Photovoltaic terms of efficient photovoltaic power generation

Photovoltaic terms of efficient photovoltaic power generation

Solar photovoltaic power generation is a form of power generation that converts sunlight into electricity and outputs it in the form of electricity. The basic principle is that the use of PN junction semiconductors will produce a physical phenomenon of voltage to produce the output current. Japan's "JIS C 8960 Photovoltaic Power Generation Term" defines it accurately, namely "the power generation method that directly converts light energy into electricity. Solar cells based on photovoltaic effect are generally used."

As of 2012, the maximum conversion efficiency of general crystalline silicon solar cells sold in the market has reached 20%, and various research institutions and manufacturers are also conducting R&D in various aspects in order to improve conversion efficiency. Japan NEDO (Integrated Administrative Agency New Energy Industry Technology Development Organization) is implementing the "Innovative Photovoltaic Power Technology R & D" program (period from 2008 to 2014), proposing that "exploration and utilization of new materials, new structures, etc 40%' and 'Implementation methods that make the cost of electricity equivalent to ordinary electricity (7 yen/kWh)', and conduct research and development with the goal of verifying feasibility."

The conversion efficiency of a solar cell is an index indicating how much energy can be output when a certain amount of light energy is input. The definition is as follows.

Conversion efficiency (%) = Output power (W) ÷ Solar energy (W) × 100

In addition, the Japanese national standard has also established standards for the measurement of photovoltaic power conversion efficiency (JIS C 8910 to 8919, etc.), which stipulates the temperature, intensity of light, and wavelength components of the simulated sunlight during measurement, and has become a global standard. The measurement conditions.

What are the benefits of improving solar cell conversion efficiency? Photovoltaic power generation is directly proportional to the area of ​​the solar panel, the sunshine duration, and the conversion efficiency. Therefore, in a place with a limited installation area such as a roof of a single-family home, increasing the efficiency contributes to increase the amount of power generated. However, if the solar panel is expensive, even if the "unit-installed area of ​​the power generation" is relatively high, but converted into "unit investment amount of power generation" when there is no advantage.

There are several ways to increase conversion efficiency.

(1) Improvement of materials and construction

Solar light contains a variety of wavelengths of light, and the most commonly used silicon materials for solar cells currently cannot convert light with a wavelength greater than that of infrared light (light with a wavelength greater than 1.1 μm) into electrical energy. The wavelength that can be effectively converted to electrical energy varies depending on the material and crystal structure. Therefore, by using materials other than silicon (such as gallium arsenide: GaAs, etc.), the industry converts light of other wavelengths into electrical energy, or overlays a variety of materials. The various wavelengths of light contained in sunlight effectively convert electricity into electricity. In May 2012, Sharp released a solar cell with the highest conversion efficiency of 43.5%. This overlaps three compounds.

In addition, the quantum dot structure currently being studied by the industry can convert light having a wavelength that cannot previously output energy from a semiconductor crystal into electric energy, and is also a highly anticipated technology that can significantly increase the conversion efficiency.

(2) Method for improving light irradiation to solar cells

As a method of photovoltaic power generation, solar light can be converged to a solar cell using a light condensing device such as a lens, so that a large amount of sunlight can be irradiated onto the solar cell. Although the conversion efficiency per area of ​​the solar cell unit is increased, the condenser device also needs a certain area. Therefore, the "mounting area" in practical use is often larger than the total value of the battery cell area.

(3) Others

In addition to sunlight, solar heat can also be used to increase output energy (electricity + heat), and this method is also used as a means of increasing efficiency in a broad sense. This method can output three times the energy of silicon photovoltaic power generation.

Tableware Set

Tableware Set,Dinnerware Set,Porcelain Dinner Plate

Chemicals,Travel Products Co., Ltd. , http://www.nschemicalindustry.com