scholarly journals Optimal Scheduling to Manage an Electric Bus Fleet Overnight Charging

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2727 ◽  
Author(s):  
Adnane Houbbadi ◽  
Rochdi Trigui ◽  
Serge Pelissier ◽  
Eduardo Redondo-Iglesias ◽  
Tanguy Bouton
Keyword(s):  
Variable Temperature ◽  
Fitness Function ◽  
Methodological Approach ◽  
Lithium Ion ◽  
Operating Conditions ◽  
Coupled Modeling ◽  
Battery Lifetime ◽  
Electric Bus ◽  
Battery Capacity ◽  
Charging Strategy

Electro-mobility is increasing significantly in the urban public transport and continues to face important challenges. Electric bus fleets require high performance and extended longevity of lithium-ion battery at highly variable temperature and in different operating conditions. On the other hand, bus operators are more concerned about reducing operation and maintenance costs, which affects the battery aging cost and represents a significant economic parameter for the deployment of electric bus fleets. This paper introduces a methodological approach to manage overnight charging of an electric bus fleet. This approach identifies an optimal charging strategy that minimizes the battery aging cost (the cost of replacing the battery spread over the battery lifetime). The optimization constraints are related to the bus operating conditions, the electric vehicle supply equipment, and the power grid. The optimization evaluates the fitness function through the coupled modeling of electro-thermal and aging properties of lithium-ion batteries. Simulation results indicate a significant reduction in the battery capacity loss over 10 years of operation for the optimal charging strategy compared to three typical charging strategies.

scholarly journals Electro-Thermal and Aging Lithium-Ion Cell Modelling with Application to Optimal Battery Charging

2020 ◽  
Vol 10 (11) ◽  
pp. 4038
Author(s):  
Sara Mohajer ◽  
Jocelyn Sabatier ◽  
Patrick Lanusse ◽  
Olivier Cois
Keyword(s):  
Nonlinear Behavior ◽  
Lithium Ion ◽  
Side Reaction ◽  
Operating Conditions ◽  
Side Reactions ◽  
Voltage Response ◽  
Control Loop ◽  
Aging Model ◽  
Battery Lifetime ◽  
Charging Strategy

This paper deals with optimal charging versus aging minimization for lithium-ion batteries. The optimal charging strategy proposed involves charging controllers whose design relies on a battery model. The model, especially designed for automotive battery management systems applications, is recalled in this paper. It provides the voltage response of a cell to an input current. It also models side reactions that produce degradation mechanisms and thus decrease battery performance. Side reaction modelling involves taking into account the temperature cell variations, which are thus also modelled. The association of the three above-mentioned sub-models leads to an electro-thermal battery aging model used to design an optimal charging strategy that simultaneously takes into account the minimization of charging time and maximization of battery lifetime. Thus, to achieve a charging controller that manages battery health, an appropriate charging trajectory was computed by solving an optimization problem minimizing aging. Then, a charge control loop was designed. The nonlinear behavior of the battery was taken into account through the linearization of the electro-thermal aging model in different operating conditions. To take into account the resulting linear model family, the CRONE design methodology was used. The principles of this methodology are recapped and the design of the charging control loop is explained. The efficiency of the resulting charge controller is illustrated by several simulations.

scholarly journals Temperature, Ageing and Thermal Management of Lithium-Ion Batteries

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1248
Author(s):  
Lena Spitthoff ◽  
Paul R. Shearing ◽  
Odne Stokke Burheim
Keyword(s):  
Lithium Ion Batteries ◽  
Thermal Management ◽  
Critical Role ◽  
Experimental Studies ◽  
Lithium Ion ◽  
High Energy ◽  
Operating Conditions ◽  
Battery Lifetime ◽  
Temperature Ageing ◽  
And Performance

Heat generation and therefore thermal transport plays a critical role in ensuring performance, ageing and safety for lithium-ion batteries (LIB). Increased battery temperature is the most important ageing accelerator. Understanding and managing temperature and ageing for batteries in operation is thus a multiscale challenge, ranging from the micro/nanoscale within the single material layers to large, integrated LIB packs. This paper includes an extended literature survey of experimental studies on commercial cells investigating the capacity and performance degradation of LIB. It compares the degradation behavior in terms of the influence of operating conditions for different chemistries and cell sizes. A simple thermal model for linking some of these parameters together is presented as well. While the temperature appears to have a large impact on ageing acceleration above room temperature during cycling for all studied cells, the effect of SOC and C rate appear to be rather cell dependent.Through the application of new simulations, it is shown that during cell testing, the actual cell temperature can deviate severely from the reported temperature depending on the thermal management during testing and C rate. It is shown, that the battery lifetime reduction at high C rates can be for large parts due to an increase in temperature especially for high energy cells and poor cooling during cycling studies. Measuring and reporting the actual battery (surface) temperature allow for a proper interpretation of results and transferring results from laboratory experiments to real applications.

scholarly journals Methodical Approach to Organisation of Transportation on Electric Bus Routes

2021 ◽  
Vol 18 (5) ◽  
pp. 152-170
Author(s):  
M. A. Kudryshov ◽  
A. V. Prokopenkov ◽  
R. S. Ayriev
Keyword(s):  
Methodological Approach ◽  
Economic Assessment ◽  
Operating Conditions ◽  
Primary Analysis ◽  
Passenger Traffic ◽  
Electric Bus ◽  
Methodical Approach ◽  
Transit Capacity ◽  
Electric Traction ◽  
Charging Stations

When developing projects for introduction of electric buses into operation and determining the required infrastructure, it is necessary to justify the concept and methodological approaches to choosing of routes, to estimate the number of charging stations, depending on their type, and to conduct economic assessment of the proposed solutions in specific operating conditions.The article discusses the main issues of organising operation of buses with electric traction (electric buses) on the routes of public urban surface transport. A primary analysis of both current and prospective electric bus routes was carried out regarding the city of Moscow.Adaptive calculation methods are proposed based on classical methods for determining the required number of vehicles for a route regarding a given transit capacity, passenger traffic flow, and a given traffic interval.The current and prospective schemes for location of charging stations are considered, a method for determining their required number is proposed.A methodological approach of determining direct costs associated with transportation has been adapted to operation of electric buses on the route.

scholarly journals The impact of working conditions package traction on the exploitation of buses with electric drive

2017 ◽  
Vol 2017 (2) ◽  
pp. 10-15
Author(s):  
Marcin Koniak
Keyword(s):  
Electric Drive ◽  
Lithium Ion ◽  
Operating Conditions ◽  
Energy Storage Devices ◽  
Storage Devices ◽  
Depth Of Discharge ◽  
Electric Bus ◽  
Operating Current ◽  
Number Of Cycles ◽  
The Impact

This paper described the impact of the traction batteries operating conditions on their parameters and the operation of the electric bus. The author in introduction pointed out the advantages of transport based on vehicles with electric drive. He also said that most of the electric buses disadvantages is related to the batteries. The most popular types of energy storage devices used in electric buses have been presented. The rest of this paper is mentioned a number of factors and their impact on the battery exploitation. Are described, among others, temperature, number of cycles, depth of discharge, the operating current. Problems arising from the use of lithium-ion batteries can be reduced by proper selection of its type preceded by an analysis of its future operating conditions.

Calendar Degradation and Self-Discharge Occurring During Short- and Long-Term Storage of NMC Based Lithium-Ion Batteries

2021 ◽  
Vol 105 (1) ◽  
pp. 3-11
Author(s):  
Vaclav Knap ◽  
Martin Molhanec ◽  
Alejandro Gismero ◽  
Daniel-Ioan Stroe
Keyword(s):  
Discharge Rate ◽  
Storage Period ◽  
Lithium Ion ◽  
Battery Lifetime ◽  
Long Term Storage ◽  
Capacity Loss ◽  
Degradation Rates ◽  
Battery Capacity ◽  
Short And Long Term

Idling periods are a major part of the Lithium-ion battery operation. Due to parasitic reactions, the battery capacity is decreasing and self-discharge occurs over time. Thus, in order to predict the battery lifetime and optimize its operation, it is required to capture this behavior. In this study, two different storage periods of 2 and 6 months were investigated and used to develop and validate models dedicated to reversible and irreversible capacity loss. It has been observed that while for the shorter storage period, the self-discharge rate does not change significantly, for the longer storage period it decreased during aging. Moreover, the degradation rates vary significantly for various time scales at low temperature, while at medium and high temperatures they are matching closely for 2- and 6-months periodic storage.

Experimental and numerical analysis to identify the performance limiting mechanisms in solid-state lithium cells under pulse operating conditions

2019 ◽  
Vol 21 (41) ◽  
pp. 22740-22755 ◽  
Author(s):  
Mei-Chin Pang ◽  
Yucang Hao ◽  
Monica Marinescu ◽  
Huizhi Wang ◽  
Mu Chen ◽  
...  
Keyword(s):  
Solid State ◽  
Numerical Analysis ◽  
Energy Density ◽  
Lithium Ion Batteries ◽  
Lithium Batteries ◽  
Safety Concern ◽  
Lithium Ion ◽  
Thermal Runaway ◽  
Operating Conditions ◽  
Lithium Cells

Solid-state lithium batteries could reduce the safety concern due to thermal runaway while improving the gravimetric and volumetric energy density beyond the existing practical limits of lithium-ion batteries.

scholarly journals Adaptive State-of-Charge Estimation for Lithium-Ion Batteries by Considering Capacity Degradation

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 122
Author(s):  
Peipei Xu ◽  
Junqiu Li ◽  
Chao Sun ◽  
Guodong Yang ◽  
Fengchun Sun
Keyword(s):  
Equivalent Circuit Model ◽  
Lithium Ion ◽  
Maximum Error ◽  
State Of Charge ◽  
Recursive Least Squares ◽  
Accurate Estimation ◽  
Model Parameters ◽  
Soc Estimation ◽  
Capacity Degradation ◽  
Battery Capacity

The accurate estimation of a lithium-ion battery’s state of charge (SOC) plays an important role in the operational safety and driving mileage improvement of electrical vehicles (EVs). The Adaptive Extended Kalman filter (AEKF) estimator is commonly used to estimate SOC; however, this method relies on the precise estimation of the battery’s model parameters and capacity. Furthermore, the actual capacity and battery parameters change in real time with the aging of the batteries. Therefore, to eliminate the influence of above-mentioned factors on SOC estimation, the main contributions of this paper are as follows: (1) the equivalent circuit model (ECM) is presented, and the parameter identification of ECM is performed by using the forgetting-factor recursive-least-squares (FFRLS) method; (2) the sensitivity of battery SOC estimation to capacity degradation is analyzed to prove the importance of considering capacity degradation in SOC estimation; and (3) the capacity degradation model is proposed to perform the battery capacity prediction online. Furthermore, an online adaptive SOC estimator based on capacity degradation is proposed to improve the robustness of the AEKF algorithm. Experimental results show that the maximum error of SOC estimation is less than 1.3%.

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