Search NASA⌕ Search

SEARCH · Search NASA

Results for “module reliability”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Evaluation of Low-Pressure-Sintered Multi-Layer Substrates for Medium-Voltage SiC Power Modules: Preprint

Direct-bonded aluminum (DBA) multi-layer substrates have been fabricated using low-pressure silver sintering. These multi-layer substrates can be used to reduce the peak electric field strength inside power modules. This benefit is particularly important for medium-voltage silicon carbide (SiC) MOSFETs due to their higher operating voltages. The voiding content and defect density of the bond used to create the multi-layer substrate stackup is critical to the thermal performance and reliability of the power module. This work two low-pressure-assisted sintering techniques; one using nano-silver preform and the other using nano-silver paste to bond 23 mm by 49 mm DBA substrates. Scanning acoustic microscopy (C-SAM) is used to evaluate the bond quality after sintering. To evaluate the reliability of the sintered multi-layer substrates, passive thermal cycling from –40 °C to 200 °C was performed. Cross-sections were cut at pre-determined intervals and imaged with Scanning Electron Microscopy (SEM). After 1,000 thermal cycles, minor cracking was observed, but no failures have occurred.

28 EE - Advanced Manufacturing Office (EE-5A)↗
DOE OSTI2021

PV Evolution in the Light of Circular Economy

As photovoltaic (PV) deployments increase, the increasing material volume presents challenges throughout the supply chain and eventual end-of-life waste management. Quantifying the value of lifetime, reliability, repair, reuse, recycling, and other options to increase circularity can help identify and prioritize research and technical solutions required to integrate PV into the circular economy. In this work, we capture the evolution of PV module technology, such as improved reliability and increasing market share of glass/glass modules. We discuss material circularity, lifetime and reliability, and energy return on investment as quantitative metrics to define and evaluate circularity and sustainability.

bifacial↗
DOE OSTI2020

Activation Energy for Solder Bond Degradation: Thermal Cycling of Field-aged Modules at Multiple Upper Temperatures

The reliability of solder joints in the solar cell metallization-interconnect system influences the lifetime of photovoltaic modules. Two field-aged modules-one with Sn 62 Pb 36 Ag 2 solder at the solder joints (Solarex MSX 60), and the other with the standard Sn 60 Pb 40 solder (Siemens M55)-were subjected to a modified thermal cycling (TC) test of IEC 61215. Three sections in each module were maintained at 85 degrees C, 95 degrees C, and 105 degrees C during the 15-minute high temperature dwell time. Current equivalent to the module short-circuit current was injected through the module when the chamber temperature was above 25 degrees C to simulate regular field operation. This novel approach aims to induce thermomechanical fatigue (TMF) at the solder joints and intermetallic compound (IMC) formation at the metal/solder interfaces. The activation energy (E a ) for solder bond degradation was calculated based on the series resistance (R s ) increase in TC testing rather than power drop to avoid the effect of confounding variables. Module-level R s increase in MSX 60 module after TC800 cycles and in M55 module after TC400 cycles was 1.22% and 183.7%, respectively. The E a determined for the module with 2wt% Ag is 0.24 eV and for that with the standard solder is 0.27 eV. The solder bond degradation seems to have been driven by TMF rather than IMC formation for both modules.

14 SOLAR ENERGY↗
DOE OSTI2020

Predictive Models and Novel Accelerated Tests for the Reliability of Cell Metallization and Solder Joints in Photovoltaic Modules

Interconnect, solder, and metallization-related failures are the primary reason for premature Si-based photovoltaic panel failure [1, 2] and can lead to a cascade of other failures, including thermal events. This combination of high severity and high occurrence means that understanding interconnect-related failures is key to the long-term health of the photovoltaic industry, and it is crucial that the industry adopt efficient and effective tests that aid in design-for-reliability and manufacturing quality control.

14 SOLAR ENERGY↗
DOE OSTI2016

Integrating a reservoir regulation scheme into a spatially distributed hydrological model

During the past several decades, numerous reservoirs have been built across the world for a variety of purposes such as flood control, irrigation, municipal/industrial water supplies, and hydropower generation. Consequently, natural streamflow timing and magnitude have been altered significantly by reservoir operations. In addition, the hydrological cycle can be modified by land use/land cover and climate changes. To understand the fine scale feedback between hydrological processes and water management decisions, a distributed hydrological model embedded with a reservoir component is of desire. In this study, a multi-purpose reservoir module with predefined complex operational rules was integrated into the Distributed Hydrology Soil Vegetation Model (DHSVM). Conditional operating rules, which are designed to reduce flood risk and enhance water supply reliability, were adopted in this module. The performance of the integrated model was tested over the upper Brazos River Basin in Texas, where two U.S. Army Corps of Engineers reservoirs, Lake Whitney and Aquilla Lake, are located. The integrated DHSVM model was calibrated and validated using observed reservoir inflow, outflow, and storage data. The error statistics were summarized for both reservoirs on a daily, weekly, and monthly basis. Using the weekly reservoir storage for Lake Whitney as an example, the coefficients of determination (R2) and the Nash-Sutcliff Efficiency (NSE) are 0.85 and 0.75, respectively. These results suggest that this reservoir module has promise for use in sub-monthly hydrological simulations. Enabled with the new reservoir component, the DHSVM model provides a platform to support adaptive water resources management under the impacts of evolving anthropogenic activities and substantial environmental changes.

Zhao, Gang↗
DOE OSTI2012

Dynamic Thermal Management for High-Performance Storage Systems

Thermal-aware design of disk drives is important because high temperatures can cause reliability problems. Dynamic Thermal Management (DTM) techniques have been proposed to operate the disk at the average case temperature, rather than at the worse case by modulating the activities to avoid thermal emergencies. The thermal emergencies can be caused by unexpected events, such as fan-breaks, increased inlet air temperature, etc. One of the DTM techniques is a delay-based approach that adjusts the disk seek activities, cooling down the disk drives. Even if such a DTM approach could overcome thermal emergencies without stopping disk activity, it suffers from long delays when servicing the requests. Thus, in this chapter, we investigate the possibility of using a multispeed disk-drive (called dynamic rotations per minute (DRPM)) that dynamically modulates the rotational speed of the platter for implementing the DTM technique. Using a detailed performance and thermal simulator of a storage system, we evaluate two possible DTM policies (- time-based and watermark-based) with a DRPM disk-drive and observe that dynamic RPM modulation is effective in avoiding thermal emergencies. However, we find that the time taken to transition between different rotational speeds of the disk is critical for the effectiveness of the DRPM based DTM techniques.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2020

Investigation of Failure Modes, Mechanisms and Driving Forces for Electrically Conductive Adhesives as Interconnects in PV Modules

In this work we describe our current progress into investigating the reliability of ECA interconnects for PV modules. Preliminary thermal cycling experiments demonstrated that both cohesive and adhesive failure of the ECA joint are relevant failure modes that result in an increase of the joints electrical resistance. A thorough viscoelastic characterization of the candidate ECA was conducted to enable accurate numerical modeling of the joint’s response to thermal cycling. Combined with critical and subcritical fracture measurements, the numerical model elucidates that an additional fatigue mechanism exists which can result in fracture well below subcritical debonding threshold values. It is also demonstrated that fracture of the ECA is more sensitive to humidity than temperature and subcritical debonding mechanisms do exist which are again more sensitive to humidity.

41 EE - Solar Energy Technologies Office (EE-4S)↗
DOE OSTI2014

Modeling the irradiance and temperature dependence of photovoltaic modules in PVsyst

In order to reliably simulate the energy yield of photovoltaic (PV) systems, it is necessary to have an accurate model of how the PV modules perform with respect to irradiance and cell temperature. Building on previous work that addresses the irradiance dependence, two approaches to fit the temperature dependence of module power in PVsyst have been developed and are applied here to recent multi-irradiance and -temperature data for a standard Yingli Solar PV module type. The results demonstrate that it is possible to match the measured irradiance and temperature dependence of PV modules in PVsyst. As a result, improvements in energy yield prediction using the optimized models relative to the PVsyst standard model are considered significant for decisions about project financing.

14 SOLAR ENERGY↗
DOE OSTI2022

Instrumented Photovoltaic Modules for Environmental Characterization and Simulation Model Validation

Photovoltaic modules are subjected to various mechanical stressors in their deployment environments, ranging from installation handling to wind and snow loads. Damage incurred during these mechanical events has the potential to initiate subsequent degradation mechanisms, reducing useful module lifespan. Thus, characterizing the mechanical state of photovoltaic modules is pertinent to the development of reliable packaging designs. In this work, photovoltaic modules with strain gauges directly incorporated into the module laminate were fabricated and subjected to mechanical loading to characterize internal strains within the module when under load. These experimental measurements were then compared against results obtained by high-fidelity finite-element simulations. The simulation results showed reasonable agreement in the strain values over time; however, there were large discrepancies in the magnitudes of these strains. Both the instrumentation technique and the finite-element simulations have areas where they can improve. These areas of improvement have been documented. Despite the observed discrepancies between the experimental and simulated results, the module instrumentation proved to be a useful gauge in monitoring and characterizing the mechanical state. With some process improvements, this method could potentially be applied to other environments that a photovoltaic module will encounter in its lifetime that are known to cause damage and degrade performance.

14 SOLAR ENERGY↗
DOE OSTI2021

PV Evolution in the Light of Circular Economy: Preprint

An ideal circular economy has no waste, end-of-life resources become new goods, and all production loops are closed. For the photovoltaic industry’s growing waste problem, quantifying the value of lifetime, reliability, repair, reuse, recycling and other options to increase circularity can help identify and prioritize research needs. In this work we capture the evolution of PV module technology, such as improved reliability and increasing market share of glass/glass modules. We then study the material and energy flows for PV production and use, and identify the circular processes and pathways yielding the most impact. We discuss material circularity and energy return on investment as quantitative metrics to define and evaluate circularity.

bifacial↗
DOE OSTI2026

Electrochemical Modeling of PID Leakage Current of PV Modules: Steady-State Current, Transient Current, and RC-Equivalent Circuit

Potential-induced degradation (PID) remains a significant reliability concern for photovoltaic (PV) modules, arising when a voltage difference between the module frame and the solar cells drives unintended leakage current through the glass-encapsulant stack. Although PID ultimately manifests as PID-s, PID-p, or PID-c, the underlying behavior of the leakage current-its magnitude and time dependence-requires clearer electrochemical interpretation. Traditional explanations attribute the initial transient current to bulk capacitive elements of the glass, encapsulant, and antireflection coatings, and the steady-state current according to their effective ohmic resistance. More recent studies, however, indicate that electrochemical charge-transfer processes at the encapsulant-metallization interface can play a dominant role in defining the leakage-current path. This paper develops a unified electrochemical framework for modeling PID leakage current. First, an RC-equivalent circuit is formulated by combining conventional RC elements with a Randles-type interface to capture transient leakage current through double-layer capacitance and faradaic processes at ionic-electronic boundaries. Second, the steady-state current-voltage behavior is explained using a linearized Butler-Volmer relationship, showing that the measured ohmic response corresponds to the low-overpotential limit of charge-transfer kinetics. Analytical results demonstrate that, for typical module materials-3.2-mm soda-lime glass and 0.45-mm encapsulant-the dominant modulators to PID leakage current are the glass surface resistance (under dry-surface conditions), the glass bulk capacitance, and the encapsulant resistance (under wet-surface conditions), with soda lime glass surface and EVA/POE encapsulant resistances primarily governing steady-state current. The proposed electrochemical model is validated against measured leakage-current data, showing good agreement in both the magnitude and the time-dependent evolution of PID leakage current.

14 SOLAR ENERGY↗
DOE OSTI2024

Energy Yield Loss Due to LETID

This presentation presents an open-source LETID model part of the PVDegradationTools, which can calculate solar modules degradation due to Light and Elevated Temperature (LETID).

degradation↗
DOE OSTI2023

Residual Stresses Affect Cell Fragment Movement

Predictive modeling tools such as the finite element method can be of tremendous help in assessing the reliability and long-term performance of photovoltaic modules. In order to obtain accurate results, the proper modeling of materials and manufacturing processes are of utmost importance. Module fabrication introduces thermo-mechanical stresses inside the module laminate, which need to be accounted for as residual stresses in finite element simulations. We found that cell fragment movement and crack opening displacements of fractured silicon cells within modules are affected by those residual stresses. Cell cracking remains a challenging topic in assessing the reliability and durability of damaged modules. Hence, accurately quantifying the separation and movement between cell fragments creates the foundation for establishing reliable lifetime and performance assessments of fractured silicon modules. Here, we present a modeling approach that uses upper and lower bounds to accurately account for the residual stresses introduced by the module lamination process. We designed a four-point flexure coupon test of a laminated, fractured silicon strip to validate our numerical results and found good agreement between our modeling methodology and the experimental data. Finally, we discuss the implications of the residual stresses on the normal crack opening and metallization wear-out of fractured silicon cells.

14 SOLAR ENERGY↗
DOE OSTI2021

PV in the circular economy, a dynamic framework analyzing technology evolution and reliability impacts

Rapid, terawatt-scale deployment of photovoltaic (PV) modules is required to decarbonize the energy sector. Despite efficiency and manufacturing improvements, material demand will increase, eventually resulting in waste as deployed modules reach end of life. Circular choices for decommissioned modules could reduce waste and offset virgin materials. We present PV ICE, an open-source python framework using modern reliability data, which tracks module material flows throughout PV life cycles. We provide dynamic baselines capturing PV module and material evolution. PV ICE includes multimodal end of life, circular pathways, and manufacturing losses. We present a validation of the framework and a sensitivity analysis. Results show that manufacturing efficiencies strongly affect material demand, representing >20% of the 9 million tons of waste cumulatively expected by 2050. Reliability and circular pathways represent the best opportunities to reduce waste by 56% while maintaining installed capacity. Shorter-lived modules generate 81% more waste and reduce 2050 capacity by 6%.

14 SOLAR ENERGY↗
DOE OSTI2021

Reliability Analysis of Large-Area, Low Pressure-Assisted Silver Sintering for Medium-Voltage Power Modules

Multi-layer insulating ceramic substrates can enable medium-voltage (MV) power modules with reduced peak electric field. This benefit is particularly important for MV silicon carbide (SiC) MOSFETs due to their higher operating voltages. Large-area, low-pressure assisted silver sintering is a potential solution for bonding substrates to create a multi-layer structure. The voiding content and defect density of the bond used to create the multi-layer substrate stack-up is critical to the reliability of the power module and the thermal performance, as this bond is in the primary path for heat dissipation in the power module structure. Here, samples of two-layer direct bonded aluminum (DBA) stacks have been fabricated and subjected to thermal cycling to analyze their reliability. Passive thermal cycling from -40 degrees C to 200 degrees C was performed. Cross-sections were cut at pre-determined intervals and imaged with Scanning Electron Microscopy (SEM). After 1000 thermal cycles, adhesive failures are observed between the sintered silver and the DBA surface. Cross-sections were cut and imaged via optical microscope and SEM. Thermal analyzer measurements are recorded on a 10-kV SiC power module utilizing the sintered DBA substrate stacks.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2020

Chapter 6: Luminescence and Thermal Imaging of Thin-Film Photovoltaic Materials, Devices, and Modules

In this chapter, we describe luminescence and thermal imaging in the context of thin-film PV devices. First, we discuss both traditional and developing experimental designs, including dark LIT (DLIT), illuminated LIT, PL using different illumination configurations, traditional EL performed under forward -bias current injection, and contactless EL induced with sub -cell illumination patterns. Next, we provide some brief theoretical background to highlight relationships between fundamental materials properties and the resulting luminescence and thermal images. Finally, we give examples of thin-film PV PL, EL, and LIT images to demonstrate the utility of these imaging methods ranging from understanding the microstructure of active layers to managing the quality and reliability of full PV modules.

41 EE - Solar Energy Technologies Office (EE-4S)↗
DOE OSTI2016

Method for reworkable packaging of high speed, low electrical parasitic power electronics modules through gate drive integration

A multichip power module directly connecting the busboard to a printed-circuit board that is attached to the power substrate enabling extremely low loop inductance for extreme environments such as high temperature operation. Wire bond interconnections are taught from the power die directly to the busboard further enabling enable low parasitic interconnections. Integration of on-board high frequency bus capacitors provide extremely low loop inductance. An extreme environment gate driver board allows close physical proximity of gate driver and power stage to reduce overall volume and reduce impedance in the control circuit. Parallel spring-loaded pin gate driver PCB connections allows a reliable and reworkable power module to gate driver interconnections.

42 ENGINEERING↗