The efficiency of perovskite solar cells (PSCs) is advancing rapidly, yet their sensitivity to am... more The efficiency of perovskite solar cells (PSCs) is advancing rapidly, yet their sensitivity to ambient conditions poses challenges. An additional degradation mechanism, potential-induced degradation (PID), can emerge during field operation, but the understanding of PID within perovskite devices is limited. To exclude environmental stressors, this study is conducted in an inert environment at room temperature. PSCs and mini-modules are subjected to a 324 h PID stress test at −1000 V, revealing relative efficiency losses of around 29% and 24% for the PSCs and mini-modules, respectively, exposing subtle degradation differences. These degradation rates are notably lower than reported in the literature, suggesting possible additional degradation pathways arising from suboptimal encapsulation combined with ambient conditions. Subsequently, half of the stressed samples are subject to +1000 V for 523 h and recover to a reduced efficiency loss of 15% and 7.7% for the PSCs and module, respectively. In contrast, storing the stressed samples on the shelf increased the efficiency losses to 32% (PSCs) and 41% (module). Therefore, the post-PID rates differ significantly between both groups, whereas both effects of voltage recovery and progressed degradation are more pronounced in modules compared to cells. This study contributes to a robust method for PID research.
A high voltage degradation mechanism on photovoltaic (PV) modules called potential-induced degrad... more A high voltage degradation mechanism on photovoltaic (PV) modules called potential-induced degradation (PID) has gained a lot of attention since 2010 when Solon published their findings about PID [1]. The research conducted on PID mainly focused on industrial scale PV systems where potential differences between the solar cell and the grounded frame in the order of 1000 V and even more are not uncommon [2–5]. In this work, a stress test for PID according to the foil method as described in IEC 62804-1 and a recovery test in the same conditions on a set of five one-cell laminates is performed. However, by stressing the one-cell laminates at different voltages (-200 V, -600 V and -1000 V) and curing them at +500 V, which is compliant with residential voltages in the PV market, and +1000 V as a reference, more insight on the impact of stress and curing voltage on PID is gained. This is the basis for a voltage dependent model for PID. Furthermore, it is shown that the impact of the stress voltage on PID as a function of time exhibits a complex behaviour. At last, the impact of PID at different stress voltages on the different operational parameters of the one-cell laminates and their physical meaning is described.
Abstract A round robin test was carried out in four PV laboratories to compare accelerated lifeti... more Abstract A round robin test was carried out in four PV laboratories to compare accelerated lifetime testing. Twenty commercial non-packaged CIGS solar cells of similar performance were spread and exposed to damp heat conditions (85 °C and 85% RH) for approximately 500 h. Their JV performance was monitored during the damp heat exposure. After the test, three of the labs reported average efficiency losses of 87 ± 4%, 89 ± 5% and 92 ± 1%, which are close to median degradation rates found in literature. A higher degradation rate (efficiency loss of 97 ± 3% after only 143 h) was observed in the fourth lab. This was attributed to a poorly designed ceiling window sealing, which caused liquid water pooling on the samples. After modifying the climate chamber, the experiment was repeated with similar samples and an efficiency loss of 72 ± 6% after 475 h was observed for this lab.
2017 IEEE International Reliability Physics Symposium (IRPS)
Potential-induced degradation (PID) of photovoltaic (PV) modules gets a lot of attention since 20... more Potential-induced degradation (PID) of photovoltaic (PV) modules gets a lot of attention since 2010 when Solon published their findings about a degradation mechanism in their PV modules caused by high potential differences between the solar cell and the grounded frame [1]. Module level efficiency drops of 30% and more caused by PID have been reported [2], [3]. A stress test for PID according to IEC 62804 and a recovery test in the same conditions were conducted on a set of 49 commercially available PV modules. In this paper we report the irreversibility of highly affected (i.e. over 85% PID) PV modules. From this point of view, it is important to detect and recover PID before the point of no return. Furthermore, the impact of PID on the different parameters of a PV module and their relevance in order to detect PID in the field are reported.
An alternative energy source that has appeared beyond expectations and has seen a lot of progress... more An alternative energy source that has appeared beyond expectations and has seen a lot of progress is the fuel cell. A proton exchange membrane (PEM) fuel cell is chosen for analysis and requires a DC-DC boost converter as an interface between the fuel cell and the load to provide a high-gain regulated voltage. Although great effort towards developing different converter topologies has been made during recent decades, less attention has been devoted to the reliability and thermal performance assessment of the present converters. In this paper, five non-isolated DC-DC converters are analyzed in terms of both thermal behavior and reliability. The temperature estimation of semiconductor devices as a critical part of the thermal analysis has been made via a detailed thermal model and the reliability is evaluated by means of a power cycling test. Finally, a performance score has been attributed using the TOPSIS ranking methodology and considering all the criteria (e.g., the number of comp...
This paper examines the practical challenges of simplified setups aimed at achieving high-power I... more This paper examines the practical challenges of simplified setups aimed at achieving high-power IGBTs’ IC–VCE curve. The slope of this I–V curve (which is defined as on-resistance RCE) and the point where the VCE–VGE curve visibly bends (threshold gate voltage) can be suitable failure precursor parameters to determine an IGBT’s health condition. A simplified/affordable design for these specific measurements can be used for in-situ condition monitoring or field testing of switching devices. First, the possible I–V curve measurement methods are discussed in detail in order to prevent self-heating. The selected design includes two IGBTs in which the high-side IGBT was the device under test (DUT) with a constant gate voltage (VGE) of 15 V. Then, the low-side IGBT was switched by a short pulse (50 μs) to impose a high-current pulse on the DUT. The VCE–VGE curve was also extracted as an important failure-precursor indicator. In the next stage, a power-cycling test was performed, and the i...
The efficiency of perovskite solar cells (PSCs) is advancing rapidly, yet their sensitivity to am... more The efficiency of perovskite solar cells (PSCs) is advancing rapidly, yet their sensitivity to ambient conditions poses challenges. An additional degradation mechanism, potential-induced degradation (PID), can emerge during field operation, but the understanding of PID within perovskite devices is limited. To exclude environmental stressors, this study is conducted in an inert environment at room temperature. PSCs and mini-modules are subjected to a 324 h PID stress test at −1000 V, revealing relative efficiency losses of around 29% and 24% for the PSCs and mini-modules, respectively, exposing subtle degradation differences. These degradation rates are notably lower than reported in the literature, suggesting possible additional degradation pathways arising from suboptimal encapsulation combined with ambient conditions. Subsequently, half of the stressed samples are subject to +1000 V for 523 h and recover to a reduced efficiency loss of 15% and 7.7% for the PSCs and module, respectively. In contrast, storing the stressed samples on the shelf increased the efficiency losses to 32% (PSCs) and 41% (module). Therefore, the post-PID rates differ significantly between both groups, whereas both effects of voltage recovery and progressed degradation are more pronounced in modules compared to cells. This study contributes to a robust method for PID research.
A high voltage degradation mechanism on photovoltaic (PV) modules called potential-induced degrad... more A high voltage degradation mechanism on photovoltaic (PV) modules called potential-induced degradation (PID) has gained a lot of attention since 2010 when Solon published their findings about PID [1]. The research conducted on PID mainly focused on industrial scale PV systems where potential differences between the solar cell and the grounded frame in the order of 1000 V and even more are not uncommon [2–5]. In this work, a stress test for PID according to the foil method as described in IEC 62804-1 and a recovery test in the same conditions on a set of five one-cell laminates is performed. However, by stressing the one-cell laminates at different voltages (-200 V, -600 V and -1000 V) and curing them at +500 V, which is compliant with residential voltages in the PV market, and +1000 V as a reference, more insight on the impact of stress and curing voltage on PID is gained. This is the basis for a voltage dependent model for PID. Furthermore, it is shown that the impact of the stress voltage on PID as a function of time exhibits a complex behaviour. At last, the impact of PID at different stress voltages on the different operational parameters of the one-cell laminates and their physical meaning is described.
Abstract A round robin test was carried out in four PV laboratories to compare accelerated lifeti... more Abstract A round robin test was carried out in four PV laboratories to compare accelerated lifetime testing. Twenty commercial non-packaged CIGS solar cells of similar performance were spread and exposed to damp heat conditions (85 °C and 85% RH) for approximately 500 h. Their JV performance was monitored during the damp heat exposure. After the test, three of the labs reported average efficiency losses of 87 ± 4%, 89 ± 5% and 92 ± 1%, which are close to median degradation rates found in literature. A higher degradation rate (efficiency loss of 97 ± 3% after only 143 h) was observed in the fourth lab. This was attributed to a poorly designed ceiling window sealing, which caused liquid water pooling on the samples. After modifying the climate chamber, the experiment was repeated with similar samples and an efficiency loss of 72 ± 6% after 475 h was observed for this lab.
2017 IEEE International Reliability Physics Symposium (IRPS)
Potential-induced degradation (PID) of photovoltaic (PV) modules gets a lot of attention since 20... more Potential-induced degradation (PID) of photovoltaic (PV) modules gets a lot of attention since 2010 when Solon published their findings about a degradation mechanism in their PV modules caused by high potential differences between the solar cell and the grounded frame [1]. Module level efficiency drops of 30% and more caused by PID have been reported [2], [3]. A stress test for PID according to IEC 62804 and a recovery test in the same conditions were conducted on a set of 49 commercially available PV modules. In this paper we report the irreversibility of highly affected (i.e. over 85% PID) PV modules. From this point of view, it is important to detect and recover PID before the point of no return. Furthermore, the impact of PID on the different parameters of a PV module and their relevance in order to detect PID in the field are reported.
An alternative energy source that has appeared beyond expectations and has seen a lot of progress... more An alternative energy source that has appeared beyond expectations and has seen a lot of progress is the fuel cell. A proton exchange membrane (PEM) fuel cell is chosen for analysis and requires a DC-DC boost converter as an interface between the fuel cell and the load to provide a high-gain regulated voltage. Although great effort towards developing different converter topologies has been made during recent decades, less attention has been devoted to the reliability and thermal performance assessment of the present converters. In this paper, five non-isolated DC-DC converters are analyzed in terms of both thermal behavior and reliability. The temperature estimation of semiconductor devices as a critical part of the thermal analysis has been made via a detailed thermal model and the reliability is evaluated by means of a power cycling test. Finally, a performance score has been attributed using the TOPSIS ranking methodology and considering all the criteria (e.g., the number of comp...
This paper examines the practical challenges of simplified setups aimed at achieving high-power I... more This paper examines the practical challenges of simplified setups aimed at achieving high-power IGBTs’ IC–VCE curve. The slope of this I–V curve (which is defined as on-resistance RCE) and the point where the VCE–VGE curve visibly bends (threshold gate voltage) can be suitable failure precursor parameters to determine an IGBT’s health condition. A simplified/affordable design for these specific measurements can be used for in-situ condition monitoring or field testing of switching devices. First, the possible I–V curve measurement methods are discussed in detail in order to prevent self-heating. The selected design includes two IGBTs in which the high-side IGBT was the device under test (DUT) with a constant gate voltage (VGE) of 15 V. Then, the low-side IGBT was switched by a short pulse (50 μs) to impose a high-current pulse on the DUT. The VCE–VGE curve was also extracted as an important failure-precursor indicator. In the next stage, a power-cycling test was performed, and the i...
Uploads
Papers