What is the relationship between the temperature coefficient of the photovoltaic module test and the actual power of the module?
2021-02-25
1. The relationship between temperature and open circuit voltage,
2. The relationship between temperature and short-circuit current,
3. The relationship between temperature and output power.
1. What determines the size of the open circuit voltage is the band gap and Fermi level of the semiconductor. Because the higher the temperature, the closer the Fermi level is to the valence band, so the higher the temperature, the lower the open circuit voltage, that is to say, the temperature- The two curves of the open circuit voltage are probably a straight line with a negative slope. This is called testing the voltage temperature coefficient of the solar module during the solar module certification process.
2. The relationship between temperature and short-circuit current is that the higher the temperature, the greater the short-circuit current, but it should be noted that the short-circuit current rises here is less than the open-circuit voltage drop in the first item above, that is, temperature-short-circuit current two The curve of the person is a straight line with a slightly positive slope. In the solar module certification test, this is called the current temperature coefficient of the solar cell.
3. Because the open circuit voltage drops very sharply when the temperature rises, and its amplitude is greater than that of the short-circuit current rise, so the total output power drops when the temperature rises, because P=UI, U drops sharply , And the increase in I is very small.