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Viewing 1 to 30 of 1503
2010-10-25
Journal Article
2010-01-2204
Yue Ma, Ho Teng, Marina Thelliez
Lithium-ion (Li-ion) batteries are becoming widely used high-energy sources and a replacement of the Nickel Metal Hydride batteries in electric vehicles (EV), hybrid electric vehicles (HEV) and plug-in hybrid electric vehicles (PHEV). Because of their light weight and high energy density, Li-ion cells can significantly reduce the weight and volume of the battery packs for EVs, HEVs and PHEVs. Some materials in the Li-ion cells have low thermal stabilities and they may become thermally unstable when their working temperature becomes higher than the upper limit of allowed operating temperature range. Thus, the cell working temperature has a significant impact on the life of Li-ion batteries. A proper control of the cell working temperature is crucial to the safety of the battery system and improving the battery life. This paper outlines an approach for the thermal analysis of Li-ion battery cells and modules.
2011-04-12
Technical Paper
2011-01-0345
Suresh Gopalakrishnan, Chandra Namuduri, Michael Reynolds
In this paper, a low-cost means to improve fuel economy in conventional vehicles by employing ultracapacitor based Active Energy Recovery Buffer (AERB) scheme will be presented. The kinetic energy of the vehicle during the coast down events is utilized to charge the ultracapacitor either directly or through a dc-dc converter, allowing the voltage to increase up to the maximum permissible level. When the vehicle starts after a Stop event, the energy stored in the capacitor is discharged to power the accessory loads until the capacitor voltage falls below a minimum threshold. The use of stored capacitor energy to power the accessory loads relieves the generator torque load on the engine resulting in reduced fuel consumption. Two different topologies are considered for implementing the AERB system. The first topology, which is a simple add-on to the conventional vehicle electrical system, comprises of the ultracapacitor bank and the dc-dc converter connected across the dc bus.
2011-04-12
Technical Paper
2011-01-0671
Kristel Coronado, John Lyons, Randy Curtis, Thomas Wang
Hybrid high voltage battery pack is not only heavy mass but also large in dimension. It interacts with the vehicle through the battery tray. Thus the battery tray is a critical element of the battery pack that interfaces between the battery and the vehicle, including the performances of safety/crash, NVH (modal), and durability. The tray is the largest and strongest structure in the battery pack holding the battery sections and other components including the battery disconnect unit (BDU) and other units that are not negligible in mass. This paper describes the mass optimization work done on one of the hybrid batteries using CAE simulation. This was a multidisciplinary optimization project, in which modal performance and fatigue damage were accessed through CAE analysis at both the battery pack level, and at the vehicle level.
2011-04-12
Technical Paper
2011-01-0666
Sowmyalatha Jayaraman, Gordon Anderson, Shailendra Kaushik, Philip Klaus
Fuel economy and stringent emissions requirements have steered the automotive industry to invest in advanced propulsion hybrids, including Plug-in hybrid vehicles (PHEV) and Fuel cell vehicles. The choice of battery technology, its power and thermal management and the overall vehicle energy optimization during different conditions are crucial design considerations for PHEVs and battery electric vehicles (BEV). Current industry focus is on Li-Ion batteries due to their high energy density. However, extreme operating temperatures may impact battery life and performance. Different cooling strategies have been proposed for efficient thermal management of battery systems. This paper discusses the modeling and analysis strategy for a thermally managed Lithium Ion (Li-Ion) battery pack, with coolant as the conditioning medium.
2011-04-12
Technical Paper
2011-01-0668
Yue Ma, Ho Teng
Lithium ion batteries can be developed for vehicle applications from high power specification to high energy specification. Thermal response of a battery cell is the main factor to be considered for battery selection in the design of an electrified vehicle because some materials in the cells have low thermal stability and they may become thermally unstable when their working temperature becomes higher than the upper limit of allowed operating range. In this paper the thermal characteristics of different sizes and forms of commercially available batteries is investigated through electro-thermal analysis. The relation between cell capacity and cell internal resistance is also studied. The authors find that certain criteria can be defined for battery selection for electric vehicles, hybrid electric vehicles and plug-in hybrid electric vehicles. These criteria can be served as design guidelines for battery development for vehicle applications.
2011-04-12
Technical Paper
2011-01-0667
Ramesh Rebba, Jeong Hun Seo, Ann Marie Sastry, Mary Fortier
Rechargeable energy storage systems with Lithium-ion pouch cells are subject to various ambient temperature conditions and go through thousands of charge-discharge cycles during the life time of operation. The cells may change their thickness with internal heat generation, cycling and any other mechanisms. The stacked prismatic cells thus experience face pressure and this could impact the pack electrical performance. The pack consists of stiff end plates keeping the pack in tact using bolts, cooling fins to maintain cell temperature and foam padding in between cells. The pack level thermal requirements limit the amount of temperature increase during normal operating conditions. Similarly, the structural requirements state that the stresses and the deflection in the end plates should be minimal. Uncertainties in cell, foam mechanical and thermal properties might add variation to the pack performance.
2011-04-12
Journal Article
2011-01-0654
Taeyoung Han, Seongyong Park, Uiseong Kim, Chee burm Shin
As battery temperature greatly affects performance, safety, and life of Li-ion batteries in plug-in and electric vehicles under various driving conditions, automakers and battery suppliers are paying increased attention to thermal management for Li-ion batteries in order to reduce the high temperature excursions that could decrease the life and reduce safety of Li-Ion batteries. Currently, the lack of fundamental understanding of the heat generation mechanism due to complex electrochemical phenomena prohibits accurate estimation of the heat generation within Li-ion cells under various operating conditions. Heat from Li-ion batteries can be generated from resistive dissipation, the entropy of the cell reaction, heat of mixing, and other side chemical reactions. Each of these can be a significant source of heat under a range of circumstances.
2011-04-12
Technical Paper
2011-01-0669
Azadeh Sheidaei, Xinran (Sharon) Xiao, Xiaosong Huang, Jixin Wang
The mechanical behavior of a commercially available single layer polypropylene (PP) separator was investigated using a dynamic mechanical analyzer (DMA). Samples were tested along the machine direction (MD) and transverse direction (TD). The tensile stress-strain, tensile creep and viscoelastic behaviors were studied. Experiments were performed in two conditions: (1) dry and (2) wet, i.e., samples submersed in dimethyl carbonate (DMC). The experimental results revealed that the mechanical properties of the separator were much lower while being submersed in DMC. This finding suggests that the mechanical properties measured at a dry condition may not be sufficient to represent the in-situ material behavior. Therefore, it is important to conduct material characterization in an environment close to the service condition.
2011-04-12
Technical Paper
2011-01-0653
Vijayakanthan Damodaran, Siva Murugan, Vinod Shigarkanthi, Sunil Nagtilak, Karthikeyan Sampath
This paper deals with the development of a generic approach for the thermal management of batteries used in electric vehicles. A lumped parameter model was used to determine the worst case scenario of the battery operation from thermal management standpoint. Certain driving conditions were identified as the worst load cases of battery thermal management and these driving conditions were then used to conduct on-road tests. Using the results obtained from the vehicle performance simulation and on-road tests CFD simulations were carried out to establish a relationship between the air flow requirements and the heat generated from the battery. These relations help to obtain a quick estimate of the air flow requirement to keep the battery within safe temperature limits. This methodology developed is valid for all types of batteries used in electric vehicles such as Lead Acid, Lithium Ion, Ni-MH etc.
2010-04-12
Journal Article
2010-01-1236
Neeraj S. Shidore, Anant Vyas, Jason Kwon
This paper evaluates the impact of energy management strategy on the cost benefits of a plug-in hybrid electric vehicle (PHEV) by taking into account the impact of PHEV energy management on battery life and petroleum displacement over the life of the vehicle. Using Battery in the Loop (BIL), a real battery is subjected to transient power demands by a virtual vehicle. The vehicle energy management strategy is varied, resulting in different battery utilization scenarios. Battery life, which varies with battery utilization, is estimated for the different energy management scenarios. The same representative drive cycle is used over the different energy management strategies to isolate the impact of energy management on battery utilization. PHEV gasoline savings, in comparison to a charge sustaining hybrid, are calculated for each of the energy management strategies, for a fixed distance of 40 miles.
2013-05-13
Technical Paper
2013-01-2006
Sung-Kwon Hong, Bogdan Epureanu, Matthew Castanier
The goal of this work is to develop an efficient numerical modeling method for the vibration of hybrid electric vehicle (HEV) battery packs to support probabilistic forced response simulations and fatigue life predictions. There are two important sources of variations in HEV battery packs that affect their structural dynamic response. One source is the uncertain level of pre-stress due to bolts or welds used for joining cells within a pack. The other source is small structural variations among the cells of a battery pack. The structural dynamics of HEV battery packs are known to feature very high modal density in many frequency bands. That is because packs are composed of nominally identical cells. The high modal density combined with small, random structural variations among the cells can lead to drastic variations in the dynamic response compared with those of the ideal nominal system.
2013-04-08
Technical Paper
2013-01-1226
Prabhavathy Rajappan, Jaishankar Cinnasamy, Ulaganathan Shanmuganathan, Dominic S M
This paper presents a case study of design, development and testing of Ultra Capacitor (UC) based energy storage system for effective voltage ride-through in Armored Fighting Vehicle (AFV) applications. It also presents the test results of UC module delivering full load of AFV. AFV is powered with 24 V, 400 Ah battery bank and 28 V, 20 kW generator located in hull. Source is connected to the load through common single wire DC bus and chassis is the return path. DC bus voltage drops down to 16 V, during starting of heavy load. As the entire mission related sensitive systems are also connected to same DC bus, voltage sag in DC bus creates undesirable effects. Due to advancement in the field of double layer capacitor, UC module based ride-through system is developed and tested. Total capacitance of 23 F, 35.1 V UC modules was developed using 13 cells of Faradigm UCs. Dynamic voltage equalization circuit is connected across all the cells to protect the cells against over voltage.
2013-04-08
Journal Article
2013-01-0474
Masanori Monde, Masataka Kosaka
For safe and fast refueling hydrogen to fuel cell vehicles (FCVs) at hydrogen refueling stations (HRSs), a refueling protocol is under discussion at SAE J2601 to be a global standard. In order to realize such a standard, we have to estimate the relation between gas temperature and pressure during a refueling and for an accurate estimation we have to correctly understand the thermal characteristics of hydrogen tank. Fast refueling test data has been offered by BMW-Powertech, some test cases have been analyzed by a simulation model developed by Monde et al. It reveals that the hydrogen temperature at the end of refueling does not exceed 85°C for these analyzed cases. The effect of the pressure drop between storage bank and hydrogen tank was negligible on the gas temperature at the end of refueling, although the gas temperature shows different profile depending on the pressure drop.
2004-03-08
Technical Paper
2004-01-0368
Sun Liqing, Chen Wei, Yu Leiyan, Yang Lianghui, Li Yufang, Sun Fengchun
The paper presents the design and analysis of pure electric bus powered by Lithium-ion battery and ultra capacitor. For the limited power energy of battery, the ultra capacitor pack is chosen as the auxiliary on-board energy storage device. The system configuration, system modeling and on-road test result analysis will be covered in the paper and the possibility of using ultra capacitors on electric bus to improve the economical efficiency in urban areas will be discussed.
2004-03-08
Technical Paper
2004-01-1504
Tomohiro Waku, Norihiko Watanabe, Joji Matsumoto, Junichi Nakanishi
A windshield defroster has an important roll of clearing up fogged window glasses of a vehicle by blowing out warm air. In simulations parameters that affect the defogging time are the velocity, humidity and temperature of the flow from a defroster nozzle. However, individually varying all the parameters and investigating their effects will lead to many computing cases and long runtime. An approach that can considerably reduce calculation time is proposed. The approach is dictated by two key-steps: 1) First, steady-state velocity distributions for several different defroster flow rates are calculated; 2) Secondly, based on the pre-calculated velocity fields, the defogging time is estimated. This approach is compared to the conventional method that always couples all the parameters in transient calculations.
2004-03-08
Technical Paper
2004-01-1584
Chakradhar Pulamarasetty, Pritpal Singh, Huiming Chen, Xiquan Wang, David Reisner, Wsewolod Hnatczuk
Automotive start, light, ignition (SLI) lead acid batteries used in tanks are prone to capacity loss due to low temperatures, self-discharge, sulfation and shorting of plates. Monitoring and charge control of these batteries can be improved by using the concept of a smart battery system (SBS). In a SBS, battery data from sensors embedded in the battery package are acquired by a smart battery controller which processes this data, and transmits charge control information, to a central processor for effecting control actions over a controller area network (CAN) bus. Smart battery circuitry has been designed, developed and implemented to monitor the SOC of a 12V automotive lead acid battery used in tanks. The hardware comprises ac impedance measuring hardware interfaced to a Motorola 68HC12 microcontroller with a built-in CAN controller interface. The SOC estimation algorithms are based on a fuzzy logic model that is directly implemented into the Motorola 68HC12 microcontroller.
2004-03-08
Technical Paper
2004-01-1474
Syed Wahiduzzaman, Babajide Kolade, Selim Buyuktur
The potential of fuel cells as an automotive power source is well recognized due to their high efficiency and zero tailpipe emissions. However, significant technical and economic hurdles need to be overcome in order to make this technology commercially viable. A proton-exchange membrane (PEM) fuel cell model has been developed to assess some of these technical issues. The fuel cell model can be operated in a standalone mode or it can be integrated with vehicle and fuel supply system models. A detailed thermal model of the fuel cell stack was used to identify significant design parameters that affect the performance of PEM fuel cell vehicles. The integrated vehicle model was used to explore the relative benefits of hybridization options.
2004-03-08
Technical Paper
2004-01-1722
John S. Stimitz, Richard V. Wagner
The automotive industry is making a transition from 12 to 36 volt electrification systems requiring a 42 volt battery charging system. This higher DC voltage is capable of producing more pronounced arcing when interrupting electrical connections and at component contacts. This paper describes the development of two new test methodologies specifically designed to evaluate the arc ignition properties of polymeric materials used in 42 V automotive applications. The first test is a DC Comparative Tracking Index (DC-CTI) Test. The second test is the DC High-Current Arc Ignition (DC-HAI) Test.
2004-03-08
Technical Paper
2004-01-1006
Akira Ohkawa
A fuel-cell-vehicle has been provided with an electric-double-layer-capacitor system (capacitor) to act as a back-up power source. The fuel cells and the capacitor have different voltages when the system is started, and for this reason the system could not be reconnected by relays. A VCU (Voltage and current Control Unit) has been positioned in the path of electrical connection between the fuel cells and the capacitor as a method of dealing with this issue. The VCU enables the charging of the capacitor to be controlled in order to equalize the voltage of the two power sources and allow a connection.
2004-03-08
Technical Paper
2004-01-1020
Yun Xia, John Cincilla, Ernie Mohley
Abstract Casting defects such as gas porosity, shrinkage, poor-fill and blistering are related to the filling pattern and flow control in Al and Mg die-casting. It is not clearly understood how atomized and turbulent flow affects the filling patterns and hence casting defects. Significant improvements in casting quality could be achieved with a better understanding of the basic morphology of atomized and turbulent flow and their relationships to the Reynolds number and J number. This paper will explore the relationship between atomized and turbulent flow in Al and Mg die castings and the relationship of wakes produced by obstacles in the flow path and casting defects.
2004-03-08
Technical Paper
2004-01-1303
Di Napoli, F. Crescimbini, A. Lidozzi, L. Solero, M. Pasquali, A. Puccetti, E. Rossi
To date hybrid-electric vehicles (HEV) make use of high-power density ac propulsion systems to provide comparable performance with vehicles using internal combustion engine (ICE) technology. Electric motor, inverter, and associated control technology has made substantial progress during the past decade and it is not the limiting factor to either vehicle performance or the large-scale production of hybrid vehicles. The search for a compact, lightweight, and efficient energy storage system that is both affordable and has acceptable life cycle remains the major roadblock to large-scale production of HEVs. This paper deals with an original HEV propulsion system that includes fuel cell generator and an energy storage system combining ultracapacitor tank and battery. The three on-board power sources supply the vehicle traction drive through a multi-input dc-to-dc power converter which provides the desired management of the power flows.
2004-03-08
Technical Paper
2004-01-1304
Tetsuhiro Ishikawa, Shigeki Hamaguchi, Tatsuhiko Shimizu, Tsuyoshi Yano, Shoichi Sasaki, Kenji Kato, Masao Ando, Hiroshi Yoshida
Toyota Motor Corporation began leasing a new generation fuel cell vehicle the FCHV (Fuel Cell Hybrid Vehicle) in December 2002. That vehicle includes a new variable voltage power electronics system and uses the Nickel Metal Hydride (Ni-MH) battery system from the Prius hybrid gasoline electric vehicle. This paper describes on-going efforts to model optimum secondary storage systems for future vehicles. Efficiency modeling is presented for the base Ni-MH storage system, an ultra capacitor system and a Lithium ion (Li-ion) battery system. The Li-ion system in combination with a new high efficiency converter shows a 4% improvement in fuel economy relative to the base system. The ultra capacitor system is not as efficient as the base system.
2004-03-08
Technical Paper
2004-01-1298
Bruno Jeanneret, Tony Markel
Fuel cell hybrid vehicles (FCHVs) use an energy management strategy to partition the power supplied by the fuel cell and energy storage system (ESS). This paper presents an adaptive energy management strategy, created in the ADVISOR™ software, for a series FCHV. The strategy uses a local or “real-time” optimization approach, which aims to reduce total energy consumption at each instantaneous time interval by dynamically adjusting the amount of power supplied by the fuel cell and ESS. Compared with a static control strategy, the adaptive strategy improved the simulated FCHV's fuel economy by 1.4%-8.5%, depending on the drive cycle.
2004-03-08
Technical Paper
2004-01-0760
Kurt Kornbluth, Andrew Burke, Geoff Wardle, Nathan Nickell
This study focuses on the design of a narrow (44 inches maximum width) vehicle capable of moving two occupants safely at freeway speeds with an emphasis on comfort, efficiency and performance. The design addresses consumer acceptance problems of past narrow vehicles such as “too small,” “too ugly,” “too unstable,” “too wet,” “too slow,” “too complicated,” and “too expensive” A full CAD model was developed to show the external vehicle shape, occupant seating and ergonomics, and the packaging of driveline components. Simulations were run using SIMPLEV and Advisor 2002 to predict vehicle performance and range. The size and mass characteristics of the driveline components used in the simulations were based on commercially-available EV products and selected for the special requirements of a relatively lightweight (450-600 kg) vehicle. Dynamic stability and safety of the vehicle are of prime importance and were considered in all phases of the design.
2004-03-08
Technical Paper
2004-01-0897
Joško Deur, Danijel Pavkovi, Nedjeljko Peri, Martin Jansz, Davor Hrovat
An adaptive electronic throttle control strategy is proposed with the aim to provide robust and precise positioning of the throttle plate. The control strategy consists of a PID controller and a nonlinear compensator of friction and limp-home effects. The adaptation mechanism includes auto-tuning and self-tuning algorithms. The auto-tuner provides automatic adjustment of the key control strategy parameters without any prior knowledge of the process parameters. The self-tuning algorithms are based on the permanent, on-line estimation of the DC motor armature resistance, battery voltage, and limp-home position. The control strategy and the adaptation algorithms are verified experimentally.
2004-03-08
Technical Paper
2004-01-0874
Gui-Ying Lu, David Zheng, Shashikumar Venkatakrishnaiah, Todd Vest
The battery support in a small car is an example of a subsystem that lends itself to mounted component dynamic fatigue analysis, due to its weight and localized attachments. This paper describes a durability analysis method that was developed to define the required enforced motion, stress response, and fatigue life for such subsystems. The method combines the large mass method with the modal transient formulation to determine the dynamic stress responses. The large mass method was selected over others for its ease of use and efficiency when working with the modal formulation and known accelerations from a single driving point. In this example, these known accelerations were obtained from the drive files of a 4-DOF shake table that was used for corresponding lab tests of a rear compartment body structure. These drive files, originally displacements, were differentiated twice and filtered to produce prescribed accelerations to the finite element model.
2004-03-08
Technical Paper
2004-01-1054
Bo-Chiuan Chen, Yuh-Yih Wu, Ying-Da Huang, Chung-Neng Huang
A Hybrid Electric Motorcycle (HEM) with a direct-driven wheel motor is proposed in this paper. The rear wheel is driven by an internal combustion engine and a powertrain system of a traditional motorcycle with minor modifications. The front wheel is driven by a direct-driven wheel motor. The proposed HEM is a parallel configuration. Both wheels can supply tractive forces simultaneously to drive the motorcycle when necessary. A rule-based structure is used to design the power split controller of the proposed HEM. Fuel economy of the proposed design will be evaluated by a dynamic simulation model in Matlab/Simulink using ECE-R40 driving cycle.
2004-10-18
Technical Paper
2004-21-0028
Yoshitaka Deguchi, Kouichi Kuroda, Makoto Shouji, Taketoshi Kawabe
This paper proposes a new charge/discharge control system for hybrid electric vehicles based on the use of car navigation information. A conventional control system feeds back the battery state of charge (SOC) and controls the amount of charge/discharge to keep the battery SOC within a specified range. In contrast, the proposed control system is a predictive control system. According to information on the traffic conditions and road grade along the route suggested by the car navigation system, the system predicts the vehicle’s operating status, schedules the battery SOC along the route and controls the amount of charging/discharging. The effectiveness of the proposed system on improving fuel economy has been confirmed using actual traffic and road condition data.
2004-11-16
Technical Paper
2004-01-3448
Vinicius Rodrigues de Moraes, Thiago de Castro Martins, Marcos de Sales Guerra Tsuzuki, Michel Vale Ferreira
The objective of this paper is to show how viable is the use of solar energy, which is accomplished by the optimal utilisation of energy in a solar racing vehicle, which is in turn achieved by optimising its energy management via racing strategy. Simulated Annealing is an optimisation process that is suited for large, multivariable, combinatorial optimisation problems such as this one: finding an optimal racing strategy, using the best way possible the energy converted by the photovoltaic panel. Based on instantaneous inputs, Simulated Annealing calculates the instantaneous velocity that allows the vehicle to proceed as fast as possible.
2004-11-30
Technical Paper
2004-01-3500
Jeffrey Baxter, Perry Carter, Tom Erekson, Robert Todd
A student team from Brigham Young University (BYU) set a new record for the world's fastest electric drag racecar. The team modified a production EV1 donated to the university by the General Motors Corporation and installed a bank of 160 UltraCapacitors rated at 2700 farads each. This paper describes the design of the capacitor pack, the car's drive train, the charging method and other modifications of the vehicle. Here we also discuss performance and race data from an official quarter-mile drag race sanctioned by the National Electric Drag Racing Association. A simulation model for vehicle performance was also developed and is presented here.
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