Photo source: DKEM
Chinese solar silver paste manufacturer DKEM (Wuxi DK Electronic Materials Co., Ltd.) has filed another 200 million yuan patent infringement lawsuit, raising its total claims against domestic rivals to 1 billion yuan, according to a stock exchange filing disclosed by DKEM on April 3.
The latest case, docketed as (2026) Humin Chu No. 2 at the Shanghai High People's Court, targets Pharos Materials Co., Ltd. and its Shanghai branch. It marks DKEM’s sixth lawsuit since 2021, all based on two core patents covering lead-tellurium-oxide thick-film paste formulations.
The disputed patents — ZL201180032359.1 and ZL201180032701.8 — originated from U.S. chemical giant DuPont de Nemours' Solamet photovoltaic paste business. DKEM gained control of the portfolio through its 696 million yuan acquisition of a 60% stake in subsidiary Solamet Materials Science Co., Ltd. in May 2025. The patents protect lead-tellurium-oxide paste systems enhanced with lithium and lithium-titanium additives — a formulation industry sources describe as essential for manufacturing mainstream solar cell technologies, including p-PERC, n-TOPCon and next-generation xBC cells. As of May 2025, Solamet Materials Science holds 227 active invention patents globally and has successfully defended the patent family against multiple invalidation challenges.
In the latest filing, DKEM alleges the defendants have used the patented technology without authorization over a long period and across a wide geographic area, causing substantial economic losses. DKEM is seeking a court order to stop the defendants from manufacturing, selling or offering infringing products, and to destroy related tooling. It also demands 200 million yuan in economic damages and reasonable enforcement costs, including treble punitive damages, plus all legal fees.
DKEM’s patent war began in August 2021, when it sued Changzhou Fusion New Material Co., Ltd. for 200 million yuan in the Suzhou Intermediate People's Court — a case timed to coincide with Fusion’s IPO process. The parties settled in August 2022.
In November 2025, DKEM sued Zhejiang Gonda Electronic Technology Co., Ltd. for another 200 million yuan in the Zhejiang High People's Court. Gonda countersued for 5 million yuan, alleging malicious IP litigation, and challenged court jurisdiction. Both the Zhejiang High Court and China’s Supreme People’s Court rejected the challenge, with the top court’s ruling final.
In January 2026, DKEM filed two separate 200 million yuan lawsuits at the Jiangsu High People's Court against Jiangsu Riyu Photovoltaic New Materials Co., Ltd. and Suzhou iSilver Materials Co., Ltd. Both cases have been docketed and are awaiting trial.
To date, DKEM has launched six lawsuits against five domestic competitors — Changzhou Fusion, Zhejiang Gonda, Jiangsu Riyu, Suzhou iSilver, and Pharos Materials — with total claims reaching 1 billion yuan.
The legal offensive comes as silver paste has overtaken polysilicon as the single largest cost component in solar modules, with its share of total module costs rising to 21.4% from 12.8% in 2023, driven by surging silver prices. DKEM's patent strategy - systematically targeting major domestic competitors across multiple high courts - reflects intensifying IP competition in solar materials, where formulation patents have become critical moats.
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DKEM Files RMB 200M Patent Lawsuit Against Gonda Electronic
