Unveiling the origin of metal contact failures in TOPCon solar cells through accelerated damp-heat testing

IF 6.3 2区材料科学 Q2 ENERGY & FUELS

Solar Energy Materials and Solar Cells Pub Date : 2024-09-30 DOI:10.1016/j.solmat.2024.113188

Xinyuan Wu , Chandany Sen , Xutao Wang , Yuhao Cheng , Ruirui Lv , Hao Song , Yuanjie Yu , Baochen Liao , Sheng Ma , Muhammad Umair Khan , Alison Ciesla , Bram Hoex

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引用次数: 0

Abstract

Tunnel oxide passivated contact (TOPCon) solar cells are expected to dominate the global photovoltaic market in the coming decade thanks to rapid advancements in power conversion efficiency (PCE). However, there are concerns about the reliability of TOPCon modules, particularly in hot and humid conditions. The current module-level fundamental analysis strategies for TOPCon solar cells provide too slow feedback for rapid process development. This study explores the degradation of metal contacts in TOPCon solar cells under accelerated testing conditions of 85 °C and 85 % relative humidity (DH85). The degradation was induced by two commonly used sodium-related salts, sodium bicarbonate (NaHCO₃) and sodium chloride (NaCl), in the testing of the solar cells. When applied to the front side, NaHCO₃ caused a ∼5%_rel PCE reduction after 100-h DH85 exposure, while NaCl leads to a more significant ∼92%_rel PCE reduction. The primary cause of degradation is a considerable increase in series resistance (R_s), likely due to electrochemical reactions within the Ag/Al paste. When the salts are applied to the rear of the TOPCon solar cell, the degradation becomes more complex. NaHCO₃ increases recombination and results in a deterioration of the contact, resulting in a ∼16%_rel PCE reduction after 100-h DH85 testing. Conversely, NaCl primarily causes a decline in open-circuit voltage (V_oc) and a ∼4%_rel PCE loss. This manuscript primarily investigates degradation mechanisms related on the rear side, with a focus on significant oxidation occurring at the interface between Ag and Si. These findings highlight the susceptibility of TOPCon solar cells to contact corrosion, emphasizing the electrochemical reactivity of metallisation as a potential risk for long-term TOPCon module operation. This study provides crucial insights into TOPCon cell degradation mechanisms, which are essential for optimising performance and enhancing the long-term reliability of TOPCon modules.

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通过加速湿热测试揭示 TOPCon 太阳能电池金属触点故障的根源

由于功率转换效率（PCE）的快速发展，隧道氧化物钝化接触（TOPCon）太阳能电池有望在未来十年内主导全球光伏市场。然而，人们对 TOPCon 组件的可靠性表示担忧，尤其是在炎热潮湿的条件下。目前针对 TOPCon 太阳能电池的模块级基本分析策略提供的反馈太慢，不利于快速工艺开发。本研究探讨了 TOPCon 太阳能电池中的金属触点在 85 °C 和 85 % 相对湿度 (DH85) 的加速测试条件下的降解情况。在太阳能电池测试中，两种常用的钠盐（碳酸氢钠 (NaHCO3) 和氯化钠 (NaCl)）诱发了降解。在正面使用 NaHCO3 时，经过 100 小时的 DH85 暴露后，NaHCO3 导致的 PCE 降低了 5%，而 NaCl 导致的 PCE 降低更为显著，达到 92%。降解的主要原因是串联电阻 (Rs) 显著增加，这可能是由于银/铝浆内的电化学反应造成的。当盐类应用于 TOPCon 太阳能电池的背面时，降解变得更加复杂。NaHCO3 会增加重组，导致接触恶化，在 100 小时的 DH85 测试后，PCE 下降了 16%。相反，NaCl 则主要导致开路电压（Voc）下降，PCE 下降 4%。本手稿主要研究与背面有关的降解机制，重点是 Ag 和 Si 之间的界面发生的显著氧化。这些发现凸显了 TOPCon 太阳能电池对接触腐蚀的敏感性，强调了金属化的电化学反应性是 TOPCon 模块长期运行的潜在风险。这项研究提供了有关 TOPCon 电池降解机制的重要见解，这对于优化 TOPCon 组件的性能和提高其长期可靠性至关重要。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Solar Energy Materials and Solar Cells 工程技术-材料科学：综合

CiteScore

12.60

自引率

11.60%

发文量

513

审稿时长

47 days

期刊介绍： Solar Energy Materials & Solar Cells is intended as a vehicle for the dissemination of research results on materials science and technology related to photovoltaic, photothermal and photoelectrochemical solar energy conversion. Materials science is taken in the broadest possible sense and encompasses physics, chemistry, optics, materials fabrication and analysis for all types of materials.