Advances in solar photovoltaics: Technology review and patent trends

Against the pressing challenges of climate change and fossil fuel depletion, renewable energy sources such as solar photovoltaics (PV) are considered a clean and sustainable alternative. PV technologies have grown into a substantial field of research and development through large stocks of scientific publications and patents. Besides cell technologies, the balance of system (BoS) components such as panels, electronics and energy storage form an important research area. The present article studies the development of the PV technological system using patent indicators. It is composed of three parts: First, it defines the system by thoroughly reviewing the various cell and BoS technologies. Second, it introduces a novel methodical approach for identifying its relevant patents. In that sense, the paper contributes with an accurate inventory of international patent classes for PV system. Finally, the geographical, organizational and technical trends over the past six decades are analysed along with a review of the most influential inventions. The analysis shows that 95% of the PV patent applications were filed by inventors from seven countries: Japan, Korea, China, USA, Germany, Taiwan, and France. Most patents were filed by companies and related to thin-film and crystalline-silicon cells as well as panel encapsulation and supporting structures. The analysis reviews the quantity, quality and technological specialization within countries’ patent profiles. It further provides an overview of the technological landscape and freedom-spaces available for manufacturers.