The long-term reliability of silicon heterojunction (SHJ) photovoltaic modules is pivotal for their outdoor deployment and commercial viability. However, prevailing reliability assessments often rely on single-factor aging tests, which inadequately represent the synergistic stresses encountered in real-world climates. This study emphasizes the critical necessity of multi-stress coupling aging for a true durability evaluation. We conducted comparative 1000-h aging tests on SHJ modules and three types of encapsulants (EVA, dsEVA, and POE) under both damp-heat (DH) and UV-damp-heat (UVDH) coupling conditions. The results demonstrated that degradation mechanisms and severity are profoundly amplified under coupled stresses. Under UVDH, massive moisture ingress caused deacetylation in EVA/dsEVA, generating acetic acid that corroded solar cells, solder ribbons, and electrodes. Conversely, POE films suffered a severe loss of interfacial adhesion, leading to pronounced delamination. A systematic analysis of optical, mechanical, and chemical property changes in the films revealed a direct correlation between encapsulant degradation and module performance loss. Critically, the degradation under UVDH coupling conditions was significantly more severe than under DH alone, highlighting the synergistic acceleration effect of combined ultraviolet radiation and humidity. This work conclusively shows that multi-stress coupling tests are imperative for an accurate reliability assessment. It is recommended to integrate such coupled-aging protocols into standard testing regimes to better predict module lifetime, guide encapsulant material optimization, and ensure sustainable field performance.
- Open Access
- Article
Multi-Stress Coupling Aging of Silicon Heterojunction Modules: Encapsulant Degradation and Reliability Implications
- Hong Luo 1,
- Yu Hu 2,*,
- Qi Deng 1,
- Xiaoying Ye 1,
- Yulin Zhang 2,
- Cheng Huang 1,
- Tao Chen 3,
- Lei Li 4,
- Wenzhu Liu 5,*,
- Jian Yu 1,*
Author Information
Received: 08 May 2026 | Revised: 07 Jun 2026 | Accepted: 12 Jun 2026 | Published: 17 Jul 2026
Abstract
Graphical Abstract
Keywords
silicon heterojunction solar cell | aging test | multi-environmental coupling | long-term reliability
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