Li-Ion Battery Charging Efficiency

Toman, Marek; Cipín, Radoslav; Cervinka, Dalibor; Vorel, Pavel; Procházka, Petr

doi:10.1149/07401.0037ecst

Cited by 15 publications

(5 citation statements)

References 3 publications

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“…This factor also depends on the battery chemistry, configuration or age. In the battery models used in this work, the ohmic losses are explicitly taken into account separately, and the value for the efficiency was taken from literature (Toman et al , 2016; Yang et al , 2018) as a way of compensating for the secondary above-mentioned effects. Values in the literature range from 90% to above 99% thus some exploration on this parameter was performed.…”

Section: Sensitivity Studiesmentioning

confidence: 99%

Optimal energy management for hybrid-electric aircraft

Leite

Voskuijl

2020

AEAT

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Purpose In recent years, increased awareness on global warming effects led to a renewed interest in all kinds of green technologies. Among them, some attention has been devoted to hybrid-electric aircraft – aircraft where the propulsion system contains power systems driven by electricity and power systems driven by hydrocarbon-based fuel. Examples of these systems include electric motors and gas turbines, respectively. Despite the fact that several research groups have tried to design such aircraft, in a way, it can actually save fuel with respect to conventional designs, the results hardly approach the required fuel savings to justify a new design. One possible path to improve these designs is to optimize the onboard energy management, in other words, when to use fuel and when to use stored electricity during a mission. The purpose of this paper is to address the topic of energy management applied to hybrid-electric aircraft, including its relevance for the conceptual design of aircraft and present a practical example of optimal energy management. Design/methodology/approach To address this problem the dynamic programming (DP) method for optimal control problems was used and, together with an aircraft performance model, an optimal energy management was obtained for a given aircraft flying a given trajectory. Findings The results show how the energy onboard a hybrid fuel-battery aircraft can be optimally managed during the mission. The optimal results were compared with non-optimal result, and small differences were found. A large sensitivity of the results to the battery charging efficiency was also found. Originality/value The novelty of this work comes from the application of DP for energy management to a variable weight system which includes energy recovery via a propeller.

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Section: Sensitivity Studiesmentioning

confidence: 99%

Optimal energy management for hybrid-electric aircraft

Leite

Voskuijl

2020

AEAT

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“…The battery efficiency is a function of the battery temperature, charging or discharging load, and the current SoC [16,17]. An average charge and discharge efficiency of 0.98 and 0.99 are assumed, respectively [18,19].…”

Section: The Batterymentioning

confidence: 99%

“…The constraints in Eq. (17) provides safety limits of the battery discharging and charging power. Since the charging process is aimed to be controlled by another control element (not by the DC-DC boost converter of the FC), the constraint P min B is neglected in this study.…”

Section: Cost Function and Constraintsmentioning

confidence: 99%

Energy Management Controller for Fuel Cell Hybrid Electric Vehicle Based on Sat‐Nav Data

Al‐Sagheer

Steinberger‐Wilckens

2020

Fuel Cells

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The hybridization of fuel cells (FC) and battery in electric vehicles necessitates designing an energy management system (EMS) for optimal energy use of the two power sources. The EMS represents a high‐level controller (HLC) calculating the optimal power split between the two power sources, using a prediction model for the vehicle's electric load over a planned journey trajectory. However, the instantaneous actual power demand of the vehicle is likely to deviate from the prediction due to varying traffic circumstances. This power offset needs to be compensated for whilst the optimality is still considered. A control approach is proposed here that converts the optimal power split into a dimensionless power split ratio (PSR). This ratio is passed to a low‐level controller (LLC) to be implemented as a set‐point. The LLC is responsible for simultaneously controlling the power of the FC and the battery using solely one control element, which is the DC‐DC boost converter. The PSR will be maintained whatever the actual power demand of the vehicle is. This approach will result in a fully controlled optimal power utilization, so that the high efficiency of the battery and the extended range enabled by the FC system are used to best effect.

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“…Applying high voltages to the conventional batteries shortens the charging period to several tens of minutes, although consequently causing the unfavorable energy (voltage) loss, self-heating, and degradation of battery components. 4,5 Former studies revealed that optimizing the crystal structures of the electrode-active materials, controlling the nanoscale geometry, and addition of nanocarbons such as graphene were effective to achieve the outstanding charge/discharge rates over 10−100 C (x C corresponds to a rate to fully charge/discharge a cell in 1/ x hours). 6−9 Still, most of the newly developed materials are yet to be commercialized because of the strict criteria for practical use, such as cyclability, energy density, voltage, reliability, toxicity, and mass producibility.…”

Section: ■ Introductionmentioning

confidence: 99%

“…In response to the rapid development of electric vehicles and portable electronic devices, accelerating the charging/discharging rates of lithium-ion batteries has become one of the most critical issues, in addition to increasing energy density. − For instance, the required time to fully charge the car batteries, typically 1–3 h, should hopefully be shortened to be compared with that for filling up petrol motor cars in several minutes. Applying high voltages to the conventional batteries shortens the charging period to several tens of minutes, although consequently causing the unfavorable energy (voltage) loss, self-heating, and degradation of battery components. , Former studies revealed that optimizing the crystal structures of the electrode-active materials, controlling the nanoscale geometry, and addition of nanocarbons such as graphene were effective to achieve the outstanding charge/discharge rates over 10–100 C ( x C corresponds to a rate to fully charge/discharge a cell in 1/ x hours). − Still, most of the newly developed materials are yet to be commercialized because of the strict criteria for practical use, such as cyclability, energy density, voltage, reliability, toxicity, and mass producibility.…”

Section: Introductionmentioning

confidence: 99%

Nonconjugated Redox-Active Polymer Mediators for Rapid Electrocatalytic Charging of Lithium Metal Oxides

Hatakeyama‐Sato

Masui

Serikawa

et al. 2019

ACS Appl. Energy Mater.

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For rapid charging of lithium-ion batteries, a series of novel electrode-active materials have been studied. However, those materials suffered from replacing conventional metal oxides, such as LiCoO2 and LiFePO4, because of the strict performance criteria for commercialization. As an alternative approach, we propose the hybridization of the conventional inorganic active materials with organic redox-active polymers which are characterized by fast electrode kinetics. A new robust organic-radical-substituted polyether was synthesized to yield one of the highest charge transportabilities of nonconjugated polymers with a charge diffusion coefficient of 10–7 cm2/s. The hybrid electrode of LiFePO4 and a small amount of the polymer was able to be charged within several minutes by virtue of the electrocatalytic oxidation of the metal oxide with the radical polymer. In addition, several 4 V class organic redox-active polymers were synthesized for the hybrid with LiCoO2. After hybridization, the LiCoO2 electrodes could also be charged within several minutes with the reduced overvoltages.

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Li-Ion Battery Charging Efficiency

Cited by 15 publications

References 3 publications

Optimal energy management for hybrid-electric aircraft

Optimal energy management for hybrid-electric aircraft

Energy Management Controller for Fuel Cell Hybrid Electric Vehicle Based on Sat‐Nav Data

Nonconjugated Redox-Active Polymer Mediators for Rapid Electrocatalytic Charging of Lithium Metal Oxides

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