Abstract

Part 17: Power Conversion; International audience; This work is focused on the design of the contactless energy transmitters and testing of their electrical parameters, varying the working frequency in the kHz range. The intended application is related to the possibility to make most efficient wireless charging of different batteries from the grid, guaranteeing more acceptable use of the electric vehicles. Document type: Part of book or chapter of book

Abstract

International audience; This paper presents a study which follows the present trend in the field of electric (or hybrid) vehicles E(H)V, having in mind that the major drawback of these last ones is the autonomy problem. Thus, by using a hybrid energy source (formed by ultracapacitors and battery) and with a proper current control (of polynomial type) one can get a good energy management which will increase the lifetime of the battery. Through numerical simulations and tests at reduced scale, the authors present a successfully energy management on board of a hybrid vehicle.

Abstract

This paper proposes a method for the combined estimation of the state of charge (SOC) and state of health (SOH) of batteries in hybrid and full electric vehicles. The technique is based on a set of five artificial neural networks that are used to tackle a regression and a classification task. In the method, the estimation of the SOC relies on the identification of the ageing of the battery and the estimation of the SOH depends on the behavior of the SOC in a recursive closed-loop. The networks are designed by means of training datasets collected during the experimental characterizations conducted in a laboratory environment. The lithium battery pack adopted during the study is designed to supply and store energy in a mild hybrid electric vehicle. The validation of the estimation method is performed by using real driving profiles acquired on-board of a vehicle. The obtained accuracy of the combined SOC and SOH estimator is around 97%, in line with the industrial requirements in the automotive sector. The promising results in terms of accuracy encourage to deepen the experimental validation with a deployment on a vehicle battery management system. Document type: Article

Abstract

Lithium-ion battery packs inside electric vehicles represents a high share of the final price. Nevertheless, with technology advances and the growth of the market, the price of the battery is getting more competitive. The greenhouse gas emissions and the battery cost have been studied previously, but coherent boundaries between environmental and economic assessments are needed to assess the eco-efficiency of batteries. In this research, a detailed study is presented, providing an environmental and economic assessment of the manufacturing of one specific lithium-ion battery chemistry. The relevance of parameters is pointed out, including the manufacturing place, the production volume, the commodity prices, and the energy density. The inventory is obtained by dismantling commercial cells. The correlation between the battery cost and the commodity price is much lower than the correlation between the battery cost and the production volume. The developed life cycle assessment concludes that the electricity mix that is used to power the battery factory is a key parameter for the impact of the battery manufacturing on climate change. To improve the battery manufacturing eco-efficiency, a high production capacity and an electricity mix with low carbon intensity are suggested. Optimizing the process by reducing the electricity consumption during the manufacturing is also suggested, and combined with higher pack energy density, the impact on climate change of the pack manufacturing is as low as 39.5 kg CO2 eq/kWh. Document type: Article

Abstract

On the path to a low-carbon future, advancements in energy storage seem to be achieved on a nearly daily basis. However, for the use-case of sustainable transportation, only a handful of technologies can be considered, as these technologies must be reliable, economical, and suitable for transportation applications. This paper describes the characteristics and aging process of two well-established and commercially available technologies, namely Lithium-Ion batteries and supercaps, and one less known system, flywheel energy storage, in the context of public transit buses. Beyond the obvious use-case of onboard energy storage, stationary buffer storage inside the required fast-charging stations for the electric vehicles is also discussed. Calculations and considerations are based on actual zero-emission buses operating in Graz, Austria. The main influencing parameters and effects related to energy storage aging are analyzed in detail.Based on the discussed aging behavior, advantages, disadvantages, and a techno-economic analysis for both use-cases is presented. A final suitability assessment of each energy storage technology concludes the use-case analysis. Document type: Article

Abstract

With the increase in electric mobility, public and private charge facilities will be required to provide solutions adjusted to the actual needs and requirements. A new methodology for dimensioning charge stations for electric vehicles (EVs) is presented in this paper. Such proposal is based on the Markov chains, and uses as output rates, the capabilities of the charge station in providing energy from the sun through photovoltaic generation, stored energy in local batteries and also as a back-up the power grid. A numerical result is also presented for a better understanding of the process. Document type: Conference object

Abstract

Nowadays, the conversion of diesel fueled public bus fleets into those powered by electricity is one of the most important tasks for public transport operators. In the frame of European Commission funded projects (“Eliptic” [Commission, 2015], “ZeEUS” [Commission, 2014]), there are at the moment several demonstrations in different European (big) cities. Besides purely demonstrating the general technical functionality, finding Business Cases is also a crucial task, since the operation with the new technology should be at least not significantly more expensive than compared to Diesel, besides having clear societal and environmental benefits."br" Within this context, the presented work focuses on the detailed comparison of two novel technological concepts of electric buses which are currently demonstrated in several European cities in the frame of the “Eliptic”-project:"br" 1) Opportunity-charging of battery electric buses taking energy from local DC tram grid"br" 2) Trolley-Hybrid buses (Buses being fed by overhead catenary and being able to cover parts of their routes by on-board batteries)"br" The investigations are based on already existing and potential future electric bus network and real operation in different cities and are performed in direct cooperation with the respective public transport operators to obtain meaningful results. A technical, economic and ecological presentation and comparison of the different approaches is the main target of the work."br" For this purpose, detailed analyses are performed in order to calculate the Total-Cost of Ownership (TCO). This comprises all relevant technical investment- and running costs over a certain period under consideration. Sine it is representing an important cost-factor of the new system, the battery is particularly considered regarding the expected lifetime in different operation scenarios.

Abstract

International audience; This paper describes an energy management strategy for an electric vehicle (EV). The proposed EV architecture contains a pack of the batteries which presents the energy source and a pack of the supercapacitors (SC) used as power source. The pack of the batteries produces the necessary energy to move forward the vehicle while the pack of the SC produces the lacking power in acceleration and in braking phases. Two DC-DC converters are used to interface the energy sources with the DC-bus. A bidirectional DC-AC converter is used to connect the traction motor to the DC-bus. The proposed control method is focused on the power flow management within the EV depending on electrical behavior of the energy sources. The validity of the proposed control strategy is proofed through some reduced scale simulations tests using the New European Driving Cycle (NEDC).