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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.

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All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Medium-Duty Delivery Truck Integrated Bidirectional Wireless Power Transfer System With Grid and Stationary Energy Storage System Connectivity

Electric vehicles (EVs) can provide power to the grid or buildings similar to distributed energy resources (DER) for energy balancing applications or optimizing the operation of the microgrids in harmony with the other DER assets. This article presents the operating modes of a bidirectional wireless power transfer (WPT) system designed for a medium-duty package delivery vehicle. The WPT system designed for this study can transfer 20 kW of power across 11 in of air gap using custom-designed double-D (DD) couplers with LCC–LCC tuning networks. The proposed system utilizes a 480-V three-phase grid connection, a plug-in hybrid delivery truck with bidirectional WPT, and a stationary energy storage system (SESS) that can be connected to the primary-side dc link. Due to the differences in primary and secondary dc bus voltages, and considering the voltage of the SESS, asymmetric voltage gains were used in the system. Sensitivity analyses of this system with respect to these voltage levels are presented. Five different operating modes of the grid, SESS, and the EV battery are investigated with experimental results. Control algorithms are described for grid-to-vehicle (G2V) and vehicle-to-grid (V2G) operating modes. A bidirectional WPT system is operated with a power factor of 0.99 on the grid side in every operating mode. The EV battery was charged with 20.3 kW with an overall efficiency of 93.02% in the G2V operating mode. Finally, in the V2G operating mode, the WPT system provided 12.82 kW of power back to the grid with an overall efficiency of 89.08%.

25 ENERGY STORAGE↗
DOE OSTI2021

Electric Drive Technology Trends, Challenges, and Opportunities for Future Electric Vehicles

The transition to electric road transport technologies requires electric traction drive systems to offer improved performances and capabilities, such as fuel efficiency (in terms of MPGe, i.e., miles per gallon of gasoline-equivalent), extended range, and fast-charging options. The enhanced electrification and transformed mobility are translating to a demand for higher power and more efficient electric traction drive systems that lead to better fuel economy for a given battery charge. To accelerate the mass-market adoption of electrified transportation, the U.S. Department of Energy (DOE), in collaboration with the automotive industry, has announced the technical targets for light-duty electric vehicles (EVs) for 2025. This article discusses the electric drive technology trends for passenger electric and hybrid EVs with commercially available solutions in terms of materials, electric machine and inverter designs, maximum speed, component cooling, power density, and performance. Additionally, the emerging materials and technologies for power electronics and electric motors are presented, identifying the challenges and opportunities for even more aggressive designs to meet the need for next-generation EVs. Some innovative drive and motor designs with the potential to meet the DOE 2025 targets are also discussed.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2021

Optimal Transactive Energy Trading of Electric Vehicle Charging Stations With On-Site PV Generation in Constrained Power Distribution Networks

This paper presents a two-level transactive energy market framework, that enables energy trading among electric vehicle charging stations (EVCSs). At the lower level, the discharging capability of EVs and on-site PV generation are leveraged by individual EVCS for participating in the transactive trading with their peers. Once the lower-level trading is completed, EVCSs trade energy at the upper level through the power grid network managed by the distribution system operator (DSO). The upper-level market is cleared while satisfying the power distribution network constraints. A cooperative game-based model is proposed to model the energy trading among EVCSs. To this end, the asymmetric Nash bargaining method is applied to allocate the grand coalition's payoff to each EVCS at the upper-level market, while a weighted proportional allocation method is used to allocate individual EVCS's payoff to its respective EVs at the lower-level market. In this work, the upper-level market formulation is further decomposed into two subproblems representing an energy scheduling and trading subproblem which maximizes EVCS payoffs, and a bargaining subproblem which allocates EVCS payoffs. The effectiveness of the proposed framework for incentivizing transactive trades among EVs and EVCSs is validated in case studies.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2015

Novel hard, tough HfAlSiN multilayers, defined by alternating Si bond structure, deposited using modulated high-flux, low-energy ion irradiation of the growing film

Hf{sub 1−x−y}Al{sub x}Si{sub y}N (0 ≤ x ≤ 0.14, 0 ≤ y ≤ 0.12) single layer and multilayer films are grown on Si(001) at 250 °C using ultrahigh vacuum magnetically unbalanced reactive magnetron sputtering from a single Hf{sub 0.6}Al{sub 0.2}Si{sub 0.2} target in mixed 5%-N{sub 2}/Ar atmospheres at a total pressure of 20 mTorr (2.67 Pa). The composition and nanostructure of Hf{sub 1−x−y}Al{sub x}Si{sub y}N films are controlled by varying the energy E{sub i} of the ions incident at the film growth surface while maintaining the ion-to-metal flux ratio constant at eight. Switching E{sub i} between 10 and 40 eV allows the growth of Hf{sub 0.78}Al{sub 0.10}Si{sub 0.12}N/Hf{sub 0.78}Al{sub 0.14}Si{sub 0.08}N multilayers with similar layer compositions, but in which the Si bonding state changes from predominantly Si–Si/Si–Hf for films grown with E{sub i} = 10 eV, to primarily Si–N with E{sub i} = 40 eV. Multilayer hardness values, which vary inversely with bilayer period Λ, range from 20 GPa with Λ = 20 nm to 27 GPa with Λ = 2 nm, while fracture toughness increases directly with Λ. Multilayers with Λ = 10 nm combine relatively high hardness, H ∼ 24 GPa, with good fracture toughness.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Excitation of the {sup 229m}Th nuclear isomer via resonance conversion in ionized atoms

Pressing problems concerning the optical pumping of the 7.6-eV {sup 229m}Th nuclear isomer, which is a candidate for a new nuclear optical reference point for frequencies, are examined. Physics behind the mechanism of the two-photon optical pumping of the isomer is considered. It is shown that, irrespective of the pumping scheme, a dominant contribution comes, in accord with what was proven earlier for the 3.5-eV isomer, from the resonance 8s–7s transition. Details of an optimum experimental scheme are discussed. It is shown that, after isomer excitation, the atom involved remains with a high probability in an excited state at an energy of about 0.5 eV rather than in the ground state, the required energy of the two photons being equal to the energy of the nuclear level plus the energy of the lowest 7s state of the atom. The estimated pumping time is about 1.5 s in the case where the field strength of each laser is 1 V/cm.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

Admittance spectroscopy of solar cells based on GaPNAs layers

Admittance spectroscopy is used to study defect levels in the layers of a GaPNAs quaternary solid solution. Centers with an activation energy of 0.22 eV and a capture cross section of ∼2.4 × 10{sup −15} cm{sup 2} are found in doped n-GaPNAs layers grown on GaP substrates. These centers correspond to already known Si{sub Ga} + V{sub P} defects in n-GaP; annealing decreases their concentration by several times. A level with an activation energy of 0.23–0.24 eV and capture cross section of ∼9.0 × 10{sup −20} cm{sup 2} is found in undoped GaPNAs layers grown on Si and GaP substrates. The concentration of these centers substantially decreases upon annealing, and, at annealing temperatures exceeding 600°C, there is absolutely no response from these defects. For undoped GaPNAs layers grown on GaP substrates, a level with an activation energy of 0.18 eV and capture cross section of ∼1.1 × 10{sup −16} cm{sup 2} is also found. The concentration of these centers remains unchanged upon annealing.

36 MATERIALS SCIENCE↗
DOE OSTI2019

The Unoccupied Electronic States of the Ultrathin Diphenylphthalide Films on the Surface of the Highly Oriented Pyrolytic Graphite

The results of diagnostics of the atomic composition of a diphenylphthalide (DPP) film thermally precipitated in vacuum by the of X-ray photoelectric spectroscopy (XPS) method are presented. The results of examination of the unoccupied electronic states of the ultrathin DPP films with the thickness up to 10 nm on the surface of the highly oriented pyrolytic graphite (HOPG) by the total current spectroscopy (TCS) method in the energy range from 5 to 20 eV above E{sub F} are presented. In this range, the main maxima in the total current spectra are identified. The analysis of the TCS results with consideration of the theoretical calculation results has shown that the low-energy maxima observed at the energies from 6 to 7.5 eV are induced predominately by π* electron orbitals of DPP films. The values of the energy E{sub vac} in relation to E{sub F}, i.e., of the electron work function in the DPP films at the film thickness of 5–10 nm, are found experimentally at a level of 4.3 ± 0.1 eV. The negative charge transfer from an organic film to the substrate corresponds to the formation of the HOPG/DPP boundary potential barrier during the thermal deposition of the DPP film.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Decomposition of Aromatic Compounds Relevant to Organic Electronics under Exposure to Low-Energy Electrons

The persistence of molecules to destruction under the action of low-energy (0–15 eV) electrons is investigated for a representative series of aromatic compounds of interest to organic electronics and photonics. The energy regions of the most effective interaction of free electrons with isolated molecules, which leads to the dissociative decay of molecules due to the formation of short-lived negative molecular ions unstable to fragmentation, are determined using resonance electron capture negative ion mass spectrometry. The characteristic fragmentation channels for molecular ions are revealed for some groups of compounds, and the threshold energies of the most significant fragmentation processes are estimated. Polycyclic aromatic hydrocarbons and oligophenyls are stable to the action of electrons in the electron energy range ~0–3 eV, above which these compounds are decomposed into the single channel of hydrogen atom detachment. For compounds with heterocycles (oxadiazole and maleimide derivatives) in their structure, the stability range narrows down to ~0–1 eV. Electrons with energies exceeding this range initiate the decay of molecules (anions) via various channels among which the detachment of a cyanate anion from a heterocyclic nucleus is the most intense and destructive process.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2014

Electric Vehicle Performance at McMurdo Station (Antarctica) and Comparison with McMurdo Station Conventional Vehicles

This report examines the performance of two electric vehicles (EVs) at McMurdo, Antarctica (McMurdo). The study examined the performance of two e-ride Industries EVs initially delivered to McMurdo on February 16, 2011, and compared their performance and fuel use with that of conventional vehicles that have a duty cycle similar to that of the EVs used at McMurdo.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2018

Characterize the Demand and Energy Characteristics of Residential Electric Vehicle Supply Equipment

The EV Project enrolled over 8,000 residential participants. These participants purchased or leased a Nissan Leaf or Chevrolet Volt. The EV Project provided and installed Blink Electric Vehicle Supply Equipment (EVSE), used to recharge their PEV, in exchange for their agreement to allow project analysts to evaluate data collected from charging their PEV at their residence and away from home. The power required to recharge a PEV can be a significant contributor to the electrical load a residence places on the electric grid. What insight can The EV Project data provide in characterizing this contribution in terms of power demand and energy consumption to assist electric utilities in PEV adoption planning?

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2015

Characterize the Demand and Energy Characteristics of Direct Current Fast Chargers

The electric vehicle supply equipment (EVSE) deployed by The EV Project included both AC Level 2 (ACL2) and DCFC units. Over 100 of the Blink dual-port DCFCs were deployed by The EV Project. These DCFCs were all publicly accessible, located in workplaces, near traffic hubs, retail centers, parking lots, restaurants, and similar locations. The Blink DCFC dual-port design sequences the charge from one port to the other, delivering power to only one of two vehicles connected at a time. The actual power delivered through a port is determined by the PEV’s on-board battery management system (BMS).The Blink DCFC is capable of charging at power up to 60 kW. For the EV Project, the Nissan Leaf was the only participating PEV capable of accepting a DC charge. The Nissan Leaf BMS allows acceptance of up to 50 kW DC power. At this rate, the DCFC is capable of recharging a Leaf battery from a 30% state of charge (SOC) to an 80% SOC in about 25 minutes. The power required by the DCFC to recharge a plug-in electric vehicle (PEV) can be a significant additional electrical load for the charging site host and contributes to the overall power demand on the electric grid.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2015

What is the Controllable Electrical Demand from Non-Residential Electric Vehicle Supply Equipment in the San Diego Region?

The EVSE deployed by The EV Project included both residential and non-residential units. Approximately 4,000 non-residential AC Level 2 (ACL2) EVSE were installed in workplace environments, fleet applications and publicly accessible locations near retail centers, parking lots, and similar locations. The power required to recharge a plug-in electric vehicle (PEV) can be a significant additional electrical load to electric grid but may also provide a controllable resource for mitigating grid overload issues. Electric utilities seek ways to reduce their generating costs by controlling the maximum (peak) load on their system, their generating resources, and frequency and voltage control on the system. This management may be achieved indirectly, through rates that incentivize their customers (including PEV owners) to manage the charging of their vehicles, or may take the form of direct utility control of non-residential EVSE. What insight can The EV Project data provide related to the magnitude of this impact and the potential controllable demand? The paper What is the Controllable Electrical Demand from Residential EVSE in the San Diego Region?1 addressed this question for residential EVSE. This paper quantifies the total controllable electrical load imposed on the electric grid by non-residential PEV charging in the San Diego region of The EV Project.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2015

What Were the Driving and Charging Behaviors of High Mileage Accumulators?

During The EV Project, data was collected from approximately 8,000 Nissan Leaf and Chevrolet Volts that together accumulated over 124 million miles while generating data. There were significant differences in the technologies employed by the two primary vehicles in The EV Project; Nissan Leaf, and Chevrolet Volt. Because the Volt has an on-board range extending internal combustion engine (ICE) to recharge the battery while driving (extended range mode), the vehicle could be driven much further between charges. The Leaf’s range is limited by the battery capacity, but unlike the Volt can be “fast-charged” providing an opportunity to extend its daily travel distance. Many Plug-In Electric Vehicle (PEV) drivers in The EV Project accumulated miles at rates similar to what one would expect from an ICE vehicle. This paper examines some of the driving and charging characteristics of those PEV drivers who accumulated the most miles on their vehicles.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2015

Characterize Clustering of Non-Residential Alternating Current Level 2 Electric Vehicle Supply Equipment

The EVSE deployed by The EV Project included both residential and non-residential units. Approximately 4,000 non-residential AC Level 2 (ACL2) EVSE were installed in workplace environments, fleet applications and those publicly accessible located near retail centers, parking lots, and similar locations. The Blink ACL2 is capable of charging at up to 7.2 kW power, although most vehicles in The EV Project charged at about 3.7 kW. The charge rate and energy consumed to recharge the battery are determined by the plug-in electric vehicle’s (PEV’s) on-board battery management system. The impact on the local electrical grid becomes greater when several EVSE are charging PEVs on a site at the same time, or when several commercial EVSE sites are geographically close and charging simultaneously. This may place stresses on the local power transformer providing energy to these sites. What insight can The EV Project data provide in characterizing the effect of several geographically close non-residential EVSE?

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2023

USAID Colombia Young Leaders Workforce Training Program Action Plans: Planning for Electric Vehicle Charging Infrastructure in Bogotá

As part of the U.S. Agency for International Development (USAID)-National Renewable Energy Laboratory (NREL) Young Leaders Workforce Training Program in Colombia, the Grupo Energía Bogotá (GEB) participants leveraged their training and professional experience to develop an action plan for modeling and evaluating Bogotá's projected electric vehicle (EV) charging needs to meet future demand. This case study summarizes the collaboration between USAID-NREL, GEB, and the Bogotá Department of Transportation Mobility Secretariat (SDM) to estimate EV charging station needs to meet projected future EV sales in the city of Bogotá and determine high-priority locations within the greater Bogotá metropolitan area for planning and applying EVSE investment and installation.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2024

Electric Vehicle Charging Infrastructure Trends from the Alternative Fueling Station Locator (Third Quarter 2023)

Electric vehicle (EV) charging infrastructure continues to rapidly change and grow. Using data from the U.S. Department of Energy's (DOE's) Alternative Fueling Station Locator, this report provides a snapshot of the state of EV charging infrastructure in the United States in the third calendar quarter of 2023 (Q3 2023) by charging level, network, and location. Additionally, this report measures the current state of charging infrastructure compared to the infrastructure requirement scenario outlined in the National Renewable Energy Laboratory (NREL) report, The 2030 National Charging Network: Estimating U.S. Light-Duty Demand for Electric Vehicle Charging Infrastructure. This information is intended to help transportation planners, policymakers, researchers, infrastructure developers, and others understand the rapidly changing landscape of EV charging infrastructure. This is the fifteenth report in a series. Reports from previous quarters can be found in the Alternative Fuels Data Center (AFDC) and NREL publication databases, as well as the AFDC Charging Infrastructure Trends page (https://afdc.energy.gov/fuels/electricity_infrastructure_trends.html).

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2023

Recommendations for Minimum Required Error Codes for Electric Vehicle Charging Infrastructure

OCPP protocol manages the interaction between the EVSE and its respective back-end communication network. It plays a pivotal role in both error reporting and troubleshooting, carried out primarily through the CSMS. OCPP defines both standard error codes and a flexible framework for creating and communicating custom error codes. The OCPI protocol orchestrates the communication between different backhaul communication networks, incorporating the exchange of error codes. These error codes are instrumental in pinpointing and rectifying issues that can surface prior to, during, or after charging operations, fortifying the reliability and resilience of the EV charging infrastructure. The flexibility offered by the OCPP and OCPI frameworks through the introduction of custom error codes also creates its own set of challenges. While the integration of custom error codes allows for enhanced granularity, it also introduces inconsistencies and fragmentation within the overarching diagnostic reporting system. To address the challenges with custom error codes this report proposes a set of Minimum Required Error Codes (MRECs) for streamlined error reporting, interpretability, and diagnostics. Recommendations in this report are based on independent analysis of custom error codes from multiple stakeholders within the EV charging ecosystem. For better error resolution, this report also assigns one or more entities responsible for the resolution of every mentioned error code. Finally, a functional classification for each mentioned error code is also identified to describe the nature of the error. In summary, the purpose of this document is to simplify the troubleshooting process and increase charging reliability for all EV users. This report serves as a recommendation for industry stakeholders, encouraging a unified methodology to define, transmit, and interpret common error codes.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2024

Electric Vehicle Charging Infrastructure Trends from the Alternative Fueling Station Locator: Fourth Quarter 2023

Electric vehicle (EV) charging infrastructure continues to rapidly change and grow. Using data from the U.S. Department of Energy's (DOE's) Alternative Fueling Station Locator, this report provides a snapshot of the state of EV charging infrastructure in the United States in the fourth calendar quarter of 2023 (Q4 2023) by charging level, network, and location. Additionally, this report measures the current state of charging infrastructure compared to the infrastructure requirement scenario outlined in the National Renewable Energy Laboratory (NREL) report, The 2030 National Charging Network: Estimating U.S. Light-Duty Demand for Electric Vehicle Charging Infrastructure. This information is intended to help transportation planners, policymakers, researchers, infrastructure developers, and others understand the rapidly changing landscape of EV charging infrastructure. This is the sixteenth report in a series. Reports from previous quarters can be found in the Alternative Fuels Data Center (AFDC) and NREL publication databases, as well as the AFDC Charging Infrastructure Trends page (https://afdc.energy.gov/fuels/electricity_infrastructure_trends.html).

33 ADVANCED PROPULSION SYSTEMS↗

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