European Patent Office Revokes Multi-Busbar Patent, Clearing Key Barrier for Europe’s Solar Manufacturing Revival

The European Patent Office (EPO) has revoked a major patent covering multi-busbar (MBB) solar cell connections, following an opposition backed by the European Solar Manufacturing Council (ESMC) and a consortium of PV manufacturers and research institutes.

The move lifts a significant legal hurdle that would have affected nearly all European module makers using modern MBB cell architectures. The revoked patent, EP4092759B1, initially owned by LG Electronics and later acquired by JA Solar, attempted to cover manufacturing practices long considered industry standard. MBB features such as six or more busbars, solder-coated round wires, and expanded pad sections have been publicly known and widely used for over a decade, with early European innovation dating back to the early 2010s.

“This patent covered technologies that have been industry standards for years. Had it stayed in force, most European module manufacturers using MBB cells would have faced infringement risks despite relying on well-established methods,” said Christoph Podewils, Secretary General of the ESMC.

The consortium’s opposition, filed on 30 October 2024, argued that the patent introduced subject matter not disclosed in the original parent application , a legal flaw known as 'added matter.' The EPO accepted the argument without needing to examine novelty or inventive step. After extensive written exchanges and an oral hearing on 15 October 2025, the Opposition Division revoked the patent in full.

The decision is seen as a boost for Europe’s efforts to re-establish competitive solar manufacturing. By removing uncertainty around widely used interconnection techniques, it ensures open access to core PV technologies and supports a level playing field for European producers. “This outcome strengthens Europe’s ability to scale up PV manufacturing without facing unjustified patent barriers,” Podewils added.

The losing party may still appeal. The deadline for filing an appeal is 7 January 2026, with grounds due by 7 March 2026.