Major Legal Obstacle Lifted by European Patent Office, Securing Competitive And Unrestricted Solar Module Production In Europe

The European Patent Office (EPO) has revoked a key patent on multi-busbar (MBB) connections in solar modules, following a claim by the European Solar Manufacturing Council (ESMC) and an industry consortium. The decision safeguards open access to widely used PV manufacturing techniques and is a positive step toward re-establishing Europe’s solar PV industry. The revoked patent, EP4092759B1, would have affected nearly all European module producers using modern MBB cell technologies, which are now an industry standard. Originally owned by LG Electronics of Korea and later acquired by Chinese company JA Solar, the patent posed a potential legal risk to European manufacturers despite the long-standing use of these techniques.

Christoph Podewils, Secretary General of ESMC, noted that the patent covered matters that have been standard practice in the industry for years. Had it remained in force, the majority of European module manufacturers using MBB cells could have faced infringement claims despite relying on well-established technologies. Multi-busbar features have been publicly known, documented, and widely used for more than a decade. Developed in Europe in the early 2010s, MBB techniques are now standard in global PV manufacturing, helping module makers reduce shading losses, lower resistance, minimize silver consumption, and ensure reliable long-term electrical connections.

The revoked patent was a divisional filing from an earlier European application claiming priority from 2014. It sought protection for solar cells with six or more busbars, the use of solder-coated round wires as interconnection leads, and the use of expanded pad sections for soldering wires to busbars. The opposition, filed on 30 October 2024, was prepared by ESMC and a consortium of European companies and research organisations with the support of an IP law firm. The group successfully demonstrated that the patent included subject matter extending beyond the original parent application, making it legally invalid. The EPO accepted these arguments without needing to examine novelty or inventiveness further.

An oral hearing took place on 15 October 2025, after extensive exchanges of documents, counter-arguments, and preliminary opinions. Following the full-day proceedings, the EPO Opposition Division issued a decision to revoke the patent in its entirety. This outcome removes a significant legal barrier for European module producers and is an important milestone in supporting competitive and open PV manufacturing in Europe. Podewils emphasized that the decision strengthens Europe’s ability to scale up solar production without facing unjustified patent restrictions and ensures a level playing field for the industry. The losing party may still appeal the decision. The deadline for filing an appeal is 7 January 2026, with grounds for appeal due by 7 March 2026.