A Multi-Point Sensor Based on Optical Fiber for the Measurement of Electrolyte Density in Lead-Acid Batteries

This article describes a multi-point optical fiber-based sensor for the measurement of electrolyte density in lead-acid batteries. It is known that the battery charging process creates stratification, due to the different densities of sulphuric acid and water. In order to study this process, density measurements should be obtained at different depths. The sensor we describe in this paper, unlike traditional sensors, consists of several measurement points, allowing density measurements at different depths inside the battery. The obtained set of measurements helps in determining the charge (SoC) and state of health (SoH) of the battery

A Polymer Optical Fiber Fuel Level Sensor: Application to Paramotoring and Powered Paragliding

A low-cost intensity-based polymer optical fiber (POF) sensor for fuel level measurements in paramotoring and powered paragliding is presented, exploiting the advantages of the optical fiber sensing technology. Experimental results demonstrate that the best option can be performed by stripping the fiber at the desired discrete points to measure the fuel level as well as with a gauge-shape fiber bending. The prototype has a good linearity, better than 4% full scale (F.S.), and sensitivity around 0.5 V per bend are obtained. Hysteresis due to residual fluid at the sensing points is found to be less than 9% F.S.This work has been supported by Spanish CICyT project TEC2009-14718-C03-03 from the Spanish Ministry of Science, and by project FACTOTEM-II-CM: S2009/ESP-1781 of Comunidad Autónoma de Madrid.Publicad

IoT Tabanlı Enstrümantasyon Sistemi ile Farklı Frekansların Kurşun Asit Akülerin Desülfasyonu Üzerine Etkilerinin İncelenmesi

Bu çalışmada, Kurşun asit (KA) akülerde sıklıkla rastlanan sülfatlanma sorununun çözümüne odaklanılmış, nesnelerin interneti (IoT) tabanlı enstrümantasyon devreleri kullanılarak, farklı frekanslardaki gerilim darbelerinin KA akülerin desülfasyonu üzerindeki etkileri deneysel olarak incelenmiştir. Bu amaçla, eşit koşullarda sülfatlandırılmış dört özdeş akü, farklı frekanslarda gerilim darbeleri ve DC gerilim uygulanarak şarj edilmiş, akü parametrelerindeki değişimler analiz edilmiştir. Analiz sonucunda akülerin yüke akım aktarabilme kapasitelerindeki düşüşün, DC gerilim ile şarj edilen aküde yüksek oranda, farklı frekanstaki gerilim darbeleriyle şarj edilen akülerde ise nispeten daha düşük oranda olduğu görülmüştür. Buna göre, yüksek frekanslı gerilim darbeleriyle desülfasyon işleminin, sülfatlanmış bir aküyü olumlu şekilde etkilediği görülmüştür

A review on various optical fibre sensing methods for batteries

Batteries have rapidly evolved and are widely applied in both stationary and transport applications. The safe and reliable operation is of vital importance to all types of batteries, herein an effective battery sensing system with high performance and easy implementation is critically needed. This also requires the sensing system to monitor the states of batteries in real time. Among the available methods, optical fibre sensors have shown a significant advantage due to their advanced capabilities of which include the fast measurement of multiple parameters with high sensitivity, working without interfering the battery performance, being able to be composited in multiplexed configurations and being robust to various harsh environment conditions. This paper mainly discusses the current optical fibre sensing methods for batteries in terms of the working principles and critical reviews the sensing performance corresponding to different sensing parameters. Moreover, the challenges and outlooks for future research on battery sensing are derived

Fiber Optic Sensor for In-Situ State-of-Charge Monitoring for Lithium-Ion Batteries

The objective of this thesis is to develop a fiber optic sensor for in-situ measurement of the optical properties of Li-ion batteries for the purpose of state-of-charge (SOC) estimation. Current methods rely on measuring the external parameters of the battery, namely voltage, current and temperature, and using various algorithms to estimate the SOC of the battery. These methods vary in accuracy and cost; generally, there is a trade-off between the two. A direct measurement of the internal state of the battery has to this point not been demonstrated as a means of SOC estimation in full cell Li-ion batteries. This could be a way to obtain more accurate estimates at a lower cost. The electrodes of Li-ion batteries have been found to exhibit changing optical characteristics at different states of charge. This is especially apparent in the graphite electrode, which visibly changes in colour. Spectroscopy studies of electrodes extracted from batteries charged to different SOC values have confirmed the visual observations and have also shown changes at non-visible wavelengths. In order to measure optical changes in a live cycling battery a sensor must be incorporated into the cell. Silica fibers lend themselves to this application as they are non-reactive to the electrolyte in the battery and they can be used to make evanescent wave sensors. The evanescent wave sensor consists of a fiber with partially removed cladding that is placed in contact with the anode such that the evanescent fields interact with the electrode. The measured signal is based on the intensity modulation of the light carried by the fiber, which allows for a low cost system to be used to detect the sensor output. A method was developed to insert the sensor in a working full cell battery prepared in a Swagelok® cell. Several tests were carried out and the sensor signal recorded as the cell was charged and discharged. The signal follows the charging and discharging of the battery consistently for both full and partial cycles and the sensor response is repeatable with different sensors and battery cells. The sensor response has three regions, with the central region, between 30-60% SOC, having very high sensitivity. The optical signal can be used to estimate the SOC with an accuracy of 14% or better. The accuracy can be greatly improved with more stable batteries and an improved signal acquisition system. The sensor response was compared to an analytical model of evanescent wave sensors. The transfer matrix method is used for the model as it provides an elegant way of modeling reflection and transmission through multi layers of optical media, such as the three layer stack formed by the core and cladding of the sensor and the battery electrode. The model may be used to relate the optical properties of the electrodes to the SOC of the battery. In summary, a fiber optic evanescent wave sensor has been developed that can be used to estimate the SOC of Li-ion batteries. The sensor is novel as it measures the internal state of the battery directly and can be used to obtain estimates in real time. A simple, low-cost system is used for acquiring the sensor signal. The sensor has high sensitivity and good accuracy in estimating the SOC

A Multi-Point Sensor Based on Optical Fiber for the Measurement of Electrolyte Density in Lead-Acid Batteries

This article describes a multi-point optical fiber-based sensor for the measurement of electrolyte density in lead-acid batteries. It is known that the battery charging process creates stratification, due to the different densities of sulphuric acid and water. In order to study this process, density measurements should be obtained at different depths. The sensor we describe in this paper, unlike traditional sensors, consists of several measurement points, allowing density measurements at different depths inside the battery. The obtained set of measurements helps in determining the charge (SoC) and state of health (SoH) of the battery

Ferrule-top micromachined devices: A universal platform for optomechanical sensing

Iannuzzi, D. [Promotor

Metrologia óptica com fibra polimérica

Doutoramento em FísicaO presente trabalho teve por objectivo global o estudo e desenvolvimento de sensores baseados em fibra óptica polimérica. O crescimento da tecnologia polimérica nos últimos anos permitiu a introdução deste tipo de fibras ópticas na área das telecomunicações e no desenvolvimento de sensores. As vantagens associadas à metrologia óptica com fibra polimérica têm vindo a atrair as atenções da comunidade científica dado que permitem o desenvolvimento de sistemas de baixo-custo ou custo competitivo face às tecnologias convencionais. Dada a actualidade do tema proposto, descreve-se, numa primeira fase, a tecnologia em fibra óptica polimérica existente no mercado e o estado de arte de sensores em fibra óptica polimérica. Segue-se a descrição de dois tipos de sensores baseados em modulação de intensidade. Projectou-se um sensor extrínseco capaz de avaliar a quantidade de luz dispersa e absorvida por partículas suspensas num líquido. Foi efectuada a caracterização do sensor quanto à concentração de partículas suspensas, tamanho e reflectividade. O sensor foi testado no âmbito da monitorização ambiental, designadamente, na análise de turbidez em amostras de sedimentos recolhidos em áreas ardidas. O sistema desenvolvido foi comparado com um sistema comercial. Um sensor intrínseco, baseado no polimento lateral de fibra óptica polimérica, foi analisado analiticamente. O modelo teórico avalia o sensor em diferentes condições de macroencurvamento e de índice de refracção do meio envolvente. O modelo teórico foi validado positivamente através de resultados experimentais. Foi avaliada a sensibilidade à temperatura e os conhecimentos adquiridos foram aplicados no desenvolvimento de um sistema capaz de monitorizar a cura de diferentes materiais. É ainda apresentada uma técnica para melhorar a sensibilidade do sensor de curvatura através da aplicação de um revestimento na zona sensível. A dependência na curvatura da potência transmitida por uma fibra óptica polida lateralmente serviu de base ao desenvolvimento de uma joelheira e de uma cotoveleira instrumentada, capazes de avaliar quantitativamente o movimento articular. A necessidade de portabilidade levou ao desenvolvimento de um sistema sem fios para aquisição e transmissão de dados. Espera-se que os protótipos desenvolvidos venham a ter um impacto significativo em sistemas futuros aplicados à medicina física e reabilitação.The global aim of this thesis was the study and development of optical sensors based on plastic optical fibre. The recent advance of polymer technology allowed the introduction of this type of optical fibre in telecommunications and sensor design. The advantages of optical metrology with plastic fibre have attracted attention from the scientific community because it allows the development of low-cost or cost competitive systems compared with conventional technologies. Given the relevance of the topic, the current plastic optical fibre technology and the state of the art of plastic optical fibre optic sensors are described. Two types of intensity-based sensors are presented. An extrinsic sensor was designed in order to measure the amount of scattered and absorbed light by particles suspended in a liquid. The characterisation of the sensor was accomplished with respect to the concentration of the suspended particles, size and reflectivity. The sensor was tested in environmental monitoring, particularly, in the analysis of turbidity in sediment samples collected from burned areas and compared to a commercial system. An intrinsic sensor based on side-polished plastic optical fibre was analytically analysed. The theoretical model assesses the sensor performance in different conditions of curvature and refractive index of the surrounding media. The theoretical model has been positively validated by experiments. The sensitivity of the sensor to the temperature was also evaluated and the knowledge acquired was applied to the development of a pressure sensor and a system capable of monitoring the cure of different materials. A technique for improving the sensor sensitivity is also presented by the application of a coating on the sensitive area. The dependence of the transmitted power of a side-polished plastic optical fibre on the curvature was used in the development of a system for monitoring knee and elbow angle. These devices allowed the quantitative assessment of the human motion. The need of portability led to the introduction of a wireless data transmission system. It is expected that the developed prototypes will play an important role in future physical medicine and rehabilitation systems.POPH; FCT; FS

Sensores em POF baseados em intensidade para a avaliação da qualidade de águas

Nowadays there is the need for low-cost and user-friendly solutions for water quality assessment which can allow for remote, in-site and real-time monitoring of water contaminants. POF sensing technologies combined with specially developed sensitive layers for chemical detection may offer these possibilities, with proper interrogation systems. POF sensing platforms based on low-cost procedures were developed and characterized using aqueous solutions of different refractive indices (RI). The POF RI sensors were optimized by varying the length and/or roughness of the sensing region. The suitability of these sensing platforms for chemical detection was evaluated through the coating with sensitive layers, namely molecularly imprinted polymers (MIPs) using different deposition techniques. The dependency of proteins immobilization on the POF’s surface was evaluated aiming future developments in chemical detection using POF biosensors. A D-shaped POF chemical sensor was successfully developed using a sensitive MIP layer, allowing the detection of perfluorooctanoate (POFA/PFO-) in aqueous media with a limit of detection of 0.20 – 0.28 ppb. The collaboration of researchers from different areas was essential for the success of the developed work.Hoje em dia há uma necessidade de soluções simples e de baixo custo para a avaliação da qualidade de águas e que permitam a monitorização remota de contaminantes, no local e em tempo real. As tecnologias baseadas em POF podem oferecer essa possibilidade através de sistemas de interrogação óptica adequados, combinados com camadas sensíveis especialmente desenvolvidas para detecção química. As plataformas ópticas baseadas em POF foram desenvolvidas e caracterizadas com soluções aquosas com diferentes índices de refracção. Os sensores foram optimizados através da variação do comprimento e/ou rugosidade da região sensível. A capacidade de detecção química das plataformas ópticas desenvolvidas foi avaliada através do revestimento com camadas sensíveis, nomeadamente polímeros molecularmente impressos (PMI), utilizando diferentes técnicas de deposição. A dependência da imobilização de proteínas na superfície de POFs modificadas foi avaliada com o objectivo de desenvolver biossensores para detecção química. Um sensor POF para detecção química, em configuração D-shape, foi desenvolvido com sucesso através do revestimento com um PMI, permitindo a detecção de perfluorooctanoato (POFA/PFO-) em soluções aquosas com um limite de detecção entre 0.20 – 0.28 ppb. A colaboração com investigadores de diferentes áreas foi essencial para o sucesso do trabalho desenvolvido.Programa Doutoral em Engenharia Físic