lot of at least 1 000 bare cells/CoCs. The production lot shall be formed from at least two epitaxial runs and three metal/ARC depositions carried out in different weeks.