On-board Storage Research Articles

Conceptual design and numerical analysis of a miscibility gap alloy-based solid-state thermal battery for electric vehicles

Heating the passenger cabin of electric vehicles at low temperatures consumes a large amount of battery power, resulting in a significant reduction in cruising range. On-board thermal energy storage is an effective way to improve the cruising range of electric vehicles in winter. Miscibility gap alloy is a new type of shape-stabilized composite phase change material, which has the advantages of high energy storage density, high thermal conductivity, low cost, and good safety. Therefore, using it to heat electric vehicles can increase their cruising range, prolong battery life, and reduce cost. In this paper, the concept of a compact on-board solid-state thermal battery based on miscibility gap alloy is proposed for the first time, and the heat charging, thermal insulation and heat discharging performance of the design are analysed based on numerical simulations. The results show that the thermal battery can reach a heat storage density of 553.8 Wh/L, and the average heat discharging power can reach 1.326 kW. The results of this paper can provide guidance for the engineering development of miscibility gap alloy-based solid-state thermal batteries.

Optimization of Inlet Hydrogen Temperature during the Fast-Filling Process Based on a Back Propagation Neural Network Model

A reasonable inflating strategy must be developed for filling an onboard hydrogen storage tank with hydrogen gas. The inflow hydrogen temperature has always been a constant value in filling cases. However, in our opinion, the optimal inflow hydrogen temperature is not supposed to be a fixed value but a value that constantly changes and adjusts with filling time, i.e., the inflow hydrogen temperature is a function of the filling time. How to determine this functional relationship is a critical problem to be addressed. Herein, an approach is introduced. A dual-zone model is presented to research the thermal effect during the process of charging hydrogen storage tanks. Based on the numerical results of the dual-zone model, the charging process was divided into three stages, allowing us to obtain data for 1331 filling cases. Then, a back propagation (BP) neural network model was built to analyze the data, and the implicit relationship between the inflow hydrogen temperatures and maximum hydrogen temperature pressure could be deduced. With this implicit relationship, the critical values of the inflow hydrogen temperatures can be obtained from the critical situation. Suppose the inflow hydrogen temperatures in a practical case are higher than the critical values. In that case, the highest hydrogen temperature in the tank will exceed the limited safety value of 358 K. In contrast, if the inflow hydrogen temperatures are lower than the critical values, then more energy will be needed to precool the inlet hydrogen temperature. Thus, theoretically, the critical inflow hydrogen temperatures should be at their optimal values.

Design principle, 4E analyses and optimization for onboard CCS system under EEDI framework: A case study of an LNG-fueled bulk carrier

With the accelerated implementation of Energy Efficiency Design Index (EEDI) phase 3 by the International Maritime Organization, shipping carbon reduction is urgently required. This paper explores the possibility to develop the onboard carbon capture and storage (OCCS) system unstraints between EEDI phases 3 and 4. The OCCS is particularly established with the utilization of exhaust gas waste heat and LNG cold energy. The proposed OCCS system is modelled in Aspen HYSYS, laying the foundation for energy, exder the EEDI framework. The OCCS system design principle for an LNG-fueled bulk carrier is determined with the conergy, economic and environment analyses. Furthermore, the multi-objective optimization is based on the energy and exergy efficiency of OCCS system (ηen,OCCS × ηen,OCCS), payback period (PBP) and metric of carbon capture efficiency degree (MCCED) by non-dominated sorting genetic algorithm-Ⅲ. The Pareto frontier indicates that the system is in optimal operation with the exhaust gas mass flow rate of 29,990 kg/h and the liquid-to-gas ratio of 1.04. The carbon capture is 1048.0 kg/h, which is 70.74% over EEDI phase 3 requirements. The optimized ηen,OCCS × ηen,OCCS is 2.92%, the PBP is 13.03 years and the MCCED is 23.00%. This study provides an important basis for the maritime post-combustion carbon reduction compliance.

Numerical simulation of leakage jet flame hazard of high-pressure hydrogen storage bottle in open space

The jet fire is a common type of fire accident in high-pressure hydrogen storage bottles. It is crucial to conduct research on the thermal radiation hazards resulting from on-board hydrogen storage bottle leaks, leading to jet fires within 35 MPa. Additionally, accurately and swiftly calculating the characteristic parameters of hydrogen jet flames, such as flame geometry and radiation heat flow, is of utmost importance. To study the jet fire hazard caused by high-pressure hydrogen storage cylinder leaks, a simplified model of the hydrogen storage cylinder was established using FLUENT software for numerical simulation analysis. The study analyzed the impact patterns of high-pressure hydrogen leakage jet flames under different scenarios, including leakage aperture, leakage pressure and ambient wind speed. The results demonstrate a positive correlation between the leakage aperture and pressure with the size of the jet flame and the extent of thermal radiation damage. The larger the leakage aperture and pressure, the larger the hydrogen jet flame size. The higher the peak value of the flame thermal radiation, the greater the hazard range. Additionally, the temperature of the stable axis of the jet flame rises with increasing leakage aperture. As the leakage pressure rises, the thermal radiation of the flame also increases. Conversely, as the ambient wind speed increases, the flame length, the burn radius, and the thermal radiation range decreases, but the high-temperature heat range expands. The empirical formula between flame length and leakage pressure and leakage aperture under different environmental wind speeds is obtained by data fitting, which can be used as a priori prediction of flame length under wind speed conditions.

Kinetic Energy Recovery from a landing aircraft: Evaluating Onboard Energy Solutions

This paper compares onboard Energy Storage Solutions (ESSs) for a Kinetic Energy Recovery System (KERS) from a landing aircraft. Energy is stored temporarily and reused so that it enables engine-less taxiing. This paper evaluates the choice of onboard Energy Storage Solutions (ESSs) (flywheels, batteries and supercapacitors) for recovering energy during the landing roll and storing it in the device. A design of an ESS with each of the three technologies was made, using commercially available products. The resulting devices are compared on the basis of weight, charging time, discharging time and complexity in retrofitting to existing systems. Results shows that while batteries have the highest energy density and will have the lowest weight, they are unable to charge/discharge quickly enough to satisfy this application. Conversely, supercapacitors have this ability but their low energy density make them heavy which in turn would offer penalty to the aircraft in flight. Flywheels emerge as the most interesting proposition due to their high energy density and fast charging ability, which satisfy the requirements for application.

A preliminary design of a hybrid train’s on-board batteries for a 25 kV-50 Hz high speed railway line

The paper reports a technical-economic comparison for a Turkey high-speed railway line, between 25 kV AC electrification and the use of hybrid trains with on-board storage systems. On-board battery storage systems have been designed to operating in specific parts of the line. Different types of technologies have been taken into account, evaluating the use of high specific power/energy lithium-ion electrochemical cells. The models of the battery pack have been designed in the MATLAB/Simulink environment, in order to carry out the complete operation check, also evaluating the time and power required for recharging. An economic evaluation and comparison have been carried out in order to evaluate the convenience of using a hybrid train on specific part of a real line in order to not totally electrified the line.

Computational Design for Enhanced Hydrogen Storage on the Newly Synthesized 2D Polyaramid via Titanium and Zirconium Decoration.

2D polyaramid (2DPA) is a porous and polymeric material that has been synthesized recently. Titanium and zirconium decoration over 2DPA increases their affinity for hydrogen substantially, making them suitable for onboard and reversible hydrogen storage, particularly in light-duty vehicles. By decorating a single unit cell of 2DPA with two transition metal (TM) atoms, hydrogen storage of up to 6.422 and 6.792 wt % of H2 with average binding energies of -0.399 and -0.480 eV is predicted for 2DPA + Ti and 2DPA + Zr, respectively. The binding of Ti and Zr with 2DPA is accompanied by a flow of charge (-1.474e for Ti and -1.696e for Zr) from the TM toward the 2DPA sheet. Further, the interaction between H2 and the TM may proceed via Kubas interaction between the d orbital of the TM in 2DPA + TM and H 1s orbitals of H2, with a net flow of charge from the TM toward H2 (-0.218e for Ti and -0.391e for Zr). The desorption of H2 bound to 2DPA + Zr is endothermic (∼0.57 eV) and close in magnitude to the binding energy of the first H2 (∼-0.544 eV). The 2DPA + TM systems show structural and dynamic stability at high temperatures, as evident from ab initio molecular dynamics simulations and phonon spectra. The movement of TM atoms across the 2DPA sheet to form clusters may be hindered by the considerable barrier energy (∼4.9 eV for Ti). Through these systematic density functional theory simulations, we predict that Ti- and Zr-decorated 2DPA are high-performance hydrogen storage materials and can be explored by experimentalists.

Study of hybrid energy storage system with energy management for electric vehicle applications

This paper conducts an in-depth study on the on-board energy storage system for electric vehicles. We analyze the advantages and disadvantages of domestic and foreign energy storage systems including battery, flywheel, superconductor and supercapacitor. We propose a hybrid energy storage system composed of battery and supercapacitor as the on-board power supply system. It adopts a two-phase staggered parallel bidirectional DC-DC converter as the main control circuit of the storage system. And we adopt the power outer loop and current inner loop control strategy. Then the rate limiter prevents the sudden change of battery power and realizes that the instantaneous power is provided by the supercapacitor individually. The purpose is to extend the battery life and achieve the purpose of reasonable and efficient utilization of energy. Finally, the simulation verification is carried out by Matlab/Simulink. And the results show that the energy management strategy is more efficient for both power and energy management, which meets the design expectation and achieves better experimental results.

Strength and fatigue study of on-board type III cryo-compressed hydrogen storage cylinder

Due to its better energy storage density and lower costs for storage, cryo-compressed hydrogen (CcH2) storage provides a wide range of research potential. Based on the grid theory, The type III CcH2 storage cylinder's layup scheme is created using the working environment for on-board hydrogen storage. The failure of the composite layer of gas cylinders was determined using the maximum stress criterion, and hydrodynamic bursting tests on small-volume gas cylinders were utilized to confirm that the design method was appropriate. The innermost layer of the ring winding is where the largest fiber stress is found, according to simulation studies. The load-bearing capacity of the cylinder is improved and can reach 115.1 MPa with layers in the order of [90/±11.8/90]. The equivalent stress and fiber stress ratio of the cylinder continuously drop as the autofrettage pressure rises, while the cylinder's fatigue life gradually lengthens.

Kaolin-based metal-organic frameworks for sustainable natural gas storage

Natural gas (NG) is increasingly regarded as one of the most environmentally friendly forms of energy. However, low volumetric density, high leakage rate and explosion during transportation and storage limit the accessibility and consumption of NG. To bridge the gap, this work reports on the formulation of metal-organic frameworks (MOFs) for onboard storage of natural gas using kaolin clay, chitosan, dimethyl sulfoxide, potassium acetate and (3-mercaptopropyl) trimethoxysilane. Results of formulated MOFs (CKO, PKT, DKT, DKO, and PKO) from the thermogravimetric analysis showed that the thermal stability ranged from 226 to 550 °C implying that the MOFs at this temperature range can maintain their structural integrity and resist decomposition throughout the adsorption process. The results of Porosimetry indicated that the synthesized MOFs exhibit a surface area within the range of 195.239–611.802 cm2/g and a pore volume ranging from 0.412 to 0.967 cm3/g. These findings suggest that the prepared MOFs possess a practical adsorption capacity for natural gas. Adsorption tests demonstrated that CKO and PKT MOFs exhibited higher natural gas (NG) adsorption capacities (0.028 and 0.017 g/g) over DKT, DKO, and PKO (0.014 g/g, 0.0095 g/g, and 0.0083 g/g) at 5 bar. These results underscore the increased capacity of MOFs to store significant quantities of natural gas under low-pressure conditions compared to previous literature. Conversely, the strong correlation coefficients (R > 0.95) observed in the adsorption isotherms of the developed MOFs provide confirmation that natural gas adsorption took place on uniform adsorption sites, aligning with the Langmuir adsorption isotherm. Overall, the findings of this study demonstrated the potential of kaolin-based metal-organic frameworks for use in the energy sector and expanded the search for sustainable onboard natural gas storage solutions.

Subcooled Liquid Hydrogen Technology for Heavy-Duty Trucks

Subcooled liquid hydrogen (sLH2) is an onboard storage, as well as a hydrogen refueling technology that is currently being developed by Daimler Truck and Linde to boost the mileage of heavy-duty trucks, while also improving performance and reducing the complexity of hydrogen refueling stations. In this article, the key technical aspects, advantages, challenges and future developments of sLH2 at vehicle and infrastructure levels will be explored and highlighted.

Li-decorated BC3 nanopores: Promising materials for hydrogen storage

In the quest of new absorbent for hydrogen storage, we investigate the capacities of slit pores formed by two BC3 sheets decorated with Li atoms. Their hydrogen storage capacities are determined using density-functional theory in conjunction with a quantum-thermodynamic model that allows to simulate real operating conditions, i.e., finite temperatures and different loading and depletion pressures applied to the adsorbent in the charge-delivery cycles. We show that the capacities of the adsorbed hydrogen phase of Li-decorated BC3 slit pores are larger than those reported recently for graphene and Li-decorated borophene slit pores. On the other hand, the usable volumetric and gravimetric capacities of Li-decorated BC3 slit pores can meet the targets stipulated by the U.S. Department of Energy (DOE) for onboard hydrogen storage at moderate temperatures and loading pressures well below those used in the tanks employed in current technology. In particular, the usable volumetric capacity for pore widths of about 10 Å meets the DOE target at a loading pressure of 6.6 MPa when depleting at ambient pressure. Our results highlight the important role played by the rotational degree of freedom of the H2 molecule in determining the confining potential within the slip pores and their hydrogen storage capacities.

Pre-Coded Inter-Satellite Routing Algorithm with Load Balancing for Mega-Constellation Networks

In order to achieve global multiple seamless coverage, space-based internet usually adopts low Earth orbit (LEO) mega-constellation networks structure, which has the characteristics of high network topology dynamics, limited on-board computing and storage capacity, and uneven distribution of ground traffic. Such features may cause problems such as high transmission delay, network congestion and link interruption. Establishing a stable, efficient and balanced satellite communication link can effectively alleviate the performance of the transmission delay, load balancing, and network throughput. Taking advantage of the regularity of network topology, a pre-coded inter-satellite routing algorithm with load balancing is proposed, which includes 3 parts: (a) the routing sequence coding method and the concept of gateway satellite Service Region (GSSR) are proposed; (b) the initial routing sequence of GSSR is generated based on the maximum network flow method under the ideal situation of uniform satellite traffic distribution; (c) aiming at the uneven distribution of traffic, the Sinkhorn algorithm is used to improve the load balancing performance of inter-satellite links. Simulation results show that, for the Starlink Group-4 constellation, the proposed method can maintain a low transmission delay and improve the load balancing together with the network throughout performance with minimal hops and low time complexity.

Improving the efficiency of route passenger transport systems by using recovered energy

This article analyzes the problems associated with increasing the efficiency of route passenger transport systems, with an in-depth consideration of tram subsystems. The focus is on using recovered electrical energy to optimize the operation of trams. The recovered energy produced during vehicle braking or deceleration can be effectively stored in on-board storage devices and then used to power the tram's traction system. The article makes the case for the relevance of this proposal, emphasizing not only the potential benefits in efficiency and resource savings, but also its significance in terms of reducing emissions and environmental sustainability of the public transport system. Schemes for implementing this approach are presented, including technical aspects of implementation and possible algorithms for controlling the energy storage and distribution system. An important element of the analysis is to determine the expected economic effect from the implementation of the proposed system. The authors of the article present an assessment of the economic benefits that can be achieved by reducing energy costs for traction and reducing the costs of maintaining and operating the transport system. Potential investments and financial aspects of implementing a new system are also discussed, which makes this study interesting both for engineers and technical specialists, as well as for economists and managers in the field of transport infrastructure.

Hydrogen Economy: Are we ready?

Hydrogen Economy: Are we ready?

The additional consumption and savings of paid energy of traction substations when using on-board and stationary storage devices

In traction power supply systems for city electric transport without storage devices, a significant part of the recovery energy is usefully reused for the load in the process of inter-train flows along the contact network. The excess part of the recuperation is dissipated by heat in the braking resistors. The use of on-board storage devices makes it possible to redirect all recovery energy from the car's traction drive to them. The remaining amount of no more than two-thirds of the received recuperation energy is supplied back to the traction drive from the storage device, excluding internal losses, since due to ohmic resistance, the actual efficiency of any type of storage device does not exceed 64 %. The on-board storage device consumes a significant amount of paid energy from the traction substation for its transportation by car, compensation for self-discharge, etc. The total balance of recovery energy returned to traction and losses from additional energy consumption for on-board storage devices is negative. When stationary storage devices operate in the contact network, useful recuperation flows are completely preserved. The excess part of the recovery is redirected to the contact network, where one part of it powers a low-power non-traction load while charging the storage device, and the other goes to the storage device, charging it. After a short period of storage in the storage device, the remainder of the excess recovery is released into the network for the load that appears in it. A stationary storage device has no energy consumption for transportation, and the consumption of paid energy for its own needs and compensation for self-discharge is significantly less than that of an on-board storage device due to its higher load factor. The stationary storage device has a positive balance of recovery energy which allows additional savings of paid energy from the traction substation in the amount of up to 10 % relative to such consumption during useful recovery flows without the use of storage devices.

Prospective life cycle inventory datasets for conventional and hybrid-electric aircraft technologies

Hybrid-electric aircraft represent a promising solution for the urgent need to decarbonize short-haul flights and bolster aviation sustainability. Nevertheless, the realization of hybrid-electric aircraft demands rigorous environmental impact analysis, given the substantial investments, time, and research required for technology development. This study offers a comprehensive life cycle inventory spanning the years 2030, 2040, and 2050 for both conventional and hybrid-electric aircraft configurations. Our inventory datasets are meticulously constructed through a systematic approach, ensuring data harmonization by drawing upon scientific literature, industry expertise, and primary data sources. This extensive dataset encompasses all pertinent systems necessary to model the environmental footprint of flights covering distances ranging from 200 to 600 nautical miles, utilizing a 50-passenger aircraft with the ATR42 as a reference model. Additionally, we furnish supplemental data for end-of-life considerations and uncertainty analysis. The systems under examination include the airframe, powertrain, power electronics and drives, batteries, fuel cells, hydrogen onboard storage, airport infrastructure, and battery charging stations. Notably, the carbon footprint of conventional aircraft aligns with data from the ecoinvent v3.8 database; however, our provided datasets are more than tenfold more detailed and incorporate a forward-looking perspective. These meticulously curated life cycle inventories can be amalgamated to simulate the potential environmental ramifications of conventional aircraft powered by kerosene or alternative aviation fuels, hybrid-electric aircraft utilizing battery technology, and hybrid-electric aircraft employing hydrogen as a fuel in conjunction with batteries. In this context, our findings play a pivotal role in nurturing the development of technology roadmaps that prioritize environmental sustainability within the realm of regional aviation.

Turbocompound energy recovery option on a turbocharged diesel engine

The transportation sector is living a transition era in which hybrid and electrified vehicles are replacing conventional vehicles, based on internal combustion engines. This is pushed by the recognized need for reducing fuel consumption and tailpipe emissions, considering primary pollutants and carbon dioxide as a greenhouse gas. In the transition path, hybridization and partial electrification of the powertrain play a crucial role. In this regard, the need for on-board electrical energy storage and utilization is increasing significantly and the possibility to recover wasted energy and convert it into electrical form is mandatory. This is especially true for commercial and heavy-duty vehicles, where full electrification is more difficult to be implemented. Waste Heat Recovery (WHR) has therefore become so important for vehicles, not only to directly reduce fuel consumption and related emissions but also to improve the feasibility of a generation of vehicles with a higher degree of hybridization that considers, for example, the electrification of auxiliaries following the so-called auxiliaries-on-demand management. Wasted heat refers mainly to exhaust heat from gases, where about one third of the fuel energy is disposed of. Among the various systems for WHR, engine turbo-compounding is approaching a mature technology. This technological option makes use of an additional turbine on the exhaust line of the engine, downstream of the turbocharging one, which converts the residual gas enthalpy into mechanical form. In this paper, the F1C Iveco 3.0 L turbocharged diesel engine is considered for verifying the performances of a turbo-compounding system. The engine was mounted on a dynamic engine test bench. In particular, the interactions with the original engine produced on the exhaust line were studied. Backpressure effects on the engine introduced by turbo-compounding were evaluated reversed in terms of extra fuel consumption. Moreover, the new equilibrium of the turbocharger was assessed and the related modifications to the engine were measured considering that the turbocharger has a control strategy based on the so-called Variable Geometry Turbine (VGT), via the modification of the Inlet Guide Vanes (IGV). The presence of a secondary turbine for WHR opens to a wider possibility of actuating the IGV and, so, the possibility to optimize the recovery considering the integrated system and all its degrees of freedom.

Ultralow Pd bimetallic catalysts boost (de)hydrogenation for reversible H2 storage

The facile catalytic reversible (de)hydrogenation of liquid organic hydrogen carriers (LOHC) using a single catalyst holds great value for onboard hydrogen storage. Herein, we develop a bimetallic catalyst Pd1Ni based on nonnoble metal Ni with ultralow Pd of 0.05 wt%, which enables reversible (de)hydrogenation of NPC and supports multiple cycles of reversible hydrogen uptake and release. Notably, the bimetallic catalyst Pd1Ni exhibits more excellent catalytic performance on the dehydrogenation reaction of dodecahydro-N-propylcarbazole (12H-NPC) than the 1%Pd catalyst and similar catalytic performance on the hydrogenation reaction of NPC compared to the 1%Ru catalyst. The astonishing catalytic efficiency of Pd1Ni catalysts is due to the ideal electronic structure between ultralow Pd and Ni NPs allowing rapid interfacial electron transfer to intermediates, as revealed by structural analyses and density functional theory (DFT) computations.

An On-Board Imaging Processing Algorithm for Stripmap Mode of Azimuth Multichannel Spaceborne SAR

In the traditional processing methods of azimuth multi-channel spaceborne synthetic aperture radar (SAR), the azimuth spectrum reconstruction and subsequent azimuth focusing are always via full-aperture processing. However, if the multi-channel full-aperture echo data are stored on the satellite, and then the full-aperture algorithms are used for the on-board imaging processing, the huge amount of echo data will require more on-board storage resources and computing resources, and the imaging processing time will become longer. To solve above problems, a novel on-board imaging processing algorithm via the idea that the data acquisition and the on-board imaging processing of the sub-aperture data are carried out simultaneously is proposed in this paper. In the algorithm, the azimuth spectrum ambiguity is eliminated by the sub-aperture azimuth spectrum reconstruction. Then, the range cell migration correction (RCMC) and the range compression for the unambiguous sub-aperture signals are accomplished by the chirp scaling algorithm (CSA). After that, the low-resolution subaperture images are got via the sub-aperture focusing. By coherently combining all sub-aperture images, the final result with high-resolution of all echo data can be obtained. At last, the simulation for the point targets is given to verify the effectiveness of the proposed algorithm.