Results for “Battery Modeling” — Page 15

NASA NTRS1995

Electrolyte management considerations in modern nickel hydrogen and nickel cadmium cell and battery designs

In the early 1980's the NASA Lewis group addressed the topic of designing nickel hydrogen cells for LEO applications. As published in 1984, the design addressed the topics of gas management, liquid management, plate expansion, and the recombination of oxygen during overcharge. This design effort followed principles set forth in an earlier Lewis paper that addressed the topic of pore size engineering. At about that same time, the beneficial effect on cycle life of lower electrolyte concentrations was verified by Hughes Aircraft as part of a Lewis funded study. A succession of life cycle tests of these concepts have been carried out that essentially verified all of this earlier work. During these past two decades, some of the mysteries involved in the active material of the nickel electrode have been resolved by careful research efforts carried out at several laboratories. At The Aerospace Corporation, Dr. Zimmerman has been developing a sophisticated model of an operating nickel hydrogen cell which will be used to model certain mechanisms that have contributed to premature failures in nickel hydrogen and nickel cadmium cells. During the course of trying to understand and model abnormal nickel hydrogen cell behaviors, we have noted that not enough attention has been paid to the potassium ion content in these cells, and more recently batteries. Several of these phenomenon have been well known in the area of alkaline fuel cells, but only recently have they been examined as they might impact alkaline cell designs. This paper will review three general areas where the potassium ion content can impact the performance and life of nickel hydrogen and nickel cadmium devices, Once these phenomenon are understood conceptually, the impact of potassium content on a potential cell design can be evaluated with the aid of an accurate model of an operating cell or battery. All three of these areas are directly related to the volume tolerance and pore size engineering aspects of the components used in the cell or battery design: (1) The gamma phase uptake of potassium ion can result in a lowering of the electrolyte concentration. This leads to a higher electrolyte resistance as well as electrolyte diffusional limitations on the discharge rate. This phenomenon will also impact the response of the cell to a reconditioning cycle. (2) The impact of low level shunt currents in multi-cell con figurations will result in the movement of potassium ion from one part of the battery to another. This will impact the electrolyte volume/vapor pressure relationships within the cell or battery. (3) The transport of water vapor from place to place under the driving force of a tempetature gradient has already impacted cells for the case where water vapor is condensed on a colder cell wall. The paper will explore the convective and diffusive movement of gases saturated with water vapor from a warmer plate pack to a cooler one - both with and without liquid communication.

Thaller, L. H.↗

NASA NTRS1984

Control algorithms and computer simulation of a stand-alone photovoltaic village power system

At Stand-Alone Photovoltaic (SAPV) power systems increase in size and load diversity, the design and simulation of control subsystems takes on added importance. These SAPV systems represent 'mini utilities' with commensurate controls requirements, albeit with the added complexity of the energy source (sunlight received) being an uncontrollable variable. This paper briefly describes a stand-alone photovoltaic power/load system computerized simulation model. The model was tested against operational data from the Schuchuli stand-alone village photovoltaic system and has achieved acceptable levels of simulation accuracy. The model can be used to simulate system designs although with probable battery modification.

Groumpos, P. P.↗

NASA NTRS1989

Surface energy and radiation balance systems - General description and improvements

Surface evaluation of sensible and latent heat flux densities and the components of the radiation balance were desired for various vegetative surfaces during the ASCOT84 experiment to compare with modeled results and to relate these values to drainage winds. Five battery operated data systems equipped with sensors to determine the above values were operated for 105 station days during the ASCOT84 experiment. The Bowen ratio energy balance technique was used to partition the available energy into the sensible and latent heat flux densities. A description of the sensors and battery operated equipment used to collect and process the data is presented. In addition, improvements and modifications made since the 1984 experiment are given. Details of calculations of soil heat flow at the surface and an alternate method to calculate sensible and latent heat flux densities are provided.

Fritschen, Leo J.↗

NASA NTRSDate not supplied

Interpretable Tree-Based and Graph Neural Network Approaches for Novel Solid State Electrolyte Design

All-solid-state batteries with Li metal anode can address the safety issues surrounding traditional Li-ion batteries as well as the demand for higher energy densities. However, the development of solid electrolytes simultaneously possessing high ionic conductivity and good chemical and electrochemical stabilities has proven to be a challenge. I will present our informatics approach to explore the Li compound space for promising solid electrolytes using high-throughput multi-property screening and interpretable machine learning. This is accomplished through the generation of a large database of battery-related materials properties of Li compounds. We use tree-based ensemble learning methods and graph neural network approaches to accurately learn relationships between crystal structures and corresponding thermodynamic and kinetic properties, with interpretability being a major focus. Our models give us the ability to enable rapid discovery and design of novel solid-state battery chemistries.

Materials discovery↗

NASA NTRSDate not supplied

Interpretable ML Approaches for Novel Solid State Electrolyte Design

All-solid-state batteries with Li metal anode can address the safety issues surrounding traditional Li-ion batteries as well as the demand for higher energy densities. However, the development of solid electrolytes simultaneously possessing high ionic conductivity and good chemical and electrochemical stabilities has proven to be a challenge. I will present our informatics approach to explore the Li compound space for promising solid electrolytes using high-throughput multi-property screening and interpretable machine learning. This is accomplished through the generation of a large database of battery-related materials properties of Li compounds. We use tree-based ensemble learning methods and graph neural network approaches to accurately learn relationships between crystal structures and corresponding thermodynamic and kinetic properties, with interpretability being a major focus. Our models give us the ability to enable rapid discovery and design of novel solid-state battery chemistries.

Shreyas J Honrao↗

NASA NTRS1987

AC impedance study of degradation of porous nickel battery electrodes

AC impedance spectra of porous nickel battery electrodes were recorded periodically during charge/discharge cycling in concentrated KOH solution at various temperatures. A transmission line model (TLM) was adopted to represent the impedance of the porous electrodes, and various model parameters were adjusted in a curve fitting routine to reproduce the experimental impedances. Degradation processes were deduced from changes in model parameters with electrode cycling time. In developing the TLM, impedance spectra of planar (nonporous) electrodes were used to represent the pore wall and backing plate interfacial impedances. These data were measured over a range of potentials and temperatures, and an equivalent circuit model was adopted to represent the planar electrode data. Cyclic voltammetry was used to study the characteristics of the oxygen evolution reaction on planar nickel electrodes during charging, since oxygen evolution can affect battery electrode charging efficiency and ultimately electrode cycle life if the overpotential for oxygen evolution is sufficiently low.

Lenhart, Stephen J.↗

NASA NTRSDate not supplied

Probability of Obstacle Collision for UAVs in Presence of Wind

For incorporation of unmanned aerial vehicles into the National Airspace, ensuring safety of the airspace including the vehicles, people, and property on the ground is of utmost importance. One of the safety-critical factors for unmanned aviation flights is the risk of deviating from a planned trajectory resulting in a variety of hazards, including potential loss of separation between vehicle and obstacles or unexpected battery energy consumption. Off-nominal conditions introduced by component failures, degraded controllability and environmental disturbances such as wind gusts can lead to unacceptable unexpected deviations from the flight trajectory. It is essential to accurately model such effects on the flight trajectory while computing safety thresholds such as minimum separation from surrounding obstacles, available battery resource to complete the mission or determining delay in the expected time of arrival of flights. In this paper, a tool is presented based on Gaussian Process Regression for wind representation over a pre-defined trajectory for fast, yet approximated, in-time evaluation of possible trajectory deviations caused by wind gusts. The deviation in the planned trajectory caused by wind is further simulated utilizing a 6 degrees-of-freedom (DOF) UAV trajectory simulator comprising of a rotorcraft lumped-mass model with LQRI controller. Both steady-state wind and wind gust effects are investigated. The probability of collision with obstacle is computed and demonstrated on real flight data from experimental flights of an octocopter at NASA Langley Research Center in the presence of simulated obstacles and wind conditions. Effect of varying wind conditions and varying UAV airspeed is further demonstrated on experimental flights in the presence of wind measured by ground based weather service stations. The proposed approach would eventually benefit timely mitigation of current and future safety-critical events in autonomous systems by enabling risk-informed decision making.

Portia Banerjee↗

NASA NTRS1977

Accelerated test program

A brief discussion on the accelerated testing of batteries is given. The statistical analysis and the various aspects of the modeling that was done and the results attained from the model are also briefly discussed.

Ford, F. E.↗

NASA NTRS1980

Status of nickel-hydrogen cell technology

Nickel hydrogen cell technology has been developed which solves the problems of thermal management, oxygen management, electrolyte management, and electrical and mechanical design peculiar to this new type of battery. This technology was weight optimized for low orbit operation using computer modeling programs but is near optimum for other orbits. Cells ranging in capacity up to about 70 ampere-hours can be made from components of a single standard size and are available from two manufacturers. The knowledge gained is now being applied to the development of two extensions to the basic design: a second set of larger standard components that will cover the capacity range up to 150 ampere-hours; and the development of multicell common pressure vessel modules to reduce volume, cost and weight. A manufacturing technology program is planned to optimize the producibility of the cell design and reduce cost. The most important areas for further improvement are life and reliability which are governed by electrode and separator technology.

Warnock, D. R.↗

NASA NTRS1985

Advanced vehicle systems assessment. Volume 4: Supporting analyses

Volume 4 (Supporting Analyses) is part of a five-volume report, Advanced Vehicle Systems Assessment. Thirty-nine individuals, knowledgeable in advanced technology, were interviewed to obtain their preferences. Rankings were calculated for the eight groups they represented, using multiplicative and additive utility models. The four topics for consideration were: (1) preferred range for various battery technologies; (2) preferred battery technology for each of a variety of travel ranges; (3) most promising battery technology, vehicle range combination; and (4) comparison of the most preferred electric vehicle with the methanol-fuled, spark-ignition engine vehicle and with the most preferred of the hybrid vehicles.

Hardy, K.↗

NASA NTRS2009

Astronaut Thermal Exposure: Re-Entry After Low Earth Orbit Rescue Mission

The STS-125 mission, launched May 11, 2009, is the final servicing mission to the Hubble Space Telescope. The repair mission's EVA tasks are described, including: installing a new wide field camera; installing the Cosmic Origins Spectrograph; repairing the Space Telescope Imaging Spectrograph; installing a new outer blanket layer; adding a Soft Capture and Rendezvous System for eventual controlled deorbit in about 2014; replacing the 'A' side Science Instrument Command and Data Handling module; repairing the Advanced Camera for surveys; and, replacing the rate sensor unit gyroscopes, fine guidance sensors and 3 batteries. Additionally, the Shuttle crew cabin thermal environment is described. A CFD model of per person CO2 demonstrates a discrepancy between crew breathing volume and general mid-deck levels of CO2. A follow-on CFD analysis of the mid-deck temperature distribution is provided. Procedural and engineering mitigation plans are presented to counteract thermal exposure upon reentry to the Earth atmosphere. Some of the procedures include: full cold soak the night prior to deorbit; modifying deck stowage to reduce interference with air flow; and early securing of avionics post-landing to reduce cabin thermal load prior to hatch opening. Engineering mitigation activities include modifying the location of the aft starboard ICUs, eliminating the X3 stack and eliminating ICU exhaust air directed onto astronauts; improved engineering data of ICU performance; and, verifying the adequacy of mid-deck temperature control using CFD models in addition to lumped parameter models. Post-mitigation CFD models of mid-deck temperature profiles and distribution are provided.

Gillis, David B.↗

NASA NTRS2009

Creating a Lunar EVA Work Envelope

A work envelope has been defined for weightless Extravehicular Activity (EVA) based on the Space Shuttle Extravehicular Mobility Unit (EMU), but there is no equivalent for planetary operations. The weightless work envelope is essential for planning all EVA tasks because it determines the location of removable parts, making sure they are within reach and visibility of the suited crew member. In addition, using the envelope positions the structural hard points for foot restraints that allow placing both hands on the job and provides a load path for reacting forces. EVA operations are always constrained by time. Tasks are carefully planned to ensure the crew has enough breathing oxygen, cooling water, and battery power. Planning first involves computers using a virtual work envelope to model tasks, next suited crew members in a simulated environment refine the tasks. For weightless operations, this process is well developed, but planetary EVA is different and no work envelope has been defined. The primary difference between weightless and planetary work envelopes is gravity. It influences anthropometry, horizontal and vertical mobility, and reaction load paths and introduces effort into doing "overhead" work. Additionally, the use of spacesuits other than the EMU, and their impacts on range of motion, must be taken into account. This paper presents the analysis leading to a concept for a planetary EVA work envelope with emphasis on lunar operations. There is some urgency in creating this concept because NASA has begun building and testing development hardware for the lunar surface, including rovers, habitats and cargo off-loading equipment. Just as with microgravity operations, a lunar EVA work envelope is needed to guide designers in the formative stages of the program with the objective of avoiding difficult and costly rework.

Griffin, Brand N.↗

NASA NTRSDate not supplied

Systems Health Management and Prognostics Approaches for Electric Aircrafts

As more and more electric vehicles emerge in our daily operation progressively, a very critical challenge lies in the prediction of remaining driving flying time/distance for the flying vehicles. This information is important, particularly in the case of auto vehicles, because such vehicles can become self-aware, autonomously compute its own capabilities, and identify how to best plan and successfully complete vehicular missions safely. In case of electric aircrafts, computing the remaining flying time is also safety-critical, since an aircraft that runs out of power (battery charge) while in the air will eventually lose control leading to catastrophe. To facilitate and solve the prediction problem, awareness of the current health state of the system is key, since it is necessary to perform condition-based predictions. To accurately predict the future state of any system, it is required to possess knowledge of its current health state and future operational conditions. Latest achievements of data-driven algorithms in regression of complex nonlinear functions and classification tasks have generated a growing interest in artificial intelligence for industrial applications. Complex multi-physics models as well as digital twins, once purely built on physics and corresponding simplified lumped parameter iterations, can now benefit from machine learning algorithms to mitigate the lack of understanding of some complex behavior. Given models of the current and future system behavior, a general approach of model-based prognostics can solve the prediction problem and further decision-making. A systematic prediction framework is implemented to identify all possible sources of uncertainty, quantify each of them individually, and mathematically estimate their combined effect on the system-level quantity of interest, in this case, the remaining flying time/distance of the unmanned aircraft. Note - This presentation contains all previously published information.

Systems Health Managent↗

NASA NTRSDate not supplied

Health Monitoring and Prognostics for Electric Aircrafts

As more and more electric vehicles emerge in our daily operation progressively, a very critical challenge lies in the prediction of remaining driving flying time/distance for the flying vehicles. This information is important, particularly in the case of auto vehicles, because such vehicles can become self-aware, autonomously compute its own capabilities, and identify how to best plan and successfully complete vehicular missions safely. In case of electric aircrafts, computing the remaining flying time is also safety-critical, since an aircraft that runs out of power (battery charge) while in the air will eventually lose control leading to catastrophe. To facilitate and solve the prediction problem, awareness of the current health state of the system is key, since it is necessary to perform condition-based predictions. To accurately predict the future state of any system, it is required to possess knowledge of its current health state and future operational conditions. Latest achievements of data-driven algorithms in regression of complex nonlinear functions and classification tasks have generated a growing interest in artificial intelligence for industrial applications. Complex multi-physics models as well as digital twins, once purely built on physics and corresponding simplified lumped parameter iterations, can now benefit from machine learning algorithms to mitigate the lack of understanding of some complex behavior. Given models of the current and future system behavior, a general approach of model-based prognostics can solve the prediction problem and further decision-making. A systematic prediction framework is implemented to identify all possible sources of uncertainty, quantify each of them individually, and mathematically estimate their combined effect on the system-level quantity of interest, in this case, the remaining flying time/distance of the unmanned aircraft. Note - This presentation contains all previously approved and published information.

Systems Health Managent↗

NASA NTRS1993

Space Station Freedom electrical performance model

The baseline Space Station Freedom electric power system (EPS) employs photovoltaic (PV) arrays and nickel hydrogen (NiH2) batteries to supply power to housekeeping and user electrical loads via a direct current (dc) distribution system. The EPS was originally designed for an operating life of 30 years through orbital replacement of components. As the design and development of the EPS continues, accurate EPS performance predictions are needed to assess design options, operating scenarios, and resource allocations. To meet these needs, NASA Lewis Research Center (LeRC) has, over a 10 year period, developed SPACE (Station Power Analysis for Capability Evaluation), a computer code designed to predict EPS performance. This paper describes SPACE, its functionality, and its capabilities.

Hojnicki, Jeffrey S.↗

NASA NTRS1996

Mathematical models for electrochemical impregnation of nickel electrodes

Single step and two-step tetramer precipitation models for electrochemical impregnation of nickel electrodes are presented. The objectives for developing the impregnation model are: to predict the impregnation conditions for uniform loading, to develop quality control tools for electrode manufacturing, and to use it as basis for predicting the performance of batteries with non-uniform loadings. This paper, with the help of graphs and charts, discusses the development and application of the impregnation model.

Ho, Chien-Hsien↗

NASA NTRS1972

Operation and maintenance, fire rescue air-pack. Volume 2: Communications

The operation and maintenance procedures are described for the development model of the fire rescue air pack (FRAP) voice amplifier assembly, including the battery charger. Operational instructions include a general description of the assembly, specifications, and installation and operation. Maintenance instructions include theory of operation, preventive maintenance, repair, adjustment, and a parts list. The FRAP is intended to permit fire rescue personnel to enter a smoke-filled, toxic or oxygen depleted environment carrying their own source of breathing air. The voice amplifier assembly permits the wearer to communicate by voice with other persons in the vicinity. The battery charger assembly provides a means of keeping the amplifier batteries fully charged.

Source record↗

NASA NTRS1981

Electrochemical energy storage subsystems study, volume 1

The effects on life cycle costs (LCC) of major design and performance technology parameters for multi kW LEO and GEO energy storage subsystems using NiCd and NiH2 batteries and fuel cell/electrolysis cell devices were examined. Design, performance and LCC dynamic models are developed based on mission and system/subsystem requirements and existing or derived physical and cost data relationships. The models define baseline designs and costs. The major design and performance parameters are each varied to determine their influence on LCC around the baseline values.

Miller, F. Q.↗