BC technology recorded an efficiency gain of 0.8 percentage points over the last 24 months
The upper bound of BC efficiency increased from 24.0% to 24.8% between early 2024 and December 2025, while the lower bound remained unchanged at 22.8% over the same period
AIKO led the BC category by reaching 24.8% efficiency, and by the end of 2025, only 3 commercial BC modules were represented in the TOP SOLAR MODULES listing
BC remained the efficiency leader of the commercial modules. Speaking of the technology’s efficiency progress over the last 24 months, its upper limit has improved by 3 times, while the lower end of the efficiency level has been constant. However, the hierarchy of the companies represented at these levels has remained the same. AIKO has always been at the forefront of BC efficiency advancements at the highest level. In contrast, the lower bound of the efficiency range remained fixed at 22.8%, represented by SPIC’s BC module.
During H2 2025, the top BC efficiency was increased once. In December, the best commercial BC module efficiency increased to a remarkable level of 24.8% from 24.4%, both represented by AIKO. This is not only the top of the BC stream, but for the entire TOP SOLAR MODULES listing. This also underscores the gradual improvement in commercial module efficiencies toward practical limits. H1 2025 also saw this top-level improve once – again, by AIKO. In June, the company increased the efficiency of its commercial BC module to 24.4%. This is a 0.2% absolute gain over its previous 24.2% record from May 2024. Like H1 2025, BC’s top efficiency increased once in 2024. In May, AIKO raised the upper limit to 24.2%, setting a new benchmark at that time by improving over an already high base of 24%.
BC recorded an absolute efficiency gain of 0.8 percentage points between January 2024 and December 2025. When comparing the lowest and highest BC efficiencies recorded by the end of 2025, the absolute spread within the technology band is 2 percentage points.
Moving on to the companies and their respective efficiencies, the most notable development in the second half of 2025 occurred in December. AIKO raised the efficiency of its commercial BC module from 24.4% to 24.8%, setting a new benchmark for commercially available modules. This marked an absolute improvement of 0.4 percentage points. AIKO’s upgrade replaced its earlier Comet 2U module with the Comet 3N72, while maintaining the same module configuration.
In the same month, LONGi also reached a new high with the commercialization of its EcoLife series module, achieving an efficiency of 24.7%, surpassing the earlier 24.2% level of the HPBC series. The EcoLife series is based on hybrid BC passivation technology that combines TOPCon- and HJT-type structures to passivate each contact polarity. The cell architecture is also the underlying structure that has achieved the highest efficiency for crystalline silicon solar cells to date. No other BC products recorded efficiency upgrades during H2 2025.
The number of listed BC modules remained constant at 4 from July to October 2025, represented by AIKO, LONGi, Maxeon, and SPIC. The delisting of Maxeon’s BC module in November reduced the number to 3 for the remainder of the year.
The most notable advancement in H1 2025 came in June when AIKO increased the top efficiency of its commercial BC module from 24.2% to a new benchmark of 24.4%, further extending its lead in the efficiency race. The same month, LONGi raised the efficiency of its HPBC module to 24.2%, improving from 24.1% in March 2025, and reclaiming exclusive hold on the 2nd rank in the TOP SOLAR MODULES list. Before this, in March, LONGi had already raised its product efficiency from 23.2% to 24.1%, matching Maxeon’s level. Throughout this period, SPIC continued to list its BC product at 22.8%, unchanged since September 2023.
As for 2024, 2 major developments reshaped the BC landscape in May. AIKO continued its legacy by commercializing its Comet 2U series, achieving a record-breaking 24.2% efficiency, reaffirming its lead among BC products. AIKO improved the efficiency from an already high base of 24%. Simultaneously, Maxeon Solar, a pioneer in back-contact technology, commercialized a 24.1% efficiency module, taking the 2nd position in the TOP SOLAR MODULES listing. These advancements remained untouched for the rest of the year, as did the remaining BC product portfolio with LONGi at 23.2% and SPIC at 22.8%.
The text is an edited excerpt from TaiyangNews’ latest TOP SOLAR MODULES Report 2025, which can be downloaded for free here.
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