Solar energy conversion efficiency and different specifications of PV modules

Different modules of Solar photovoltaic modules (modules) are used in solar cells. The most common PV modules are monocrystalline silicon and polycrystalline silicon.

Based on the PV module of single crystal silicon structure, the highest efficiency of solar energy converted into electric energy current is 14-20%.

The outline of the single crystal silicon module is shown in Fig. 1. This Solar photovoltaic modules has a maximum power of 36W (output DC voltage 12V), but it ensures the power supply for small electronic devices.

( figure 1 )

Particular attention should be paid to the service life (lifetime) and reliability of these modules. REC Solar REC 240 PE module with output power (DC-rated power) PN=240W, output voltage (DC-open circuit voltage) VOC=37.7V, DC-max power current IMP=7.9A, the average service life is 25 Year (loss of 80%). When the module's external dimensions are 1665×99.1×38mm, according to the March 2015 market, its retail price is about US$3,000 (equivalent to RMB 87.5/W).

The polycrystalline silicon-based PV Solar photovoltaic modules is shown in Fig. 2, which is less expensive than the single crystal silicon processing process, and thus can make the module cost lower. The quality of the material is worse, which is manifested by the boundary effect and the unevenness of the graininess, so the efficiency of the PV module is 13-15%.

( figure 2 )

In addition to monocrystalline silicon and polycrystalline silicon, the third form is a thin film micro-silicon based PV module, the configuration of which is less common, as shown in FIG. When the external dimensions are 1300×1100×6.8mm, it has a maximum output power of 130W, a weight of 26kg, and a working surface area of 1.4 M2.

( image 3 )

The structure of the Solar photovoltaic modules includes the following components, such as thin film micro silicon, which is composed of CdTe (cadmium telluride), Cu(In,Ga)Se2 [copper (indium, gallium) selenium 2] and the like. It is characterized by a relatively low price, the material is free to maintain shape and light weight. Compared to monocrystalline/polycrystalline silicon, this PV module requires a large area at the same power.

Thin film silicon-based PV modules have the lowest conversion efficiency and only 6 to 10% efficiency in the above three forms, but at the same time they have a broader spectrum of absorption of solar radiation. The module is characterized by its softness and can be mounted on uneven surfaces.