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Smith, Kandler A

Publications and source records attributed to Smith, Kandler A.

13 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Field-Aging Test Bed for Behind-the-Meter PV + Energy Storage

Small DC-coupled battery test systems are deployed at the National Renewable Energy Laboratory to evaluate capacity fade models and report on performance parameters such as round-trip efficiency under indoor and outdoor deployment scenarios. Initial commercial battery products include LG Chem RESU lithium-ion (Li-ion) and Avalon vanadium redox flow batteries. Adapting indoor lab-scale test methods to outdoor systems has challenges, including maintaining constant temperature and fully controlling batteries through standard discharge curves. Initial measurements show the Li-ion battery systems performing within expectations, near 85% round-trip efficiency. Initial lifetime modeling and measurements indicate that battery capacity could degrade by 20%-35% over 10 years at current rates.

14 SOLAR ENERGY↗
DOE OSTI2019

Field Aging Testbed for Behind-the-Meter PV + Energy Storage

Small DC-coupled battery test systems are deployed at NREL to evaluate capacity fade models and report on performance parameters such as round-trip efficiency under indoor and outdoor deployment scenarios. Initial commercial battery products include LG Chem RESU Lithium-ion and Avalon vanadium-redox flow batteries. Adapting indoor lab-scale test methods to outdoor systems has challenges, including maintaining constant temperature and fully controlling batteries through standard discharge curves. Initial measurements show the Lithium Ion battery systems performing within expectation, near 85% round-trip efficiency. Initial lifetime modeling and measurements indicate battery capacity may degrade by 20%-35% over 10 years.

25 ENERGY STORAGE↗
DOE OSTI2019

Safer Batteries via Active Fault Tolerant Control

Safety remains a critical technological barrier for Lithium-ion batteries. Besides safer battery materials, intelligent battery management can be the key to safer batteries. Motivated by this scenario, we propose an active fault tolerant control scheme which can potentially improve battery safety. Essentially, we focus on battery internal thermal faults which may lead to thermal runaway, and design a control scheme to alleviate such fault effect at an early stage. The control scheme consists of a fault tolerant control algorithm coupled with a fault and state co-estimator. A multi-objective optimal control technique has been used to design the control algorithm whereas an unknown state-input co-estimation approach is used for the fault and state estimator. Finally, simulation studies illustrate the effectiveness of the proposed control scheme.

25 ENERGY STORAGE↗
DOE OSTI2019

Microstructure Characterization and Modeling for Improved Electrode Design

This presentation summarizes fiscal year 2018-2019 work under U.S. Department of Energy's Computer-Aided Engineering of Batteries (CAEBAT) program to develop computational tools for improved electrode design and to provide deeper fundamental understanding of the physics that limit the performance and cause degradation in lithium-ion batteries. Successes include (1) development of an electrode microstructure characterization tool box to be published open source later in 2019, (2) development of a large deformation electrochemical model capturing the volume expansion and performance limits of electrodes utilizing silicon and (3) development of a solid mechanics damage model describing the fracture of polycrystalline nickel-manganese-cobalt cathode materials with cycling.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2019

Understanding Impact of Local Heterogeneities During Fast Charge

Reducing battery charging time to 10 minutes would improve the market acceptance and utility of electric vehicles. Such a fast charge rate is difficult to achieve in energy-dense thick battery electrodes, however. In particular, fast charge can drive a lithium plating side reaction that is unsafe and degrades battery capacity. The onset of the lithium plating side reaction is accelerated due to non-uniformities, or heterogeneities that exist within the negative electrode active material particles, within the coating, and at larger battery length scales as well. This presentation summarizes fiscal year 2018-2019 work by NREL, Argonne National Laboratory and Purdue University in the atomistic modeling of Li transport within graphite and continuum modeling of electrochemical heterogeneities that cause early lithium plating onset. non-uniformities, or heterogeneities that exist within the negative electrode active material particles, within the coating, and at larger battery length scales as well. This presentation summarizes fiscal year 2018-2019 work by NREL, Argonne National Laboratory and Purdue University in the atomistic modeling of Li transport within graphite and continuum modeling of electrochemical heterogeneities that cause early lithium plating onset.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2019

Numerical investigation of thermal runaway mitigation through a passive thermal management system

Prevention of thermal runaway and its propagation remains a technical barrier to the application of lithium-ion batteries. To mitigate thermal runaway in lithium-ion battery packs, heat sinks have been designed using various materials, such as phase-change materials or metal plates. In this study, aluminum plates were assembled into battery modules as heat sinks and the effect of plate thickness on thermal runaway mitigation was numerically investigated. A three-dimensional integrated multiphysics model was validated and calibrated with experimental data. It identified the mechanism and sequence of thermal runaway propagation in detail. Thermal mass and contact resistance are found to be the key design parameters for preventing thermal runaway propagation for the studied battery module configuration. In addition, this study provides further insights into the design of aluminum heat sinks for lithium-ion battery packs.

25 ENERGY STORAGE↗
DOE OSTI2018

Determining Electrode Tortuosity and Rate Limitations from Experiments and Modeling

CAE models efficiently address 3D large battery performance and safety design. Further work is needed to increase electrochemical model fidelity, reduce expense of parameter ID, and integrate degradation mechanisms, enabling optimization of designs for lifetime. Microstructure models provide deeper insight into predict effective properties of macro-homogeneous models and heterogeneous utilization of electrode degradation. Enabling 10-minute fast charge of BEV200+ requires electrolytes with enhanced transport and low electrode tortuosity.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2018

Microstructure Characterization and Modeling for Improved Electrode Design

As part of DOE's Computer-Aided Engineering of Batteries Program, the National Renewable Energy Laboratory is developing detailed models capturing the influence of lithium-ion battery electrode design, recipe and processing on the electrode's microstructure and relating that microstructure to device-level performance. Given the difficulty in obtaining 3D microstructural images of the electrode's inert components, team member Purdue University developed an algorithm to computationally generate the so-called carbon-binder domain (CBD) for any given recipe. Mesoscale models explore the device-level impact of the CBD phase on multiple idealized and actual electrode geometries. With the inclusion of this CBD phase, microstructure models are used to predict the tortuosity of 14 different graphite and NMC electrode designs. Tortuosity predictions are shown in good agreement with experimental direct measurement and electrochemical rate studies.

25 ENERGY STORAGE↗
DOE OSTI2018

Micro/Macro-Scale Modeling for Battery Fast Charge Applications

In conjunction with experiments at Argonne and Idaho National Laboratories, the National Renewable Energy Laboratory is applying physics-based electrochemical models at several length-scales to understand limitations and guide design of future battery electrodes for extreme fast charge of electric vehicles. Macro-homogeneous models show that today's battery technologies must use thin electrodes to avoid electrolyte depletion and lithium plating at a 6C (10-minute) charge rate. This compromises cost and energy density however. Goals are provided for next generation electrode tortuosity and electrolyte transport requirements to achieve 6C charge in a thick electrode system. Microstructure models provide quantitative understanding of tortuosity for several graphite electrodes and further predict heterogeneous utilization of the electrodes due to their morphology.

25 ENERGY STORAGE↗
DOE OSTI2018

Performance and Health Test Procedure for Grid Energy Storage Systems

A test procedure to evaluate the performance and health of field installations of grid-connected battery energy storage systems (BESS) is described. Performance and health metrics captured in the procedures are: round-trip efficiency, standby losses, response time/accuracy, and useable energy/state of charge at different discharge/charge rates over the system's lifetime. The procedures are divided into reference performance tests, which require the system to be put in a test mode and are to be conducted in intervals, and real-time monitoring tests, which collect data during normal operation without interruption. The procedures can be applied on a wide array of BESS with little modification and can thus support BESS operators in the management of BESS field installations with minimal interruption and expenditure. Simulated results based on a detailed system simulation of a prototype system are provided as guideline.

25 ENERGY STORAGE↗