| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 1.73 MB | Adobe PDF |
Authors
Abstract(s)
As fontes renováveis são cada vez mais utilizadas na produção de energia elétrica em todo
o mundo. À medida que a população global aumenta e os respetivos preços das
tecnologias de produção diminuem, prevê-se um aumento exponencial da sua utilização.
Face às características intrínsecas dos recursos naturais, as soluções de armazenamento
da energia elétrica são cada vez mais importantes e determinantes no balanço energético.
O recente crescimento exponencial da eletrificação e mobilidade elétrica tem sido um
fator determinante no aumento da produção de sistemas de armazenamento de energia,
principalmente de baterias de lítio. De entre as várias soluções disponíveis, as baterias
de lítio apresentam-se, atualmente, como a tecnologia mais madura para suportar as
soluções de armazenamento atuais.
O presente trabalho tem como objetivo o estudo da impedância das baterias de lítio
através da técnica de Espectroscopia de Impedância Eletroquímica (EIS). Para modelar
a bateria, desenvolveu-se um modelo equivalente elétrico baseado nesta técnica. Os
dados obtidos são analisados através de gráficos de Nyquist. Para reduzir o erro
encontrado entre os resultados estimados e os obtidos experimentalmente, foi
desenvolvido um algoritmo de otimização capaz de extrair os parâmetros elétricos do
modelo. Desta forma, os resultados estimados são equivalentes aos obtidos
experimentalmente. Esta modelação matemática foi feita para diferentes condições de
funcionamento, i.e., diferentes estados de carga da bateria e diferentes valores de
temperatura. Pretendeu-se avaliar o desenvolvimento do estado de saúde da bateria, pelo
que se provocou um envelhecimento cíclico à bateria e procedeu-se a uma análise
posterior. No final são estudados os gráficos de Nyquist, os parâmetros estimados e a
progressão da degradação do estado da bateria é analisada.
Renewable sources are increasingly used in the production of electricity worldwide. As the overall population increases and the respective prices of production technologies decreases, an exponential increase in its use is expected. Given the intrinsic characteristics of natural resources, electric energy storage solutions are becoming more important and determining on the energy balance. The recent exponential growth of electrification and electrical mobility has been a determining factor in developing the production of energy storage systems, especially of lithium batteries. Among the various solutions available, lithium batteries are currently present as the most mature technology to support current storage solutions. The present work aims to study the impedance of lithium batteries by using the technique of Electrochemical Impedance Spectroscopy (EIS). To create a model of the battery, an electrical equivalent model based on this technique was developed. The data obtained from this technique is analyzed through Nyquist charts. To reduce the error found between the estimated results and those obtained experimentally, an optimization algorithm capable of extracting the model parameters from the model was developed. In this way, the estimated results are equivalent to those obtained experimentally. This mathematical modeling was made for different operating conditions, i.e., different state of charge and temperature values. For the evaluation of the state of the health parameter, a cyclical aging process was imposed, which allowed a posterior data analysis. In the end the Nyquist graphics and the estimated parameters are studied, and the progression of the battery state degradation is analyzed.
Renewable sources are increasingly used in the production of electricity worldwide. As the overall population increases and the respective prices of production technologies decreases, an exponential increase in its use is expected. Given the intrinsic characteristics of natural resources, electric energy storage solutions are becoming more important and determining on the energy balance. The recent exponential growth of electrification and electrical mobility has been a determining factor in developing the production of energy storage systems, especially of lithium batteries. Among the various solutions available, lithium batteries are currently present as the most mature technology to support current storage solutions. The present work aims to study the impedance of lithium batteries by using the technique of Electrochemical Impedance Spectroscopy (EIS). To create a model of the battery, an electrical equivalent model based on this technique was developed. The data obtained from this technique is analyzed through Nyquist charts. To reduce the error found between the estimated results and those obtained experimentally, an optimization algorithm capable of extracting the model parameters from the model was developed. In this way, the estimated results are equivalent to those obtained experimentally. This mathematical modeling was made for different operating conditions, i.e., different state of charge and temperature values. For the evaluation of the state of the health parameter, a cyclical aging process was imposed, which allowed a posterior data analysis. In the end the Nyquist graphics and the estimated parameters are studied, and the progression of the battery state degradation is analyzed.
Description
Keywords
Algoritmo de Otimização Baterias Li-Ion Envelhecimento Cíclico Mecanismos de Degradação Modelação Modelo Equivalente Resistência Interna