On the design of a direct cell coupled hybrid energy storage system for plug-in hybrid electric vehicles
27 Jun 2016-pp 1-7
TL;DR: In this paper, a case study based on an 18650 NMC lithium ion battery cell and a non-aqueous symmetric ultracapacitor is presented to investigate replacement tradeoffs between the two energy storage components.
Abstract: A pack design methodology is proposed to meet USABC PHEV-40 performance targets using battery and ultracapacitor energy storage elements in direct coupled topologies. Simulated responses of temperature dependent power capability and cold cranking requirements are embedded in the hybrid pack analysis and design process. A case study based on an 18650 NMC Lithium-ion battery cell and a non-aqueous symmetric ultracapacitor is presented to investigate replacement tradeoffs between the two energy storage components. Among the performance metrics in the case study, ultracapacitors give the greatest improvement for short term two second power. However, the 10-second discharge power requirement is shown to be a limiting design factor to which the replacement of battery cells with ultracapacitors is less effective.
Citations
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TL;DR: The effects correlations and possible solutions are explained to provide a detailed, yet broader understanding of the Li-ion batteries low-temperature operating scenarios.
Abstract: The purpose of this paper is to review the recent literature regarding the effects of low temperatures on Lithium ion (Li-ion) batteries for electric vehicle, plug-in hybrid electric vehicle, and hybrid electric vehicle applications. Special consideration is given to nine major effects that directly or indirectly impact the battery use at low temperatures and it is presented that they are correlated to each other. The main discussions in this paper are capacity loss, power loss, life degradation, safety hazard, unbalanced capacity, charging difficulty, thermal management system complexity, battery model and state estimation method complexity, and incremental cost. The effects correlations and possible solutions are explained to provide a detailed, yet broader understanding of the Li-ion batteries low-temperature operating scenarios.
90 citations
Cites background from "On the design of a direct cell coup..."
...performance, safety and cost can make the difference for a good project, even if it’s a small difference [10], [11]....
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...At a system level, however, there is still room for design improvement, as the ESS can be overdesigned, adding more cost to the vehicle [11], [83]....
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...1 [2], [11], [14] visually represents the electrodes struc-...
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...It’s assumed that part of this overdesign is the consequence of the difficulty in understanding and predicting the nonlinearities of the batteries under different driving and temperature conditions [11], [94], [95]....
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...The SCs have much higher power density than li-ion batteries and are less sensitive to temperature variations, but, up to now have not been cost effective solution as the SC needs to be reduced about to 1/3 of its cost and weight to be commercially attractive for PHEV application [11], [52], [96]....
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TL;DR: In this article , a centralized local energy storage modular multilevel converter (MMC-CLES) between the distributed MMC-ES and the centralized MMC was proposed to solve the problems of power difference, voltage fluctuation and effective improvement of power quality in the grid caused by the integration of new energy caused by new energy grid connection.
Abstract: The energy storage modular multilevel converter (MMC-ES) has been widely studied for its excellent performance in solving the problems of power difference, voltage fluctuation and effective improvement of power quality in the grid caused by the integration of new energy caused by new energy grid connection. Aiming at the problems that energy storage units of the traditional distributed MMC-ES are scattered, inconvenient to assemble and maintain, complex system control, and the traditional centralized MMC-ES has poor capacity selection flexibility, in this paper, a centralized local energy storage modular multilevel converter (MMC-CLES) between the distributed MMC-ES and the centralized MMC-ES is proposed. On the premise of not affecting the advantages of MMC-ES, by reducing the number of energy storage units, the switching loss is reduced, and the problems of complex SOC (state of charge) balance control strategy, large power conversion system loss, the AC side current imbalance caused by the grid connection of new energy sources and high system cost caused by too many energy storage units are solved. Matlab/simulink simulation shows that compared with traditional distributed MMC-ES, MMC-CLES reduces a total of 52 power devices, and under the condition of three-phase voltage unbalance, MMC-CLES effectively suppresses power fluctuations, the SOC balance control and the fast balance of the three-phase current are realized. The unbalance degree of the three-phase current is 8.16%, and the total harmonic distortion rate of the current is 3.11%.
References
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TL;DR: In this article, an improved Thevenin model, named dual polarization (DP) model, is put forward by adding an extra RC to simulate the electrochemical polarization and concentration polarization separately.
Abstract: To improve the use of lithium-ion batteries in electric vehicle (EV) applications, evaluations and comparisons of different equivalent circuit models are presented in this paper. Based on an analysis of the traditional lithium-ion battery equivalent circuit models such as the Rint, RC, Thevenin and PNGV models, an improved Thevenin model, named dual polarization (DP) model, is put forward by adding an extra RC to simulate the electrochemical polarization and concentration polarization separately. The model parameters are identified with a genetic algorithm, which is used to find the optimal time constant of the model, and the experimental data from a Hybrid Pulse Power Characterization (HPPC) test on a LiMn2O4 battery module. Evaluations on the five models are carried out from the point of view of the dynamic performance and the state of charge (SoC) estimation. The dynamic performances of the five models are obtained by conducting the Dynamic Stress Test (DST) and the accuracy of SoC estimation with the Robust Extended Kalman Filter (REKF) approach is determined by performing a Federal Urban Driving Schedules (FUDS) experiment. By comparison, the DP model has the best dynamic performance and provides the most accurate SoC estimation. Finally, sensitivity of the different SoC initial values is investigated based on the accuracy of SoC estimation with the REKF approach based on the DP model. It is clear that the errors resulting from the SoC initial value are significantly reduced and the true SoC is convergent within an acceptable error.
831 citations
"On the design of a direct cell coup..." refers methods in this paper
...Although there are other characterization procedures available such as dynamic stress test [4], [5], hybrid pulse power characterization [6], and others [8,10], the MEP test performs the test by operating at the extreme current and voltage limits....
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25 May 2015
TL;DR: In this article, enabling technologies and solutions for the electrified transportation are discussed in terms of power electronics, electric machines, electrified powertrain architectures, energy storage systems (ESSs), and controls and software.
Abstract: In order to achieve lower fuel consumption and less greenhouse gas (GHG) emissions, we need higher efficiency vehicles with improved performance. Electrification is the most promising solution to enable a more sustainable and environmentally friendly transportation system. Electrified transportation vision includes utilizing more electrical energy to power traction and nontraction loads in the vehicle. In electrified powertrain applications, the efficiency of the electrical path, and the power and energy density of the components play important roles to improve the electric range of the vehicle to run the engine close to its peak efficiency point and to maintain lower energy consumption with less emissions. In general, the electrified powertrain architecture, design and control of the powertrain components, and software development are coupled to facilitate an efficient, high-performance, and reliable powertrain. In this paper, enabling technologies and solutions for the electrified transportation are discussed in terms of power electronics, electric machines, electrified powertrain architectures, energy storage systems (ESSs), and controls and software.
340 citations
01 Nov 2011
TL;DR: A BMS that estimates the critical characteristics of the battery (such as SOC, SOH, and RUL) using a data-driven approach is proposed and the proposed framework provides a systematic way for estimating relevant battery characteristics with a high-degree of accuracy.
Abstract: The battery management system (BMS) is an integral part of an automobile. It protects the battery from damage, predicts battery life, and maintains the battery in an operational condition. The BMS performs these tasks by integrating one or more of the functions, such as protecting the cell, thermal management, controlling the charge-discharge, determining the state of charge (SOC), state of health (SOH), and remaining useful life (RUL) of the battery, cell balancing, data acquisition, communication with on-board and off-board modules, as well as monitoring and storing historical data. In this paper, we propose a BMS that estimates the critical characteristics of the battery (such as SOC, SOH, and RUL) using a data-driven approach. Our estimation procedure is based on a modified Randles circuit model consisting of resistors, a capacitor, the Warburg impedance for electrochemical impedance spectroscopy test data, and a lumped parameter model for hybrid pulse power characterization test data. The resistors in a Randles circuit model usually characterize the self-discharge and internal resistance of the battery, the capacitor generally represents the charge stored in the battery, and the Warburg impedance represents the diffusion phenomenon. The Randles circuit parameters are estimated using a frequency-selective nonlinear least squares estimation technique, while the lumped parameter model parameters are estimated by the prediction error minimization method. We investigate the use of support vector machines (SVMs) to predict the capacity fade and power fade, which characterize the SOH of a battery, as well as estimate the SOC of the battery. An alternate procedure for estimating the power fade and energy fade from low-current Hybrid Pulse Power characterization (L-HPPC) test data using the lumped parameter battery model has been proposed. Predictions of RUL of the battery are obtained by support vector regression of the power fade and capacity fade estimates. Survival function estimates for reliability analysis of the battery are obtained using a hidden Markov model (HMM) trained using time-dependent estimates of capacity fade and power fade as observations. The proposed framework provides a systematic way for estimating relevant battery characteristics with a high-degree of accuracy.
251 citations
"On the design of a direct cell coup..." refers methods in this paper
...Although there are other characterization procedures available such as dynamic stress test [4], [5], hybrid pulse power characterization [6], and others [8,10], the MEP test performs the test by operating at the extreme current and voltage limits....
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01 Dec 2010
TL;DR: The battery test procedure manual for PHEVs was published by the United States Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Program.
Abstract: This battery test procedure manual was prepared for the United States Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Program. It is based on technical targets established for energy storage development projects aimed at meeting system level DOE goals for Plug-in Hybrid Electric Vehicles (PHEV). The specific procedures defined in this manual support the performance and life characterization of advanced battery devices under development for PHEV’s. However, it does share some methods described in the previously published battery test manual for power-assist hybrid electric vehicles. Due to the complexity of some of the procedures and supporting analysis, a revision including some modifications and clarifications of these procedures is expected. As in previous battery and capacitor test manuals, this version of the manual defines testing methods for full-size battery systems, along with provisions for scaling these tests for modules, cells or other subscale level devices.
181 citations
TL;DR: In this paper, a training-free battery parameter/state estimator is presented based on an equivalent circuit model using a dual extended Kalman filter (DEKF), where the model parameters are no longer taken as functions of factors such as SOC (state of charge), temperature, and aging.
86 citations
"On the design of a direct cell coup..." refers methods in this paper
...A so-called maximum-energy-pulse (MEP) test procedure [3] is employed for this purpose....
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