Applied Technology

First Solar PVt Plant in China

The first MW level solar PV tower plant in China – the Beijing Badaling Solar Thermal Power Plant was put into full operation on Aug. 9, 2012, with its first power generation commission completed successfully, which marks that China has become the fourth country with integrated CSP technology in the world. During the commission, the superheated steam from the solar field had driven the steam turbine rotating from 660 rpm to 2500 rpm, 5000 rpm, 6000 rpm and all the way steadily to the rated speed of 6500 rpm. With this constant speed for 10 minutes, the power plant’s loads were switched on, which met the loads instantly. The project team is composed of eleven stakeholders that have joined hands to implement and complete the whole process: from concept design, equipments installment and all the way to the commissioning and testing of the integrated system. In the process of implementation, R&D system of solar power tower technology has been established, including system design, high-precision heliostat, heliostats field, cavity receiver, heat transfer, thermal storage and power generation. With the commissioning of the 1MW tower plant, the owner -- Institute of Electrical Engineering, CAS will further improve and optimize the components design and system control. So far, a number of innovative results have been achieved through the project, 43 invention patents in total have been applied, among which 11 patents have been granted, and the first national standard on CSP technology has been established.

New High-efficiency Solar Cells

The first solar cell prototype (2cm*2cm) of Heterojunction with Intrinsic thin-layer -- Interdigitated back contact (HIT-IBC) in China has been developed by Prof. Jia Rui’s research group on high-efficiency solar cell at the Institute of Microelectronics, CAS. Taking advantage of the newly developed advanced equipment, the high-efficiency interdigitated back contact solar cells (IBCs) has been developed using independently developed paste. Based on this, the group adopted the novel HIT-IBC solar cells, which combined the advantages of high open circuit voltage (Voc) from HIT structure and the high short circuit current (Isc) from IBC structure. Therefore, the efficiency of silicon solar cells can be sharply increased. The HIT-IBC solar cell in IME/CAS, which was fabricated on the N-type 4-inches wafer (different technical scheme was used for P-type wafer), was developed using both the traditional solar cell technologies, such as screen-printing, plasma-enhanced chemical vapour deposited (PECVD) and photolithography, and the advanced fabrication technologies, such as novel passivation technology and heterojunction fabrication process. The open-circuit voltage of this HIT-IBC solar cell may reach 658mV, because of HIT cell’s high open circuit voltage, which was obviously higher than the Voc of conventional silicon solar cells. At the same time, the group is now working on the HIT-IBC solar cells based on P-type substrate.