Two‐Dimensional Hot Spot Temperature Simulation for c‐Si Photovoltaic Modules

Abstract

A two‐step method to simulate the spatially resolved temperature of a partially shaded cell in a crystalline silicon photovoltaic (PV) module is presented and tested. First, an efficient module electronic simulation tool computes the operating conditions of a module's constituent cells. Second, a two‐dimensional finite‐element analysis simulation, utilizing forward‐, and revers‐bias electroluminescence measurements, is performed to spatially resolved cell temperature. With an outdoor experiment, un‐encapsulated cell temperatures are directly measured under controlled heat transfer conditions. A peak local cell temperature of 144 °C is observed on a multi crystalline silicon cell dissipating 54 W heat in the experiment, 57 °C higher than the result from a non‐spatially resolved simulation. Experimental results indicate cells without significant Ohmic shunts are suitable for temperature simulation with the aid of reverse bias electroluminescence imaging, which yields a maximum temperature prediction error of less than 15 °C. However, simulation for cells with significant Ohmic shunts is prone to underestimate the cell temperature by up to 45 °C. Multiple shading fractions from 12 to 80% lead to severe heating scenarios in such case.

Design of shading‐ and hotspot‐resistant shingled modules

“…In our previous work, we demonstrated how a commercial mono c-Si shingled module could develop peak temperatures as high as 145 C under partial shading conditions. 10 While previous works report high hotspot temperatures (>130 C) due to point defects that become localized concentrations of current, 2,11,12 our study showed comparable temperatures could be reached even without said defects; it is possible to reach such temperatures through uniformly distributed heating alone. Furthermore, secondary heating of unshaded cells was also observed in strings parallel to the shaded string, adding to the risks of hotspots and degradation.…”

Three Bypass Diodes Architecture at the Limit

“…Especially multi crystalline silicon (mc-Si) solar cells are prone to hot spots due to the local junction breakdown [11,12]. Hence, many studies have investigated this effect for mc-Si solar cells and developed electrical and thermal models to simulate the effects of inhomogeneous illumination on PV panel [13][14][15][16][17][18].…”