Renewable energy expansion, supported by efficient back-contact (BC) technologies, is essential for climate action, especially as CO₂ emissions have already hit 2030 levels, making the 1.5°C limit unrealistic, said AIKO’s Channel Marketing Director, Bernhard Weber.
He presented the latest technology trends from AIKO's perspective at the TaiyangNews & AIKO Solar Workshop on Back Contact Technology held in Munich, Germany, on November 13, 2025, with leading EPCs and installers in attendance.
Before addressing current innovations, he briefly looked back at the origins of back-contact technology, emphasizing that it consistently delivers the highest performance among cell designs.
He explained that BC technology first appeared in the early 2000s, at a time when the market was dominated by polycrystalline modules – the familiar blue, shimmering products known for being inexpensive. Although monocrystalline BC modules were already available, they were considered too costly and unlikely to gain traction. Over time, however, monocrystalline technology proved to be superior, and it is now the only technology widely used.
Weber then compared this with early front-contact modules, which were cheap to produce but delivered low power outputs of around 170–180 W and were smaller than today’s modules. Even then, BC modules exceeded 200 W and later reached 215 W and 250 W. He recalled that SunPower’s introduction of a 300 W module was a significant milestone for performance, though its high cost limited market adoption despite its technical advantages.
Turning to modern technologies – PERC, TOPCon, and BC – Weber noted that PERC is now effectively obsolete. It once offered 17% to 18% module efficiency, later reaching around 20% to 22% and about 420 W of power, but market demand has moved beyond those levels.
TOPCon, he said, is the current mainstream technology. It is inexpensive and widely produced, leading to intense price competition. However, its performance still falls short of what back-contact technology can deliver. TOPCon module efficiencies typically reach around 20% to 22%, slightly better than earlier technologies but not at the level of BC designs.
Today, module efficiencies of 23% are common, and forecasts point toward 25%. Module outputs have also increased, with 465 W to 485 W products now available, while standard TOPCon modules remain around 450 W to 455 W. According to Weber, TOPCon will soon reach its practical limits, and manufacturers relying solely on it may lose competitiveness. Customers naturally prefer higher-power modules – for example, choosing 475 W or 485 W modules over 450 W products – to maximize system performance.
He emphasized that system design must reflect actual electricity needs, including heat pumps or electric-vehicle charging. Because roof space is limited and cannot be expanded, it becomes essential to use the most powerful modules available to meet increasing household energy demand.
Advantage Back-Contact
Weber explained that only a few companies currently produce BC modules, even though this technology offers the highest efficiencies available today. He noted that upcoming options, such as perovskite-tandem cells, still face challenges, particularly with stability and degradation, and will need more time before reaching market readiness. Until then, manufacturers must maximize the potential of BC technology.
According to Weber, the limited number of providers is mainly due to the complexity of the manufacturing process. Unlike TOPCon, which is relatively straightforward, BC production requires a deeper understanding of the technology to achieve top performance. He said AIKO leads in this area through continuous process optimization.
Weber highlighted AIKO’s technological advantages in materials and product design. The company’s 3rd generation module clearly differs from standard designs, including how cells are installed and how ribbons and connectors are integrated.
He emphasized that AIKO’s leadership is rooted in its long history. Although the company began marketing ABC modules in 2023, it was founded in 2009 and has consistently advanced cell development, module design, manufacturing, and process optimization. By 2024, AIKO had already introduced a module with 25% efficiency. This progress is supported by significant R&D investment – over $450 million – along with numerous patents, a large R&D workforce, and 3 research centers. He also noted that one of these centers is located in Germany, which he described as strong in basic research. He added that combining German research strengths with AIKO’s manufacturing capabilities in China creates an ideal setup for innovation and commercialization.
Optimized Manufacturing Process
Talking about how AIKO sets itself apart from other BC module manufacturers, Weber said the key difference lies in AIKO’s manufacturing know-how. In conventional production, the wafer is washed, coated with oxide and polysilicon layers, and then an ADS etching process is used to create the gap for rear-side contacts. According to Weber, this approach has disadvantages when forming the poles on the back of the cell.
AIKO uses a different method. The company completes all rear-side contacting first and then applies a laser process. Weber said this allows much cleaner and more precise work while avoiding contamination of the cell and wafer. Once the second pole is applied, this process enables the highest possible efficiencies, and he described this as a core area of AIKO’s expertise in cell manufacturing.
He also highlighted AIKO’s choice of materials. Traditional BC designs often rely on silver for metallization, but Weber noted that silver forms a coarse structure that does not sit optimally on the silicon surface, which limits electron transfer. AIKO instead uses copper, which offers better contacting and supports higher efficiencies. Because silver typically requires sintering – heating that lightly bakes the wafer – its use can stress the cell. AIKO’s copper-based approach avoids this step, preserving the wafer.
Weber added that AIKO eliminates silver entirely from the contact fingers and busbars, using only copper, which provides a more uniform material and better power extraction from the cell. Ultimately, he said, the goal is to deliver the highest possible energy yield to the customer.
Module Generations and Architecture
Weber explained the historical development of AIKO’s module generations in Europe. The company first introduced its Black Hole modules, along with versions using white and black backsheets. These early products delivered 440-445 W, while the white-backsheet models reached 455-460 W – already higher than the TOPCon modules available at that time.
The 2nd generation increased output to about 465 W for full-black modules and 470–475 W for white-backsheet versions. According to Weber, these modules still showed visible gaps between cells. The cell connectors, or ribbons, took up space in the middle of the module, reducing usable area. AIKO, therefore, looked for ways to optimize the layout. In the 3rd generation, the cells were arranged differently to free more active area.
By relocating the connectors, which previously ran along the top, bottom, and center, to the back of the module, AIKO increased the power and is now approaching 500 W. Weber pointed out that this relocation is difficult for TOPCon modules, as their front contacts would need to be wrapped around the cell, increasing the risk of micro-cracks and efficiency losses.
Since AIKO already uses a back-contact design, the company can place all connectors and contacts on the rear side. This allows the cells to be placed more continuously across the surface, extending further toward the edge. As a result, the modules gain around 1.8% more active cell area, which increases output. Weber said that this design gives AIKO a consistent performance advantage over other BC modules and aligns with its goal of remaining the efficiency leader in the TaiyangNews rankings (see TOP SOLAR MODULES Listing – November 2025).
Shingling vs. AIKO Connection
Weber also discussed overlapping cell designs. Earlier approaches used ‘shingled technology,’ where cells overlapped by about 3 millimeters and were connected with conductive adhesive. However, this adhesive did not maintain reliable conductivity over a 30-year lifetime, so very few manufacturers still use it.
Another option would be to extend the front busbars so the next cell can overlap and be contacted from the back. But this creates uneven support: the cells rest on the thick busbars while lacking support on either side, making them more prone to micro-cracks under load, he explained.
In AIKO’s design, all contacts are already on the back. This allows the cells to be placed slightly over each other without any components running between the layers. The cells lie flat, no adhesive is required, and soldering is done automatically on the rear side. Weber pointed out that this approach has enabled AIKO to commercialize this new cell arrangement, which is already in use and contributes to the company delivering some of the most powerful modules on the market.
Future Roadmap
Weber stated that AIKO plans to launch a 500 W module next year. The 3P and 3P+ series with a white backsheet will reach 500 W, while the Full-Black 3S+ double-glass and single-glass versions will offer around 490 W. These products are expected to be available for installation by the middle of next year. He emphasized that AIKO is proud to deliver power levels earlier than what research had predicted for 2026 or 2027. According to him, AIKO will be able to offer a real 500 W module by mid-2026, enabling customers to install it soon after. He highlighted this as a major advantage of AIKO’s technology.
He summarized AIKO’s strengths as high product quality, high power output, and strong yield security. AIKO modules consistently deliver more power than comparable TOPCon products. They include partial shading optimization, a standard benefit of back-contact modules, but slightly improved in AIKO’s design. This means that when part of a module is shaded, the bypass diodes deactivate the affected cell area more slowly.
He noted that AIKO modules also have a better temperature coefficient, enabling higher power when the modules heat up. Their degradation is very low, with more than 90% power remaining after 25 years. Hotspot Control reduces temperature buildup under conditions such as bird droppings. While TOPCon cells can heat up to around 160°C, AIKO modules rise only to about 100°C due to their breakdown voltage, improving safety and lowering hotspot risk.
In terms of hail performance, the back-contact structure provides strong mechanical stability. The single-glass module meets hail protection class 4 and can withstand 40 mm hailstones, while double-glass modules tolerate 35 mm. He noted that recent hailstorms with 30 mm hailstones appeared in the news, and AIKO systems offer an extra level of reassurance in such events. The modules also meet fire protection class A and feature copper connections on the back.
Audience Interaction
Audience Question: Does the change from 2nd to 3rd generation affect partial shading?
Bernhard Weber: No. Partial shading performance is the same in both generations.
Audience Question: What is the fire protection class compared to standard TOPCon modules?
Bernhard Weber: Double-glass modules are IEC Class A, and other double-glass designs usually fall in this range, sometimes in Class B. Single-glass modules with backsheets perform worse because backsheets are not flame-retardant.
Audience Question: Why does single-glass have better hail resistance than double-glass?
Bernhard Weber: Double-glass modules use 2 mm glass on both sides, while single-glass modules use 3.2 mm glass on the front. The thicker front glass provides better impact resistance. As a result, single-glass modules meet hail class 4 (40 mm hailstones), while double-glass modules meet 35 mm. That difference comes purely from glass thickness.
The idea that double-glass is always more stable mainly comes from TOPCon manufacturers, whose single-glass modules are less stable because of front-side contacts routed around the cell. AIKO modules do not have this issue, so their single-glass modules offer similar stability with lower weight. Single-glass modules with backsheets typically fall under fire class C.
Audience Question: What comes next in innovation now that the white areas have been replaced with cell area and the module is fully black?
Bernhard Weber: They are already close to the efficiency limit, but still work on small improvements, such as narrower and more conductive contacts. Their cells have reached 27.3% efficiency in the lab, so further gains are possible. They are also exploring features beyond efficiency, such as intelligent junction boxes that allow module-level monitoring similar to optimizers.
Audience Question: Are there smaller AIKO modules planned? Complex roof layouts often require them.
Bernhard Weber: Standard module sizes have become the norm due to transport and palletization. AIKO produces a smaller module for Japan, but there are no plans to bring it to Europe. Using multiple module formats would raise costs and reduce economies of scale, so they expect to continue with the current standard size.
Audience Question: With the previous generation, the highest power classes were advertised but rarely available. Why?
Bernhard Weber: At the start of production, cell performance varies, and most cells fall into mid-range power levels. Only a small share reaches the highest classes, which is why few 465 W modules were available early on. Availability improved over time, and today, 475 W modules are widely available. Toward the end of the year, AIKO will offer 485 W Full-Black modules, and these will be available on the market.
At the end of his presentation, Weber briefly addressed economic performance, saying that AIKO modules often deliver better LCOE than TOPCon under certain conditions. BC modules can increase total energy yield, and AIKO’s data shows higher kWh per kW-peak.