Integration of Electrical Energy Storage Devices with Photovoltaic Solar Cells in One Hybrid System

In this chapter, we classify previous efforts when combining photovoltaic solar cells (PVSC) and energy storage components in one device. PVSC is a type of power system that uses photovoltaic technology to convert solar energy directly into electricity and is therefore capable of operating only when illuminated. Because the sun does not shine at all hours of the day, solar power is intermittent. For this reason, PVSCs are unable to provide electricity during the evening and night. Due to the intermittent nature of solar irradiation, it becomes vital to hybridize the PVSCs with electrical energy storage (EES) devices such as Li-ion batteries, capacitors, and supercapacitors (SCs) in one single power unit component. Here presented a brief description of the principles of operation and features of various types of both solar cells and energy storage devices. It was noted that as much as 90% of the worldwide PV market is currently dominated by Si-based PVSCs to have a high power conversion efficiency, good stability and fixed industrial production standards. Nevertheless, certain limitations attributed to their high cost, environmental pollution issues, as well as rigidness serve as an obstacle in their wider market scattering. Inorganic thin-film solar cells based on amorphous α-Si, GaAs, and other III-V compounds, CdTe and CuInGaSe (CIGS), organic and hybrid organic-inorganic lead or tin halide-based perovskite solar cells, quantum dot solar cells and dye-sensitized solar cells (DSSCs) have gradually replaced these cells. Further, it was noted that electrochemical Li-ion batteries, capacitors, and (SCs) are the primary electrochemical EES components. It showed the features of SCs and the advantages of their use compared with other EES devices. SCs can store huge amounts of energy and have a long service life. They also have a fast charge-discharge time, excellent cyclic stability, and outstanding low-temperature performance. Growing demand for green energy, miniaturization and wearable mini-electronic devices will result from the combination of PVSCs and SCs into a single hybrid device. Finally, we present the construction of the hybrid PVSC device integrated with an SC and the main steps to its fabrication. This device combines SC based on NiO nanotubes grown in Anodic aluminum oxide (AAO) template with PVSC based on an array of CdS/CdTe nanostructured heterojunctions which are also grown inside an AAO template. It is a fully integrated device, with a monolithic structure, where the solar cell and energy storage segments share a common substrate in the form of a transparent glass wafer, both sides of which are covered with conductive InSnO (ITO) layers and AAO templates. The structural, optical and morphological properties of Glass/ITO/AAO/CdS structures were investigated through XRD, scanning electron microscopy, energy dispersive X-ray spectroscopy, Raman, and UV-Visible spectroscopy. The obtained materials demonstrated to be quite suitable raw materials for the production of solar cells.