The European Patent Office (EPO) has revoked patent EP4092759B1 covering multi-busbar (MBB) solar cell technology, lifting a legal barrier that would have affected many European solar module manufacturers. The patent, originally filed by LG Electronics and later acquired by JA Solar, applied to widely used MBB designs found across the global solar industry.
MBB technology uses multiple thin round wires, or busbars, to collect and transfer energy from solar cells. Most European module producers rely on round-wire MBB layouts to reduce shading losses, lower resistance, cut silver use, and ensure reliable long-term electrical connections. Because the revoked patent covered features already considered standard in the sector, many European manufacturers risked infringement despite using long-established designs.
The decision follows an opposition filed in October 2024 by the European Solar Manufacturing Council (ESMC) together with several European manufacturers and research institutes, supported by an intellectual property law firm. The patent in question was a divisional application stemming from earlier filings dating back to 2014. It sought protection for solar cells with six or more busbars, the use of solder-coated round wires as interconnection leads, and expanded pad sections for soldering these wires.
ESMC noted that these multi-busbar features have been publicly documented and widely used for more than a decade, originally developed in Europe in the early 2010s and now standard in global manufacturing. Christoph Podewils, Secretary General at ESMC, said the ruling ensures a level playing field and keeps access open for continued MBB innovation.
The losing party may appeal the decision by 7 January 2026, with grounds for appeal due by 7 March 2026. The solar sector has seen several intellectual property disputes in recent years as technology advances. LONGi and JinkoSolar recently announced a global settlement resolving their patent disputes, while JA Solar’s conflicts with Astronergy continued earlier this year, with the EPO confirming the validity of JA Solar’s TOPCon-related patents.
Source: GE Vernova
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