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Technical Paper

Technical Challenges for Vehicle 14V/28V Lithium Ion Battery Replacement

2011-04-12
2011-01-1375
Modern commercial and military vehicles are equipped with more electrical accessories and demand more power than ever before. This causes an increase in the weight of the battery as well as drives the battery to end of life when the vehicle is stationary with the engine off. Lithium ion batteries, which are known for their high power and energy to weight density, long cycle life, and low self-discharge rate, are considered to be an alternative for the replacement of existing Starting, Lighting, and Ignition (SLI) lead acid batteries. Lithium ion battery chemistry offers double the reserve time of the stock battery and a significantly greater number of charging and discharging cycles while providing weight savings. There is no acid inside a lithium ion battery to cause corrosion, which eliminates potential damage to a vehicle from chemical spills and poisonous gases.
Technical Paper

Evaluation of a Hybrid Energy Storage System for EV's

2011-04-12
2011-01-1376
Electric energy storage is among the most significant hurdles to deployment of electric vehicles (EVs). Present storage methods struggle to provide the capacity and the service life demanded by automotive use. Hybrid energy storage systems (HESS) use a combination of storage types, for example, different types of batteries and ultracapacitors, to tailor the characteristics of the storage system to each application. In addition to sizing the system for the intended application, a suitable strategy for the integration of the energy storage system must be adopted. In the present application, a HESS has been designed for the electrification of a 2004 Chrysler Pacifica, through consideration of a combination of high capacity batteries, high power batteries, and capacitors. Hybrid storage systems using batteries alone, batteries and capacitors, and dual batteries have been considered.
Technical Paper

Development of Lithium-Ion-Battery System for Hybrid System

2011-04-12
2011-01-1372
A battery module structure and a battery management system that is optimal for the structure were developed, in order to facilitate the work of equipping hybrid cars with lithium-ion batteries (LIBs) that are expected to improve vehicle performance. This paper describes the structure of the LIB and the battery management system that is optimal for it. The battery module structure has cells with a sturdy holding structure and a highly efficient cooling system. The structure has enabled the improvement of battery pack system power output by 80% per unit weight and by 20% per unit volume compared to the previous model. The optimal management system prevents battery overcharge by detecting and controlling the state of charge (SOC) of each cell with a high degree of accuracy.
Journal Article

VOLTEC Battery System for Electric Vehicle with Extended Range

2011-04-12
2011-01-1373
Mid 2006 a study group at General Motors developed the concept for the electric vehicle with extended range (EREV),. The electric propulsion system should receive the electrical energy from a rechargeable energy storage system (RESS) and/or an auxiliary power unit (APU) which could either be a hydrogen fuel cell or an internal combustion engine (ICE) driven generator. The study result was the Chevrolet VOLT concept car in the North American Auto Show in Detroit in 2007. The paper describes the requirements, concepts, development and the performance of the battery used as RESS for the ICE type VOLTEC propulsion system version of the Chevrolet Volt. The key requirement for the RESS is to provide energy to drive an electric vehicle with “no compromised performance” for 40 miles. Extended Range Mode allows for this experience to continue beyond 40 miles.
Technical Paper

Test Center for Aging Analysis and Characterization of Lithium-Ion Batteries for Automotive Applications

2011-04-12
2011-01-1374
A test center for aging analysis and characterization of Lithium-Ion batteries for automotive applications is optimized by means of a dedicated cell tester. The new power tester offers high current magnitude with fast rise time in order to generate arbitrary charge and discharge waveforms, which are identical to real power net signals in vehicles. Upcoming hybrid and electrical cars show fast current transients due to the implemented power electronics like inverter or DC/DC converter. The various test procedures consider single and coupled effects from current profile, state of charge and temperature. They are simultaneously applied on several cells in order to derive statistical significance. Comprehensive safely functions on both the hardware and the software level ensure proper operation of the complex system.
Technical Paper

New Battery Monitoring Unit for HEV/EV Lithium-ion Battery

2011-08-30
2011-01-1740
Lithium-ion batteries have higher energy content and power density than Nickel-metal hydride (NiMH) batteries, but require carefully management for durability and safety. Unlike NiMH batteries, which are controlled on a battery unit basis, each lithium-ion cell generates a different voltage. Typically, the complex controllers required to equalize individual cell voltages are large and costly. We have developed a low-cost battery monitoring unit that performs the same function with a proprietary cell-voltage equalizing system. This new unit also offers various innovative technologies, such as detecting overcharge and over-discharge, fault diagnosis and the measurement of the batteries internal resistance to monitor degradation.
Technical Paper

Introduction of 2011 CIVIC Hybrid system

2011-08-30
2011-01-1748
Technologies related to electrical systems for the 2011 hybrid model have been developed. In order to increase energy recovery during driving, improvements were made compared to the 2006 model in terms of motor output increase and high-efficiency range expansion. In consideration of vehicle control associated with the use of lithium-ion batteries (LIBs) as well as reliability, a system to control effective use of battery performance was developed which involves detection of battery conditions. Control of energy management was optimized compared to nickel metal hydride (NiMH) batteries through the use of higher-output LIBs and a high-output motor.
Technical Paper

Standardization of Wiring Harness Data Formats between Truck OEMs and Suppliers

2011-09-13
2011-01-2270
The continuously integration of electrics and electronics (EE) in the last decades is one of the main key drivers for innovation and business success of the Automotive OEMs. This is also applicable for truck manufacturers. On the other side factors like the rising vehicle complexity, number of variants and the warranty costs for EE issues are increasing the pressure on the engineering teams responsible for the mechatronic systems. To address these issues one of the key activities in the European market (focus on Germany) during the last decade was to introduce industry-wide standards for the data transfer of wiring harness data between OEM and harness supplier. In this paper the benefits and technical background of using the standards KBL and KOMP formats within the MB-Trucks brand will be presented. Moreover the role of the Information Technology (IT) will be explained in detail.
Journal Article

Impact of Model-Based Lithium-Ion Battery Control Strategy on Battery Sizing and Fuel Economy in Heavy-Duty HEVs

2011-09-13
2011-01-2253
Electrification and hybridization show great potential for improving fuel economy and reducing emission in heavy-duty vehicles. However, high battery cost is unavoidable due to the requirement for large batteries capable of providing high electric power for propulsion. The battery size and cost can be reduced with advanced battery control strategies ensuring safe and robust operation covering infrequent extreme conditions. In this paper, the impact of such a battery control strategy on battery sizing and fuel economy is investigated under various military and heavy-duty driving cycles. The control strategy uses estimated Li-ion concentration information in the electrodes to prevent battery over-charging and over-discharging under aggressive driving conditions. Excessive battery operation is moderated by adjusting allowable battery power limits through the feedback of electrode-averaged Li-ion concentration estimated by an extended Kalman filter (EKF).
Technical Paper

A Comparative Analysis of Techniques for Electric Vehicle Battery Prognostics and Health Management (PHM)

2011-09-13
2011-01-2247
Batteries are widely used as storage devices and they have recently gained popularity due to their increasing smaller sizes, lighter weights and greater energy densities. These characteristics also render them suitable for powering electric vehicles. However, a key gap exists in that batteries are solely used as storage devices with a lack of information flow. Next-generation battery technologies will constitute the enabling tools that would lead to information-rich batteries, thus allowing the transparent assessment of a battery's health as well as the prediction of a battery's remaining-useful-life (RUL) and its subsequent impact on vehicle mobility. Various methods and techniques have been employed to predict battery RUL in order to improve the accuracy of the State of Charge (SoC) estimation.
Journal Article

Thermal Characterization of a Li-ion Battery Module Cooled through Aluminum Heat-Sink Plates

2011-09-13
2011-01-2248
The temperature distribution is studied theoretically in a battery module stacked with 12 high-power Li-ion pouch cells. The module is cooled indirectly with ambient air through aluminum heat-sink plates or cooling plates sandwiched between each pair of cells in the module. Each of the cooling plates has an extended cooling fin exposed in the cooling air channel. The cell temperatures can be controlled by changing the air temperature and/or the heat transfer coefficient on the cooling fin surfaces by regulating the air flow rate. It is found that due to the high thermal conductivity and thermal diffusivity of the cooling plates, heat transfer of the cooling plate governs the cell temperature distribution by spreading the cell heat over the entire cell surface. Influence of thermal from the cooling fins is also simulated.
Journal Article

An Analysis of a Lithium-ion Battery System with Indirect Air Cooling and Warm-Up

2011-09-13
2011-01-2249
Ideal operation temperatures for Li-ion batteries fall in a narrow range from 20°C to 40°C. If the cell operation temperatures are too high, active materials in the cells may become thermally unstable. If the temperatures are too low, the resistance to lithium-ion transport in the cells may become very high, limiting the electrochemical reactions. Good battery thermal management is crucial to both the battery performance and life. Characteristics of various battery thermal management systems are reviewed. Analyses show that the advantages of direct and indirect air cooling systems are their simplicity and capability of cooling the cells in a battery pack at ambient temperatures up to 40°C. However, the disadvantages are their poor control of the cell-to-cell differential temperatures in the pack and their capability to dissipate high cell generations.
Technical Paper

Dual Battery System for Commercial Plug-In Hybrid Electric Vehicles

2011-09-13
2011-01-2250
Plug-In Hybrid Electric Vehicles (PHEV) require high power density energy storage system (ESS) for hybrid operation and high energy density ESS for EV mode range. The dual ESS allows the best utilization of battery technologies for both high power density and high energy density. In this paper, we have conducted vehicle level study and modeling to quantify the benefit of bi-directional DC-DC converter in dual battery systems for commercial heavy duty vehicles. The goal of this study is to increase the overall efficiency and fuel economy of PHEV. The simulation results show that PHEV with two sets of battery packs and a DC-DC converter has better performance and higher overall efficiency over the conventional PHEV.
Journal Article

Single Cylinder Diesel Engine Startup Experiments with Fast Cycle Resolved In-cylinder and Exhaust Sampling

2009-06-15
2009-01-1973
Single cylinder diesel engine cycle resolved startup experiments were performed at two different Compression Ratios. At CR18 (CR = 18) conventional engine starting resulted in a broad range of acceptable startup equivalence ratios (φ). However, reducing the CR to 16 resulted in problematic engine starting regardless of fuel level. In an effect to produce robust engine starting at lower CRs the engine was motored first. This allowed for strong starting performance coupled with high load fueling levels. For both CRs, IMEPg and exhaust CO2% increased as fueling level increased. However, while in-cylinder CO2% exceeded exhaust CO2% for moderate φ, this trend was reversed as fueling was reduced. Exhaust CO% was minimal except for stoichiometric fueling at CR18. Peak NOx production occurred at CR18 and φ = 0.55. Exhaust UHCs were maximized for higher fueling cases but dropped quickly after start. Similarly, ignition delay increased with φ but decreased during warm-up.
Technical Paper

Well-To-Wheel Energy Analysis of Conventional and Electric Motorcycles in Malaysia

2009-11-03
2009-32-0061
In this paper we investigate well-to-wheel energy consumption of a conventional carbureted four stroke 110cc motorcycle and comparable electric motorcycle using lead acid batteries and Li-polymer batteries. The vehicles are tested on a chassis dynamometer using a steady-state test based on the ECER40 drive cycle. Vehicle energy consumption was measured and compared on a cost per kilometer basis. Vehicle life cycle analysis was performed based on expected or measured life times of the major components such as engines, batteries and electric motors. This study indicates that electric motorcycles cost less to operate than conventional motorcycles, but are unlikely to be competitive at current prices due to the cost and life span of the battery packs.
Technical Paper

Hybrid Power Pack (Ultra Capacitor + Battery) for Two Wheelers Fitted with Starter Motor

2009-01-21
2009-26-0077
Self-start two-wheelers, including motorcycles and scooters between 50 - 200 cc capacity, use standard lead-acid battery of 5, 9 and 12 Ah rating as energy source. Battery is a well-known energy source but cannot supply large amount of power in short time. The size of the battery is decided based on the starter motor requirement. Deep discharge at the time of cranking reduces the life of the battery drastically as compared to normal use. Extra factor of safety is provided for cold weather cranking performance, poor maintenance and end of life performance in view of deep discharge. Hence it is heavy and bulky. On the other hand, ultracapacitors can supply large burst of power for short time but can not store much energy (hence limited number of starts).
Technical Paper

Effects of Fretting Corrosion on Lift Glass

2011-04-12
2011-01-1434
The electrical architecture design of a rear back glass defrost grid system encompasses many critical criteria that must be integrated into the design. For example, the defrost clip location and interface to the glass must meet all vehicle performance requirements. If the defrost clip to the glass interface is not resistant to vibration and relative movement, detachment and loss of function can occur. This paper describes a back glass defrost clip with a solder joint that is robust to manufacturing variations and customer usage conditions. A designed experiment using Design for Six Sigma methodologies was performed to understand the effects of the attachment interface to the electrical wiring pigtail, and parameters that affect performance. The working constraints, testing set up, validation, and root cause investigation of the clip detachment phenomenon is covered in this paper.
Technical Paper

Wiring Harness Protection Against Short Circuit Condition: Design Calculation and Vehicle Level Validation

2011-04-12
2011-01-1435
Day by day customer's demands on vehicle features and functionalities are increasing which results in complex wiring harness systems. This in turn requires robust protection in the circuits to ensure proper working as well as avoid malfunction or damage to wiring system during short circuit or over current scenarios in the vehicle. Short circuit test gives you assurance of wire capacity to withstand high current till the fuse blow. If fuse don't blow within specified time as per selection of fuse, it is essential to check wire size as well as fuse rating. This paper gives details of short circuit and over load test of circuits to verify its performance. The methodology involves the compliance to S.C test criteria at every stage of development through simulation, bench testing & vehicle level validation.
Technical Paper

A New Approach to the Thermal Analysis of Electrical Distribution Systems

2011-04-12
2011-01-1437
The optimum design of an electrical distribution system (EDS) is based on the profound understanding and measurement of its thermal behavior, because this determines wire diameter and insulation material, has a major impact on the fusing strategy, and enables minimizing technical risk. Current methods of calculation require an extensive database, whereas the temperature measurements at selected points with normal sensors allow neither the precise rating of the actual insulation temperature within a wire bundle, nor the determination of the thermal impact of load currents. The presented approach is based on both a new measurement method and on a related evaluation algorithm. A common automotive wire is applied as a sensing device using its resistance temperature coefficient as the measurement principle.
Technical Paper

Thermodynamic Study on the Solubility of NaBH4 and NaBO2 in NaOH Solutions

2011-08-30
2011-01-1741
Extensive research has been performed for on-board hydrogen generation, such as pyrolysis of metal hydrides (e.g., LiH, MgH₂), hydrogen storages in adsorption materials (e.g., carbon nanotubes and graphites), compressed hydrogen tanks and the hydrolysis of chemical hydrides. Among these methods, the hydrolysis of NaBH₄ has attracted great attention due to the high stability of its alkaline solution and the relatively high energy density, with further advantages such as moderate temperature range (from -5°C to 100°C) requirement, non-flammable, no side reactions or other volatile products, high purity H₂ output. The H₂ energy density contained by the system is fully depend on the solubility of the complicated solution contains reactant, product and the solution stabilizer. In this work, an approach based on thermodynamic equilibrium was proposed to model the relationship between the solubility of an electrolyte and temperature, and the effect of another component on its solubility.
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