Detection and Isolation of Small Faults in Lithium-Ion Batteries via the Asymptotic Local Approach

This contribution presents a diagnosis scheme for batteries to detect and isolate internal faults in the form of small parameter changes. This scheme is based on an electrochemical reduced-order model of the battery, which allows the inclusion of physically meaningful faults that might affect the battery performance. The sensitivity properties of the model are analyzed. The model is then used to compute residuals based on an unscented Kalman filter. Primary residuals and a limiting covariance matrix are obtained thanks to the local approach, allowing for fault detection and isolation by chi-squared statistical tests. Results show that faults resulting in limited 0.15% capacity and 0.004% power fade can be effectively detected by the local approach. The algorithm is also able to correctly isolate faults related with sensitive parameters, whereas parameters with low sensitivity or linearly correlated are more difficult to precise.Comment: 8 pages, 2 figures, 3 tables, conferenc

Fault diagnosis of lithium ion battery using multiple model adaptive estimation

Indiana University-Purdue University Indianapolis (IUPUI)Lithium ion (Li-ion) batteries have become integral parts of our lives; they are widely used in applications like handheld consumer products, automotive systems, and power tools among others. To extract maximum output from a Li-ion battery under optimal conditions it is imperative to have access to the state of the battery under every operating condition. Faults occurring in the battery when left unchecked can lead to irreversible, and under extreme conditions, catastrophic damage. In this thesis, an adaptive fault diagnosis technique is developed for Li-ion batteries. For the purpose of fault diagnosis the battery is modeled by using lumped electrical elements under the equivalent circuit paradigm. The model takes into account much of the electro-chemical phenomenon while keeping the computational effort at the minimum. The diagnosis process consists of multiple models representing the various conditions of the battery. A bank of observers is used to estimate the output of each model; the estimated output is compared with the measurement for generating residual signals. These residuals are then used in the multiple model adaptive estimation (MMAE) technique for generating probabilities and for detecting the signature faults. The effectiveness of the fault detection and identification process is also dependent on the model uncertainties caused by the battery modeling process. The diagnosis performance is compared for both the linear and nonlinear battery models. The non-linear battery model better captures the actual system dynamics and results in considerable improvement and hence robust battery fault diagnosis in real time. Furthermore, it is shown that the non-linear battery model enables precise battery condition monitoring in different degrees of over-discharge

Adaptive Nonlinear Model-Based Fault Diagnosis of Li-ion Batteries

In this paper, an adaptive fault diagnosis technique is used in Li-ion batteries. The diagnosis process consists of multiple nonlinear models representing signature faults, such as overcharge and overdischarge, causing significant model parameter variation. The impedance spectroscopy of a Li-ion LiFePO4 cell is used, along with the equivalent circuit methodology, to construct nonlinear battery signature-fault models. Extended Kalman filters are utilized to estimate the terminal voltage of each model and to generate residual signals. The residual signals are used in the multiple-model adaptive estimation technique to generate probabilities that determine the signature faults. It can be seen that, by using this method, signature faults can be detected accurately, thus providing an effective way of diagnosing Li-ion battery failure

Sensor Fault Detection and Isolation for Degrading Lithium-Ion Batteries in Electric Vehicles

With the increase in usage of electric vehicles (EVs), the demand for lithium ion (Li-ion) batteries is also on the rise. A Li-ion battery pack in an EV consists of hundreds of cells and requires a battery management system (BMS). The BMS plays an important role in ensuring the safe and reliable operation of the battery in EVs. Its performance relies on the measurements of voltage, current and temperature from the cells through sensors. Sensor faults in the BMS can have significant negative effects on the system, hence it is important to diagnose these faults in real-time. Existing sensor fault detection and isolation (FDI) methods are mostly state-observer-based. State observer methods work under the assumption that the model parameters remain constant during operation. Through experimental results, this thesis shows that degradation can affect the long-term performance of the battery and its model parameters, hence it can cause false fault detection in state observer FDI schemes. This thesis also presents a novel model-based sensor FDI scheme for a Li-ion cell, that takes into consideration battery degradation. The proposed scheme uses the recursive least squares (RLS) method to estimate the equivalent circuit model (ECM) parameters in real-time. The estimated ECM parameters are put through weighted moving average (WMA) filters, and then cumulative sum control charts (CUSUM) are implemented to detect any significant deviation between unfiltered and filtered data, which would indicate a fault. The current and voltage sensor faults are isolated based on the responsiveness of the parameters when each fault occurs. Finally, the proposed FDI scheme is validated by conducting a series of experiments and simulations. Various injection times, fault sizes, fault types and cell capacities are considered. The results show that the proposed scheme consistently detects and isolates voltage and current sensor faults at different cell capacities in a reasonable time, with no false or missed detection. The preliminary findings are promising, but in order for the proposed FDI scheme to be utilized in practical settings, more work is needed to be done. The scheme should be expanded to include FDI for temperature sensors. In addition, other battery models as well as other fault diagnosis methods, specifically knowledge-based ones, should be investigated. Furthermore, additional experiments, including longer test cycles and extension to modules and packs testing, need to be conducted to obtain more data to improve the reliability of the FDI scheme

Battery Management Systems of Electric and Hybrid Electric Vehicles

The topics of interest in this book include significant challenges in the BMS design of EV/HEV. The equivalent models developed for several types of integrated Li-ion batteries consider the environmental temperature and ageing effects. Different current profiles for testing the robustness of the Kalman filter type estimators of the battery state of charge are used in this book. Additionally, the BMS can integrate a real-time model-based sensor Fault Detection and Isolation (FDI) scheme for a Li-ion cell undergoing degradation, which uses the recursive least squares (RLS) method to estimate the equivalent circuit model (ECM) parameters. This book will fully meet the demands of a large community of readers and specialists working in the field due to its attractiveness and scientific content with a great openness to the side of practical applicability. This covers various interesting aspects, especially related to the characterization of commercial batteries, diagnosis and optimization of their performance, experimental testing and statistical analysis, thermal modelling, and implementation of the most suitable Kalman filter type estimators of high accuracy to estimate the state of charg

Lithium-ion cell modeling, state estimation, and fault detection considering state of health for battery management systems

Lithium-ion batteries (LIBs) with high energy density and longer cycle life enable a comparable driving range per charge for electric vehicles (EVs) with their gas counterparts. However, the LIBs are very sensitive to variations in operating conditions, such as overcharge/discharge, high/low temperatures, and mechanical abuse. A battery management system (BMS) is employed to orchestrate safe and reliable operation by monitoring the voltage, current, temperature, state of charge (SOC), and state of health (SOH) and optimizing the charging and discharging cycles. The SOC and SOH, which determine the performance of the LIB, are governed by several stress-inducing factors, such as operating temperature, C-rate, aging, and internal faults. So, it is important to estimate the SOC and SOH in real time, considering the factors affecting the degradation of the battery. On the other hand, an internal fault in LIB leads to thermal runaway. Early detection and diagnosis of these faults are necessary to avoid catastrophic failures of LIBs.In this dissertation, we developed health-inclusive dynamic models for simultaneous state and parameter estimations and fault detection (FD) schemes. First, we proposed a nonlinear parameter-varying equivalent circuit model (ECM) integrated with the parameter dynamics for simultaneous state and parameter estimation using nonlinear observer-based approaches. Second, the proposed model is extended to integrate the SOH and thermal behavior with ECM. The SOH-coupled nonlinear electric-thermal-aging model comprehends the interplay between the SOC and SOH and couples the ECM dynamics with capacity fade. The proposed model is further extended by integrating the ohmic resistance dynamics for simultaneous SOC, SOH, and parameter estimation using filtering algorithms. Finally, two FD schemes, based on the SOC-based and SOH-coupled models, are proposed to detect internal (thermal and side-reaction) faults by tracking the temperature and parameter residuals of the battery. Adaptive thresholds are designed to account for modeling uncertainties and the effect of degradation in the residuals and avoid false positives. In addition, a novel neural network-based observer is proposed to learn the fault dynamics and estimate the SOC, SOH, and core temperature under internal faults. Experimental and numerical validation results are presented to corroborate the designs

Algorithms for Fault Detection and Diagnosis

Due to the increasing demand for security and reliability in manufacturing and mechatronic systems, early detection and diagnosis of faults are key points to reduce economic losses caused by unscheduled maintenance and downtimes, to increase safety, to prevent the endangerment of human beings involved in the process operations and to improve reliability and availability of autonomous systems. The development of algorithms for health monitoring and fault and anomaly detection, capable of the early detection, isolation, or even prediction of technical component malfunctioning, is becoming more and more crucial in this context. This Special Issue is devoted to new research efforts and results concerning recent advances and challenges in the application of “Algorithms for Fault Detection and Diagnosis”, articulated over a wide range of sectors. The aim is to provide a collection of some of the current state-of-the-art algorithms within this context, together with new advanced theoretical solutions

A Study of Computationally Efficient Advanced Battery Management: Modeling, Identification, Estimation and Control

Lithium-ion batteries (LiBs) are a revolutionary technology for energy storage. They have become a dominant power source for consumer electronics and are rapidly penetrating into the sectors of electrified transportation and renewable energies, due to the high energy/power density, long cycle life and low memory effect. With continuously falling prices, they will become more popular in foreseeable future. LiBs demonstrate complex dynamic behaviors and are vulnerable to a number of operating problems including overcharging, overdischarging and thermal runaway. Hence, battery management systems (BMSs) are needed in practice to extract full potential from them and ensure their operational safety. Recent years have witnessed a growing amount of research on BMSs, which usually involves topics such as dynamic modeling, parameter identification, state estimation, cell balancing, optimal charging, thermal management, and fault detection. A common challenge for them is computational efficiency since BMSs typically run on embedded systems with limited computing and memory capabilities. Inspired by the challenge, this dissertation aims to address a series of problems towards advancing BMSs with low computational complexity but still high performance. Specifically, the efforts will focus on novel battery modeling and parameter identification (Chapters 2 and 3), highly efficient optimal charging control (Chapter 4) and spatio-temporal temperature estimation of LiB packs (Chapter 5). The developed new LiB models and algorithms can hopefully find use in future LiB systems to improve their performance, while offering insights into some key challenges in the field of BMSs. The research will also entail the development of some fundamental technical approaches concerning parameter identification, model predictive control and state estimation, which have a prospect of being applied to dynamic systems in various other problem domains

Sensor Fault Detection for Rail Vehicle Suspension Systems with Disturbances and Stochastic Noises

This paper develops a sensor fault detection scheme for rail vehicle passive suspension systems, using a fault detection observer, in the presence of uncertain track regularity and vehicle noises which are modeled as external disturbances and stochastic process signals. To design the fault detection observer, the suspension system states are augmented with the disturbances treated as new states, leading to an augmented and singular system with stochastic noises. Using system output measurements, the observer is designed to generate the needed residual signal for fault detection. Existence conditions for observer design are analyzed and illustrated. In term of the residual signal, both fault detection threshold and fault detectability condition are obtained, to form a systematic detection algorithm. Simulation results on a realistic vehicle system model are presented to illustrate the observer behavior and fault detection performance