Energy efficiency improvement of Li-ion battery packs via balancing techniques

Due to worldwide energy consumption increase, different energy strategies are growing in order to reduce fossil fuel consumption, increase renewable energy impact and increase energy efficiency. Renewable energy impact in the electric grid is increased by combination with energy storage systems. Energy storage systems storage energy during low consumption periods and insert energy during high power demand time. The efficiency and the stability of the electric grid are improved. The thesis work is focused on the energy improvement of Li-ion based energy storage systems. To improve the energy of series connected Li-ion energy storage system balancing systems are required. The thesis deals with the analysis of unbalancing processes in series connected Li-ion cells and the balancing system design to improve the Li-ion battery pack energetic behavior. The search of a low complexity active balancing system to compete against the passive balancing system is one of the most important research lines.Mundu mailako energia kontsumoa igotzen ari denez, araudi energetiko berriak sortzen ari dira erregai fosilen kontsumoa murritzeko, energia berriztagarriak ezartzeko eta efizientzia energetikoa handitzeko. Energia berriztagarrien ezartzea eta beraien erabilpena sare elektrikoan, asko hobetzen da metatze sistemen laguntzarekin. Metatze sistemek energia batzen dute kontsumo txikiko uneetan energia txertatuz sare elektrikora kontsumo handiko aldiuneetan, sare elektrikoaren efizientzia eta egonkortasuna hobetuz. Tesi lana litio ioizko metatze sistemen energia efizientzia hobetzean datza. Litio ioizko metatze sistemak litio zelden serie konekzioak dira. Seriean konektatuko sistema hauen efizientzia hobetzeko beharrezkoa da sistema orekatzaileak erabiltzea zelden artean sortutako desberdintasunak konpentsatzeko. Tesi hau zelden arteko desoreken analisian eta desoreka hauek konpentsatzeko beharrezkoak diren oreka sistemen diseinuan zentratzen da. Oreka sistema aktibo konpetitiboen diseinua, oreka sistema pasiboekin lehiatzeko da tesiaren lan inguru nagusienetakoa

Forward converter current fed equalizer for lithium based batteries in ultralight electrical vehicles

In this paper, the concept of a forward balancing technique fed by a buck converter for lithium-based batteries in Electrical Vehicle (EV) applications is investigated. The proposed active topology equalizes eight cells in a series in a battery pack, by using a forward converter for each battery pack and the whole battery packs, using a buck converter. The battery bank consists of four battery packs, which are in series. Therefore, the proposed system will equalize 32 cells in series. In this paper, the proposed circuit employs a single transistor used in a Zero Voltage Switch (ZVS) for the forward converter. In practice, this means a capacitor in parallel with the switch at the same time a demagnetizing of the transformer is obtained. The circuit realizes a low Electromagnetic Interference (EMI) and reduces ringing. To overcome the problem of many pins on a coil former, the transformer secondary windings are made by using hairpin winding, on a ring core. It permits, e.g., having eight secondaries and uniform output voltages. Each secondary winding is made by two hairpin turns using two zero-Ohm resistors in series. The proposed topology has less components and circuitry, and it can equalize multiple battery packs by using a single buck converter and several forward converters for each battery pack. Experimental and simulation results are performed to verify the viability of the proposed topology

Advances in Batteries, Battery Modeling, Battery Management System, Battery Thermal Management, SOC, SOH, and Charge/Discharge Characteristics in EV Applications

The second-generation hybrid and Electric Vehicles are currently leading the paradigm shift in the automobile industry, replacing conventional diesel and gasoline-powered vehicles. The Battery Management System is crucial in these electric vehicles and also essential for renewable energy storage systems. This review paper focuses on batteries and addresses concerns, difficulties, and solutions associated with them. It explores key technologies of Battery Management System, including battery modeling, state estimation, and battery charging. A thorough analysis of numerous battery models, including electric, thermal, and electro-thermal models, is provided in the article. Additionally, it surveys battery state estimations for a charge and health. Furthermore, the different battery charging approaches and optimization methods are discussed. The Battery Management System performs a wide range of tasks, including as monitoring voltage and current, estimating charge and discharge, equalizing and protecting the battery, managing temperature conditions, and managing battery data. It also looks at various cell balancing circuit types, current and voltage stressors, control reliability, power loss, efficiency, as well as their advantages and disadvantages. The paper also discusses research gaps in battery management systems.publishedVersio

Desenvolvimento de Métodos Inteligentes de Carregamento e Balanceamento para Sistemas de Armazenamento

Entre a grande diversidade de baterias existentes tecnologicamente maduras, as baterias de Iões de Lítio (Li-ion) tornaram-se populares devido à sua longevidade, alta densidade de energia, alta eficiência e não sofrerem de efeito de memória. Este trabalho tem como objetivo desenvolver novos métodos de carregamento que incluam balanceamento para sistemas de baterias de Iões de Lítio. Este pode ser dividido em duas fases distintas: a primeira fase tem que ver com o desenvolvimento de toda a plataforma, a segunda fase refere-se ao desenvolvimento de novos algoritmos. De forma resumida a primeira fase teve como objetivo desenvolver todo o hardware e software necessários para a criação de uma plataforma versátil e intuitiva onde fosse possível criar algoritmos de carregamento e balanceamento de forma eficiente. O sistema principal do hardware implementado trata-se do Battery Management System (BMS), responsável por toda a monitorização do pack de baterias utilizado. A segunda fase do trabalho focou-se no desenvolvimento de novos algoritmos inteligentes de carregamento que incluam o balanceamento. A opção por esta abordagem refere-se ao facto de ser essencial controlar os desequilíbrios entre células durante o carregamento, resultando numa maior eficiência do sistema de armazenamento. Os resultados obtidos são comparados com os algoritmos tradicionais existentes na literatura.Among the wide diversity of existing technologically mature batteries, lithium-ion (Li-ion) batteries have become popular because of their longevity, high energy density, high efficiency and lack of memory effect. This work aims to develop new charging methods that include balancing for lithium-ion battery systems. This can be divided into two distinct phases: the first phase has to do with the development of the entire platform; the second phase refers to the development of new algorithms. Briefly in the first phase was developed all the hardware and software required to create a versatile and intuitive platform where it was possible to create charging and balancing algorithms. The main hardware implemented system is the Battery Management System (BMS), responsible for all the monitoring of the battery pack used. The second phase of the work focused on developing new intelligent charging algorithms that include balancing. The option for this approach has to do with the fact that it is essential to control the imbalances between cells during charging, resulting in greater efficiency of the storage system. The obtained results are compared with the traditional algorithms present in the literature

Trends in electric vehicles research

Electrification of vehicles has been recognised as a key part of meeting global climate change targets and a key aspect of sustainable transport. Here, an integrative and bird\u27s-eye view of scholarly research on Electric Vehicles (EV) is provided with a focus on an objective and quantitative determination of research trends. The analyses suggest that areas of EV research linked to (i) charging infrastructure, (ii) EV adoption, (iii) thermal management systems and (iv) routing problem have been the distinct trending topics in recent years. While hybrid EV proves to have been a dominant keyword, its frequency of use has either flattened out in recent years or is notably on the decline across major subfields of EV research. The findings provide objective indications about the directions to which EV research is currently headed. A secondary outcome is the determination of references that have been most instrumental in developing each major stream of EV research

Powering the future: a comprehensive review of battery energy storage systems

Global society is significantly speeding up the adoption of renewable energy sources and their integration into the current existing grid in order to counteract growing environmental problems, particularly the increased carbon dioxide emission of the last century. Renewable energy sources have a tremendous potential to reduce carbon dioxide emissions because they practically never produce any carbon dioxide or other pollutants. On the other hand, these energy sources are usually influenced by geographical location, weather, and other factors that are of stochastic nature. The battery energy storage system can be applied to store the energy produced by RESs and then utilized regularly and within limits as necessary to lessen the impact of the intermittent nature of renewable energy sources. The main purpose of the review paper is to present the current state of the art of battery energy storage systems and identify their advantages and disadvantages. At the same time, this helps researchers and engineers in the field to find out the most appropriate configuration for a particular application. This study offers a thorough analysis of the battery energy storage system with regard to battery chemistries, power electronics, and management approaches. This paper also offers a detailed analysis of battery energy storage system applications and investigates the shortcomings of the current best battery energy storage system architectures to pinpoint areas that require further study.This publication is part of the project TED2021-132864A-I00, funded by MCIN/ AEI/10.13039/501100011033 and by the European Union “NextGenerationEU”/PRTR”.Peer ReviewedPostprint (published version

A Ćuk converter cell balancing technique by using coupled inductors for lithium-based batteries

In this paper, a ćuk converter balancing method by using a coupled inductor for lithium based batteries is investigated. The proposed circuit is an active balancing circuit that will equalize eight battery cells in a series. In electrical vehicles (EV), a battery management system (BMS) is a vital task to achieve the best performance of the batteries and longer lifetime. The problem of voltage difference in a battery pack is an important issue to be improved. To overcome the voltage differences in battery string, an equalizing method is mandatory. The conventional ćuk converter requires 2(n-1) switches to balance n cells, while the proposed circuit requires only n switches for n cells in series. In addition, the proposed developed topology uses coupled inductors instead of un-coupled inductors, unlike the traditional ćuk converter balancing method. Since the ćuk balancing transfers the energy among two adjacent cells, it requires a proportionately long equalization time particularly for long string battery packs, but the coupled inductor ćuk converter type overcomes this problem. The switches are N-channel metal-oxide field-effect transistor (MOSFET) to achieve lower drain-source on-resistance, RDS(on), and less voltage drop as compared to the P-channels. The switches are triggered by complementary signals. The coupled inductor is made in such a way to hold the same magnetizing inductance. It can be done by using five wires in one hand. The circuit contains five inductors, one magnetic core, with five winding for eight cells, and one capacitor for two cells. Therefore, the overall circuitry and complexity of the circuit are reduced, resulting in a more cost-effective and easy to implement circuit. The system also does not demand complicated control for battery equalizing. The experimental circuit was implemented and simulation results were obtained to confirm the validity of the proposed system