Cell Temperature Control Research Articles

Performance enhancement for a novel cylindrical system Li‐ion battery with MXene‐based dielectric fluid for immersion cooling

AbstractThis research looks at the impact of dielectric fluids and fluid speeds on cell temperature control in innovative cylindrical lithium‐ion batteries during high‐rate discharges (C‐rate) using the multiscale multidomain battery model. The goal is to improve the battery thermal management system to increase battery performance, longevity, and safety. The present study includes reducing thermal strains, enhancing efficacy, and forestalling overheating risks across various applications in electrified systems. The assessment focuses on four dielectric fluids—ester, mineral, kerosene, and Novec 7200—flowing at 0.01 m/s to gauge their efficiency in managing cell temperatures. Results demonstrate the criticality of effective thermal management in maintaining optimal battery performance and longevity. Ester oil emerges as the most efficient coolant, maintaining cell temperatures at 305.84 K and showcasing a 44% reduction compared with scenarios without coolant. In contrast, kerosene oil, mineral oil, and Novec 7200 yield temperature reductions of 42.86%, 42.51%, and 43.11%, respectively. Furthermore, combining 1% v/v. MXene nanoparticles with ester oil enhance cooling capabilities, with remarkable cell temperature reductions of 50% at 0.01 m/s velocity. Subsequent increments in flow velocity lead to enhanced cooling effects: at 0.05 and 0.1 m/s, reductions reach 51.89% and 52.155%, escalating to 52.58% and 54% at 0.5 and 1.0 m/s, correspondingly.

Fuel cell temperature control based on nonlinear transformation mitigating system nonlinearity

The operational temperature significantly impacts the efficiency and lifespan of fuel cells. However, precise fuel cell temperature control poses a challenge due to the inherent nonlinear characteristics within the thermal management system. In this study, an in-depth quantitative analysis is undertaken to dissect the intricacies of nonlinearity embedded in temperature control. The results show that the nonlinearity arises from the nonlinear mapping between the thermostat opening and the distribution of coolant flow between the inner and outer loops. To address this nonlinearity, a pre-experiment is implemented to determine the flow ratio of the outer loop coolant flow rate concerning the total stack coolant flow rate under different thermostat openings. Furthermore, a robust temperature control method based on nonlinear transformation is designed, ensuring that stack coolant inlet temperature quickly tracks the target value when load currents change. The proposed control method is verified on a 5 kW fuel cell test bench, and the results demonstrate improvement in dynamic characteristics and enhanced system's robustness. Small-step tests indicate stable tracking of the stack coolant inlet temperature, with a steady-state error of less than 0.2 °C. Besides, under a large-load step response test, the thermostat exhibits a rapid response with merely a 0.6 °C temperature overshoot.

Algorithm-Based Linearly Graded Compositions of GeSn on GaAs (001) via Molecular Beam Epitaxy.

The growth of high-composition GeSn films in the future will likely be guided by algorithms. In this study, we show how a logarithmic-based algorithm can be used to obtain high-quality GeSn compositions up to 16% on GaAs (001) substrates via molecular beam epitaxy. Herein, we use composition targeting and logarithmic Sn cell temperature control to achieve linearly graded pseudomorph Ge1-xSnx compositions up to 10% before partial relaxation of the structure and a continued gradient up to 16% GeSn. In this report, we use X-ray diffraction, simulation, secondary ion mass spectrometry, and atomic force microscopy to analyze and demonstrate some of the possible growths that can be produced with the enclosed algorithm. This methodology of growth is a major step forward in the field of GeSn development and the first ever demonstration of algorithmically driven, linearly graded GeSn films.

Heat Integration of Liquid Hydrogen-Fueled Hybrid Electric Ship Propulsion System

This study introduced the methodology for integrating ethylene glycol/water mixture (GW) systems which supply heat energy to the liquid hydrogen (LH2) fuel gas supply system (FGSS), and manage the temperature conditions of the battery system. All systems were designed and simulated based on the power demand of a 2 MW class platform supply vessel assumed as the target ship. The LH2 FGSS model is based on Aspen HYSYS V11 and the cell model that makes up the battery system is implemented based on a Thevenin model with four parameters. Through three different simulation cases, the integrated GW system significantly reduced electric power consumption for the GW heater during ship operations, achieving reductions of 1.38% (Case 1), 16.29% (Case 2), and 27.52% (Case 3). The energy-saving ratio showed decreases of 1.86% (Case 1), 21.01% (Case 2), and 33.80% (Case 3) in overall energy usage within the GW system. Furthermore, an examination of the battery system’s thermal management in the integrated GW system demonstrated stable cell temperature control within ±3 K of the target temperature, making this integration a viable solution for maintaining normal operating temperatures, despite relatively higher fluctuations compared to an independent GW system.

Fuzzy logic approach for failure analysis of Li-ion battery pack in electric vehicles

Vehicle electrification is one of the changes in the modern-day car enterprise trend. The battery pack is the most vital and precarious part of a battery-powered electric vehicle, which necessitates accurate and reliable designs to ensure acceptable safety. To this end, one of the tried and tested methods that help identify problems and make products more reliable is Failure Modes and Effect Analysis (FMEA). This paper presents a Fuzzy FMEA for risk assessment of an immersion-cooled battery pack (ICBP) in electric vehicles. As a new technology, immersion cooling can facilitate high-rate fast charging and a longer battery life cycle for lithium-ion batteries. Different failure modes and relevant causes and effects are investigated in this vein. Each failure's severity, occurrence, and detection rank are extracted and displayed as a standard FMEA table. The monitoring results of all stages of design, manufacture, and initial tests indicate that the most important causes of failure in an ICBP are the sealing method, BMS function, cell temperature control, structure, and assembly of mechanical components. To some extent, it was attempted to reduce the occurrence of failures by recommending actions to reduce the occurrence of those failures. Consequently, a significant improvement was achieved, and the production and installation of problematic parts were managed efficiently and effectively with the help of an FMEA control plan table.

Design of Portable Self-Oscillating VCSEL-Pumped Cesium Atomic Magnetometer

With the demand for fast response of magnetic field measurement and the development of laser diode technology, self-oscillating laser-pumped atomic magnetometers have become a new development trend. In this work, we designed a portable self-oscillating VCSEL-pumped Cs atom magnetometer, including the probe (optical path) and circuits. The signal amplification and feedback loop of the magnetometer, VCSEL laser control unit, and atomic cell temperature control unit were realized. We tested the performance of the magnetometer in the metering station. Finally, The performance of the VCSEL-pumped magnetometer designed in this work was compared with that of a CS-3 lamp-pumped self-oscillating atomic magnetometer; their performance was found to be mostly in the same order of magnitude, while the power consumption of our magnetometer was 3 W less than that of the CS-3. This work represents an exploratory attempt to integrate and miniaturize a portable self-oscillating VCSEL-pumped Cs atomic magnetometer.

Effect of Temperature on Energy Consumption and Polarization in Reverse Osmosis Desalination Using a Spray-Cooled Photovoltaic System

Reverse osmosis (RO) desalination is considered a viable alternative to reduce water scarcity; however, its energy consumption is high. Photovoltaic (PV) energy in desalination processes has gained popularity in recent years. The temperature is identified as a variable that directly affects the behavior of different parameters of the RO process and energy production in PV panels. The objective of this study was to evaluate the effect of temperature on energy consumption and polarization factor in desalination processes at 20, 23, 26 and 30 °C. Tests were conducted on a RO desalination plant driven by a fixed 24-module PV system that received spray cooling in the winter, spring and summer seasons. The specific energy consumption was lower with increasing process feed temperature, being 4.4, 4.3, 3.9 and 3.5 kWh m−3 for temperatures of 20, 23, 26 and 30 °C, respectively. The water temperature affected the polarization factor, being lower as the temperature increased. The values obtained were within the limits established as optimal to prevent the formation of scaling on the membrane surface. The spray cooling system was able to decrease the temperature of the solar cells by about 6.2, 13.3 and 11.5 °C for the winter, spring and summer seasons, respectively. The increase in energy production efficiency was 7.96–14.25%, demonstrating that solar cell temperature control is a viable alternative to improve power generation in solar panel systems.

Effects of inclination angle and heat power on heat transfer behavior of flat heat pipe with bionic grading microchannels

Bionic structure has become a popular tool to design heat pipes for its ability of heat transfer enhancement and liquid transport. Inspired by the powerful water collection and transfer capability of pitcher plant surface, this paper presents a new flat heat pipe design with bionic grading microchannels (BGFHP) based on special high-low structured surface. Firstly, the performance advantages of BGFHP are revealed by comparing the heat transfer performance and visible internal flow characteristics of BGFHP and conventional FHP. Secondly, the performance variation and influence trend of BGFHP are investigated experimentally with inclination angle and thermal power as variables. Finally, thermal management effects of natural cooling, FHP and BGFHP in fuel cells are compared to demonstrate the practical application of BGFHP. Results show that the high-low channel structure of BGFHP has the advantages of micro-channel hydraulic transport, and the small channel increases the heat transfer area, circulation efficiency and gas phase flow area, resulting in better start-up time and heat transfer capacity than the traditional FHP. The thermal resistance of BGFHP is reduced by 22%, while the thermal conductivity is increased by more than 40%. In the load range of 10–26 W and inclination angle range of 0–90°, the overall thermal resistance and temperature uniformity of BGFHP decreases and then increases as the inclination angle increases. With the increase of heat power, the thermal resistance of BGFHP gradually decreases, whereas the temperature uniformity first decreases and then increases. The optimal working condition of BGFHP is 45° and 24 W, with a minimum thermal resistance of 0.21 K/W. In the fuel cell temperature control test, the BGFHP was able to maintain the temperature below 52 °C, which is 5 °C lower compared to the FHP. This result shows the advantage of the BGFHP in terms of temperature control.

Fuel cell passenger car temperature tracking control based on cascade internal model control with nonlinear feedforward compensate

The heat dissipation capacity of the radiator of vehicle fuel cell thermal management system is easily affected by the ambient, so the system needs to have a high ability to suppress disturbance. Based on cascade internal model control with nonlinear feedforward compensate (CIFC), a temperature tracking control scheme is designed for a real vehicle fuel cell system. By defining the heat dissipation coefficient, CIFC can compensate the heat dissipation capacity of the radiator in different environment and driving condition for real vehicle so that reduce the impact of environmental factors on the fuel cell temperature management system. The control scheme is applied on a real fuel cell passenger car. Simulation and real vehicle experiments show that the scheme has good accuracy, stability, rapidity and robustness. The simulation results show that the algorithm can track the set temperature under each load current without steady-state error, the step response adjustment time is 54s and there is no overshoot both under normal atmospheric temperature and higher atmospheric temperature. The real vehicle experiment results show that the overshoot is less than 2°C, the temperature tracking speed can reach 1.1°C, and the system can stay stable with the change of vehicle speed and load without steady-state error. • Model based controller is proposed for fuel cell temperature control. • Experiments on a real fuel cell vehicle are implemented. • There is no steady-state error in the experiment. • Overshooting can be limited to less than 2 °C in the experiments.

Comparison of different fuel cell temperature control systems in an anode and cathode ejector-based SOFC-GT hybrid system

Solid oxide fuel cell-gas turbine (SOFC-GT) hybrid systems are facing challenges in terms of fuel cell temperature control due to its significant effect on safe and efficient operation. In this study, five different temperature control systems are designed according to different SOFC control strategies and control points in anode and cathode ejector-based SOFC-GT hybrid systems. Firstly, three SOFC temperature control strategies including only anode-side control, only cathode-side control, and two-side control are compared. The comparison results indicate that the cathode-side temperature control strategy can effectively maintain the system efficiency. In addition, the two-side control strategy is better than one-side control strategies considering the safe operation of the anode and cathode differential temperature. Then, three SOFC temperature control points including input temperature, output temperature, and average temperature are chosen in order to investigate the effect of control variables. The comparison results indicate that maintaining the average temperature is better than the other temperature control points. Therefore, the two-side average temperature control system of SOFC is more appropriate to guarantee efficient and safe operation. The temperature distribution in SOFC is more feasible, and the efficiency of SOFC and the whole hybrid system is most efficient at a part load condition.

Liquid-Based Battery Temperature Control of Electric Buses

Previous research identified that battery temperature control is critical to the safety, lifetime, and performance of electric vehicles. In this paper, the liquid-based battery temperature control of electric buses is investigated subject to heat transfer behavior and control strategy. Therefore, a new transient calculation method is proposed to simulate the thermal behavior of a coolant-cooled battery system. The method is based on the system identification technique and combines the advantage of low computational effort and high accuracy. In detail, four transfer functions are extracted by a thermo-hydraulic 3D simulation model comprising 12 prismatic lithium nickel manganese cobalt oxide (NMC) cells, housing, arrestors, and a cooling plate. The transfer functions describe the relationship between heat generation, cell temperature, and coolant temperature. A vehicle model calculates the power consumption of an electric bus and thus provides the input for the transient calculation. Furthermore, a cell temperature control strategy is developed with respect to the constraints of a refrigerant-based battery cooling unit. The data obtained from the simulation demonstrate the high thermal inertia of the system and suggest sufficient control of the battery temperature using a quasi-stationary cooling strategy. Thereby, the study reveals a crucial design input for battery cooling systems in terms of heat transfer behavior and control strategy.

Experimental analysis on battery based health monitoring system for electric vehicle

Electric vehicles are the future and the most important part of an electric vehicle is its battery which provides the power to the vehicle and also its weakest part. Batteries are prone to degradation, heating and general age related effects. So a constant monitoring system is required to keep the battery in check and keep the user posted about its various variables. This project provides a management system for a battery by monitoring various factors like main power voltage, cell voltage, etc. It includes monitoring cell condition, states estimation, temperature control and heat management, all aimed at enhancing the overall performance of the system. This data is then acquired and sent to the cloud where it can be remotely accessed by the user or a common access point at any given situation and thus also thereby making removable battery station much more possible and reliable.

Extended State Filter Based Disturbance and Uncertainty Mitigation for Nonlinear Uncertain Systems With Application to Fuel Cell Temperature Control

The filter design for nonlinear uncertain systems is quite challenging since efficient estimation is required against stochastic noises, nonlinear uncertain dynamics as well as their concurrent effects. To this end, this article develops a novel filter algorithm by augmenting the disturbance as well as unknown nonlinear dynamics as an extended state and constructing consistent Kalman–Bucy algorithm. The proposed extended state based Kalman–Bucy filter (KBF) is shown to be of bounded estimation error, and the estimation accuracy can be online evaluated. More importantly, the estimation of asymptotic minimum variance is realized in condition that the changing rate of uncertainty approaches to zero. Therefore, the proposed extended state filter enables effective mitigation of disturbance and unknown nonlinear dynamics in real time by feedback control. The proposed algorithm is experimentally verified via a temperature control application in proton exchange membrane fuel cell, in which the thermocouple noise and the electrochemical uncertainty are seriously presented. The temperature variation of the extended state based KBF-based control is greatly reduced, in comparison with the conventional control. The results in this article depict a promising prospect of the proposed method for industrial control applications to handle both noises and nonlinear uncertain dynamics.

Research on applications of phase change materials in solar cell thermal control

In order to grasp the characteristics of phase change material (PCM) in solar cell thermal control, a two-dimensional thermal control structure model of PV/PCM solar cell thermal control system was established, and study was conducted on influence of PCM phase change temperature, thermal conductivity, latent heat value, etc. on the temperature control characteristics of solar cells. The results show that PCM phase change temperature, thermal conductivity, latent heat value will affect solar cell temperature control characteristics in varying degrees. At the same time, thermal control characteristics of PCM are greatly affected by environmental meteorological conditions (solar irradiance, ambient temperature). The research results provide a reference for optimization design of PV/PCM solar cell thermal control system.

Voltage-induced pseudo-dielectric heating and its application for color tuning in a thermally sensitive cholesteric liquid crystal

ABSTRACTWe previously proposed an electrical approach enabling the tuning of the center wavelength λc of the cholesteric liquid crystal (CLC) bandgap in the full-color visible spectrum based on the electro-thermal effect. The idea involved the design of a negative CLC with a thermally sensitive bandgap feature and the use of a sandwich-type cell with finite electrode conductivity, allowing the control of cell temperature by applied voltage via pseudo-dielectric heating. It has been demonstrated experimentally that the induced pseudo-dielectric heating is predominated by the pseudo-dielectric relaxation originating from the designated cell geometry. On the basis of this technique, key factors determining the tuning efficacy of the temperature and thus λc are primarily investigated in this study. Our results suggest that lowering the electrode resistivity and the specific heat conductivity of the cell can promote the maximum tunable temperature range. Expectedly, optimizing the electrode area, cell gap and dielectric permittivity of the CLC favors a decreased relaxation frequency and, in turn, reducing the voltage as well as the frequency required for λc tuning.

Initial approaches in benchmarking and round robin testing for proton exchange membrane water electrolyzers

As ever-increasing amounts of renewable electricity enter the energy supply mix on a regional, national and international basis, greater emphasis is being placed on energy conversion and storage technologies to deal with the oscillations, excess and lack of electricity. Hydrogen generation via proton exchange membrane water electrolysis (PEMWE) is one technology that offers a pathway to store large amounts of electricity in the form of hydrogen. The challenges to widespread adoption of PEM water electrolyzers lie in their high capital and operating costs which both need to be reduced through R&D. An evaluation of reported PEMWE performance data in the literature reveals that there are excessive variations of in situ performance results that make it difficult to draw conclusions on the pathway forward to performance optimization and future R&D directions. To enable the meaningful comparison of in situ performance evaluation across laboratories there is an obvious need for standardization of materials and testing protocols. Herein, we address this need by reporting the results of a round robin test effort conducted at the laboratories of five contributors to the IEA Electrolysis Annex 30. For this effort a method and equipment framework were first developed and then verified with respect to its feasibility for measuring water electrolysis performance accurately across the various laboratories. The effort utilized identical sets of test articles, materials, and test cells, and employed a set of shared test protocols. It further defined a minimum skeleton of requirements for the test station equipment. The maximum observed deviation between laboratories at 1 A cm−2 at cell temperatures of 60 °C and 80 °C was 27 and 20 mV, respectively. The deviation of the results from laboratory to laboratory was 2–3 times higher than the lowest deviation observed at one single lab and test station. However, the highest deviations observed were one-tenth of those extracted by a literature survey on similar material sets. The work endorses the urgent need to identify one or more reference sets of materials in addition to the method and equipment framework introduced here, to enable accurate comparison of results across the entire community. The results further imply that cell temperature control appears to be the most significant source of deviation between results, and that care must be taken with respect to break-in conditions and cell electrical connections for meaningful performance data.

用于激光气体同位素探测的多通池温度控制系统研制

用于激光气体同位素探测的多通池温度控制系统研制

Three-dimensional modeling of pressure effect on operating characteristics and performance of solid oxide fuel cell

A three-dimensional (3-D) model for planar, anode-supported, solid oxide fuel cell (SOFC) is developed to investigate the effect of operating pressure on cell characteristics. The results show that the elevated operating pressure can improve cell performance by increasing open circuit voltage and reducing activation overpotential, and enhance the electrochemical reaction in the vicinity of electrolyte. Besides, the high pressure can also change the distributions of species and internal reforming reactions. Compared to the case using syngas as fuel, the operating pressure has more significant effects on temperature gradient along flow direction when partly pre-reformed gas is supplied. In addition, efficient control of cell temperature could be achieved by decreasing fuel utilization in the case of partly pre-reformed gas, but this is achieved at the expense of cell efficiency, especially under high pressure condition. Another way to reduce the temperature gradient is to adopt higher air ratio. Moreover, when partly pre-reformed gas is used, the counter-flow configuration has a better performance due to the higher overall temperature.

Study on Nonlinear Identification SOFC Temperature Model Based on Particle Swarm Optimization–Least-Squares Support Vector Regression

In order to facilitate valid solid oxide fuel cell (SOFC) temperature control scheme, a nonlinear identification method of SOFC temperature dynamic behaviors is proposed using an autoregressive network with exogenous inputs (NARX) model, whose nonlinear function is described by a least-squares support vector regression (LSSVR) method with radial basis kernel function (RBF). During the identifying process, a particle swarm optimization (PSO) algorithm is introduced to optimize the parameters of LSSVR. On the other hand, a mechanism model is developed to sample the training data to regress the NARX model. Investigations are conducted to analyze the effects of training data size and PSO fitness function on the accuracy of the NARX model. The results demonstrate that the NARX model with tenfold cross-validation fitness function and large size data is precise enough in predicting the SOFC temperature dynamic behaviors. The maximum errors of cathode and anode outlet temperature are 0.3081 K and 0.3293 K, respectively. Furthermore, the simulation speed of NARX model is much faster than the mechanism model because NARX model avoids the internal complex computation process. The training time of the NARX model with large size data is about 1.2 s. For a 20,000 s simulation, the predicting time of the NARX model is about 0.2 s, while the mechanism model is about 36 s. In consideration of its high computational speed and accuracy, NARX model is a powerful candidate for valid multivariable model predictive control (MPC) schemes.

Fuel Cell Temperature Control With a Precombustor in SOFC Gas Turbine Hybrids During Load Changes

The use of high temperature fuel cells, such as solid oxide fuel cells (SOFCs), for power generation is considered a very efficient and clean solution for conservation of energy resources. When the SOFC is coupled with a gas turbine, the global system efficiency can go beyond 70% on natural gas lower heating value (LHV). However, durability of the ceramic material and system operability can be significantly penalized by thermal stresses due to temperature fluctuations and noneven temperature distributions. Thermal management of the cell during load following is therefore essential. The purpose of this work is to develop and test a precombustor model for real-time applications in hardware-based simulations, and to implement a control strategy to keep constant cathode inlet temperature during different operative conditions. The real-time model of the precombustor was incorporated into the existing SOFC model and tested in a hybrid system facility, where a physical gas turbine and hardware components were coupled with a cyber-physical fuel cell for flexible, accurate, and cost-reduced simulations. The control of the fuel flow to the precombustor was proven to be effective in maintaining a constant cathode inlet temperature during a step change in fuel cell load. With a 20 A load variation, the maximum temperature deviation from the nominal value was below 0.3% (3 K). Temperature gradients along the cell were maintained below 10 K/cm. An efficiency analysis was performed in order to evaluate the impact of the precombustor on the overall system efficiency.