Currently, the photovoltaic industry is accelerating its iteration towards efficient N-type battery technology, and heterojunction (HJT) cells have become a highly promising development direction due to their outstanding advantages such as high conversion efficiency, low temperature coefficient, and high bilayer ratio. However, due to the double-sided power generation structure used by HJT, low-temperature silver paste needs to be coated on both sides of the battery, resulting in much higher silver powder consumption than single-sided PERC cells. The high cost of silver powder has become a key bottleneck restricting its large-scale commercialization and further cost reduction. Driven by the core goal of continuously promoting "cost reduction and efficiency improvement" in the photovoltaic industry, it is urgent to find a "replacement" for silver powder.

Compared to silver powder, copper powder demonstrates a huge cost advantage at its extremely low price. However, the biggest inherent disadvantage of copper powder is its high susceptibility to oxidation. In electrode preparation and usage environments, its conductivity deteriorates sharply due to oxidation, making it difficult to meet the long-term reliable operation requirements of photovoltaic cells. Therefore, the silver coated copper powder technology, which combines cost advantages and potential performance guarantees, has emerged as an important exploration direction in the cost reduction path of double-sided structured batteries such as HJT.

Silver coated copper powder is formed by uniformly and continuously coating a layer of silver shell ranging from tens to hundreds of nanometers on the surface of copper powder, forming a typical "core-shell structure". This special structure allows the copper core to occupy the majority of the powder mass, significantly reducing the consumption of expensive silver metal. On the other hand, it endows silver copper powder with excellent properties similar to pure silver powder:

1. Antioxidant activity
The dense and chemically inert silver layer on the surface of silver coated copper powder acts as a physical barrier, effectively isolating the internal copper core from the external environment (oxygen, moisture), thereby significantly delaying the oxidation process of the copper core.

2. Conductivity: As a conductive filler in electrodes, silver coated copper powder can conduct current through an externally wrapped silver layer. In theory, a well coated silver shell ensures effective conduction of current on the electrode surface, providing high conductivity close to the surface of silver powder.

With the acceleration of technological iteration, especially in collaboration with emerging low-temperature battery processes such as HJT, the industrial application potential of silver coated copper powder is gradually emerging. However, the introduction of copper element has raised concerns about its long-term reliability. How to ensure that copper does not oxidize or migrate during the outdoor operation of silver clad copper batteries for many years is a common concern for both paste and component factories. In addition, the current mainstream chemical plating method has a complex preparation process, requiring precise control of parameters such as plating solution composition, reaction temperature, and time in order to produce structurally stable and uniformly coated silver coated copper powder. Therefore, whether silver coated copper powder can ultimately replace photovoltaic silver powder on a large scale remains to be tested in practice. But it can be confirmed that with the continuous optimization of preparation technology, silver coated copper powder is still one of the important exploration paths to promote the continuous cost reduction of the photovoltaic industry.

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