BS EN IEC 62788-6-2:2020
$142.49
Measurement procedures for materials used in photovoltaic modules – General tests. Moisture permeation testing of polymeric materials
| Published By | Publication Date | Number of Pages |
| BSI | 2020 | 24 |
This document provides methods for measuring the steady-state water vapour transmission rate (WVTR), water vapour permeability (P), diffusivity (D), solubility (S), and moisture breakthrough time (Ƭ10) (defined as the time to reach 10 % of the steady state WVTR) for polymeric materials such as encapsulants, edge seals, frontsheets and backsheets. These measurements can be made at selected temperatures and humidity levels as deemed appropriate for evaluation of their performance in PV modules. Measurement is accomplished by inspection of the transient WVTR curve and by fitting it to a theoretical Fickian model. This document is best applied to monolithic films. If multilayer films are used, the D and S values are only apparent values, but the steady-state values can still be measured.
This document was written for the measurement of water permeation, but it can equally be used for other permeants such as O2. In this case the same diffusion equations, fitting procedures, and scaling arguments are used.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 2 | undefined |
| 5 | Annex ZA(normative)Normative references to international publicationswith their corresponding European publications |
| 6 | English CONTENTS |
| 7 | FOREWORD |
| 9 | INTRODUCTION |
| 10 | 1 Scope 2 Normative references |
| 11 | 3 Terms, definitions and symbols 3.1 Terms and definitions 3.2 Symbols |
| 12 | 4 Apparatus 5 Test specimens |
| 13 | 6 Procedure |
| 14 | 7 Calculations 7.1 Determination of diffusivity and solubility of moisture Figures Figure 1 – Diagram of a diffusion cell |
| 15 | 7.2 Determination of breakthrough constant |
| 16 | 7.3 Variable temperature measurement |
| 17 | 7.4 Variable relative humidity measurement 8 Test report |
| 19 | Annex A (informative)Example data A.1 Example of Fickian diffusion |
| 20 | A.2 Example of failed measurement of Fickian diffusion Figure A.1 – Example of Fickian diffusion in EVA at 85 °C and 100 % RH with a 2,84 mm thick film |
| 21 | A.3 Example of non-Fickian diffusion Figure A.2 – Example of a failed data set for Fickian diffusion in polyethylene terepthalate at 22 °C and 100 % RH |
| 22 | Figure A.3 – Example of non–Fickian diffusion in a desiccant filled polyisobutylene material used as an edge seal |
| 23 | Bibliography |
