As the solar industry transitions from Mono PERC to TOPCon technology and countries emphasize domestic manufacturing, we have seen a surge in intellectual property disputes related to TOPCon solar technology in recent months, particularly in China, Europe, and the U.S.

TOPCon (tunnel oxide passivated contact) technology is an advanced solar cell architecture that has gained popularity rapidly because it enhances energy yield and efficiency compared to Passivated Emitter and Rear Cell (PERC) technology.

The increasing adoption of TOPCon technology has also given rise to patent infringement claims by TOPCon cell manufacturers.

Recently, the European Patent Office (EPO) confirmed the validity of JA Solar’s patents concerning TOPCon solar cell technology, strengthening its position in its ongoing litigation against Astronergy, another Chinese solar manufacturer.

JA Solar filed two lawsuits in the European Unified Patent Court. The first patent relates to tunneling silicon oxide layers and the doped polysilicon layer used on the back surface of TOPCon solar cells. JA Solar claims this patent is enforceable until 2034 across several European countries, including Germany, the UK, and France.

The second patent relates to the design of the electrodes and lead structures used in these products has an expiry date of 2035, according to JA Solar.

Several similar lawsuits were filed earlier this year. In April, Maxeon Solar Technologies initiated three patent infringement lawsuits related to its TOPCon technology. Filed in the Eastern District of Texas, these lawsuits target Hanwha Q CELLS, Canadian Solar, and REC Solar Holdings and allege unauthorized use of its patents.

U.S.-based First Solar has also been considering legal action against competitors found to be infringing its patents acquired through its 2013 purchase of TetraSun. The patents, covering proprietary cell architecture and manufacturing processes, are valid in various countries, including the U.S., Canada, and Japan, with expiration dates extending to 2030.

More recently, Chinese module manufacturer Trina Solar filed a patent infringement lawsuit against three U.S. subsidiaries of Canadian Solar in the U.S. District Court for the District of Delaware. The lawsuit claims that Canadian Solar’s subsidiaries violated two of Trina’s U.S. patents pertaining to TOPCon technology. Canadian Solar has dismissed the lawsuit as frivolous.

Trina Solar has also lodged a complaint with the U.S. International Trade Commission against two other companies – China-headquartered Runergy and India-based Adani Green Energy, alleging that they have imported and sold products in the U.S. that infringe on Trina’s TOPCon patents. Trina is seeking a limited exclusion order and cease-and-desist orders to halt the import of these products.

In a counter move, Runergy has initiated legal proceedings at the U.S. Patent and Trademark Office to challenge the validity of two of Trina Solar’s patents, claiming they are unpatentable. Runergy argues that these patents, purchased by Trina in February 2024, attempt to cover technology already disclosed in a 2013 publication by the Fraunhofer Institute for Solar Energy.

Indian solar module manufacturers have also leaned towards TOPCon module technology over its other mainstream rival HJT (Heterojunction) because the former performs better in terms of degradation rate and temperature coefficient. However, companies need to exercise caution and make sure intellectual properties are not infringed in a rapidly evolving chaotic market.

JA Solar and Trina Solar were among the top solar module suppliers in the calendar year 2023, according to Mercom’s India Solar Market Leaderboard 2024.