Dynamic Electro-Thermal Li-ion Battery Model for Control Algorithms

This paper presents a fast and effective approach to evaluate the heat generation of a Li-ion battery system. The thermal characterization of Li-ion batteries is a relevant topic for the correct monitoring of the battery pack. In particular, a reduced-order model, that estimates the thermal dynamics of a Li-ion battery cell, is reported. The proposed approach relies on the definition of a boundary-value problem for heat conduction, in the form of a linear partial differential equation with the integration of Equivalent Circuit Model. The model is based on the double polarization Thévenin equivalent circuit model since it represents an optimal trade-off between accuracy and computation effort, which justifies its implementation in a Battery Management System (BMS) for automotive real-time monitoring and control. The resulting model predicts the temperature dynamics at the external surface in relation with the rate of the internal heat generation. In this paper, the model is applied to estimate the temperature of a cylindrical cell during a discharging transient and it uses electrical data acquired from experimental tests and is validated Computational fluid dynamics simulation. The results of the test are suitable for the future implementation of a proper algorithm for State of Charge SOC and State of Health SOH estimations

Electrothermal battery pack model for automotive application: Design and validation

Thermal modeling of the battery is an important way to understand how the design and operating variables affect the thermal response during its operation. This paper presents a method for modeling the electrical and thermal behavior of a battery pack, starting from the characterization of the single Lithium-ion battery cell up to extend its validity to module and pack level. The model takes into account both the reversible entropic heat generation and the irreversible resistive heat to predict the temperature of the battery. A coupled CFD and thermal analysis on an elementary module is proposed and experimentally tested to validate the results obtained from the proposed model. Furthermore, the experimental test will verify the effectiveness of air cooling

Temperature-Dependent Thévenin Model of a Li-Ion Battery for Automotive Management and Control

This paper focuses on the analysis of Li-ion battery behavior at different temperatures through the Thévenin electrical circuit model. First, evaluations for both steady-state and dynamic battery applications are provided, then an overview of the different battery models to describe their dynamic behavior is analyzed. The focus is dedicated to the double polarization Thévenin-based equivalent circuit model since it represents an optimal trade-off between accuracy and computation effort, which justifies its implementation in a Battery Management System (BMS) for automotive real-time monitoring and control. The model is composed of a voltage source, one series resistor and two series RC blocks. The Hybrid Pulse Power Characterization test (HPPC) is performed inside a climatic chamber to extract the electrical parameters of the model and their dependency from both temperature and State Of Charge (SOC). The load-current effects on the battery performance are not considered for the simplicity and lightness of the presented model. The presented procedure has broader validity and is mostly independent of cell format and Li-ion chemistry, despite a specific cylindrical battery cell is chosen for the study. The results of the test are suitable for the future implementation of a proper algorithm for SOC and State Of Health SOH estimations. Moreover, they provide an effective electrical and thermal characterization of the cell to evaluate the heat generation rate inside the cell

Non-linear kalman filters for battery state of charge estimation and control

In this paper, two different non-linear Kalman Filters for lithium-ion battery state of charge estimation are presented and compared. Nowadays, lithium-ion batteries are extensively used for hybrid and electric vehicles; in such applications, cells are assembled in module and pack to achieve high performance. At this scope, a Battery Management Systems BMS is required to control each cell and improve the battery pack performance, safety, reliability, and lifecycle. One of the major tasks a BMS must fulfill is an accurate online estimation of the State Of Charge (SOC) of the battery pack. In this paper, the Extended Kalman Filter and Sigma Points Kalman filter are developed and compared. A battery equivalent circuit model has been chosen to have a good compromise between complexity and accuracy and model parameters have been identified from Hybrid Pulse Power Characterization (HPPC) tests carried out at different temperatures and current rates to obtain a model valid for a wide range of operating conditions. The SOC estimation strategies are developed starting from the experimental results and it is validated through different driving cycling simulations. The results show that the Sigma Points Kalman filter produces a better estimate of SOC with respect to the Extended Kalman Filter, due to its better capability to deal with system non-linearities, with comparable computational complexity

Single-Lung Transplantation in the Setting of Aborted Bilateral Lung Transplantation

Background. The outcome of patients undergoing a single-lung transplant in the setting of an aborted bilateral lung transplant is unclear. Methods. A retrospective review of single lung transplants at an institutional program. Results. Of the 543 lung transplants performed over the last 10 years, 31 (5.7%) were single-lung transplants. Nineteen of 31 (61%) were planned single-lung transplants, while 12/31 (39%) were intraoperatively aborted, double lung transplants converted to single-lung transplants. The aborted and planned groups were similar in age, lung allocation score and NYHA status. The reasons for aborted double lung transplantation were cardiac/hemodynamic instability 4/12 (33%), difficult pneumonectomy 3/12 (25%), size mismatch 4/12(33%), and technical issues 1/12 (8%). The aborted group had higher CPB utilization (5/12 versus 1/19, P = .02), similar ischemic times (260 versus 234 min) and similar incidence of grade 3 primary graft dysfunction (6/12 versus 3/19, P = .13). ECMO was required for graft dysfunction in 2 patients in the aborted group. The one and two-year survival was 84% and 79% in the planned group and 62% and 52% in the aborted group, respectively. Conclusions. Patients undergoing single-lung transplantation in the setting of an aborted bilateral lung transplant may be at a higher risk of worse outcomes

Vibration characteristics of a large wind turbine tower on non-rigid foundations

Vibration characteristics of the Mod-OA wind turbine supported by nonrigid foundations were investigated for a range of soil rigidities. The study shows that the influence of foundation rotation on the fundamental frequency of the wind turbine is quite significant for cohesive soils or loose sand. The reduction in natural frequency can be greater than 20 percent. However, for a foundation resting on well graded, dense granular materials or bedrock, such effect is small and the foundation can be treated as a fixed base

Origin of the solid-state luminescence of MIL-53(Al) and its connection to the local crystalline structure

Metal-organic frameworks (MOFs) are extensively studied due to their unique surface properties, enabling many intriguing applications. Breathing MOFs, a subclass of MOFs, have gained recent interest for their ability to undergo structural changes based on factors like temperature, pressure, adsorbed molecules. Certain MOFs also exhibit remarkable optical properties useful for applications such as sensors, light-emitting diodes, and scintillators. The most promising MOFs possess high porosity, breathing properties, and photoluminescence activities, allowing for improved device responsiveness and selectivity. Understanding the relationship between crystal structures and photoluminescence properties is crucial in these cases. As studies on this topic are still very limited, we report for the first time an exhaustive study on the solid-state luminescence of the breathing MOF MIL-53(Al), that can stabilize in three different crystalline structures: open-pore, hydrated narrow-pore and closed-pore. We unveil a fascinating solid-state luminescence spectrum, comprising three partially overlapping bands, and elucidate the intricate electronic transitions within each band as well as their intimate correlation with the local crystalline structures. Our characterizations of spectroscopic properties and decay times provide a deeper understanding of the luminescent behaviour of MIL-53(Al) and demonstrate that is possible to identify present crystalline structures by optical measurements or to modify the optical properties inducing structural transitions for this type of materials. These insights could help to design next-generation, selective sensors or smart light emitting devices

Recent Advances in the Synthesis and Application of SF5-Containing Organic Compounds

It is well known that fluorinated molecules play an important role in daily life. For example, organic molecules bearing either a fluorine atom itself or a short polyfluorinated substituent such as mono-, difluoro-, and trifluoromethyl groups, or pentafluoroethyl and perfluoropropyl groups are already widely used in medicinal and agricultural chemistry. In contrast, molecules with long perfluorinated chains have found vast application in materials science. Among the fluorine-containing moieties, the pentafluorosulfanyl (SF5) substituent occupies a special place.1 The pentafluorosulfanyl group brings unique properties to organic compounds and often improves their biological activities due to the group’s high chemical and metabolic stability, significant lipophilicity, substantial steric effect, unique geometry, and low surface energy. Here we present new routes towards SF5-substituted aliphatic and heterocyclic compounds