TOPCon Patent War Heating Up: Trinasolar & Canadian Solar New Additions

The ongoing patent war between the world’s leading solar PV manufacturers for TOPCon solar cell technology seems nowhere near an end. Of late, there has been a spurt of patent lawsuits being filed or being quashed, globally.  

The latest in the list is Trinasolar’s patent infringement complaint against Canadian Solar in the US District Court for the District of Delaware, filed on October 8, 2024. Trina has named 3 of the latter’s US subsidiaries as directly or indirectly infringing on 2 of its TOPCon-related US patents.  

Canadian Solar has now responded calling it a ‘frivolous lawsuit.’ The General Counsel, Americas for Canadian Solar’s Modules and Systems Solutions business Adam Walters said, “Canadian Solar respects and takes very seriously its own intellectual property rights and those of third parties. In our view, this is a frivolous lawsuit, and we expect the court will find that our proprietary TOPCon technology does not infringe on the patents claimed by Trina.”  

This move follows Trina accusing Runergy Alabama of infringing on 2 of its TOPCon patents. In response, Runergy recently appealed to the US Patent and Trademark Office (USPTO) to declare these Trinasolar’s TOPCon-related patents as unpatentable (see Runergy Wants USPTO To Cancel Trinasolar’s TOPCon Patents). 

Runergy claims it does not practice the patents that Trinasolar is asserting and that the latter did not file the same until more than a year after Fraunhofer ISE published its work in 2013.  

The web of TOPCon patent infringement stories is spreading now as more and more names get added to the list in Europe as well as China, staking claim to the technology.  

A few days back, leading Chinese solar PV company Tongwei Solar’s request to invalidate 2 patents of Maxeon Solar Technologies was rejected by the State Intellectual Property Office in China.    

However, according to Yicai Global, Tongwei still has the option to pursue the lawsuit with the Beijing Intellectual Property Court within 3 months from the date of receipt of the decision.  

Notably, Maxeon Solar Technologies filed a patent infringement lawsuit against Chinese manufacturer Tongwei Solar in Germany accusing it of infringing on its shingled solar cell technology (see Another Patent Fight Brewing).  

Back then, Tongwei stated that the Maxeon lawsuit was worth €1 million, accounting for about 0.0128% of the company’s latest audited net assets, hence it won’t have a significant material impact. Interestingly, Tongwei has been a long-term solar cell supplier to TCL Zhonghuan Renewable Energy Technology (TZE) which owns a majority stake in Maxeon.  

Maxeon’s TOPCon patent claim is strong as its TOPCon patents predate any other TOPCon IP portfolio, according to Philip Shen of ROTH MKM. Yet, the manufacturer had to face a setback in one of its several lawsuits against other manufacturers.  

China’s AIKO reported a win in May 2024 after the District Court of The Hague in the Netherlands denied a preliminary injunction sought by Maxeon for alleged patent infringement. The court said it is not plausible that AIKO’s products would infringe on Maxeon’s patent.  

Later, Maxeon accused AIKO of infringing on its EP3065184B1 patent, a family patent of EP2297788B1 which the latter said it would defend.  

The list doesn’t stop here. China’s JA Solar’s claim of patent infringement against Astronergy continues to gain momentum too (see TOPCon Patent Ownership War Heating Up, Now Moving To China).  

After JA filed 2 patent infringement lawsuits against Astronergy and its subsidiaries in Europe, Astronergy said it would actively respond to the lawsuit and defend its position, without sharing many details.  

Recently, JA Solar received a morale boost when the European Patent Office (EPO) upheld its patent claim for EP2787541B1 as valid. It was followed by a French company raising an objection to its validity in the Unified Patent Court (UPC). Identified as France’s Carbon, the French company’s objection has now led the EPO to conduct an opposition procedure to assess the validity (see Europe Solar PV News Snippets: ‘Largest’ Solar Park In Baltics Online & More).   

Meanwhile, Astronergy issued a statement saying that the patent validity dispute being processed in EPO and the patent lawsuit being processed in the UPC are 2 distinct legal procedures. It clarifies that Astronergy is not a direct party, but a related party in the Carbon Opposition Case that focuses on the reasons and evidence previously raised by Carbon.   

Astronergy added that it has self-researched and developed n-type TOPCon technology products that are already in use globally.  

“In Astronergy’s view, photovoltaic technology is universal. Its technological advantages and patent capabilities are apparent to all. Astronergy hopes that by localizing manufacturing and inputting as well as sharing of photovoltaic technology rather than erecting high, closed patent walls. It can actively respond to the manufacturing incentives offered in various countries,” it added.  

Why manufacturers are laying claim to TOPCon patents? 

The patent war continues unabated since solar PV is a capital-intensive technology that commands a higher investment in R&D. Vertically integrated companies, especially take it seriously, investing a significant amount in continued R&D efforts to stake a larger market share of innovative PV technologies.   

JA Solar, for instance, invested RMB 1.959 billion in R&D during H1 2024, accounting for 5.24% of its operating income, and had 1,827 valid patents, including 977 invention patents (see Overseas Markets Led JA Solar’s H1 2024 Module Shipments). 

Trina Solar invested RMB 2.71 billion ($381 million) alone on R&D during H1 this year. It had filed over 5,649 patent applications with more than 500 patents on TOPCon technology by July 2024 (see Trina Solar’s H1 2024 Module Shipments Grew By 26 Percent YoY).  

TOPCon is not a new technology, but rather an improvement over Passivated Emitter and Rear Cell (PERC). It basically involves applying a passivation layer to the back surface of the cell that helps minimize recombination losses.  

In TOPCon, a thin tunnel oxide layer is used on the rear side of the n-type wafer topped with a p-doped crystalline silicon layer. This tunnel oxide layer acts as a passivation layer. TOPCon is a proprietary name for passivated contacts from Fraunhofer ISE of Germany that announced a high efficiency of 25.1% for these cells in 2013.   

Since then, several solar PV manufacturers, mainly from China, claim to have worked and refined TOPCon further. Several technical personnel changed companies along the way bringing in their knowledge from the previous organizations. In all this melee, as TOPCon becomes the next workhorse for the global solar PV industry, it has fueled several claims over its patent, including the above-mentioned ones.  

Nevertheless, according to the International Energy Agency’s (IEA) Energy Technology Patents Data Explorer, between 2000 and 2023, out of the 529,898 energy-related patents, solar accounted for only 8.7%. The number of solar patents filed peaked at 3,712 in 2011, but has since declined to a mere 112 in 2023. This dataset comprises only published applications for patents of invention.   

What next?  

The situation is not likely to cool down anytime soon with an international law firm Osborne Clarke claiming that the ongoing and new litigation in this area has the potential to disrupt the market significantly.  

An Associate with the Commercial Team at Osborne Clarke, Sophie Chesterman said, “It will be interesting to see how these disputes progress and if further litigation is on the horizon, as new technologies, such as those relating to TOPCon and thin film, emerge and mature and more companies in this field become alive to the risks and opportunities from their and their competitors' patent portfolios.”