Demand For Hybrid Electric Vehicles Research Articles

Advanced Power Management and Control for Hybrid Electric Vehicles: A Survey

With the trend of low emissions and sustainable development, the demand for hybrid electric vehicles (HEVs) has increased rapidly. By combining a conventional internal combustion engine with one or more electric motors powered by a battery, HEVs have the advantages over traditional vehicles in better fuel economy and lower tailpipe emissions. Nevertheless, the power management strategies (PMSs) for conventional vehicles which mainly focus on the efficiency of internal combustion engine are no longer applicable due to the complex internal structure of HEVs. Hence, a large number of novel strategies appropriate for HEVs have been surveyed, but most of the researches concentrate on discussing the classifications of PMSs and comparing their cons and pros. This paper presents a comprehensive review of power management strategies adopted in HEVs aiming at specific challenges for the first time. The categories of the existing PMSs are presented based on the different algorithms, followed by a brief study of each type including the analysis of its pros and cons. Afterwards, the implementation and optimization of power management strategies aiming at proposed challenges are introduced in detail with the description of their optimization objectives and optimized results. Finally, future directions and open issues of PMSs in HEVs are discussed.

Synthesis of Ternary Blended Materials of Li1.2Mn0.4Ni0.16Co0.24O2, the Li2MnO3-Stabilized Compound, and Olivine Fluorides (Li2MPO4F) As a High Capacity Cathode Materials for Lithium Ion Batteries

The area of blended cathode materials is still evolving and there are very few research on the subject. The blending parent cathode materials typically involves high capacity electrode materials; layered oxides compounds with spinel cathode compounds that are lower in cost, more environmentally benign and higher operating voltage. These blended cathode materials are expected to be resilient in terms of storage capacity, cycle life, cheaper and environmentally safer. However, chemically, there are exist challenges in pairing a high- operating voltage material and high capacity material and still achieving less resistance, greater storage and cycle life may be difficult to achieve, since high voltages are likely to enable more degradation pathways. This paper seeks to explore a composite systems made of three different cathode materials involving lithium rich compounds Li1.2Mn0.4Ni0.16Co0.24O2, the Li2MnO3-stabilized compounds, spinel, or Olivine fluorides (Li2MPO4F). This study aims to design a better ternary system that meets the high energy density demand for hybrid electric vehicles and at the same time, minimizes the salient but important material properties like the thermal stability, longer life, high capacity and yet meet bottom line. The paper therefore explores a thorough understanding of the various interaction of each of the compounds so as to tailor their properties to have that synergy, conducting basic scientific analysis of the particle-to particle interaction at the atomic level, as well as the chemical interaction of the constituents in the ternary system to achieve the synergistic effect.

The spatial distribution of hybrid electric vehicles in a sprawled mid-size Canadian city: Evidence from Windsor, Canada

Technological advancements in recent years have allowed hybrid electric vehicles (HEVs) to improve in terms of associated tailpipe emissions and fuel efficiency. As a result, the demand for HEVs in Canada has been on the rise, but the market share is still negligible. In this paper, the population of HEVs in the Windsor Census metropolitan area (CMA), Ontario, Canada for the year 2010 is considered to study the determinants that led to the observed spatial distribution of this class of vehicles across the different census tracts within the CMA. Vehicle-specific characteristics along with locational variables are employed in the analysis. Locational factors are based on census tract profile attributes (namely socio-economic factors) that were acquired from the 2011 Census National Household Survey (NHS). Other variables used in the analysis include mixed density index, average commuting distance and a measure of spatial clustering. Discrete choice modeling is used to explain the residential location of HEV owners in the CMA. Moran's I statistics analysis suggests that the spatial distribution of HEV owners exhibits a clustering pattern. This was also reinforced by the significance of the spatial term used in the choice model. Area-based socio-economic factors pertaining to the size of population, gender, type of occupation, education, size of household of the people living in an area, and income explain the spatial prevalence of HEVs. Also, areas housing long distance commuters as well as areas with mixed density tend to house HEV owners.

Ceramic Composite Separators Coated with Moisturized ZrO2 Nanoparticles for Improving the Electrochemical Performance and Thermal Stability of Li-Ion Batteris

In recent years, the demand for hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs) has increased due to the desire to reduce increased emission of greenhouse gases and consumption of fossil fuels. Lithium ion batteries (LIBs) are regarded as suitable power sources for EV applications because of their high energy and power. However, safety is still an important and serious concern in the development of LIBs for these applications. To improve the safety of these batteries, many researchers have focused on the improvement of the thermal and mechanical properties of separators. The separator plays a key role in ensuring the safety of LIBs by preventing short circuit between the cathode and anode.This implies that the separator must be a good electrical insulator and must possess good mechanical and dimensional stability as well as electrochemical stability toward electrolyte and electrode materials. Polyethylene (PE) separators have been widely used in commercial LIBs and have many advantages such as good electrochemical stability, high mechanical strength, small pore size, and thin frames.Despites these properties, the poor thermal stability of PE separators is a disadvantage that needs to be resolved. When exposed to high-temperature environments, PE separators exhibit extensive thermal shrinkage and significant structural degradation, which may trigger internal short circuits in the LIBs. Consequently, the thermal stability of PE separators needs to be further improved to meet the rigorous safety standards for LIBs for EV applications. Since the introduction of separators such as safety-reinforced separators (SRS) by LG Chem., various ceramic composite separators have been proposed for practical use in LIBs. For example, Takemura et al. proposed a ceramic composite separator that was made of Al2O3 ceramic powder and a polymer binder on a PE framework and that exhibited good thermal stability. Zhang et al. also reported a CaCO3-based composite separator with excellent thermal stability, in which CaCO3 ceramic particles coating the separator acted as a heating-resistant material suppressing the thermal shrinkage of the separator.Previous works have largely focused on the improvement of thermal properties of separators by incorporating various ceramic particles. However, the effect of the ceramic particles on the electrochemical performance of LIBs has not yet been intensively studied. We herein propose a ceramic composite separator that is coated by a polymeric binder [poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-12wt%HFP) copolymer] and moisturized ZrO2 nanoparticles. We demonstrate the structural changes of the polymer coating layer induced by the moisture adsorbed on ZrO2 nanoparticles, and discuss the correlation between the microstructure of the ZrO2-composite separator and its electrochemical and thermal properties. Our findings can lead to robust ceramic composite separator designs that will improve thermal stability of LIBs for EV applications. Fig . 1. FE-SEM images of the composite separators with different coatings at different magnifications. (a) A separator coated with only PVDF-12wt%HFP copolymer. (b) The same separator at 1µm. (c) A composite separator coated in PVDF-12wt%HFP copolymer and dried ZrO2 nanoparticles (moisture content : 100 ppm). (d) The same separator at 1µm. (e) A composite separator coated in PVDF-12wt%HFP copolymer and moisturized ZrO2 nanoparticles (moisture content : 3000 ppm). (f) The same separator at 1µm. Figure 1

SOI-Based Integrated Gate Driver Circuit for High-Temperature Applications

The growing demand for hybrid electric vehicles (HEVs) has increased the need for high-temperature electronics that can operate at the temperatures that exist under the hood of these vehicles. In many cases this requires the use of thermal management systems to allow for the use of components not designed to operate at the ambient temperatures found in the engine compartment of an HEV. These systems add weight and complexity, which can increase the overall cost and reduce the efficiency of the vehicle. The alternative is to develop circuits and systems capable of operating with reduced or no thermal management. To this end, the latest version of our high-temperature gate driver integrated circuit (IC) has been developed. Designed and implemented on a 0.8-micron bipolar-CMOS-DMOS (BCD) on silicon-on-insulator (SOI) process, this gate driver chip is intended to drive silicon carbide (SiC) and other wide-bandgap (WBG) power field-effect transistors (FETs) for DC-DC converters and traction drives in HEVs. To enable this, the gate driver IC, which includes on-chip voltage regulators and protection circuitry, has been designed to operate at and successfully tested up to 200°C ambient temperature. Successful operation of the circuit at this temperature with minimal or no heat sink, and without liquid cooling, will help to achieve higher power-to-volume as well as power-to-weight ratios for the power electronics modules in HEVs.

A UNIVERSAL SOI-BASED HIGH TEMPERATURE GATE DRIVER INTEGRATED CIRCUIT FOR SiC POWER SWITCHES WITH ON-CHIP SHORT CIRCUIT PROTECTION

In recent years, increasing demand for hybrid electric vehicles (HEVs) has generated the need for reliable and low-cost high-temperature electronics which can operate at the high temperatures under the hood of these vehicles. A high-voltage and high temperature gate-driver integrated circuit for SiC FET switches with short circuit protection has been designed and implemented in a 0.8-micron silicon-on-insulator (SOI) high-voltage process. The prototype chip has been successfully tested up to 200°C ambient temperature without any heat sink or cooling mechanism. This gate-driver chip can drive SiC power FETs of the DC-DC converters in a HEV, and future chip modifications will allow it to drive the SiC power FETs of the traction drive inverter. The converter modules along with the gate-driver chip will be placed very close to the engine where the temperature can reach up to 175ΰC. Successful operation of the chip at this temperature with or without minimal heat sink and without liquid cooling will help achieve greater power-to-volume as well as power-to-weight ratios for the power electronics module.

Hybrid Cars and HOV Lanes

From 2005 to early 2007, California issued 85,000 Clean Air Access stickers that allowed three models of hybrid cars to avoid congestion by driving on High Occupancy Vehicle (HOV or carpool) lanes with a single occupant. Using data on used car prices, we estimate the willingness-to-pay for one of these Clean Air Access stickers as approximately $625 per sticker per year, or $270 million for all 85,000 of the stickers which were valid for six years. Despite having a high value, the stickers were less effective at stimulating the demand for hybrid electric vehicles than an equivalent cash subsidy. Many stickers were given out to vehicles that had been purchased before the program started. While many hybrid owners were willing to pay upwards of $3,200 per sticker, for others the stickers amounted to an under-valued perk. Given the high value drivers place on HOV access, a more effective policy would sell space in the HOV lane to drivers of any vehicle and use the revenue to stimulate hybrid demand.

Algorithms for Advanced Battery-Management Systems

Lithium-ion (Li-ion) batteries are ubiquitous sources of energy for portable electronic devices. Compared to alternative battery technologies, Li-ion batteries provide one of the best energy-to-weight ratios, exhibit no memory effect, and have low self-discharge when not in use. These beneficial properties, as well as decreasing costs, have established Li-ion batteries as a leading candidate for the next generation of automotive and aerospace applications. In the automotive sector, increasing demand for hybrid electric vehicles (HEVs), plug-in HEVs (PHEVs), and EVs has pushed manufacturers to the limits of contemporary automotive battery technology. This limitation is gradually forcing consideration of alternative battery technologies, such as Li-ion batteries, as a replacement for existing leadacid and nickel-metal-hydride batteries. Unfortunately, this replacement is a challenging task since automotive applications demand large amounts of energy and power and must operate safely, reliably, and durably at these scales. The article presents a detailed description and model of a Li-ion battery. It begins the section Intercalation-Based Batteries by providing an intuitive explanation of the fundamentals behind storing energy in a Li-ion battery. In the sections Modeling Approach and Li-Ion Battery Model, it present equations that describe a Li-ion cell's dynamic behavior. This modeling is based on using electrochemical principles to develop a physics-based model in contrast to equivalent circuit models. A goal of this article is to present the electrochemical model from a controls perspective.