admin 
In order to conserve limited energy, the application of solar street lights is becoming increasingly widespread in the market. As a manifestation of renewable energy, solar street lights have the advantages of being green and sustainable, leading to their adoption by more and more cities. So, are you aware of the performance parameters of the photovoltaic cells used in solar street lights? Below is an introduction from the editor of Century Sunshine Lighting.
Performance parameters of solar street light photovoltaic cells:
(1) Short Circuit Current (Isc): The short circuit current is the current that flows through the solar cell when it is shorted at the output terminal under standard light source exposure. To measure the short circuit current, an ammeter with a resistance of less than 1Ω is connected across the solar cell. The short circuit current varies with the intensity of light.
(2) Peak Current (Im): Also known as maximum operating current or optimal working current, the peak current refers to the operating current when the solar cell module outputs maximum power, measured in amperes (A).
(3) Peak Voltage (Um): Also known as maximum operating voltage or optimal working voltage, the peak voltage is the operating voltage of the solar cell when it outputs maximum power, measured in volts (V). The peak voltage of a module varies with the number of cells connected in series. A module with 36 cells in series has a peak voltage of about 17 to 17.5V.
(4) Open Circuit Voltage (Uoc): Under light exposure, the output voltage value of the solar cell when the terminals are open (not connected to a load) is known as the open circuit voltage. The open circuit voltage is measured in volts (V). This value also changes with the number of cells in series; a module with 36 cells in series has an open circuit voltage of approximately 21V. A high-resistance DC millivoltmeter is used to measure the open circuit voltage.
(5) Maximum Output Power: If the chosen load resistance allows the product of output voltage and current to be maximized, the maximum output power, represented by the symbol Pm, can be obtained. The working voltage and current at this time are called optimal working voltage and optimal working current, represented by Um and Im, respectively, where Pm=UmIm. The product of rated voltage and rated current equals the rated power, which is the maximum output power under normal conditions (suitable for long-term operation). The rated output power of solar cells is related to conversion efficiency; generally, the higher the conversion efficiency per unit area of the solar module, the greater the output power. Current conversion efficiencies range between 14% and 17%, with an output of 14 to 16 mW per square centimeter of cell, resulting in an output power of approximately 120W per square meter.
(6) Peak Power (Pm): Also known as maximum output power or optimal output power, peak power refers to the maximum output power of the solar cell under normal operating or testing conditions, calculated as the product of peak current and peak voltage: Pn=ImUm. The unit of peak power is watts (W). The peak power of the solar cell module depends on solar irradiance, spectral distribution of sunlight, and operating temperature, thus measurements must be conducted under standard conditions. The testing standard for solar cells specifies that the atmospheric mass is AM1.5 with a solar irradiance of 1000W/m2 at a temperature of 25℃. Under these conditions, the output power of the solar cell is defined as the peak power.
(7) Fill Factor (ff): The fill factor is the ratio of the maximum power of the solar cell module to the product of open circuit voltage and short circuit current: f=Pm/(IsUoc). It reflects the output power variation characteristics of the cell concerning load changes and is an important parameter for assessing the quality of solar cells. A higher fill factor indicates better performance of the solar cell.
The information shared above regarding the performance parameters of photovoltaic cells in solar street lights outlines their numerous advantages as an outdoor lighting product. They address many environmental issues and generate economic benefits for society. Thanks to their unique secondary optical design, they effectively direct light to the required areas, further enhancing efficiency and achieving energy savings.
