Key takeaways:
Emerging BC architectures and multi-cut cell formats are reshaping interconnection requirements in CTS equipment
Interest in 0BB has grown due to potential silver savings, but process stability and double-sided complexity, particularly for TOPCon, have limited adoption
Multi-cut formats (1/3 and 1/4) are gaining traction as a practical path to lower resistive losses and optimized busbar counts, supported by modular upgrade strategies in newer stringer platforms
Interconnection is a process that is accomplished in combined tabber and stringer (CTS) tools. From a CTS perspective, starting with cell technologies, TOPCon remains the dominant near-term technology, while back contact (BC) is emerging in parallel, especially in China. At the module level, Chinese manufacturers are increasingly evaluating multi-cut formats – 1/3- and 1/4-cut. Zero busbar (0BB) is yet another technology trend related to CTS tools. Some of these technologies are also interdependent, complementary, or mutually exclusive. From a European perspective, Mongdragon notes that super multi busbar (SMBB) designs and larger cell formats (up to M12) are key trends in interconnection.
Interconnecting BC cells, as mentioned above, requires considerable optimization. However, CTS equipment has evolved to offer such flexibility that the majority of the products can be optimized to interconnect BC. The tools from ConfirmWare, Mondragon, and XN Automation listed in the survey are explicitly specified as having this capability in their respective product specification tables. ConfirmWare has already deployed several TOPCon tools that are BC-ready, said R&D director Kang. 0BB has attracted significant attention in 2025; nearly every leading supplier has introduced a 0BB-based module and showcased it at major solar trade shows over the past year. The key motivation is to reduce costs, particularly by reducing silver consumption. The beauty of 0BB technology is that it enables the interconnection of cells with no busbars, which are typically silver-based.
This approach is technically easier to implement in BC cells than in TOPCon. That’s because BC processes operate at lower temperatures and require interconnection on only one side, reducing hotspot risks and material costs. Nearly every leading BC module maker has successfully developed the technology. However, according to ConfirmWare, while the benefit was initially attractive, many manufacturers have found that 0BB’s overall process stability, production yield, and performance do not meet expectations. This is especially true for TOPCon, which requires double-sided interconnection processing, making 0BB more complex and expensive.
As an alternative, multi-cut technology gained prominence. Here, instead of cutting cells in half, 3 or 4 slices are cut from the fully processed cells, which offers additional advantages beyond facilitating cell interconnection. This is not a new idea altogether; a few companies have previously commercialized modules based on this approach. Even shingled module technology follows the same track but takes a more complex route for interconnection. The main reason the 1/3- or 1/4-cutstrip-based modules did not reach mainstream is the high edge losses originating from cell slicing. What has changed now is the latest cell technology trend: edge passivation. Several deposition tool suppliers are offering very high throughput and low-cost edge passivation tools that reduce the risk of edge losses in sliced cells. Moving to multi-cut reduces resistive losses and is relatively less complex, while keeping the costs in a manageable range. As a result, many module makers now see multi-cut formats as a more practical path to higher module performance, according to ConfirmWare’s Le Kang.
In addition, multi-cut also offers the flexibility to optimize the number of busbars. For example, a 210R mm half-cut cell uses 20 busbars, while a 1/4-cut cell of the same wafer format allows a reduction to 16BB, which also means lower silver consumption. Therefore, as manufacturers transition to multi-cut architectures, the benefit of 0BB diminishes. ConfirmWare emphasized that its latest stringer platforms were designed with modularity in mind, enabling customers to upgrade existing machines to support 1/3- and 1/4-cut formats through upgradation kits. Such an upgrade would cost around 20-30% of the machine’s cost, while an upgradation kit for 0BB compatibility would cost close to 50% of the machine’s cost, according to Kang. This modular approach is intended to help manufacturers adapt to evolving interconnection strategies without replacing entire production lines, especially for Indian customers, most of whom have installed GW-scale module lines only in the past few years.
Mondragon, also acknowledging the trend toward multi-cut formats, says that its current product platform is already compatible with 1/3-cell slices. “But anything beyond that will require fundamentally new machinery,” says the sales manager of the company, Haitz Alzola. To be future-ready, Mondragon is developing a next-generation stringer that is designed to handle higher processing speeds while remaining compatible with current and future technologies. For example, it allows customers to start with PERC, later upgrade to TOPCon, and even BC architectures. It also offers the flexibility for multi-cut, different busbar layouts, with options to move beyond infrared soldering toward ECA-based interconnection for future technology generations. Another trend in the interconnection process is a string layout consisting of overlapping cells. This is also compatible with the multi-cut approach. However, such a layout increases mechanical stress at the cell edges. To address this, ConfirmWare developed a solution integrated into its stringer that inserts a film at the overlapping area between 2 adjacent cells. This reduces stress and the risk of cell cracking at the edges during lamination, improving overall mechanical stability.
All these approaches aim to improve the module output. However, technological progress is driven not only by benefits but sometimes also by competition. Kang estimates that BC may also soon adopt multi-cut architectures, potentially with even higher busbar counts of 30 to 34-BB. If BC advancements accelerate, then TOPCon manufacturers may respond by exploring even finer slicing beyond 1/4-cut to remain competitive.
The text is an edited excerpt from TaiyangNews’ latest Market Survey on Solar Module Production Equipment 2026, which can be downloaded for free here.