Back contact (BC) solar technology has seen rapid advancements across cell, metallization, and module levels. As manufacturers scale up, module design and bifacial performance are emerging as critical areas of innovation. The requirements for BC modules are similar in many respects, but there are some specific differences. AIKO noted that an insulating glue is required to separate the p and n electrodes. The absence of front-side metallization also allows the use of a thinner front encapsulant, while the rear side, housing both polarities, may require a thicker or more robust film. Additionally, since BC cells eliminate front-side solder ribbons, the rear-side ribbons can be wider and made of more cost-effective materials, offering greater flexibility in interconnect design (see Module Design Strategies For Back Contact Integration).

Bifacial

Bifacial, which was not even on the BC radar until recently, is now a buzzword related to BC. Traditionally viewed as a limitation of the architecture, given that both contacts are placed on the rear side, BC is now making steady progress in improving rear-side light utilization. As manufacturers push BC modules toward broader adoption, particularly in utility-scale applications, enhancing bifaciality is seen as a key enabler. Indeed, BC manufacturers have made notable progress, reporting bifaciality levels in the 70% to 80% range. AIKO, for instance, is pushing toward 80%, estimating a theoretical potential of 85%. LONGi also highlighted design optimizations such as refined metallization and patterning to reduce shading and absorption losses, improving bifaciality. Across the board, the consensus is clear: enhanced bifacial performance is essential, and BC is undergoing optimization to close the gap.

In an exclusive interview with TaiyangNews Managing Director Michael Schmela during the TaiyangNews SNEC Solar Leadership Conversations 2025 at SNEC 2025, LONGi Group Vice President Dennis She highlighted the company's efforts to make back contact technology a cost-effective solution across diverse application scenarios.

This text is an excerpt from the TaiyangNews Cell & Module Technology Trends 2025 report, which can be downloaded for free here.