Use In Hybrid Electric Vehicles Research Articles

Studies of interfacial reaction characteristics for high power lithium-ion battery

The widespread use of hybrid electric vehicles brings a great challenge to meet the power density requirement in the full temperature and state of charge (SOC) intervals while balancing the energy density, cost and lifetime. The research on the interfacial reaction mechanism of high power lithium-ion batteries would be the basis for the above problem. In this paper, a symmetrical cell made from the electrodes of the commercial high power lithium-ion batteries is targeted. Moreover, electrochemical impedance spectroscopy (EIS) is used as the main characterization method to systematically investigate the variation of EIS of high power lithium-ion batteries LiNi0.33Co0.33Mn0.33O2 and graphite electrodes. The EIS data are fitted using Z-View software, and the Ls element is used to achieve an effective separation of the liquid phase diffusion resistance Rion and the charge transfer resistance Rct of lithium ions inside the porous electrode, thus obtaining the variation patterns of Rion and Rct with the temperature and SOC. The relevant kinetic parameters are tested and the boundary conditions for Rion and Rct are explored as the speed control step respectively, providing a reference for the design and performance improvement of commercial high power lithium-ion batteries, especially those in specific temperature and SOC intervals.

Emission Characteristics of Hybrid Electric Bus During Peak Period Based On Remote Monitoring

Based on the OBD remote monitoring system, the real-time data of Tianjin 607 bus is collected, and two representative groups of data are selected for analysis. The results show that the vehicles start and stop frequently during peak period, the frequency of electric motor use increases from 27.72% in off-peak period to 53.72% in peak period, the average driving speed is faster than usual, and the drivers tend to drive more intensely for catching up time. Under the same working conditions, the frequency of electric motor use is positively correlated with the emission reduction benefits brought by the use of hybrid electric vehicles. Under different road conditions, especially in the peak operation, the exhaust temperature is low, which has a greater impact on the actual emission reduction benefits of the electric motor. The key to fundamentally alleviate the emission problem of bus in peak period is to improve the vehicle operation conditions and the conversion rate of SCR system.

Fuzzy Logic-Based Duty Cycle Controller for the Energy Management System of Hybrid Electric Vehicles with Hybrid Energy Storage System

Due to increasing fuel prices, the world is moving towards the use of hybrid electric vehicles (HEVs) because they are environmentally friendly, require less maintenance, and are a green technology. The energy management system (EMS) plays an important role in HEVs for the efficient storage of energy and control of the power flow mechanism. This paper deals with the design, modeling, and result-oriented approach for the development of EMS for HEVs using a fuzzy logic controller (FLC). Batteries and supercapacitors (SCs) are used as primary and secondary energy storage systems (ESSs), respectively. EMS consists of the ultra-power transfer algorithm (UPTA) and FLC techniques, which are used to control the power flow. The UPTA technique is used to charge the battery with the help of a single-ended primary inductor converter (SEPIC) during regenerative braking mode. The proposed research examines and compares the performance of FLC with a proportional integral (PI) controller by using MATLAB (Simulink) software. Three scenarios are built to confirm the efficiency of the proposed design. The simulation results show that the proposed design with FLC has a better response as its rise time (2.6 m) and settling time (1.47 µs) are superior to the PI controller.

Modelling and Simulation of Series Parallel Hybrid Electric Vehicle

The present paper intends to discuss the architectural structure and the different modes of operation of a series parallel hybrid electric vehicle during a drive cycle. Here an attempt has been made to simulate a standard series parallel HEV using the MATLAB and SIMULINK software to estimate the consumption of fuel for the different drive cycles. The results obtained from the model in terms of the fuel consumption have also been compared with that of a conventional internal combustion engine based vehicle. The study thus reinforces the need and viability of the use of hybrid electric vehicles as an intermediate transition and a pre-requisite to the full electric vehicle for the developing countries like India.

ANN Based Current Controller for Hybrid Electric Vehicles

The use of Hybrid Electric Vehicles (HEVs) across the world is growing enormously every day. The single-phase bi-directional convertors are presented in this study for HEVs on-board charging(OBC). In HEVs, we use power electronics converters for the converting and inverting operations. Artificial Neural Network(ANN) is presented in this study for simple operation and high optimization approaches. ANN control technique regulates the system's THD and enhances charging system optimization, enables two-way power delivery that is from the grid to vehicle and the vehicle to grid. An ANN based current controller model that achieves fast-dynamic reaction and that improves grid current harmonic characteristics is proposed in this study. The system's THD is reduced by the ANN controller being suggested. The results prove the validity and feasibility of design and control technique of the proposed integrated charging system.

Optimization of low temperature hydrogen sensor using nano ceramic-particles for use in hybrid electric vehicles

Optimization of low temperature hydrogen sensor using nano ceramic-particles for use in hybrid electric vehicles

Experimental analysis of Dynamic Charge Acceptance test conditions for lead-acid and lithium iron phosphate cells

This paper presents the results of a series of tests to determine the Dynamic Charge Acceptance (DCA) performance of small form-factor carbon-enhanced VRLA cells designed for use in Hybrid Electric Vehicle (HEV) applications, together with standard lead-acid and lithium iron phosphate (LFP) cells. The results demonstrate how varying the conditions and parameters of the standard DCA test regime can provide a superior evaluation of DCA performance and lead to a better understanding of cell behaviour under real-world conditions. A modified test procedure is proposed, based on the DCA Short Test profile (EN50342-6). Results are presented for a batch of carbon-enhanced cells, tested at various temperatures, rest periods and States of Charge (SoC) for the cell. These conditions having been chosen to mimic a range of real-life scenarios which could potentially be encountered during HEV operation. The resulting analysis demonstrates clear variations and trends in DCA performance which may be used to inform conditions for future testing regimes. The modified test procedure is then applied to standard lead-acid and LFP 26650-type cells and the results compared.

Neural network approach on loss minimization control of a PMSM with core resistance estimation

Permanent magnet synchronous motors (PMSMs) are often used in industry for high-performance applications. Their key features are high power density, linear torque control capability, high efficiency, and fast dynamic response. Today, PMSMs are prevalent especially for their use in hybrid electric vehicles. Since operating the motor at high efficiency values is critically important for electric vehicles, as for all other applications, minimum loss control appears to be an inevitable requirement in PMSMs. In this study, a neural network-based intelligent minimum loss control technique is applied to a PMSM. It is shown by means of the results obtained that the total machine losses can be controlled in a way that keeps them at a minimum level. It is worth noting here that this improvement is achieved compared to the case with I$_{d}$ set to zero, where no minimum loss control technique is used. Within this context, hysteresis and eddy current losses are primarily obtained under certain conditions by means of a PMSM finite element model, initially developed by CEDRAT as an educational demo. A comprehensive loss model with a dynamic core resistor estimator is developed using this information. A neural network controller is then applied to this model and comparisons are made with analytical methods such as field weakening and maximum torque per ampere control techniques. Finally, the obtained results are discussed.

Cathode to Cathode Lithium Ion Battery Recycling

Due to their high energy density, long lifespan and light weight, lithium ion (Li-ion) batteries accounted for $11.8 billion dollars in sales in 2012, that makes up 60% of total portable battery sales and 37% of total battery sales. The same factors also make them the best candidate for use in hybrid electric vehicles (HEVs) and electric vehicles (EVs). Currently in the US almost all spent lithium ion batteries are land filled, compared to other types of batteries, such as lead acid batteries, in which 97% are recycled. This presents a large amount of environmental waste. Based on current trends in Li-ion battery use, if Li-ion batteries are not recycled, global lithium reserves are expected to be depleted by 2050. Additionally, recycling Li-ion batteries presents an economic opportunity in through the recovery of key valuable metals, such as cobalt, nickel and copper. Currently, most Li-ion battery recyclers focus on recovering cobalt from LiCoO2 cathode material or through the recovery of Co and Ni from the cathode materials via a high temperature pyrometallurgical approach. We propose a new methodology that uses a low temperature hydrometallurgical approach that has the advantage of having high efficiency of recovery. This process works regardless of the Li-ion batteries chemistry, shape and size and recovers Co, Ni, and Mn in the form of their hydroxides, which when sintered with recovered Li2CO3 produces new LiNixMnyCozO2 cathode materials. The regenerated cathode material, LiNixMnyCozO2 , has been tested and exhibits good electrochemical performance. In addition to the cathode material, copper, aluminium, steel, etc are also recycled. Figure 1

Performance analysis of a novel coaxial power-split hybrid powertrain using a CNG engine and supercapacitors

Energy conservation is a very important task for the automotive industry. The use of hybrid electric vehicles can improve energy efficiency, thus reducing fuel consumption and carbon emissions. In this research, the performance characteristics of a novel coaxial power-split hybrid powertrain for a transit bus are presented. The power sources are a combination of a compressed natural gas (CNG) engine and supercapacitors. A mathematical model for the coaxial power-split hybrid powertrain is established. Subsequently, an analysis program is developed based on Matlab and Advisor. The parameters are specified using experimental data. Afterwards, a rule-based control strategy is designed and optimized from the viewpoint of energy efficiency. Later, the system performance is evaluated using the Chinese Transit Bus City Driving Cycle and compared to a conventional powertrain. The results indicate that the proposed coaxial power-split hybrid powertrain can fulfill the requirements of the transit bus and enhance the energy efficiency dramatically. Moreover, the average energy efficiency of the supercapacitors was found to be above 97% over the entire driving cycle. Using supercapacitors as energy storage devices for the coaxial power-split hybrid powertrain can effectively recover the kinetic energy during regenerative braking and is a good solution for transit buses that require frequent acceleration and deceleration.

Design and optimisation of interior PM machines with distributed and fractional-slot concentrated-windings for hybrid electric vehicles

This paper presents an optimisation of an interior permanent magnet (PM) machine with fractional-slot concentrated-windings (FSCW) based on a machine with integer-slot distributed windings (ISDW), and a performance comparison between the two machines for use in hybrid electric vehicles. Finite element analysis (FEA) is used to investigate the characteristics of the two machines which have the same dimensions and rated power. The effect of the number of slots on the back-EMF, cogging torque, d- and q-axis inductances and efficiency is analysed for the two machines. The measured results have good agreement with the FEA results.

Electrochemical performance of LiCoO2/SrLi2Ti6O14 batteries for high-power applications

LiCoO2/SrLi2Ti6O14 Li-ion rechargeable batteries with ∼6 Ah capacities are designed and assembled for use in hybrid electric vehicle (HEV) applications. For comparison, LiCoO2/Li4Ti5O12 batteries are also constructed using similar processing parameters. Power tests are carried out using the hybrid pulse power characterization (HPPC) method. Experimental results show that the LiCoO2/SrLi2Ti6O14 batteries have better power performance and more stable charge/discharge direct current (DC) resistances compared with the LiCoO2/Li4Ti5O12 batteries. At a 50% depth of discharge (DOD), LiCoO2/SrLi2Ti6O14 batteries have an excellent specific charge power density of 3973 W kg−1, which can be attributed to the high Li diffusion capability and high electronic conductivity of the SrLi2Ti6O14 material.

In Situ Solid-State NMR Spectroscopy of Electrochemical Cells: Batteries, Supercapacitors, and Fuel Cells

Electrochemical cells, in the form of batteries (or supercapacitors) and fuel cells, are efficient devices for energy storage and conversion. These devices show considerable promise for use in portable and static devices to power electronics and various modes of transport and to produce and store electricity both locally and on the grid. For example, high power and energy density lithium-ion batteries are being developed for use in hybrid electric vehicles where they improve the efficiency of fuel use and help to reduce greenhouse gas emissions. To gain insight into the chemical reactions involving the multiple components (electrodes, electrolytes, interfaces) in the electrochemical cells and to determine how cells operate and how they fail, researchers ideally should employ techniques that allow real-time characterization of the behavior of the cells under operating conditions. This Account reviews the recent use of in situ solid-state NMR spectroscopy, a technique that probes local structure and dynamics, to study these devices. In situ NMR studies of lithium-ion batteries are performed on the entire battery, by using a coin cell design, a flat sealed plastic bag, or a cylindrical cell. The battery is placed inside the NMR coil, leads are connected to a potentiostat, and the NMR spectra are recorded as a function of state of charge. (7)Li is used for many of these experiments because of its high sensitivity, straightforward spectral interpretation, and relevance to these devices. For example, (7)Li spectroscopy was used to detect intermediates formed during electrochemical cycling such as LixC and LiySiz species in batteries with carbon and silicon anodes, respectively. It was also used to observe and quantify the formation and growth of metallic lithium microstructures, which can cause short circuits and battery failure. This approach can be utilized to identify conditions that promote dendrite formation and whether different electrolytes and additives can help prevent dendrite formation. The in situ method was also applied to monitor (by (11)B NMR) electrochemical double-layer formation in supercapacitors in real time. Though this method is useful, it comes with challenges. The separation of the contributions from the different cell components in the NMR spectra is not trivial because of overlapping resonances. In addition, orientation-dependent NMR interactions, including the spatial- and orientation-dependent bulk magnetic susceptibility (BMS) effects, can lead to resonance broadening. Efforts to understand and mitigate these BMS effects are discussed in this Account. The in situ NMR investigation of fuel cells initially focused on the surface electrochemistry at the electrodes and the electrochemical oxidation of methanol and CO to CO2 on the Pt cathode. On the basis of the (13)C and (195)Pt NMR spectra of the adsorbates and electrodes, CO adsorbed on Pt and other reaction intermediates and complete oxidation products were detected and their mode of binding to the electrodes investigated. Appropriate design and engineering of the NMR hardware has allowed researchers to integrate intact direct methanol fuel cells into NMR probes. Chemical transformations of the circulating methanol could be followed and reaction intermediates could be detected in real time by either (2)H or (13)C NMR spectroscopy. By use of the in situ NMR approach, factors that control fuel cell performance, such as methanol cross over and catalyst performance, were identified.

Minimizing Seat Track Vibration That is Caused by the Automatic Start/Stop of an Engine in a Power-Split Hybrid Electric Vehicle

The use of hybrid electric vehicles is an effective means of reducing pollution and improving fuel economy. Certain vehicle control strategies commonly automatically shut down or restart the internal combustion engines of hybrid vehicles to improve their fuel consumption. Such an engine autostart/stop is not engaged or controlled by the driver. Drivers often do not expect or prepare for noticeable vibrations, noise, or an unsmooth transition when the engine is autostarted/stopped. Unsmooth engine autostart/stop transitions can cause driveline vibrations, making the ride uncomfortable and the customer dissatisfied with the vehicle. This research simulates the dynamic behaviors associated with the neutral starting and stopping of a power-split hybrid vehicle. The seat track vibration results of analysis and hardware tests of the baseline control strategy are correlated. Several antivibration control strategies are studied. The results reveal that pulse cancellation and the use of a damper bypass clutch can effectively reduce the fluctuation of the engine block reaction torque and the vibration of the seat track by more than 70% during the autostarting and stopping of the engine. The initial crank angle can have an effect on the seat track vibration as well.

A Microsimulation of Energy Demand and Greenhouse Gas Emissions from Plug-in Hybrid Electric Vehicle Use

A population of drivers was simulated using a microsimulation model. Consistent with the 2001 National Household Travel Survey (NHTS), a wide range of daily driving distance was observed. This heterogeneity implies that some drivers will realize greater fuel savings from driving a plug-in hybrid electric vehicle (PHEV) than others, therefore, consumers who choose to purchase PHEVs may tend to be those who drive farther than average. The model was used to examine the effects of this difference in driving by estimating fuel use, electricity demand and GHG emissions by two populations, one assigned PHEVs at random to some fraction of drivers, and the other assigned PHEVs to drivers who realized operating cost savings at least as great as the amortized incremental cost of the PHEV relative to a comparable conventional vehicle. These two populations showed different distributions of daily driving distance, with the population of PHEV drivers selected on the basis of operating cost savings driving 40% farther per day on average than average drivers. This difference indicates the possible range of driving patterns of future PHEV drivers, which should be taken into account when estimating fuel savings and GHG reductions from PHEVs. For example, if 20% of U.S. vehicles were PHEVs, we find a potential reduction of fuel use of 0.17 gal per day per vehicle if PHEVs substitute randomly for conventional vehicles, whereas the fuel savings is as large as 0.26 gal per day per vehicle if PHEVs are substituted according to operating cost savings. Similar differences in GHG emissions were estimated as well. The effects of electricity demand management on charging PHEVs was examined for these two populations. It was found for both that only a small fraction of PHEVs were impacted by interruptible electricity service (no charging permitted during peak hours). Most PHEV drivers were able to charge sufficiently during off-peak hours and saw little change in operating costs. This implies that interruptible electricity service may impact operating costs of only a small fraction of PHEV drivers.

Sufficient conditions of optimal control based on Pontryagin’s minimum principle for use in hybrid electric vehicles

Over 10 years ago, the equivalent consumption minimization strategy was introduced as an effective approach, using the concept of equivalent fuel consumption for electricity use, to solve a control problem for hybrid electric vehicles. Although numerous studies have documented outstanding results as a consequence of applying the concept and have shown that the equivalent consumption minimization strategy could be explained on the basis of an optimal control concept such as Pontryagin’s minimum principle, few studies have proven, mathematically, its optimal performance when solving the control problem of hybrid electric vehicles. The present research builds upon previous research studies that proved that the control based on Pontryagin’s minimum principle can be a global optimal solution for hybrid electric vehicles under the assumption that the battery efficiency is not a function of the state of charge. In this paper, we expand upon the original concept, deriving the optimality within more generalized cases than previously reported. In conclusion, if the battery efficiency is a concave function of the state of charge, which is possibly a natural characteristic of the battery, the optimal control based on Pontryagin’s minimum principle enables optimal performance to be achieved. We can therefore apply this control concept to hybrid electric vehicles which use a wide range of states of charge, such as plug-in hybrid electric vehicles.

Flexible solid-state paper based carbon nanotube supercapacitor

This paper presents a flexible solid-state supercapacitor of high energy density. The electrodes of the supercapacitor are made of porous and absorbent cotton paper coated with single-wall carbon nanotubes. To ensure all solid-state configuration, a solid-state polymer-based electrolyte (poly (vinyl alcohol)/phosphoric acid) is used. The as-fabricated supercapacitor can be charged to over 3 V. It has high specific capacitance and high energy density of 115.8301 F/g carbon and 48.8587 Wh/kg carbon. Its performance is comparable to that of commercial supercapacitors, which need to utilize liquid electrolytes. Flexible solid-state supercapacitors offer several significant advantages for use in hybrid electric vehicles.

SVDD기법을 이용한 하이브리드 전기자동차 충-방전시스템의 고장검출 알고리듬

A fault detection algorithm of a charge and discharge system to ensure the safe use of hybrid electric vehicle is proposed in this paper. This algorithm can be used as a complementary way to existing fault detection technique for a charge and discharge system. The proposed algorithm uses a SVDD technique, which additionally utilizes two methods for learning a large amount of data; one is to incrementally learn a large amount of data, the other one is to remove the data that does not affect the next learning using a new data reduction technique. Removal of data is selected by using lines connecting support vectors. In the proposed method, the data processing speed is drastically improved and the storage space used is remarkably reduced than the conventional methods using the SVDD technique only. A battery data and speed data of a commercial hybrid electrical vehicle are utilized in this study. A fault boundary is produced via SVDD techniques using the input and output in normal operation of the system without using mathematical modeling. A fault detection simulation is performed using both an artificial fault data and the obtained fault boundary via SVDD techniques. In the fault detection simulation, fault detection time via proposed algorithm is compared with that of the peak-peak method. Also the proposed algorithm is revealed to detect fault in the region where conventional peak-peak method is never able to do.

Who will drive electric vehicles, olivine or spinel?

Lithium iron phosphate olivine (LFP) and lithium manganese oxide spinel (LMO) are competitive and complementary to each other as cathode materials for lithium ion batteries, especially for use in hybrid electric vehicles and electric vehicles. Interest in these materials, due to their low cost and high safety, has pushed research and development forward and toward high performance in terms of rate capability and capacity retention or cyclability at a high temperature of around 60 °C. From the view point of basic properties, LFP shows a higher gravimetric capacity while LMO has better conductivities, both electrically and ionically. According to our comparison experiments, depending on the material properties and operational potential window, LFP was favored for fast charging while LMO led to better discharge performances. Capacity fading at high temperatures due to metal dissolution was revealed to be the most problematic issue of LFP and LMO-based cells for electric vehicles (EVs), with thicker electrodes, in the case of no additives in the electrolyte and no coating to prevent metal dissolution on cathode materials. Various strategies to enhance the properties of LFP and LMO are ready for the realization of EVs in the near future.

The Development of a New Type of Rechargeable Batteries Based on Hybrid Electrolytes

Lithium ion batteries (LIBs), which have the highest energy density among all currently available rechargeable batteries, have recently been considered for use in hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and pure electric vehicles (PEV). A major challenge in this effort is to increase the energy density of LIBs to satisfy the industrial needs of HEVs, PHEVs, and PEVs. Recently, new types of lithium-air and lithium-copper batteries that employ hybrid electrolytes have attracted significant attention; these batteries are expected to succeed lithium ion batteries as next-generation power sources. Herein, we review the concept of hybrid electrolytes, as well as their advantages and disadvantages. In addition, we examine new battery types that use hybrid electrolytes.