German solar equipment manufacturer RENA Technologies GmbH has announced plans to initiate legal proceedings in the United States and India against what it describes as unauthorized use of its patented water cap technology. The infringement, according to the company, stems from certain unnamed Chinese equipment suppliers involved in the production and sale of machines used in solar cell manufacturing.
The contested technology—central to RENA’s Function Layer (RFL) process—is covered under patent EP 2 491 584 B1. It enables single-sided etching in solar cell production by protecting the upper side of a wafer with a controlled water cap or liquid film, allowing precise chemical treatment on only one surface. This approach has become an industry standard in advanced solar cell designs, particularly in Passivated Emitter and Rear Cell (PERC) and Tunnel Oxide Passivated Contact (TOPCon) technologies.
Allegations of Widespread Unauthorized Use
RENA Technologies claims to have gathered evidence showing that certain manufacturers are building and promoting etching equipment that utilizes this patented process without proper licensing. While RENA has not disclosed the names of the offending companies, it confirmed that infringements were detected in both U.S. and Indian markets, where solar cell production has expanded significantly in recent years.
“We have invested considerable resources over the past decade to develop and refine the RFL technology,” a spokesperson from RENA said. “Unauthorized replication of our patented process not only undermines our intellectual property but also compromises the principles of fair competition within the solar manufacturing industry.”
Global Footprint and Industry Relevance
Over 630 machines featuring RENA’s RFL technology have been deployed globally, reinforcing the widespread adoption and commercial value of the innovation. The company has highlighted that the patented water cap method is now a critical enabler in high-efficiency solar cell manufacturing, particularly as the industry transitions from PERC to more advanced TOPCon architectures.
The technology’s impact extends beyond performance. By allowing single-side chemical processing without physical contact or damage to the solar wafer, it improves production yield, reduces contamination, and lowers overall manufacturing costs.
Legal and Industry Context
The solar sector has seen a notable rise in patent-related disputes as competition intensifies, especially around next-generation technologies. Several leading Chinese solar manufacturers, including Trina Solar and JA Solar, have recently filed lawsuits in Europe and the U.S. over intellectual property linked to TOPCon advancements.
RENA’s legal initiative reflects a broader trend within the solar industry to safeguard innovation amid increasing global demand for cleaner energy and more efficient photovoltaic solutions.
Legal experts note that the outcome of this case could set a precedent for cross-border IP enforcement in the renewable energy space, especially between European and Asian players. With growing investments in solar infrastructure in India and North America, ensuring robust IP protections is seen as essential to encourage research and attract global partnerships.
Looking Ahead
RENA Technologies’ move to protect its patented water cap system sends a strong signal to the global solar industry about the value of innovation and the importance of enforcing intellectual property rights. As the case unfolds, stakeholders across the manufacturing and legal sectors will be watching closely to see how courts in the U.S. and India respond to these claims.
If successful, the legal action could lead to stricter enforcement of patent licensing in the rapidly evolving solar equipment market and reinforce the importance of respecting proprietary technologies in sustainable energy development.