Jean-Marc Timmermans

Assessment of performance of lithium iron phosphate oxide, nickel manganese cobalt oxide and nickel cobalt aluminum oxide based cells for using in plug-in battery electric vehicle applications

This paper represents a comprehensive comparison of three battery chemistries for use in plug-in battery electric vehicles: lithium iron phosphate oxide, lithium nickel manganese cobalt oxide and nickel cobalt aluminum oxide anodes. The battery characteristics at different temperature conditions have been investigated, using test procedures as defined in the standard IEC 62660–1/2 and introducing new load profiles. Main focus key parameters are the energy density, power capabilities, rate performances during charge and discharge as well as the energy efficiency, thermal behaviour and life cycle. The results indicate that the lithium iron phosphate based cells have good performances at low temperatures (such as down to −18° C). However, the situation regarding the nickel cobalt aluminum oxide and nickel manganese cobalt oxide anodes demonstrates less favorable performances, especially at low temperatures where the power and energy capabilities are considerably poor. In addition, the cycle life properties are discussed in order to evaluate the long-term performances, and battery parameters such as cost and thermal behaviors are compared. Finally, this study contains a new definition for the well-known Peukert relationship during the discharge phase. Furthermore, an adapted equation during the charge phase is presented based on the charge characteristics of the proposed batteries at different environmental conditions.

Modelling and design of super capacitors as peak power unit for hybrid electric vehicles

This paper reports about the design of a peak power unit for hybrid electric vehicles and the modelling of the power control strategy to optimise the drive trains performance. A common DC bus of the hybrid drive train is defined and was provided with a peak power unit using super capacitors, connected via a bi-directional DC/DC converter. This architecture allows a fast load response and a high efficiency of the total electric drive train. An optimised control strategy is needed to ensure an optimal distribution of the power flow between the peak power unit and the main energy source.

Comparison of Fuel Cell Hybrid Propulsion Topologies with Super-Capacitor

Electric and hybrid electric vehicles are possible solutions to reduce the air-pollution and oil dependence of the transportation sector [1,2]. The fuel cell electric vehicle is currently considered to be the car of the future and consequently the automotive industry devotes great research effort and important resources to develop these technologies and to integrate them in their future vehicles. Hybrid electric propulsion systems are an interesting concept to increase the energy efficiency of the road transportation [3,4]. Peak power units (e.g. supercapacitors, flywheels...) can be introduced in the electric propulsion system to supply the peak power demands for vehicle acceleration [5,6]. This form of hybridisation of the electrical power system allows increasing the life-time of the main energy source in case of a battery-electric vehicle or allows improving or optimizing the dynamic performance of the energy storage system of fuel cell electric vehicles [7,8]. In this paper, several series hybrid propulsion system topologies are analysed on the basis of the simulation programme VSP. Especially the use of a DC/DC converter connected between the DC-bus and the fuel cell stack or the super capacitor or the use of 2 convertres are investigated.

Lithium Iron Phosphate - Assessment of Calendar Life and Change of Battery Parameters

This paper represents the calendar life cycle test results of a 7Ah lithium iron phosphate battery cell. In the proposed article and extended analysis has been carried out for the main aging parameters during calendar life and the associated impact of the used battery model. From the analysis, it has been showed that the impact of high temperatures and state of charge is harmful for the lifetime of the battery. Therefore, there is a need for having a dedicated control strategy for keeping the battery in the most appropriate operating condition. The FreedomCar battery model parameters have been analyzed during calendar life.

The Influence of Potential Policy Measures On the Eco-Efficiency of Personal Vehicle Mobility in Brussels

This paper on the eco-efficiency of personal vehicle mobility in Brussels is from the proceedings of 14th international Conference on Urban Transport and the Environment in the 21st Century, which was held in Malta in 2008. The authors consider the influence of potential policy measures on the eco-efficiency of personal vehicle mobility, noting that urban areas such as the Brussels Capital Region (BCR) are facing air quality issues, due to a dense road network, a high degree of motorization, and a large influx of commuters entering the city daily. The authors then outline several possible policy measures that could be implemented by the Brussels Regional Government to influence the characteristics or intensity of urban traffic as well as its impact on the environment. These measures include a reorientation of the fiscal system for vehicles (registration and circulation tax), applying a road or congestion charge, variable parking fees, and other strategies. The Brussels Regional Government has commissioned a study to investigate the effects of these different policy measures on the traffic intensity in the city, as well as on the environment and the eco-efficiency of the vehicle fleet. The study will include costs and purchasing behavior as well as how the use of vehicles could evolve. The authors briefly describe how the Ecoscore, an environmental indicator for vehicles, is applied as a tool for policy support.

Data-Driven Nonlinear Identification of Li-Ion Battery Based on a Frequency Domain Nonparametric Analysis

Lithium ion batteries are attracting significant and growing interest, because their high energy and high power density render them an excellent option for energy storage, particularly in hybrid and electric vehicles. In this brief, a data-driven polynomial nonlinear state-space model is proposed for the operating points at the cusp of linear and nonlinear regimes of the battery’s electrical operation, based on the thorough nonparametric frequency domain characterization and quantification of the battery’s behavior in terms of its linear and nonlinear behavior at different levels of the state of charge.

Nonparametric analysis of the short-term electrical response of Li-ion battery cells

In order to develop a complete dynamic model of a lithium ion (Li-ion) batterys electrical behaviour, which is suitable for virtual-prototyping of battery-powered systems, accurate estimation of the state of charge (SoC) and state of health (SoH) is required. This in-turn depends on the quality of the models which are used for the estimation of these quantities. Hence, even before proceeding towards the modelling step, it is important to fully characterize and understand the electrical behaviour of the battery over its full operating range, so that a flexible and accurate dynamic model can be developed. In this paper, a novel frequency domain non-parametric methodology is proposed to characterize the battery short-term electrical behaviour, in terms of: Presence of the non-linearities as well as the time-variations (non-stationary behaviour) over its full operating range. This information can later be used by battery modeller to decide on the modelling methodology.

Batteries 2020 – Lithium - ion battery first and second life ageing, validated battery models, lifetime modelling and ageing assessment of thermal parameters

The European Project “Batteries 2020” unites nine partners jointly working on research and the development of competitive European automotive batteries. The project aims at increasing both the energy density and lifetime of large format pouch lithium-ion batteries towards the goals targeted for automotive batteries (250 Wh/kg at cell level, over 4000 cycles at 80% depth of discharge). Three parallel strategies are followed in order to achieve those targets: (i) Highly focused materials development; two improved generations of NMC cathode materials allows to improve the performance, stability and cyclability of state of the art battery cells. (ii) Better understanding of the ageing phenomena; a robust and realistic testing methodology has been developed and was carried out. Combined accelerated, real driving cycle tests, real field data, post-mortem analysis, modelling and validation with real driving profiles was used to obtain a thorough understanding of the degradation processes occurring in the battery cells. (iii) Reduction of battery cost; a way to reduce costs, increase battery residual value and improve sustainability is to consider second life uses of batteries used in electric vehicle application. These batteries are still operational and suitable to less restrictive conditions, such as those for stationary and renewable energy application. Therefore, possible second life opportunities have been identified and further assessed. In this paper, the main ageing effects of lithium ion batteries are explained. Next, an overview of different validated battery models will be discussed. Finally, a methodology for assessing the performance of the battery cells in a second life application is presented.

Evaluation of lithium-ion battery second life performance and degradation

Reusing electric vehicle batteries once they have been retired from the automotive application is stated as one of the possible solutions to reduce electric vehicle costs. Many publications in the literature have analyzed the economic viability of such a solution, and some car manufacturers have recently started running several projects to demonstrate the technical viability of the so-called battery second life. Nevertheless, the performance and degradation of second life batteries remain an unknown topic and one of the biggest gaps in the literature. The present work aims at evaluating the effects of lithium-ion (Li-ion) battery State of Health (SOH) and ageing history over the second life performance on two different applications: a residential demand management application and a power smoothing renewable integration application. The performance and degradation of second life batteries are assessed both at the cell level and at stack level. Homogeneous and heterogeneous stacks are analyzed in order to evaluate the impact of cell-to-cell history and SOH differences over the stack level battery cell performance and degradation behaviour.

Environmental Breakeven Point:An Introduction Into EnvironmentalOptimization For PassengerCar Replacement Schemes

This paper gives insights in how to introduce environmental aspects in automobile replacement policies. These policies aim at accelerating the adoption of cleaner vehicles by taking old vehicles out of the fleet, while supporting the vehicle industry. A scrappage policy must take the whole life cycle of a vehicle into account. Scrapping an old vehicle and manufacturing a new one creates additional environmental impacts which must be taken into consideration. This analysis is based on the comparison of the well-to-wheel (WTW) emissions with the cradle-to-grave (manufacturing, dismantling, recycling and waste treatment) emissions for vehicles with different ages, Euro standards and technologies. Optimizing vehicle’s LTDD (Life Time Driven Distance) causes an LCA (Life Cycle Assessment) challenge, combining two contradictory environmental engineering concepts. Letting a vehicle have a longer use phase avoids specific impacts during manufacturing, such as mineral extraction damage and energy usage. Conversely, replacement of an old vehicle with a new, more efficient one can lower the impacts introduced during the use phase. To differentiate between vehicle technologies it is investigated how long it takes until a newly produced car has an environmental return on investment. This period is called the environmental breakeven point.