Dongliang Lü

University of Colorado Colorado Springs

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Gregory L. Plett

University of Colorado Colorado Springs

M. Scott Trimboli

University of Colorado Colorado Springs

Sheng‐Guo Lu

Guangdong University of Technology

Ruirui Zhao

Dalian Maritime University

Guodong Fan

Shanghai Jiao Tong University

Jiuming Ma

Zhengzhou Railway Vocational & Technical College

Ruigang Zhang

Huazhong University of Science and Technology

Shuanghao Wu

South China Normal University

Tao Tao

Guangdong University of Technology

Yingbang Yao

Guangdong University of Technology

Cooperative Institutions

South China Normal University

Guangdong University of Technology

Chinese Academy of Sciences

Wuhan University of Technology

Xi'an Jiaotong University

China Agricultural University

University of Chinese Academy of Sciences

Nanjing Tech University

Shanghai Institute of Microsystem and Information Technology

Shandong University

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Behavior of types A and B hole traps in n-type GaAs during long-period operation

Solid-State Electronics (1992)

Jicheng Zhou Zhan Qianbao FU Zhi-ping Dongliang Lü Limin Guan

Trap (plumbing)

Degradation

10.1016/0038-1101(92)90167-b

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Citations (3)

Investigations on the properties of Li3xLa2/3-xTiO3 based all-solid-state supercapacitor: Relationships between the capacitance, ionic conductivity, and temperature

Journal of the European Ceramic Society (2020)

Dongliang Lü Ruirui Zhao Shuanghao Wu Jiuming Ma Meilin Huang

10.1016/j.jeurceramsoc.2020.02.006

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Citations (28)

Structure and morphology of the in situ composites of a liquid crystalline polymer and polycarbonate

Journal of Microscopy (1997)

Xiao Hu Qinghuang Lin Albert F. Yee Dongliang Lü

In situ composites were prepared via melt blending of a liquid crystalline polymer (LCP) and polycarbonate using a twin screw extruder. The structure and morphology of these composites were analysed using both transmission electron microscopy (TEM) and scanning electron microscopy. The LCP phases were able to orientate and form in situ submicrometre fibres during the extrusion and post‐extrusion drawing. TEM images as well as selected‐area diffraction patterns were obtained from the materials. The effects of both composition, i.e. LCP content, and post‐extrusion draw‐down ratio on the development of the in situ formed LCP fibres were studied in detail. A skin–core morphological differentiation is observed in these materials where well‐defined LCP fibres of higher aspect ratios were formed in the skin region. However, a significant amount of unelongated LCP particles were found coexisting with the less well‐defined fibres in the core region of the extrudates. This skin–core differentiation was found to be dependent on the composition and the processing conditions, e.g. draw ratio. In this instance, electron microscopy is proven to be a powerful technique not only for direct observation of the formation, dimensions and morphology of the in situ LCP fibres, but also for the qualitative and quantitative characterization of the molecular orientation and crystalline structures in these fibres using selected‐area electron diffraction. It is observed that the skin–core differentiation becomes more distinct in the in situ composites containing a higher percentage of LCP but diminishes when the material is processed at higher post‐extrusion draw ratio.

Polycarbonate

Morphology

Characterization

10.1046/j.1365-2818.1997.1750731.x

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Citations (9)

Implementation of a Physics-Based Model for Half-Cell Open-Circuit Potential and Full-Cell Open-Circuit Voltage Estimates: Part II. Processing Full-Cell Data

Journal of The Electrochemical Society (2021)

Dongliang Lü M. Scott Trimboli Guodong Fan Ruigang Zhang Gregory L. Plett

Physics-based models of lithium-ion battery cells require models of electrode open-circuit-potential (OCP) functions, as well as the stoichiometric values that bound the normal operating windows within the electrodes. In Part I of this series, we presented five approaches to estimate electrode OCP relationships, in which the proposed methods require no prior knowledge of physical parameters and can be applied to general cell chemistries. These methods rely in part on a physics-based multiple-species multiple-reaction (MSMR) thermodynamic model to overcome the "missing-data problem" and the "inaccessible-lithium problem". This paper applies these same five methodologies to estimate the full-cell open-circuit voltage (OCV) function. The results for OCP and OCV are then combined to determine the operating boundaries of the electrodes via a nonlinear optimization algorithm. To assess the utility and generality of the five methods, their performance is validated in simulations and also applied to a commercial cell. It is often preferred to avoid destructive procedures when acquiring cell properties; therefore, we also analyze the possibility of determining models for OCP relations and regressing operating boundaries without actually tearing down a cell and collecting half-cell data. We find that there are limitations to how well we can do this and show that these are due to two distinct "observability problems."

Open-circuit voltage

Observability

Experimental data

10.1149/1945-7111/ac11a5

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Citations (18)

Implementation of a Physics-Based Model for Half-Cell Open-Circuit Potential and Full-Cell Open-Circuit Voltage Estimates: Part I. Processing Half-Cell Data

Journal of The Electrochemical Society (2021)

Dongliang Lü M. Scott Trimboli Guodong Fan Ruigang Zhang Gregory L. Plett

Physics-based electrochemical models of lithium-ion cells require knowledge of electrode open-circuit potential (OCP) as a function of stoichiometry. To determine the OCP relationships for a cell built from unknown active materials, we might run low-rate constant-current laboratory tests on half cells built from harvested electrodes to collect related discharge and charge data. However, processing data from these tests must overcome three problems: the "data-quality problem," the "missing-data problem," and the "inaccessible-lithium problem." This paper introduces a simple histogram-based method to overcome the data-quality problem and compares five different approaches to overcome the missing-data and inaccessible-lithium problems. These methods rely in part on a physics-based thermodynamic model for multiple-species multiple-reaction (MSMR) systems, which is flexible enough to accommodate different cell chemistries and simple enough to be utilized in real-time battery management systems. The five methods are validated in simulations and are then applied to physical half-cell data to produce OCP estimates for graphite and NMC electrodes from a commercial cell.

Open-circuit voltage

Electrochemical cell

10.1149/1945-7111/ac11a4

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Citations (38)

Cell Discharge Testing to Calibrate a Positive-Electrode Open-Circuit-Potential Model for Lithium-Ion Cells

Journal of The Electrochemical Society (2022)

Dongliang Lü M. Scott Trimboli Gregory L. Plett

Previous work by our research team has proposed methods to estimate the open-circuit-potential (OCP) vs electrode stoichiometry relationships required by physics-based models of lithium-ion battery cells. It has also shown how to estimate the boundaries of the stoichiometric operating windows of both electrodes as the cell is cycled between 0% and 100% state of charge. In this earlier work, we sought to calibrate the OCP relationships by fitting them to a physics-based multi-species multi-reaction model; however, we have found that even this fitting is insufficient for producing unbiased estimates of the OCP relationships for some common positive-electrode materials such as LCO, NCA, and NMC. The primary contribution of this paper is to propose a new method that can calibrate the positive-electrode OCP relationship and its stoichiometric operating boundaries. It requires only commonly available constant-current discharge data from the cell, and when combined with methods from the earlier papers promises to mitigate the need for cell teardown to find the OCP relationships of a physical cell in many cases. The method is first validated in simulation and is then applied to a physical graphite//NMC cell. Results agree closely with others in the literature that were found using a teardown approach.

Open-circuit voltage

Stoichiometry

10.1149/1945-7111/ac8249

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Citations (13)

Interfacial study and modulation of high-voltage layered cathode based all-solid-state batteries

Journal of Colloid and Interface Science (2024)

Xiaojin Wang Haiqi Huang Jiawei Hu Zhuohua Li HuanMin Fan

Energy density

10.1016/j.jcis.2024.08.035

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Citations (1)

High performance electrostatically driven thermal switch incorporated with a mini-channel cooling

Energy Sources Part A Recovery Utilization and Environmental Effects (2020)

Jiuming Ma Xiaotong Lin Mingjian Xian Xiufang Ke Dongliang Lü

Thermal switches are a type of heat control devices widely used in electronics, engineering machinery, and other applications. Electrostatically driven thermal switches (EDTS) have received wide attention due to their high specific mass density, precise control of heat flow, and flexibility. However, most of the actuating components of EDTS are made of polymers with a poor thermal conductivity, which seriously affects the effectiveness of the thermal switch. This paper presents a highly efficient, reliable, and easy-to-implement EDTS with a mini-channel cooling, which combines the convective cooling with the electrostatic actuation by adding a cooling module to the radiator. The proposed EDTS controls its ON/OFF state using the electric field, and the water is used as the cooling fluid for absorbing the heat generated from the heat source. The experimental results demonstrated that the proposed EDTS achieves a switch ratio of 2964 ± 135 and a coefficient of performance (COP) of 11.6, indicating that it can effectively regulate the heat flow in the hot path. It demonstrates the prospect of becoming widely used in the thermal management of engineering machinery and electronic devices.

Active cooling

Computer cooling

Radiator (engine cooling)

Thermal mass

Electronics cooling

Passive cooling

10.1080/15567036.2020.1800867

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Citations (3)

Nondestructive EIS Testing to Estimate a Subset of Physics-based-model Parameter Values for Lithium-ion Cells

Journal of The Electrochemical Society (2022)

Dongliang Lü M. Scott Trimboli Guodong Fan Yujun Wang Gregory L. Plett

This paper is the final installment in a series of articles that collectively shows how to estimate parameter values for lumped-parameter physics-based models of lithium-ion cells without requiring cell teardown. In this paper, we leverage electrochemical impedance spectroscopy (EIS) to find estimates of all as-yet-unresolved parameter values. The characterization process regresses the measured cell impedance spectrum to exact analytic closed-form expressions of the frequency response of an extended Doyle–Fuller–Newman model to identify thirteen lumped parameters plus multiple reaction-rate constants. A nonlinear optimization algorithm performs the regression, and so it is important to provide reasonable initial parameter estimates and constraints, which we also discuss. As part of this process, the generalized distribution of realization times technique is used to isolate time constants from the two electrodes as well as to calibrate the laboratory EIS-test data. The overall methodology is studied on a virtual cell and on a laboratory cell (both having graphite//NMC chemistries). Parameter estimates found in the simulation study are highly accurate, leading us to have confidence in the values estimated for the physical cell as well.

Leverage (statistics)

Realization (probability)

10.1149/1945-7111/ac824a

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Citations (7)

Nondestructive Pulse Testing to Estimate a Subset of Physics-Based-Model Parameter Values for Lithium-Ion Cells

Journal of The Electrochemical Society (2021)

Dongliang Lü M. Scott Trimboli Guodong Fan Ruigang Zhang Gregory L. Plett

Battery-management systems require mathematical models of their cells to be able to compute estimates of state-of-charge, state-of-health, state-of-power or -function, and state-of-energy. These models may be empirical in nature, like equivalent-circuit models. Alternately, they may be based on physical principles, and we believe that such physics-based models provide benefits over empirical models in terms of their ability to be leveraged by battery-management-system algorithms to enhance battery safety, lifetime, and performance. A roadblock to using physics-based models is the difficulty in determining their parameter values to model a physical cell accurately and inexpensively. This paper proposes a method to identify a subset of the physics-based model parameter values that can be performed with the kind of equipment found in many battery labs and which does not require teardown of the cell. It applies a very short duration pulse to the cell to measure instantaneous resistance as a function of state of charge and amplitude. These resistances are then fit to a reduced-complexity physical model to determine model parameter values. The method is first applied to a virtual cell in simulation to explore its features and limitations, and is then applied to estimate parameter values for a commercial automotive lithium-ion cell.

State of health

State of charge

10.1149/1945-7111/ac1cfa

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Citations (13)