Ageing

Aim:

The aim is to identify the driven factors for PV device ageing and model the ageing process under different stress levels.

Research development:

Damp-heat, thermal cycling and light soaking accelerated tests have been implemented at different stress levels in order to investigate the effects of temperature, humidity and light on ageing. Performance  are evaluated based on different characterisation methods, including I-V curves, EL images, differential scanning calorimetry (DSC) analysis of EVA, gel content extraction, adhesion between glass and encapsulant as well as encapsulant and backsheet, ATR analysis for humidity ingress, yellowness and whiteness analysis of backsheet and encapsulant. Mini-modules used for ageing tests are prepared and laminated at CREST. Effect of lamination condition on device ageing is investigated.

Main findings/impact:

1. Dose functions are developed to assess the combined stress level of different environmental stresses;

2. PV device power degradation is modelled by using environmental doses;

3. Degradation model of adhesion between EVA and backsheet is developed based on module micro-climatic stresses, i.e. water vapour pressure on the surface of module

 

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Contact: J. Zhu