Inductive Power Transfer System Integration for Battery-Electric Vehicles

In this work the effect of weight reduction using advanced lightweight materials on the mass, energy use, and cost of conventional and battery electric passenger vehicles is compared. Analytic vehicle simulation is coupled with cost assessment to find the optimal degree of weight reduction minimizing manufacturing and total costs. The results show a strong secondary weight and cost saving potential for the battery electric vehicles, but a higher sensitivity of vehicle energy use to mass reduction for the conventional vehicle. Generally, light weighting has the potential to lower vehicle costs, however, the results are very sensitive to parameters affecting lifetime fuel costs for conventional and battery costs for electric vehicles. Based on current technology cost estimates it is shown that the optimal amount of primary mass reduction minimizing total costs is similar for conventional and electric vehicles and ranges from 22% to 39%, depending on vehicle range and overall use patterns. The difference between the optimal solutions minimizing manufacturing versus total costs is higher for conventional than battery electric vehicles.

To date inductively coupled power transfer (ICPT) systems have already found many practical applications including battery charging pads. In fact, current charging platforms tend to largely support only one- or two-dimensional planar movement in load. This paper proposes a new concept of extending the aspect ratios of the operating power transfer volume of ICPT systems to support arbitrary three dimensional load movements with respect to the primary coils. This is done by use of modern finite element method analysis software to propose the primary and secondary magnetic structures of such an ICPT system. Firstly, two primary magnetic structures are proposed based on contrasting modes of operation and different field directions. This includes a single-phase and multi-phase current model. Next, a secondary magnetic structure is customized to be compatible with both primary structures. The resulting system is shown to produce a 3D power transfer volume for battery cell charging applications.

In this paper, the generalized model of an inductively coupled power transfer (ICPT) system, which could transfer power efficiently, is built to predict the output power and voltage of the system. The basic concept and structure of ICPT systems is described and a current source push-pull resonant converter for ICPT is presented, and some characteristics of the ICPT system are discussed. The equivalent circuit model is built with mutual inductance concept. Based on this model, equations are obtained to calculate the output power, voltage and resonant frequency, which are verified by experimental results. A brief loss analysis based on Steinmetz equation is given to explain the difference between the predicted and measured values, which are verified by experimental results to make the model more accurate.

<div class="section abstract"><div class="htmlview paragraph">Rapid technological advancement of electric vehicles (EV) contributed to a significant increase of its market share worldwide. Among them battery technologies are key in extending the range of battery electric vehicles (BEV) and easing range anxiety for drivers. To further enhance the range for BEVs, continued downsizing of the battery system together with an increased energy density would be required. Cell to body (CTB) technology was release by BYD Auto in 2022 as its answer to the next generation of battery pack design and system level integration. The battery pack features a sandwich structure that consists of an upper cover, the company’s signature Blade Battery cells, and an underbody protection tray. The battery pack features a higher level of integration, with the volume utilization rate increasing to 66%. The integrated battery pack-body structure enhances its structural strength, with significant reductions in the intrusions across front, small-overlap and side pole impacts. 70% and 57% increases in the torsional and the bending stiffness of the body results in better handling performance and improved passenger comfort. The CTB technology has shown its great potential for high performance BEV design.</div></div>

Battery electric vehicle (BEV) sales in the United States (US) are constantly growing since 2010, resulting in 238,000 units in 2017. While the impact of various factors on the energy efficiency of internal combustion engines vehicles (ICEVs) was vastly explored in the past, research is recently focusing on BEVs. The primary, major restraint for electric vehicles is the range limitation. The range of current vehicles on the market vary between 93-315 miles per charge. Combined with the long charging times for batteries, the suitability for daily use is restricted, yet their range is a significant factor of daily requirements of users. Drivers of electric vehicles sometimes fear running out of power, a phenomenon called range anxiety. In order to extend the range of electric vehicles and because BEVs market share is growing globally and nationally, understanding the impact of different range impacting factors (e.g., traffic, temperature, driver behavior) is essential. The impact of traffic should be understood carefully since it is impressionable by driver behavior, eco-driving strategies, and range management. However, the impact of traffic on the range and, thus, the efficiency of electric vehicles under real-world conditions has not yet entirely transitioned to include BEVs. To quantify the impact of traffic on electric vehicle efficiency, an empirical experiment was conducted with a 2017 eGolf on a predetermined test route. All 30 participants drove the test route twice: once with increased traffic congestion during the morning commute, and once in low traffic congestion during the day. Time was a controlling factor to distinguish two scenarios with different traffic intensities. Finally, both data sets (i.e., traffic data and non-traffic data) were compared to quantify the impact of traffic on the efficiency of BEV under real-world conditions. Different measures were investigated to provide evidence of differences in the intensity of traffic on the chosen test route based on daytime. Outcomes provide evidence that traffic influences the acceleration and change in acceleration on the test route. A multiple linear regression was applied to quantify the impact of traffic on the difference in state of charge per mile of BEVs. Additionally, driver, temperature and initial state of charge were included in the model and investigated for significance. Results show that among all considered factors, temperature has the highest impact on the energy consumption of BEVs. A stepwise regression was carried and based on the results of both regression models, the influence of traffic could

<div>The initial cost of battery electric vehicles (BEVs) is higher than internal combustion engine-powered vehicles (ICEVs) due to expensive batteries. Various factors affect the total cost of ownership of a vehicle. In India, consumers are concerned with a vehicle’s initial purchase cost and prefer owning an economical vehicle. The higher cost and shorter range of BEVs compared to ICEVs severely limit their penetration in the Indian market. However, government subsidies and incentives support BEVs. The total cost of ownership assessment is used to evaluate the entire cost of a vehicle to find the most economical option among different powertrains. This study compares 2W (two-wheeler) and 4W (four-wheeler) BEV’s cost vis-à-vis equivalent ICEVs in Delhi and Mumbai. The cost analysis assesses the current and future government policies to promote BEVs. Two assumed policies were applied to estimate future scenarios. Annual distance traveled, battery replacement assumptions, and fuel/electricity prices were used for sensitivity analyses. It was found that the total cost of ownership of 2W BEVs in Mumbai and Delhi was lower than the ICEVs, only if heavily supported by government subsidies and incentives. In contrast, with assumed future policies, owning 4W BEVs was costlier, even with government subsidies. This study showed that if a vehicle travels more than the average annual distance traveled, BEVs can be a better option and make sense for niche applications such as taxi fleet operations or ride-hailing services. The current incentives were much more for 4W than 2W, implying a disproportionate allocation of subsidies to the wealthier, who can afford 4W vehicles. The funds required for subsidies, losses in fuel taxes because of lower sales, and tax exemptions offered to BEVs could cost up to ₹146,062 crores (i.e., $19 billion) annually to the Indian government in 2030, which is ~ ₹973 per capita, excluding investments required to build charging infrastructure. Therefore, India needs a targeted subsidy allocation plan, prioritizing 2W, and a phased strategy for an orderly and inclusive transition to a sustainable mobility future.</div> <section> <h2>Graphical Abstract</h2> <figure> <div><img/></div> </figure> </section>

Decarbonizing heavy-duty vehicles is becoming increasingly important, yet multiple renewable-based decarbonization pathways have not been compared systematically. To fill this gap, this study develops a techno-economic and environmental model that integrates the fuel cycle and vehicle cycle to assess these pathways for China. The model includes two energy storage technologies: batteries and hydrogen, three energy transmission options, and two vehicle types: fuel cell electric vehicles and battery electric vehicles. Five distinct low-carbon pathways are evaluated on a ton-kilometer basis, including cost, greenhouse gas emissions, and abatement cost relative to conventional diesel trucks. Results indicate that the most cost-effective battery electric vehicle pathway offers a 7 % lower ton-km cost than diesel trucks for a 49-ton gross vehicle weight. Battery electric vehicle charging combined with hydrogen for power generation is more cost-effective than direct use of hydrogen in fuel cell electric vehicles. All studied pathways can achieve over 80 % emission reduction compared to diesel trucks, with fuel cell electric vehicle pathways having the highest abatement costs of 103–117 USD/tonCO2. Analysis of the impact of gross vehicle weight and vehicle range indicates that battery electric vehicle pathways outperform fuel cell electric vehicle pathways across most dimensions. Costs of battery electric vehicle pathways do increase sharply for vehicle ranges beyond about 700 km, and fuel cell electric vehicles become more cost-effective relative to battery electric vehicles for ranges above approximately 1100 km, although all pathways are much more costly than diesel trucks at long ranges. The sensitivity analysis highlights the importance of powertrain efficiency and cost projections show that fuel cell electric heavy-duty vehicles can achieve cost-parity before 2030. These results highlight the desirability of promoting the adoption of heavier battery electric vehicles and providing more targeted subsidies for long-range fuel cell electric vehicles.

The driving range of an electric vehicle depends on the vehicle weight, road load conditions, battery capacity, and battery performance. The battery rated capacity and its characteristics could be heavily affected by the ambient temperature. This paper investigates the effects of ambient temperature on the electric vehicle driving range, equivalent fuel economy, and performance. A production-type battery electric vehicle is modeled and simulated in the AVL-Cruise platform using semi-empirical data. The modeled vehicle battery pack consists of 20Ah Lithium-Nickel-Manganese-Cobalt-Oxide (LiNiMnCoO2) cells. The battery cell characteristics are experimentally measured to build the battery pack model. The simulated driving range and equivalent fuel economy are correlated with the published information as vehicle model validation. Series of simulations on driving cycles (UDDS, HWFET, US06, and WLTP) with across a broad range of ambient temperatures are conducted to investigate the quantified effects of ambient temperature on driving range, equivalent fuel economy, and vehicle performance. Simulation results show that driving range and fuel economy are much reduced to 70% at low ambient temperature. Driving range and fuel economy are almost not affected by high ambient temperature, such as 50 C, since this model does not include accessory load of thermal management. The vehicle performance is almost not affected by the ambient temperature.

<div class="section abstract"><div class="htmlview paragraph">The demand for eco-friendly electric powertrains has increased significantly in recent years. Cells are the most crucial component of a battery pack, directly influencing the dimensions, range, lifespan, performance, and cost of electric vehicles. Lithium-ion cells outperform other cell chemistries due to their higher energy density, allowing for more compact and lightweight designs while providing longer operational ranges. It is crucial that lithium-ion cell packaging complies with assembly requirements to maximize its lifespan and ensure operational safety. Assembly force requirements of lithium-ion cells are critical to ensure optimal cell performance throughout its lifetime & enhance the longevity of the battery pack. The compression pad between cells ensures appropriate cell assembly pressure. The service life is how long a lithium-ion cell can operate effectively, while the cyclic life refers to the number of charge-discharge cycles before cell functional degradation. The cell surface pressure varies from the cell's beginning of life till its end of life.</div><div class="htmlview paragraph">This manuscript details the meticulous process for selecting a compression pad based on cell force requirements at the beginning and end of its life. It also considers cell swelling, thermal insulation and other factors crucial for compression pad selection. The chosen compression pad must ensure even pressure distribution across all cells in the module to prevent varying rates of cell ageing. The document also explains how different cell ageing rates within the module affect the overall battery pack cycle life. Additionally, a module-level 3D model swelling simulation was conducted to estimate cell pressure distribution with the selected compression pad. Based on the simulation results, a recommendation for maintaining even pressure distribution is provided and verified through another iteration of the swelling simulation. This proposed solution aims to maintain uniform cell ageing within the module and improve the cycle life of the cell, module, and battery pack.</div></div>

Based on full-bridge topology, different capacitor compensation circuits of the inductively coupled power transfer (ICPT) system are compared and investigated in this paper. Compensation capacitor on primary side can reduce both switches stress and requirement of the power supply capacity. Compensation capacitor on secondary side can improve system efficiency and power transfer capability. From the reflect impedance analysis, there is no direct effect between the primary series compensation capacitor and the load. System efficiency with secondary compensation capacitor is higher than without it. Switches can realize zero voltage switching when the operating frequency is above the resonant frequency slightly. Finally, simulation results verify the analyses presented in the paper.

In this paper a novel battery electric vehicle (BEV) concept based on a small fixed and a big swappable li-ion battery pack is proposed in order to achieve: longer range, lower initial purchase price and lower energy consumption at short ranges. For short ranges the BEV is only powered by the relatively small fixed battery pack, without the large swappable battery pack. In this way the mass of the vehicle is reduced and therefore the energy consumed per unit distance is improved. For higher ranges the BEV is powered by both battery packs. This concept allows the introduction of subscription-based ownership models to distribute the cost of the large battery pack over the vehicle lifetime. A methodology is proposed for the analysis and evaluation of the proposed concept in comparison with a direct owned non swappable single pack BEV, proving that significant improvements on city fuel economy (up to 20 %) and economic benefits are achievable under several scenarios. These results encourage further study of battery swapping service plans and energy management strategies.

This paper presents a new electromagnetic coupling mechanism called pot coil focusing on improving the inductively coupled power transfer (ICPT) system with limited transmission distance and range. Pot coil allows pick-up coil in electromagnetic field to move at larger range and ensure the output power remains unchanged. The contrast for the magnetic flux intensity distribution of pot coil and conventional spiral coil is brought out by using Ansoft Maxwell, a kind of 3D finite element analysis software. The simulation results demonstrate that pot coil increases energy transmission distance and promotes equilibrium of magnetic circuit. Finally, the experiment results prove the validity of the theory analysis.

We characterize the effect of regional temperature differences on battery electric vehicle (BEV) efficiency, range, and use-phase power plant CO2 emissions in the U.S. The efficiency of a BEV varies with ambient temperature due to battery efficiency and cabin climate control. We find that annual energy consumption of BEVs can increase by an average of 15% in the Upper Midwest or in the Southwest compared to the Pacific Coast due to temperature differences. Greenhouse gas (GHG) emissions from BEVs vary primarily with marginal regional grid mix, which has three times the GHG intensity in the Upper Midwest as on the Pacific Coast. However, even within a grid region, BEV emissions vary by up to 22% due to spatial and temporal ambient temperature variation and its implications for vehicle efficiency and charging duration and timing. Cold climate regions also encounter days with substantial reduction in EV range: the average range of a Nissan Leaf on the coldest day of the year drops from 70 miles on the Pacific Coast to less than 45 miles in the Upper Midwest. These regional differences are large enough to affect adoption patterns and energy and environmental implications of BEVs relative to alternatives.

<div class="section abstract"><div class="htmlview paragraph">Data of battery electric vehicles (BEV) with and without a range extender internal combustion engines (ICE) are reviewed and integrated with weight and performance models. A BEV with an on-board, high efficiency, electricity generator based on positive ignition (PI) ICEs is proposed to improve the uptake of the BEV targeting city commuters while improving their economic and environmental impacts. The small ICE, that is working stationary, fixed load and speed, and the generator similarly optimized for a single point operation, permit an efficiency fuel chemical-to-electric of about 49%. This is much better than producing electricity centralized from combustion fuels (average efficiency with included distribution and recharging losses), and it does not require any electric recharging infrastructure. The range of cars can be extended to about the same values of today's car with traditional combustion engines. Simple but reliable extrapolations from production BEV, with or without range extender and with different battery capacity on the same platform, demonstrate this BEV may deliver miles-per-gallon (MPG) working gasoline 13% better than any plug-in-hybrid-electric-vehicle (PHEV) currently available, and MPGe (MPG-equivalent) working electric 12% better than BEV with a larger battery pack and no range extender, or 27% better than the BEV with a larger battery pack and a traditional range extender. Thanks to the high energy density of gasoline fuel, the range can be increased dramatically at minimal costs for weight and packaging. The proposed architecture is not only promising for passenger cars. With minimal changes to the existing rules, a prototype hypercar for the novel World Endurance Championship of 2021 could be built by using most of the present LMP1-H hardware components.</div></div>

As battery electric vehicle (BEV) market share grows so must our understanding of the noise, vibration, and harshness (NVH) phenomenon found inside the BEVs which makes this technological revolution possible. Similar to the conventional vehicle having encountered numerous NVH issues until today, BEV has to face many new and tough NVH issues. For example, conventional vehicles are powered by the internal combustion engine (ICE) which is the dominant noise source. The noises from other sources were generally masked by the combustion engine, thus the research focus was on the reduction of combustion engine while less attention was paid to noises from other sources. A BEV does not have ICE, automatic transmission, transfer case, fuel tank, air intake, or exhaust systems. In their place, there is more than enough space to accommodate the electric drive unit and battery pack. BEV is quieter without a combustion engine, however, the research on vehicle NVH is even more significant since the elimination of the combustion engine would expose many noise behaviors of BEV that were previously ignored but would now seem clearly audible and annoying. Researches have recently been conducted on the NVH of BEV mainly emphasis on the reduction of noise induced by powertrain, tire, wind and ancillary system and the improvement of sound quality. This review paper will focus on recent progress in BEV NVH research to advance the BEV systems in the future. It is a review for theoretical, computational, and experimental work conducted by both academia and industry in the past few years.