Steady-state Discharge Research Articles

Real-time plasma boundary shape reconstruction using visible camera on EAST tokamak

Abstract Accurate plasma shape reconstruction is crucial for the stable operation of tokamak devices. In this study, a plasma optical boundary reconstruction system is constructed on the Experimental Advanced Superconducting Tokamak (EAST), and real-time shape reconstruction based on an optical method is realized for the first time on EAST. First, a boundary extraction algorithm based on gray features is designed to extract the optical boundary from plasma optical images. Then, to reconstruct the optical boundary in the tokamak coordinate system, a camera calibration algorithm is developed based on feature point matching, and a coordinate mapping algorithm is designed based on plasma geometric features. Then, the system reconstructs the plasma boundary shape based on images acquired by a camera. Finally, the system is deployed in real-time on EAST, and its reconstruction rate meets the requirement of the EAST plasma shape control system. This study validates the feasibility of using an optical boundary shape reconstruction method on a tokamak device for real-time plasma shape reconstruction, providing a new shape reconstruction approach during steady-state discharge in future fusion devices.

Creating CoRu Dual Active Sites Codecorated Stable Porous Ceria Support for Enhanced Li-CO2 Batteries Cathodes.

Lithium-carbon dioxide (Li-CO2) battery represents a high-energy density energy storage with excellent real-time CO2 enrichment and conversion, but its practical utilization is hampered by the development of an excellent catalytic cathode. Here, the synergistic catalytic strategy of designing CoRu bimetallic active sites achieves the electrocatalytic conversion of CO2 and the efficient decomposition of the discharge products, which in turn realizes the smooth operation of the Li-CO2 battery. Moreover, obtained support based on metal-organic frameworks precursors facilitates the convenient diffusion and adsorption of CO2, resulting in higher reaction concentration and lower mass transfer resistance. Meanwhile, the optimization of the interfacial electronic structure and the effective transfer of electrons are achieved by virtue of the strong interaction of CoRu at the support interface. As a result, the Li-CO2 cell assembled based on bimetallic CoRu active sites achieved a discharge capacity of 19,111mAhg-1 and a steady-state discharge voltage of 2.58V as well as a cycle life of >175 cycles at a rate of 100mAg-1. Further experiments combined with density-functional theory calculations achieve a deeply view of the connection between cathode and electrochemical performance and pave a way for the subsequent development of advanced Li-CO2 catalytic cathodes.

Numerical and experimental study on fractal flow field for improving the performance of non-aqueous redox flow battery

The flow field design of the non-aqueous redox flow battery (RFB) decides the electrolyte flow and mass transfer of active species inside porous electrode, which has a significant influence on the operation of RFB. In this work, a fractal tree-like flow channel is proposed to enhance the electrolyte convection and optimize the concentration distribution of active species inside the graphite felt electrode, thus boosting the overall battery performance. Using the finite element simulation method, a three-dimensional numerical model of single cell is established to comparatively study the steady-state discharge process characteristics of deep eutectic solvent (DES) electrolyte-based vanadium‑iron RFBs with fractal and serpentine flow fields, respectively. Moreover, by assembling the single cell of this RFB and building the full cell test system, an experimental study is conducted to compare the discharging output voltage and power of the RFBs with serpentine flow field and fractal flow fields of different fractal dimensions. The numerical results show that the fractal tree-like flow field can improve the discharging power of RFB as well as reduce the pumping loss compared with the conventional serpentine flow field. That is mainly attributed to that fractal flow field is conducive to reducing the polarization loss and strengthening the convection in porous electrode simultaneously. What's more, the role of fractal dimension of flow field is also investigated numerically, thus knowing that large fractal dimension promotes lower pumping loss while small fractal dimension is in favor of higher output voltage. In addition, the experimental results also demonstrate that the fractal flow field could improve the output voltage and maximum discharging power of RFB compared to serpentine flow field. This work provides an optimization method for the flow field design of DES electrolyte-based vanadium‑iron RFB, and is expected to be employed in the other non-aqueous RFBs.

Overview of the KSTAR experiments toward fusion reactor

Abstract The KSTAR has been focused on exploring the key physics and engineering issues for future fusion reactors by demonstrating the long pulse operation of high beta steady-state discharge. Advanced scenarios are being developed with the goal for steady-state operation, and significant progress has been made in high ℓi, hybrid and high beta scenarios with βN of 3. In the new operation scenario called FIRE, fast ions play an essential role in confinement enhancement. GK simulations show a significant reduction of the thermal energy flux when the thermal ion fraction decreases and the main ion density gradient is reversed by the fast ions in FIRE mode. Optimization of 3D magnetic field techniques, including adaptive control and real-time machine learning (ML) control algorithm, enabled long-pulse operation and high-performance ELM-suppressed discharge. Symmetric multiple shattered pellet injections and real-time DECAF are being performed to mitigate and avoid the disruptions associated with high-performance, long-pulse ITER-like scenarios. Finally, the near-term research plan will be addressed with the actively cooled tungsten divertor, a major upgrade of the NBI and helicon current drive heating, and transition to a full metallic wall.

Inward particle transport driven by biased endplate in a cylindrical magnetized plasma

The inward particle transport is associated with the formation of peaked density profiles, which contributes to improve the fusion rate and the realization of steady-state discharge. The active control of inward particle transport is considered as one of the most critical issues of magnetic confinement fusion. Recently, it is realized preliminarily by adding a biased endplate in the Peking University Plasma Test (PPT) device. The results reveal that the inward particle flux increases with the bias voltage of the endplate. It is also found that the profile of radial electric field ( ) shear is flattened by the increased bias voltage. Radial velocity fluctuations affect the inward particle more than density fluctuations, and the frequency of the dominant mode driving inward particle flux increases with the biased voltage applied to the endplate. The experimental results in the PPT device provide a method to actively control the inward particle flux using a biased endplate and enrich the understanding of the relationship between shear and turbulence transport.

The first plasma in a newly constructed linear device for plasma turbulence research

Parameters of the first plasma in a newly built middle-size multi-functional linear plasma device named LEAD (Linear Experimental Advanced Device) were presented. The LEAD device is built to serve as a multi-purpose laboratory plasma experiment platform for various topics, including plasma turbulence, plasma-material interaction, and other fundamental plasma physics. This device is also useful for testing new diagnostic systems. It will be complementary to the HL-2A/HL-3 tokamaks in Southwestern Institute of Physics. The plasma was generated by a large-area helicon plasma source with a multi-ring antenna driven by a 13.56 MHz, 5 kW radio frequency (RF) power source. Argon plasma parameters were measured by a Langmuir probe in different external parameters including RF power, axial magnetic field, and neutral pressure. The threshold power for helicon mode transition is empirically confirmed to be 180 W. Steady-state argon plasma with a density of higher than 1019 m-3 was generated when RF power reached 3 kW. Plasma parameters are crucially influenced by the axial magnetic field. With a weak magnetic field, the radial density profile is Gaussian-like. However, with a stronger magnetic field, shear and reversion of azimuthal rotation velocity reversion appear, resulting in a hollow-shaped density profile. When further increasing the magnetic field, plasma density decreases. Steady-state plasma discharges were achieved under a wide range of argon neutral pressure from 0.1 Pa to over 10 Pa. With increasing neutral pressure, plasma density increases to its maximum at 2.5 Pa and then drops, while electron temperature drops monotonically.

Two-dimensional analytical description of the plasma potential in a magnetron discharge

Simple analytical formulas are proposed to describe the plasma potential in a steady-state magnetron discharge, based on the results of various experiments and numerical simulations reported in the literature. The description is two-dimensional (2D), covering two main regions, the cathode sheath and the ionization region, both contributing to electron energization. A parabolic potential in the axial direction governs the cathode sheath. The thickness of the cathode sheath is obtained from the 1D collisionless Child–Langmuir law. A parabolic or linear potential in the axial direction characterizes the ionization region. The local ion current density to the cathode, estimated from the target erosion profile, sets the radial dependence of the potential. The proposed formulas use a set of input parameters that can be experimentally obtained. The analytical description captures all characteristics of the highly inhomogeneous plasma potential of a steady-state magnetron discharge operated in a reduced magnetic field BRT/p lower than 0.1 T/Pa, as revealed by the comparison to self-consistent 2D numerical simulations.

Study of trigger mechanisms of a pseudospark switch configuration with a steady-state auxiliary glow discharge

This paper presents data on investigation of the pseudospark switch whose trigger unit uses a low-current auxiliary glow discharge with hollow cathode and hollow anode. The electrode system of this unit communicates with the main high-voltage gap of the switch due to the aperture in the flat part of one of the trigger electrodes. It is shown that when the electrode with the aperture plays of role of the hollow cathode of the auxiliary discharge, a low parasitic current through the aperture is provided by the ion flow. This ion current does not practically influence on the static breakdown voltage of the main gap. Applying the trigger pulse between the trigger electrodes leads to the pulsed trigger discharge with an enhanced current. At a negative polarity of the trigger pulse, the cavity with aperture turns out into the hollow anode so that the current is able to be intercepted through the aperture to the grounded cavity of the main gap. The plasma is generated in the cavity and the switch is triggered. With the proper selection of the geometry of the trigger electrodes, the delay time to trigger at a level of several tens of nanoseconds is achievable.

Inertial and anisotropic pressure effects on cross-field electron transport in low-temperature magnetized plasmas

In this paper, a one-dimensional (1D) particle-in-cell Monte Carlo collision (PIC-MCC) model is developed to investigate the effects of anisotropic pressure and inertial terms due to non-Maxwellian velocity distribution functions on cross-field electron transport. The conservation of momentum is evaluated by taking the moments of the first-principles gas-kinetic equation. A steady-state discharge is obtained without any low-frequency ionization oscillations by considering an anomalous electron scattering profile. The results obtained from the 1D PIC-MCC model are compared with fluid models, including the quasi-neutral drift-diffusion (DD), non-neutral DD, and full fluid moment models. The discharge current obtained from the PIC-MCC model is in good agreement with the fluid models. The cross-field electron transport due to the inertial terms, i.e. the gradient of axial and azimuthal drift, is evaluated. Moreover, PIC-MCC simulation results show non-zero, anisotropic, off-diagonal pressure tensor terms due to asymmetric non-Maxwellian electron velocity distribution function, potentially contributing to cross-field electron transport.

Numerical assessment of thermal performance of W/Cu monoblock during steady-state operation and plasma vertical displacement events under ITER-like conditions

This paper employs a two-dimensional conduction model to assess the spatiotemporally thermal performance of ITER W/Cu monoblock under ITER-like conditions. The model considers the heat conduction processes including the evaporation, radiation and melting of both W armor and Cu heat sink materials under a heat load either during steady-state discharge or during plasma vertical displacement event (VDE). Moreover, the model employs coupling cooling water condition instead of the fixed cooling temperature at bottom in authors’ previous work. For the steady-state case, the heat flux distribution on the target tile, the input data to the model, was specifically evaluated by a particle-in-cell code to take into account its geometrical effect. For the VDE case, the heat flux distribution was simply assumed to be uniform on the tile surface. The simulated results obtained from the heat conduction model indicate that cooling water conditions have important influence on the thermal performance of W/Cu monoblock, especially for Cu heat sink materials during steady state. In the case of VDE, the baffle tile surface would undergo intense vaporization and melting, while whether Cu heat sink materials melted was determined by the combination of the exposed heat load and its duration. Based on typical VDE heat loads, detailed analysis is presented herein.PACS: 52.55.Fa, 52.55.Rk, 52.40.Hf, 52.65.-y

Cardiac rhythmicity and burstiness are major characteristics of neuronal firing in medullary autonomic networks across sleep-wake states in freely moving rats

Cardiac rhythmicity is a hallmark of the autonomic control system from its sensory inputs all the way to sympathetic efferent nerve discharge directed to the heart and vasculature. Neuron firing in brainstem networks, essential in this control, was studied in great detail under anesthesia but recordings of sympathetic-related neuron firing in freely moving animals remain extremely scarce. We have shown recently [1], that such recordings are possible to perform in freely behaving rats and reported that the pattern of neural activity adheres to the basic principles of organization proposed earlier [2] based on data collected within the constraints of anesthesia, decerebration, or head-restrain. Here we analyzed the firing of sympathetic-related neurons from these recordings over different arousal states. We hypothesized that the essential characteristics, such as rhythmicity and burstiness remain preserved during different sleep-wake states. To address this issue, 23 neurons recorded continuously during waking and sleep in 3 rats were selected. Electrocardiogram, cortical electroencephalogram, and neck muscle electromyogram were recorded along with simultaneous recordings of multiple single neurons using tetrode electrodes or fine wire bundles aimed at central autonomic structures in the medulla as described in [1]. Firing characteristics were analyzed in steady state segments of quiet waking (QW) and slow wave sleep (SWS) as well as during transient events in SWS and REM sleep. We found that steady state discharge of rhythmic bursts was dominant in both QW and SWS even though the average firing rate in the group decreased (from 12.6+1.6 to 7.4+1.3 spike/s) from wake to SWS. Quite remarkably, fluctuations in firing rate within and between QW and SWS were associated with a decrease in the number of bursts rather than the spike per burst ratio. On the other hand, phasic events, such as microarousal associated with transient muscle activity and tachycardia were associated with short (2-5 s) episodes of increase in firing rate characterized by relatively weak cardiac rhythmicity and increased synchronization within the network (i.e. between neurons detected on the same tetrodes).The results show that the study of multiple single neuron relationships in central sympathetic networks is a viable tool to explore autonomic control mechanisms and we emphasize the importance of neural control of cardiovascular adjustments in complex behaviors, including stress, exercise, arousal, sleep-wake states, and different tasks.[1] Kocsis, B.; Topchiy, I., Rhythmic firing of neurons in the medulla of conscious freely behaving rats: rhythmic coupling with baroreceptor input. Pflugers Archiv: Eur J physiol 2022.[2] Barman, S. M., 2019 Ludwig Lecture: Rhythms in sympathetic nerve activity are a key to understanding neural control of the cardiovascular system. Am J Physiol Regul Integr Comp Physiol 2020. NIMH This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Azimuthal structures and turbulent transport in Penning discharge

Azimuthal structures in cylindrical Penning discharge are studied with a 2D3V radial–azimuthal PIC/MCC model with the axial magnetic field. The discharge is self-consistently supported by ionization due to the axial injection of electrons. It is shown that the steady-state discharge can be supported in two different regimes with different types of observed azimuthal structures. The transition between the regimes is controlled by the mechanism of the energy input to the discharge. In the first regime (low energy of the injected electrons), with the pronounced m = 1 spoke activity, the power input is dominated by the energy absorption due to the radial current and self-consistent electric field. In the other regime (higher energy of the injected electrons), with prevalent small-scale m > 1 spiral structures, and the lower values of the anomalous transport, the total energy deposited to the discharge is lower and is mostly due to the direct input of the kinetic energy from the axial electron beam. We show that the large (m = 1) spoke and small-scale structures occur as a result of Simon–Hoh and lower hybrid instabilities driven by the electric field, density gradient, and collisions.

Development of Methods for Determining Near-Surface Plasma Parameters During Tests of Fusion Reactor First-Wall Prototypes Using the PLM Device

Plasma-surface interaction and high heat flux on plasma-facing materials in magnetic fusion devices cause surface ablation and degradation, while the influx of eroded materials into plasma can have a shielding effect. The reduction of the power load due to the plasma detachment effect over tungsten fuzz is an important phenomenon to be investigated for the ITER divertor problem. Measuring near-wall plasma parameters is a challenging task, requiring the development of improved and advanced techniques, including high-resolution spectroscopic methods. In this paper, we present study results of steady-state plasma over tungsten fuzz formed in plasma linear multicusp (PLM). The PLM device is a linear plasma trap composed of an eight-pole multicusp magnetic field with steady-state plasma discharge with parameters similar to the scrape-off layer and divertor plasma in a tokamak. We used spectroscopic measurements to estimate spatial distributions of plasma radiation in the vicinity of the sample surface exposed to the plasma column. Thus, we obtained information on the temperature and composition of the boundary layer plasma and the temperature of the sample surface. Helium plasma exhibits ionization-type nonequilibrium even at atmospheric pressure, necessitating the use of specific methods to estimate its electron temperature Te. When the helium ion spectral line He II 468.5 nm is present in the spectra, its intensity ratio to one of the atomic lines He I can be described by using coronal approximation. Spectrum analysis has shown that emitting helium ions are highly sensitive indicators of average electron energy = 3kTe/2. Therefore, utilizing intensity ratios of the strongest emitting lines in the ultraviolet-visible near-infrared range, He II 468.6 nm and several He I lines with well-known electron excitation functions were found to be a reliable Te measurement method in the case of magnetized low-pressure helium plasma. We also propose a method for determining the concentrations of the metallic admixture in the plasma on the data on relative intensities of its spectral lines.

Study of the influence of temperature dependent viscosity on fluid flow in annular channels

For all liquids, a change in viscosity depending on temperature is characteristic. In most cases, this dependency is commonly overlooked; however, when studying the flow of liquids under conditions of intense heat exchange, the temperature-dependent viscosity can have a significant impact on mass and heat transfer processes. It should be noted that for some liquids, such as polymer solutions or biological fluids, the temperature dependence of viscosity can be extremely complex and nonlinear. In such cases, ignoring this dependence can lead to inaccurate results and errors. Annular channels find wide applications in various technical systems, including heat exchangers and hydraulic devices. Understanding the factors influencing the fluid flow and discharge in such channels is a key aspect of optimizing their design and operation. One of the main factors influencing the flow process and fluid discharge in annular channels is the temperature-dependent viscosity of the fluid. This work investigates the influence of the thermo-viscous parameter with monotonic and non-monotonic temperature-dependent viscosity, as well as the geometric parameter of the annular channel on the fluid flow process and discharge. The mathematical model includes the continuity equation, Navier-Stokes equations, and the temperature equation. The method of control volume and the SIMPLE algorithm, modified to account for the variable viscosity coefficient, were applied for the numerical solution of these equations. It is shown that in the case of liquid flow in an annular channel with a monotonic dependence of viscosity on temperature, the steady-state discharge closely approaches the discharge at maximum viscosity. However, in the case of a liquid with non-monotonic viscosity dependence on temperature, the discharge significantly depends on the thermo-viscous parameter.

The influence of full drifts on density shoulder formation at the midplane by numerical modeling

The density shoulder at the midplane may influence core plasma confinement during H-mode discharge, thus affecting long-pulse steady-state discharge. Drifts in the edge plasma play a remarkable role in plasma transport and the divertor operation regime, which determine density shoulder formation (DSF). In this work, the SOLPS-ITER code package is used to evaluate the influence of full drifts on DSF in poloidal and radial coordinates. An open divertor of DIII-D-like geometry with weak neutral compression is chosen for the modeling. Cases without drifts, with only E × B drifts in forward B t and with full drifts in both forward and reversed B t are simulated for comparison. It is confirmed that the high upstream density promotes DSF when the drift is not considered, which has also been observed in various investigations. When the drifts are taken into account, the divertor in/out asymmetry (or upstream ionization source) is determined by the direction of B t due to the variation of particle transport, thus the shoulder can be facilitated or suppressed. Two mechanisms of DSF with full drifts are elucidated: (1) E × B and B × ∇B drifts promote DSF at the inner midplane (IMP) by raising the ionization source (at IMP) in forward B t; (2) the drifts contribute to DSF at the outer midplane by enhancing the particle transport loss in reversed B t. In a high-recycling regime, ionization is the dominant term for DSF, while in the low-recycling regime enhanced particle transport loss plays a more important role. Comprehensively understanding the mechanisms of DSF is of great importance for the improvement of core–edge compatibility in fusion reactors.

Erosion of Fuzz Layers Formed in Steady-State Plasma Discharge

The erosion of nanostructured tungsten and titanium by high-heat plasma flux, laser, and arcing is investigated. To fabricate nanostructural fuzz layers and hierarchical granularity on the surfaces, samples were exposed to helium plasma in the steady-state plasma device PLM-M, which is a linear plasma trap of an eight-pole multicusp magnetic field with parameters similar to the scrape-off layer and divertor plasma in a tokamak. Arcing ignited with a Nd:YAG laser pulse on the target fuzzy surface in the helium plasma resulted in the melting of fibers and the creation of craters of several microns in depth and several tens of microns in diameter.

The microscopic principle and traits on pulsed discharge of negative corona

A systematic investigation of the dynamical behaviors and traits of negative corona discharge in pure oxygen is performed and the microscopic physical mechanism of the discharge is studied. In the meantime, a new dynamical model is presented, which can predict different discharge phases including steady-state discharge and periodic discharge of saw-tooth pulses. The change in the discharge outputs with time is analyzed comprehensively using the nonlinear dynamics method, and the Trichel pulsed oscillation and the dynamical characteristics are described. In addition, the positive ions impacting the cathode and the negative ions can be treated as feedback signals for maintaining pulsed discharge at the constant external excitation. It is found that the gas pressure levels significantly affect the discharge behaviors and the pulsed characteristics of charged particles and glow radiation. In particular, the microscopic mechanism of gas pressure level influencing the negative corona discharge is discovered. Meanwhile, the pulsed characteristics of the discharge outputs are studied, and an explanation of the microscopic formation mechanism of the symmetrical and asymmetrical jagged pulses of diverse outputs is given. It is revealed that the mass, migration speed, and migration time of various particles have a great influence on discharge behaviors.

Characterization of beam ion loss in high poloidal beta regime on EAST

A critical issue for achieving the integrated operation of steady-state long-pulse high-confinement (H-mode) plasmas on experimental advanced superconducting tokamak (EAST) is to improve beam ion population confinement during neutral beam injection (NBI). To study the characterization of beam ion loss and improve beam ion confinement, the steady-state long pulse scenario discharges were conducted on EAST (β p ⩾ 2.0, β N ⩾ 1.7, q 95 ⩾ 6.7 and H 98y2 ⩾ 1.1) with NBI heating. Based on neutron yield, the beam voltage and line-averaged electron density were adjusted from 50 kV to 60 kV and 4.4 × 1019 m−3 to 5.0 × 1019 m−3, respectively. The results show that the dominant mechanisms of beam ion loss are shine-through loss, prompt loss, and stochastic ripple loss. The shine-through loss fraction is determined by initial velocity, flight time and entire beam path. The change in prompt loss fraction is caused by the change in the deposition of beam ions. The change in stochastic ripple loss fraction is caused by the change in the initial fraction of trapped-confined ions. Detailed physics shows that the prompt loss fraction during counter-Ip injections (∼45%) is far larger than during co-Ip injections (∼5%) due to the finite orbit width. The lost ions are mainly deposited on the lower divertor or below the midplane since the direction of magnetic drift is vertical down. The orbit types of prompt loss during counter-Ip injections are mainly trapped-lost and ctr-passing lost. To minimize the prompt loss fraction during counter-Ip injections, a reversed Ip configuration (rev-Ip) discharge #94758 was conducted. The result suggests that the beam ion wall load fraction during counter-Ip tangential injection (∼3%) is far lower than that in normal Ip configuration (nor-Ip) discharge #94820. It is also found that the confinement of beam ion population in the counter-Ip injection #94758 was greatly improved when compared to #94820. This study can provide unique support for the improvement of beam ion population confinement and for the performance evaluation of the NBI system on EAST and future tokamaks.

Quenching of O2(b1Σg + ) by O(3P) atoms. Effect of gas temperature

We present a detailed study of the density and kinetics of O2(b1Σg +) in steady-state and partially-modulated DC positive column discharges in pure O2 for gas pressures of 0.3–10 Torr and 10–40 mA current. The time-resolved density of O2(b1Σg +) was determined by absolutely-calibrated optical emission spectroscopy (OES) of the A-band emission at 762 nm. Additionally, the O2(b1Σg +) density was determined by VUV absorption spectroscopy using the Fourier-transform spectrometer at the DESIRS beamline at Synchrotron Soleil, allowing the absolute calibration of OES to be confirmed. The O(3P) atoms were detected by time-resolved sub-Doppler cavity ringdown spectroscopy (CRDS) using the O(3P2) → O(1D2) transition at 630 nm. The CRDS measurements were synchronized to the discharge modulation allowing the O(3P) dynamics to be observed. As a function of gas pressure the O2(b1Σg +) density passes through a maximum at about 2 Torr. Below this maximum, the O2(b1Σg +) density increases with discharge current, whereas above this maximum it decreases with current. The gas temperature increases with pressure and current, from 300 to 800 K. These observations can only be explained by the existence of fast quenching process of O2(b1Σg +) by O(3P), with a rate that increases strongly with gas temperature, i.e. with a significant energy barrier. The data are interpreted using a 1D self-consistent model of the O2 discharge. The best fit of this model to all experimental data (including the O2(b1Σg +) average density as a function of pressure and current, the radial profiles, and the temporal response to current modulation) is achieved using a rate constant of k Q = 10−10 exp(−3700/T) cm3 s−1.

Modeling and total cost optimization of battery thermal management system in a hybrid electric vehicle

In the present study, the battery thermal management of a series hybrid electric vehicle is modeled and optimized for different standard driving conditions. The heat generation of the battery is comprehensively studied in previous works for the steady-state charge or discharge of the battery. Despite the previous investigations, the heat generation of the battery in the present study is modeled for the real driving conditions in terms of battery state of charge and power consumption. The model is validated with the experimental data. The validated model is implemented to minimize the total cost of ownership of the battery thermal management system. In this way, the battery thermal management system is optimized for three different standard driving cycles. The independent variables are the compressor speed, fan speed, chiller size, radiator size, and condenser size. The results reveal that the total cost of optimization is converged to 200 US dollars for all driving cycles. The optimum configuration of the battery thermal management system does not considerably vary for different driving cycles. Therefore, one of the optimum configurations can be considered the overall optimum for battery thermal management.