Built To Stand The Test Of Time: GCL SI TOPCon Modules
Source：TaiyangNews
Vertically integrated PV module company discusses how to ensure quality & reliability with continuous advancements
GCL SI shared insights into the company’s strategies for maintaining the long-term quality and reliability of its TOPCon PV modules. (Photo Credit: TaiyangNews)
Published on:
A key metric for evaluating the quality and reliability of conventional TOPCon modules is their warranted power output over a 30-year lifespan, a factor that significantly influences the long-term levelized cost of electricity (LCOE) of an installed plant. The inability of vertical supply chain integration – spanning from polysilicon to cell production – to fully guarantee long-term module reliability underscores the critical importance of continuous process improvements and stringent quality control during module manufacturing.
GCL SI, a leading Chinese vertically integrated TOPCon module manufacturer, boasts an impressive annual production capacity of 420,000 tons of FBR polysilicon, 58 GW of wafers, 20 GW of n-type cells, and 30 GW of PV modules. At the recent TaiyangNews Reliable PV Module Design 2024 Conference, Rojen Malachi, Technical Support Director (Europe) at GCL SI, shared insights into the company’s strategies for maintaining the quality and reliability of its PV modules (see GCL SI presentation here).
Cell level advancement: The adoption of multiple technologies, including the LECO metallization process and SMBB technology, at the cell fabrication stage, improves TOPCon cell-level efficiency level. (Photo Credit: TaiyangNews)
Cell-Level Improvements
The core innovation of the Tunneling Oxide Passivating Contact (TOPCon) cell structure lies in its rear-side passivation technology. This involves an ultra-thin tunneling oxide layer and subsequent polysilicon layer deposition with a follow-up n-type doping, forming a passivating contact structure with excellent passivation properties. According to GCL SI, the Laser-Enhanced Contact Optimization (LECO) process ensures precise control of heat-affected areas during the metallization stage, minimizing power loss and the formation of microcracks while enhancing cell efficiency.
The company has also adopted advanced super multi-busbar (SMBB) technology, utilizing 16 round ribbons. This innovation reduces the current path between busbars, decreases internal resistance, and leverages the light-trapping effect of round ribbons to boost power output compared to flat ribbons. GCL SI reports a 1% to 1.5% improvement in cell wattage attributed to these advancements, which translates to a 0.4% to 0.6% increase in TOPCon module efficiency.
Process Improvements
GCL SI has implemented a non-destructive TOPCon cell-cutting process, which avoids creating exposed cutting surfaces along the cell edges. This approach reduces the risk of welding cracks and fragments while narrowing the cell-to-cell distance from 2 mm to 0.8 mm. The result is improved structural stability, higher production yields, and lower manufacturing costs.
Manufacturing quality control: GCL SI follows a strict manufacturing quality control framework spanning across incoming quality control to final quality control. (Photo Credit: TaiyangNews)
Quality Control
In addition to cell and process-level advancements, GCL SI employs a rigorous quality control framework throughout its manufacturing process. It begins with Incoming Quality Control (IQC) for raw materials such as glass, cells, backsheets, EVA, frames, and junction boxes. Specific stress tests, including TC100 + HF10 for glass and DH1000 + HF10 + TC20 for junction boxes, validate the technical specifications of these materials.
To enhance production efficiency and product quality, GCL SI has integrated robotics and AI technology into its PV module manufacturing processes. These innovations have reduced labor costs while improving overall quality.
Validation
GCL SI validates the quality and reliability of its TOPCon modules through rigorous in-house and third-party testing. Finished modules undergo periodic stress tests, including PID, LID, LeTID, TC200, DH1000, and hail tests, at accredited facilities. Notably, GCL SI’s TOPCon modules have performed exceptionally well in industry benchmarks. In the 2024 Kiwa PVEL PV Module Reliability Scorecard, they demonstrated superior durability, achieving less than 0.21% LeTID degradation, below 2.74% degradation after TC600, and under 0.79% degradation following sequence tests that include dynamic load evaluations.