[From Top Engineers] ③ "Tandem Cell is a Solar Game Changer... Hanwha Solutions Leads the Market"

28.6% Power Conversion Efficiency Surpasses Conventional Silicon Cells
Hundreds and Thousands of Hours Dedicated to Mass Production Research
Jincheon Pilot Line... Targeting Full-Scale Production by 2026
Aiming to Become a 'Total Energy Solution Provider'

Editor's NoteSouth Korea's industry is facing a comprehensive crisis. The rapid rise in raw material prices, the restructuring of global supply chains, and the US-China trade conflicts have compounded to worsen the business environment. The key to overcoming this crisis ultimately lies in technology. Technology is the lifeline and value of companies. This is why companies are placing greater emphasis on the role of Chief Technology Officers (CTOs). CTOs have established themselves not only as developers of new technologies but also as strategists who analyze changing markets and present future visions for their companies. Asia Economy met with CTOs of major domestic companies to hear about the core technologies and differentiation strategies that each industry is focusing on. Through the technology strategies of leading companies, we seek ways to enhance the competitiveness of our industries and create future value.

"High-efficiency tandem cells are the 'game changer' in the solar power market. We must lead the global solar market based on technological competitiveness."

Kim Ki-hong, Head of the Tandem Commercialization Task Force (Executive Director) at Hanwha Solutions Q CELLS, said in a recent interview with Asia Economy at the Hanwha headquarters in Janggyo-dong, Seoul, "Mass production of tandem cells will significantly improve product efficiency compared to conventional silicon cells," adding, "It can have a dominant impact on the global solar cell market landscape."

Kim Ki-hong, head of the Hanwha Solutions Q CELLS Tandem Commercialization Task Force (TF), is being interviewed by Asia Economy. Photo by Yoon Dong-joo

Tandem cells refer to perovskite-crystalline silicon tandem cells. They are manufactured by layering a perovskite cell with excellent electrical conductivity on top of a silicon cell. This next-generation cell stacks solar cells that absorb light in different wavelength ranges to maximize power generation efficiency. When high-efficiency tandem cells are commercialized, they can produce about 15% more electricity, greatly accelerating the speed and economic feasibility of the transition to renewable energy. Because perovskite exhibits a small variation in output with changes in temperature and sunlight intensity, tandem cells using perovskite can stably generate power even in hot climates or cloudy weather.

Hanwha Q CELLS has focused on developing tandem cells because the solar module market is currently saturated due to an influx of Chinese products. Even Chinese manufacturers targeting the market with low prices are struggling to avoid losses. This is why Kim calls tandem cells a 'game changer.'

Hanwha Q CELLS has already introduced tandem cells in sizes suitable for mass production. The M10 size tandem cell, developed and manufactured in-house, achieved a power conversion efficiency of 28.6% and received certification from the internationally recognized Fraunhofer Institute for Solar Energy Systems in Germany. It is the world's first to produce large-area tandem cells applicable to modules currently sold on the market, not just small research-scale cells, and receive third-party certification.

Kim emphasized that technological leadership is essential for survival. He said, "If the Chinese government suddenly stops subsidies or if US tariff policies are eased, Chinese companies could invade the US market as well. We must prepare for such scenarios."

In April 2024, Hanwha Q CELLS' tandem cells, developed and manufactured in-house, were exhibited at the Hanwha Q CELLS booth at the International Green Energy Expo held in Daegu. Provided by Hanwha Solutions

Kim added, "Many of the materials used in these products, including perovskite, have never been mass-produced before. We are looking for ways to mass-produce these materials ourselves or make them more cheaply."

This technology did not emerge overnight. Researchers specializing in chemical engineering and materials engineering gathered, followed by researchers with experience in mass-producing solar cells. When preparing for mass production, developers who have commercialized OLED and other similar technologies also joined to collaborate.

Kim also drew on his past experience in mass production and development of solar cells to outline the blueprint for tandem cell mass production. He said, "Many early researchers came to companies after earning their doctorates and working in research institutes. We made efforts to teach them concepts of mass production and large-scale manufacturing."

There were many trials and errors. Kim recalled, "At first, we tried water-repellent coatings several times to solve the vulnerability to moisture, but the cells would break as soon as they were immersed in water." He added, "We made the upper and lower cells of the tandem cell well individually, but when combined, the efficiency dropped."

Hanwha Q CELLS' cell research also involves its R&D center in Thalheim, Germany. Germany is one of the most active countries in next-generation solar power development research. It is recognized for having accumulated technology, excellent personnel, and optimal infrastructure.

After long-term research and development of tandem cells, Hanwha Q CELLS aims for mass production next year. Currently, it is internalizing key process equipment for cell and module performance and mass production.

Kim Ki-hong, head of the Hanwha Solutions Q CELLS Tandem Commercialization Task Force (TF), is being interviewed by Asia Economy. Photo by Yoon Dong-joo

Market demand is expected to increase. Recently, home energy solutions have been widely adopted, especially in the US and Europe. Unlike Korea, where apartments are common, detached houses are the main residential type in the US and Europe, allowing households to install 7 to 8 solar modules in yards or storage spaces. Kim said, "We are currently focusing on the US market," adding, "Our goal is to raise production to the level where two local factories in the US can fully manufacture module products."

Hanwha Q CELLS' ultimate goal is to become a 'total energy solution provider.' Beyond manufacturing and supplying modules, it aims to implement home energy solutions that provide services for the entire process?from generating electricity at home, storing surplus energy, to selling it elsewhere. This will be conducted through remote services. Kim explained, "Consumers can not only use the energy produced at home but also profit as business operators. Existing companies buy Chinese modules to create home energy solutions, but Hanwha Q CELLS manufactures modules directly, allowing the application of high-quality products."

He also introduced a strategy to exploit the weaknesses of Chinese companies and win customers. Kim said, "Simply competing one-on-one with Chinese companies on modules is not a good approach. As a total energy provider, we will differentiate ourselves through after-sales service and customer-friendly services that Chinese companies are not good at, and efficient technology that delivers more than 20% higher output than existing modules."

▶Kim Ki-hong, Head of Tandem Commercialization Task Force (Executive Director) at Hanwha Solutions Q CELLS = Joined in 2010 as a senior researcher at Hanwha Chemical Solar Research Center. Served as head of the cell development team at Hanwha Q CELLS China factory and technical team leader for the new wafer project at the Malaysia factory in 2014. From 2022 to 2023, served as head of commercialization development team at Q CELLS Germany R&D center. Currently, he is an R&D executive at Hanwha Solutions and concurrently leads the tandem solar cell commercialization development team.