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A Tanks-in-Series Approach to Estimate Parameters for Lithium-Ion Battery Models

Journal of the Electrochemical Society

Kolluri, Suryanarayana; Mittal, Prateek; Subramaniam, Akshay; Preger, Yuliya; De Angelis, Valerio; Ramadesigan, Venkatasailanathan; Subramanian, Venkat R.

Advanced Battery Management Systems (BMS) play a vital role in monitoring, predicting, and controlling the performance of lithium-ion batteries. BMS employing sophisticated electrochemical models can help increase battery cycle life and minimize charging time. However, in order to realize the full potential of electrochemical model-based BMS, it is critical to ensure accurate predictions and proper model parameterization. The accuracy of the predictions of an electrochemical model is dependent on the accuracy of its parameters, the values of which might change with battery cycling and aging. Parameter estimation for an electrochemical model is generally challenging due to the nonlinear nature and computational complexity of the model equations. To this end, this work utilizes the recently proposed Tanks-in-Series model for Li-ion batteries (J.Electrochem. Soc., 167, 013534 (2020)) to perform parameter estimation. The Tanks-in-Series approach allows for substantially faster parameter estimation compared to the original pseudo two-dimensional (p2D) model. The objective of this work is thus to demonstrate the gain in computational efficiency from the Tanks-in-Series approach. A sensitivity analysis of model parameters is also performed to benchmark the fidelity of the Tanks-in-Series model.

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TYPE Journal Article YEAR 2022
DOIOSTIScopus

Front-End Design for SiPM-Based Monolithic Neutron Double Scatter Imagers

Sensors

Cates, Joshua W.; Steele, J.; Balajthy, Jon A.; Negut, Victor; Hausladen, Paul; Ziock, Klaus; Brubaker, Erik M.

Neutron double scatter imaging exploits the kinematics of neutron elastic scattering to enable emission imaging of neutron sources. Due to the relatively low coincidence detection efficiency of fast neutrons in organic scintillator arrays, imaging efficiency for double scatter cameras can also be low. One method to realize significant gains in neutron coincidence detection efficiency is to develop neutron double scatter detectors which employ monolithic blocks of organic scintillator, instrumented with photosensor arrays on multiple faces to enable 3D position and multi-interaction time pickoff. Silicon photomultipliers (SiPMs) have several advantageous characteristics for this approach, including high photon detection efficiency (PDE), good single photon time resolution (SPTR), high gain that translates to single photon counting capabilities, and ability to be tiled into large arrays with high packing fraction and photosensitive area fill factor. However, they also have a tradeoff in high uncorrelated and correlated noise rates (dark counts from thermionic emissions and optical photon crosstalk generated during avalanche) which may complicate event positioning algorithms. We have evaluated the noise characteristics and SPTR of Hamamatsu S13360-6075 SiPMs with low noise, fast electronic readout for integration into a monolithic neutron scatter camera prototype. The sensors and electronic readout were implemented in a small-scale prototype detector in order to estimate expected noise performance for a monolithic neutron scatter camera and perform proof-of-concept measurements for scintillation photon counting and three-dimensional event positioning.

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TYPE Journal Article YEAR 2022
DOIOSTIScopus

Entangling-gate error from coherently displaced motional modes of trapped ions

Physical Review A

Ruzic, Brandon; Barrick, T.A.; Hunker, J.D.; Law, Ryan; Mcfarland, Brian; Mcguinness, Hayden J.E.; Parazzoli, L.P.; Sterk, Jonathan D.; Van Der Wall, Jay W.; Stick, Daniel L.

Entangling gates in trapped-ion quantum computers are most often applied to stationary ions with initial motional distributions that are thermal and close to the ground state, while those demonstrations that involve transport generally use sympathetic cooling to reinitialize the motional state prior to applying a gate. Future systems with more ions, however, will face greater nonthermal excitation due to increased amounts of ion transport and exacerbated by longer operational times and variations over the trap array. In addition, pregate sympathetic cooling may be limited due to time costs and laser access constraints. In this paper, we analyze the impact of such coherent motional excitation on entangling-gate error by performing simulations of Mølmer-Sørenson (MS) gates on a pair of trapped-ion qubits with both thermal and coherent excitation present in a shared motional mode at the start of the gate. We quantify how a small amount of coherent displacement erodes gate performance in the presence of experimental noise, and we demonstrate that adjusting the relative phase between the initial coherent displacement and the displacement induced by the gate or using Walsh modulation can suppress this error. We then use experimental data from transported ions to analyze the impact of coherent displacement on MS-gate error under realistic conditions.

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TYPE Journal Article YEAR 2022
DOIOSTIScopus

SIESTA a Fatigue Solution: User's and Theory Manual

Ross, Michael

This report documents the fatigue code SIESTA that has been used for recently here at Sandia National Laboratories. It is written in two parts: the first as a user manual and the second as a theory manual. Currently employed in SIESTA are stress-life cycle approaches. Clients have requested the use of standards in particular analyses; therefore, the American Society of Mechanical Engineers, Boiler Pressure Vessel Code fatigue standards have been implemented. These include an elastic, an elastic-plastic, and a weld fatigue method. All three methods use a Max-Min cycle counting method that is appropriate for non-proportional loading. A Signed von Mises method that used a Rainflow Cycle Counting Method is also implemented. The Signed von Mises with the Rainflow Cycle Counting Method is appropriate for proportional loading. Several verification examples are noted and include comparisons to experimental data.

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TYPE SAND Report YEAR 2022
DOIOSTI

Phase transitions in high-purity zirconium under dynamic compression

Physical Review B

Greeff, C.W.; Brown, Justin L.; Velisavljevic, N.; Rigg, P.A.

We present results from ramp compression experiments on high-purity Zr that show the α→ω, ω→β, as well as reverse β→ω phase transitions. Simulations with a multiphase equation of state and phenomenological kinetic model match the experimental wave profiles well. While the dynamic α→ω transition occurs ∼9GPa above the equilibrium phase boundary, the ω→β transition occurs within 0.9 GPa of equilibrium. We estimate that the dynamic compression path intersects the equilibrium ω-β line at P=29.2GPa, and T=490K. The thermodynamic path in the interior of the sample lies ∼100K above the isentrope at the point of the ω→β transition. Approximately half of this dissipative temperature rise is due to plastic work, and half is due to the nonequilibrium α→ω transition. The inferred rate of the α→ω transition is several orders of magnitude higher than that measured in dynamic diamond anvil cell (DDAC) experiments in an overlapping pressure range. We discuss a model for the influence of shear stress on the nucleation rate. We find that the shear stress sji has the same effect on the nucleation rate as a pressure increase δP=cϵijsji/(ΔV/V), where c is a geometric constant ∼1 and ϵij are the transformation shear strains. The small fractional volume change ΔV/V≈0.1 at the α→ω transition amplifies the effect of shear stress, and we estimate that for this case δP is in the range of several GPa. Correcting our transition rate to a hydrostatic rate brings it approximately into line with the DDAC results, suggesting that shear stress plays a significant role in the transformation rate.

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TYPE Journal Article YEAR 2022
DOIOSTIScopus

A study of sacrificial mirrors for use prior to a laser wakefield accelerator driven by the Z-Petawatt laser

Galloway, Benjamin R.; Rambo, Patrick K.; Geissel, Matthias; Kimmel, Mark; Kellogg, Jeffrey; Elle, Jennifer; Garrett, Travis; Porter, John L.; Rochau, Gregory A.

Many experiments at Sandia’s Z Pulsed Power Facility require x-ray backlighting diagnostics to understand experiment performance. Due to limitations in present-day source/detection modalities, most x-ray diagnostics at Z are restricted to photon energies <20 keV, ultimately limiting the density, amount, and atomic number of targets diagnosable in experiments. These limitations force the use of low-Z materials like Beryllium, and they prevent acquisition of important backlighting data for materials/densities that are opaque to soft x-rays and where background emission from the Z load and transmission lines overwhelm diagnostics. In this LDRD project, we have investigated the design and development of a laser wakefield acceleration platform driven by the Z-Petawatt laser – a platform that would enable the generation of a pulsed, collimated beam of high energy x-rays up to 100 keV. Geometrical considerations for implementation on the Z Machine require the use of sacrificial mirrors, which have been tested in offline experiments in the Chama target chamber in building 983. Our results suggest the use of sacrificial mirrors would not necessarily inhibit the laser wakefield x-ray process, particularly with the benefits stemming from planned laser upgrades. These conclusions support the continuation of laser wakefield source research and the development of the necessary infrastructure to deliver the Z-Petawatt laser to the Z center section along the appropriate lines of sight. Ultimately, this new capability will provide unprecedented views through dense states of matter, enabling the use of previously incompatible target materials/designs, and uncovering a new set of observables accessible through diffraction and spectroscopy in the hard x-ray regime. These will amplify the data return on precious Z shots and enhance Sandia’s ability to investigate fundamental physics in support of national security.

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TYPE SAND Report YEAR 2022
DOIOSTI
Results 8801–8850 of 101,000
Results 8801–8850 of 101,000
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