Module Technology Flashcards
7 cards from real NABCEP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Module Technology flashcards as text
What is the primary cause of potential-induced degradation (PID) in crystalline silicon PV modules?
Answer: High voltage potential between cells and grounded frame causing ion migration
PID occurs when a high voltage difference between the cell circuit and the grounded module frame drives sodium ions through the glass, degrading the anti-reflective coating and cell junction.
Which cell technology is most commonly used in bifacial PV modules to maximize rear-side light absorption?
Answer: PERC (Passivated Emitter and Rear Cell) cells
PERC cells use a dielectric passivation layer on the rear that reflects unabsorbed light back into the cell and allows rear-side bifacial generation, making them the dominant bifacial module technology.
On a PV module datasheet, what does the temperature coefficient of Pmax (γ) indicate?
Answer: The percentage change in maximum power output per degree Celsius change in cell temperature
γ (gamma) is the temperature coefficient of Pmax, expressing how much the maximum power output changes (typically negative, e.g., -0.35%/°C) for each degree of cell temperature deviation from STC.
What is 'light-induced degradation' (LID) and which cell type is most susceptible?
Answer: Initial power loss in the first hours of sunlight exposure, most common in boron-doped p-type crystalline silicon
LID is a reversible initial power loss (typically 1–3%) in boron-doped p-type c-Si cells caused by the formation of boron-oxygen defect complexes when first exposed to light.
A module's bypass diode is rated for a forward current of 15 A. What is its primary purpose?
Answer: To provide a current path around shaded or damaged cells, limiting hot-spot heating
Bypass diodes conduct when cells in their protected group are reverse-biased due to shading or damage, preventing those cells from dissipating power as heat and becoming hot spots.
What is the standard irradiance level used for Standard Test Conditions (STC) ratings on PV modules?
Answer: 1000 W/m²
STC is defined as 1000 W/m² irradiance, AM1.5 spectrum, and 25°C cell temperature — the universal baseline for comparing PV module performance ratings.
Which property of a PV module's I-V curve is most directly used to determine the maximum power point (MPP)?
Answer: The knee of the I-V curve where the product of voltage and current is maximized
The MPP is found at the knee of the I-V curve where the P-V curve peaks, i.e., where V × I is at its maximum value, defining Vmpp and Impp.