Standards development for modules in high temperature micro‐environments

Abstract

Photovoltaic (PV) module qualification standards, IEC 61215 and IEC 61730, were designed to apply to “general open‐air climates” and IEC 61730 specifically indicated applicability of ambient air temperature of 40°C. Additionally, these standards provided allowances for so‐called “open rack mounted PV modules” without a clear definition of “open‐rack.” These implied restrictions and allowances meant that hotter climates or thermally restrictive installation methods may not be covered by these often customer‐mandated certification standards. This is particularly salient for the significant growth regions of the Middle East and India that would be expected to operate at significantly higher temperatures. The applicability of these documents raised issues over the definition of “open rack” and the fact that the geographic location is just as important as the mounting configuration in assessing the impact of the micro‐environment of a PV module. This work summarizes the scientific background for IEC Technical Specification 63126:2020 ED1, titled “Guidelines for qualifying PV modules components and materials for operation at high temperatures.” This standard was recently published by the IEC and is the first step in a systematic effort to rework these standards to address the question of temperature more directly. Instead of specifying a mounting condition, we specify different suites of tests suitable for a system (PV module, mounting style, and location) defined by the 98th percentile cell temperature. With a defined temperature regime to work from, this allowed us to use existing literature research combined with additional modeling work to determine, which tests would need to be modified. This resulted in suggested changes to material thermal indices, thermal cycling temperatures, hot spot testing, ultraviolet testing, and bypass diode testing among other tests and characteristics described herein.

Long‐Term Degradation of Passivated Emitter and Rear Contact Silicon Solar Cell under Light and Heat

“…al. [ 48 ] In this experiment, we did not specifically determine the relationship between irradiance level and degradation rate. Here we assumed two possibilities to help illustrate the range of possible relationships: one where degradation is not dependent on light (Figure 5a) and another where the degradation rate is linearly related to light intensity (Figure 5b).…”

“…These maps are generated by modeling a single‐axis tracking system using the King thermal model [ 36 ] for modules with a glass front and white opaque polymeric backsheet. [ 48 ] Furthermore, because moisture and interactions with the encapsulant are not included in the stress conditions of this experiment, these effects are also not included. However, the degradation mode here is related to V OC losses which are less likely to be affected by humidity and encapsulant type.…”

Simulation Investigation of the Wind Load of Photovoltaic Panels

“…In turn, mechanical damage occurs under the influence of climatic factors, defects in production and installation, and force majeure circumstances. The greatest influences of climatic factors have the load of wind and snow, temperature, hail and ultraviolet rays [10,11,12]. The analysis shows for the load from wind and snow that the structures on a sloping roof have with relatively the least load, and the structures on a flat roof -with the highest (due to the height of the building).…”

Long‐Term Performance and Shade Detection in Building Integrated Photovoltaic Systems

“…In BIPV systems, it is expected that temperature-and shadedinduced degradation will be more prevalent. [1][2][3][4] In fact, IEC TS 63126 addresses the first, and describes modifications to typical module qualification and safety tests (MQT and MST) to account for applications for which high temperatures are expected, such as in BIPV and hot climates. [3,13] Shade-induced degradation is less well understood.…”

“…[1][2][3][4] In fact, IEC TS 63126 addresses the first, and describes modifications to typical module qualification and safety tests (MQT and MST) to account for applications for which high temperatures are expected, such as in BIPV and hot climates. [3,13] Shade-induced degradation is less well understood. Modules typically contain two or more substrings of solar cells, each protected by a bypass diode (BPD) that helps mitigate the effect of partial shading conditions by allowing current to bypass the shaded or bad cell or cells in a string.…”