Backsheets, given their multilayer construction, offer substantial potential for both technical and economic optimization, with the emphasis shifting based on market demand. Once considered the backbone of module reliability, these polymer wraps have undergone several changes over the last 2 decades. These changes are mainly driven by cost pressure.
Initially, backsheets used fluoropolymer layers to protect the core polyester layer. Polyester, while strong, low-cost, and an excellent electrical insulator, is unsuitable for outdoor applications as it hydrolyzes easily. To avoid this, PET is filled completely with stabilizers. However, the PV industry mostly favored fluoropolymer layers to protect PET from both sides. The configuration was then gradually optimized to reduce costs. First, the thickness of fluoropolymer layers was reduced. One of the fluoropolymer layers was then replaced by a cheaper alternative, such as PVDF, and its thickness was also reduced. The industry then started using fluoropolymers only on one side (see Different Backsheet Structures In PV Modules).
What changed this backsheet segment trend in 2022 was the rising price of PVDF, a key raw material used in creating the popular KPC backsheet structure. As a result, the market quickly pivoted to the CPC structure, which gained significant traction. This shift also brought non-fluoropolymer backsheets to the fore, which saw increased interest from module makers, particularly in China, where the manufacturers believed that fluoropolymer films were essential for UV protection. However, this perspective has begun to change. With bifacial technology gaining prominence in utility-scale solar, a segment primarily favoring the glass-glass configuration, the residential sector has grown increasingly important for backsheet manufacturers. Meanwhile, the popularity of bifacial and n-type technologies has prompted a stronger shift in the PV market toward glass-glass modules due to cost performance benefits over polymers. The adoption of new cell technologies, such as TOPCon and HJT, has only given this market shift further impetus. The glass-backsheet configuration has fewer takers than before, with only a few companies focusing on this segment. Nonetheless, a few developments in this segment do warrant mention (see Advanced Solar Technologies Drive Changes In Module Materials).
Since price has been such an influential factor in transforming the backsheets market, here is a brief analysis of its price developments. Unlike encapsulation materials, backsheet prices have been decreasing methodically, always maintaining a consistent difference of 0.4 RMB/m² within the given range. For the main backsheet configuration – CPC with fluorine coatings on both sides - prices have been consistently declining over the past 2 years. For example, prices dropped from a range of 6.9 to7.3 RMB/m² in H1 2023 to 6.4 to 6.8 RMB/m² later that year. A similar trend continued in 2024, with the price range falling from 5.7 to 6.1 RMB/m² during the first half to 5.4 to 5.8 RMB/m² in the latter half.
Interestingly, the prices of non-fluoropolymer backsheets - including both coated and PET based variants - appear to be derived from the CPC configuration, being meticulously set at 0.1 RMB/m²lower. A similar pricing strategy is observed with the transparent variants of the CPC configuration, which are always priced 4 RMB/m² higher than the opaque variant. For PVDF-based backsheets - the former leading configuration - prices also dropped significantly in2023, declining from a range of 8.9 to 9.3 RMB/m² to8.4 to 8.8 RMB/m². In H1 2024, the price range was between 7.2 and 7.6 RMB/m², dropping further to 6.9 to 7.4 RMB/m² in H2 2024.
