What are the characteristics of solar cells besides energy saving and environmental protection? With the continuous emergence of solar panels, many families are using photovoltaic power generation, solar automobiles, so the basic characteristics of solar cells is essential to popularize science, in addition to open-circuit voltage, short-circuit current, what other knowledge is needed to understand?
At present, silicon-based solar cells are widely used, which can be divided into monocrystalline silicon, polycrystalline silicon and amorphous silicon solar cells. Its main function is to directly convert solar energy into electrical energy. In the process of photovoltaic power generation, solar cells have the following characteristics:
Open circuit voltage
Open-circuit voltage UOC: The solar photovoltaic cell is placed under the illumination of 100mW/cm2 light source, and the output voltage value of the cell is when the two ends are open-circuit.
Short-circuit current ISC: The solar photovoltaic cell is placed under the irradiation of standard light source. When the output terminal is short-circuit, the current flows through both ends of the cell.
Another important parameter of solar photovoltaic cells is filling factor FF, which is the ratio of the maximum output power to the product of open-circuit voltage and short-circuit current.
High output power
The working voltage and current of solar photovoltaic cells vary with the load resistance. Volt-ampere characteristic curves of solar cells can be obtained by making curves of working voltage and current corresponding to different resistance values. If the selected value of load resistance can maximize the product of output voltage and current, the maximum output power can be obtained, which is expressed by symbol Pm. At this time, the working voltage and current are called the best working voltage and the best working current, which are expressed by symbols Um and Im respectively.
The conversion efficiency of solar photovoltaic cells refers to the maximum energy conversion efficiency when the optimal load resistance is connected to the external circuit, which is equal to the ratio of the output power of the cells to the energy incident on the surface of the cells. Photoelectric conversion efficiency of solar photovoltaic cells is an important parameter to measure the quality and technical level of solar cells. It is related to the structure, junction characteristics, material properties, working temperature, radiation damage of radioactive particles and environmental changes of solar cells.