Self-activation is a process that takes advantage of the gases emitted from the pyrolysis process of biomass to activate the converted carbon. The pyrolytic gases from the biomass contain CO2 and H2O, which can be used as activating agents. As two common methods, both of physical activation using CO2 and chemical activation using ZnCl2 introduce additional gas (CO2) or chemical (ZnCl2), in which the CO2 emission from the activation process or the zinc compound removal by acid from the follow-up process will cause environmental concerns. In comparison with these conventional activation processes, the self-activation process could avoid the cost of activating agents and is more environmentally friendly, since the exhaust gases (CO and H2) can be used as fuel or feedstock for the further synthesis in methanol production. In this research, many types of biomass were successfully converted into activated carbon through the self-activation process. An activation model was developed to describe the changes of specific surface area and pore volume during the activation. The relationships between the activating temperature, dwelling time, yield, specific surface area, and specific pore volume were detailed investigated. The highest specific surface area and pore volume of the biomass-derived activated carbon through the self-activation process were up to 2738 m2 g-1 and 2.209 cm3 g-1, respectively. Moreover, the applications of the activated carbons from the self-activation process have been studied, including lithium-ion battery (LIB) manufacturing, water cleaning, oil absorption, and electromagnetic interference (EMI) shielding.

Bei der Assemblierung von Lithium-Ionen-Batterien ist ein zentraler Arbeitsschritt die Herstellung der elektrischen Verbindung von einzelnen Lithium-Ionen-Zellen in Reihen- und/oder Parallelschaltung. Dazu kommen in der Regel Überlappschweißverbindungen aus Blechen mit Dicken von unter 2 mm zum Einsatz. Typischerweise werden Eisen-, Aluminium- und Kupferwerkstoffe genutzt. Dieser Produktionsschritt ist wegen der Wichtigkeit für die gesamte Batteriefunktion in seiner Qualität zu überwachen. Im Rahmen dieser Arbeit wird ein dafür geeignetes Verfahren identifiziert. Es wurden Ultraschallprüfverfahren, Durchstrahlungsverfahren, die Messung des elektrischen Widerstands sowie thermografische Verfahren auf ihre Eignung zur Prüfung derartiger Überlappschweißverbindungen hin untersucht. Dabei zeigte sich, dass die nach dem Stand der Technik verfügbaren Verfahren im betrachteten Anwendungsfall wegen unzureichender Zugänglichkeit, mangelnder Fähigkeit der Fehlerdetektion oder wirtschaftlicher Gründe häufig nur eingeschränkt einsetzbar sind. Demzufolge war ein neues Verfahren zur Prüfung der Schweißnähte zur elektrischen Verbindung von Zellen zu entwickeln. Als Ansatz wurde die optisch angeregte Thermografie gewählt. Diese konnte erfolgreich eingesetzt werden, wenn ein Laser zur Anregung sowie eine Photonendetektorkamera zur Detektion genutzt wurde. Durch die Anwendung der Lockin-Thermografie konnten Rauscheinflüsse auf die Messung minimiert werden. Es konnte gezeigt werden, dass Lockin-Messungen auch dann ausgewertet können, wenn das gemessene Temperatursignal neben einer harmonischen Schwingung und Rauschen einen stetigen Temperaturtrend aufweist. Die Anwendung von im Rahmen der Arbeit entwickelten Abschirmelementen, die für die Anregungsstrahlung transparent und die von der genutzten Kamera erfassten Strahlung undurchlässig sind, erlaubte die Prüfung metallischer Schweißverbindung in der Nähe von hochabsorptiven Flächen. Unter Nutzung eines neu entwickelten Auswertealgorithmus, der auf die Kompensation des Effekts lateraler Wärmeflüsse im untersuchten Bauteil zielt, konnte die Ergebnisqualität der Thermografie hinsichtlich einer besseren optischen Korrelation der Ergebnisbilder zu Referenzprüfungen sowie einer verringerten Messunsicherheit der angebundenen Fläche verbessert werden. Insgesamt zeigte sich das Verfahren in seiner weiterentwickelten Form als für die Prüfung tauglich.:1 Einleitung 1.1 Motivation und Ziel 1.2 Einführung in die Arbeit 2 Stand der Technik 2.1 Lithium-Ionen-Batterien für Elektrofahrzeuge 2.1.1 Lithium-Ionen-Batterien im Vergleich zu anderen Energiespeichern in der Elektromobilität 2.1.2 Aufbau und Funktion von Lithium-Ionen-Batterien 2.2 Fertigungstechnik der Kontaktierung von Lithium-Ionen-Zellen 2.2.1 Kontaktierung von Lithium-Ionen-Zellen 2.2.2 Schweißverfahren zur Kontaktierung von Lithium-Ionen-Zellen 2.3 Schweißnahtanforderungen und -fehler 2.4 Zerstörungsfreie Prüfung von Kontaktierverbindungen 2.4.1 Qualitätssicherung von Kontaktierverbindungen 2.4.2 Anforderungen an zerstörungsfreie Prüfverfahren 2.4.3 Ultraschallprüfung 2.4.4 Durchstrahlungsprüfung 2.4.5 Messung des elektrischen Widerstands 2.4.6 Oberflächenprüfung 2.4.7 Infrarotthermografie 3 Vorauswahl eines geeigneten Verfahrens der zerstörungsfreien Prüfung 3.1 Untersuchte Verfahren 3.2 Ultraschallverfahren 3.3 Durchstrahlungsverfahren 3.4 Messung des elektrischen Widerstands 3.5 Infrarotthermografie 3.6 Verfahrensauswahl 4 Anwendung der optisch angeregten Thermografie zur Schweißnahtprüfung 4.1 Herausforderungen bei der Messung von Kontaktierschweißverbindungen von Lithium-Ionen-Batterien 4.2 Narzisseffekt und Perspektivenkorrektur 4.3 Techniken der optischen Anregung 4.4 Signalaufbereitung durch Lockin-Verfahren 4.4.1 Lockin-Thermografie 4.4.2 Lockin-Thermografie im Nicht-Gleichgewichtszustand 5 Unterdrückung des Einflusses von Reflexionen bei der thermografischen Prüfung von Kontaktierverbindungen 5.1 Hintergrund 5.2 Lösungsansatz 5.3 Werkstoffauswahl 5.4 Erprobung 6 Kompensation des Einflusses lateraler Wärmeströme 6.1 Mehrdimensionaler Wärmefluss 6.2 Simulation des Einflusses lateraler Wärmeströme 6.2.1 Simulationsmodell 6.2.2 Simulationsresultate 6.3 Entwicklung eines Kompensationsalgorithmus 6.3.1 Ansatz 6.3.2 Ergebnis 6.3.3 Sensitivitätsanalyse 6.3.4 Fazit der simulativen Untersuchung des Kompensationsalgorithmus 6.4 Umsetzung und Verifikation des Kompensationsalgorithmus 6.4.1 Untersuchte Proben 6.4.2 Emissionsgradmessung 6.4.3 Ergebnisqualität 6.4.4 Grenzen des Algorithmus 7 Zusammenfassung 8 Ausblick / The electrical connection of a multitude of lithium-ion cells is of high importance for producing lithium-ion batteries. These connections are usually carried out with lap welds of steel, aluminium and copper sheets with a thickness of less than 2 mm. Due to its importance the electrical connection should be subject to non-destructive evaluation. Therefore, a suitable method was identified to evaluate the electrical connection. Technologies based on ultrasonic, radiographic and thermographic evaluation as well as measurement of electrical resistance have been studied regarding their potential to non-destructively test aforementioned lap welds. It was found that in the studied case state of the art technologies are limited by restraints regarding accessibility, cycle time and detectability of ctitical flaws. Therefore, a new technique for non-destructive testing of lap welds between cell connections, had to be be defined. Optically excited thermography was considered a promising approach. Optically excited thermography was applied successfully using a laser as excitation source and a photon detector camera to record infrared radiation. The application of the lock-in principle allowed significant noise reduction. It was shown that the evaluation of temperature sequences using the lock-in algorithm does not depend on a temperature signal that shows strict harmonic behaviour but could also be applied when the raw temperature sequence incorporated a trend. The application of newly developed radiation shields, which are transparent to the wavelengths of the excitation signal, but opaque to the wavelengths of infrared detection, allowed thermographic testing of metal surfaces in proximity to highly absorbing surfaces. A new algorithm was developed for evaluating thermographic sequences aimed at reducing the impact of lateral thermal flux. It was proven to increase the quality of thermographic results in terms of visual correlation to reference technologies and measurement uncertainty of the joined area. Overall, the improved technology was found to be feasible for non-destructive testing of lap welds in lithium-ion batteries.:1 Einleitung 1.1 Motivation und Ziel 1.2 Einführung in die Arbeit 2 Stand der Technik 2.1 Lithium-Ionen-Batterien für Elektrofahrzeuge 2.1.1 Lithium-Ionen-Batterien im Vergleich zu anderen Energiespeichern in der Elektromobilität 2.1.2 Aufbau und Funktion von Lithium-Ionen-Batterien 2.2 Fertigungstechnik der Kontaktierung von Lithium-Ionen-Zellen 2.2.1 Kontaktierung von Lithium-Ionen-Zellen 2.2.2 Schweißverfahren zur Kontaktierung von Lithium-Ionen-Zellen 2.3 Schweißnahtanforderungen und -fehler 2.4 Zerstörungsfreie Prüfung von Kontaktierverbindungen 2.4.1 Qualitätssicherung von Kontaktierverbindungen 2.4.2 Anforderungen an zerstörungsfreie Prüfverfahren 2.4.3 Ultraschallprüfung 2.4.4 Durchstrahlungsprüfung 2.4.5 Messung des elektrischen Widerstands 2.4.6 Oberflächenprüfung 2.4.7 Infrarotthermografie 3 Vorauswahl eines geeigneten Verfahrens der zerstörungsfreien Prüfung 3.1 Untersuchte Verfahren 3.2 Ultraschallverfahren 3.3 Durchstrahlungsverfahren 3.4 Messung des elektrischen Widerstands 3.5 Infrarotthermografie 3.6 Verfahrensauswahl 4 Anwendung der optisch angeregten Thermografie zur Schweißnahtprüfung 4.1 Herausforderungen bei der Messung von Kontaktierschweißverbindungen von Lithium-Ionen-Batterien 4.2 Narzisseffekt und Perspektivenkorrektur 4.3 Techniken der optischen Anregung 4.4 Signalaufbereitung durch Lockin-Verfahren 4.4.1 Lockin-Thermografie 4.4.2 Lockin-Thermografie im Nicht-Gleichgewichtszustand 5 Unterdrückung des Einflusses von Reflexionen bei der thermografischen Prüfung von Kontaktierverbindungen 5.1 Hintergrund 5.2 Lösungsansatz 5.3 Werkstoffauswahl 5.4 Erprobung 6 Kompensation des Einflusses lateraler Wärmeströme 6.1 Mehrdimensionaler Wärmefluss 6.2 Simulation des Einflusses lateraler Wärmeströme 6.2.1 Simulationsmodell 6.2.2 Simulationsresultate 6.3 Entwicklung eines Kompensationsalgorithmus 6.3.1 Ansatz 6.3.2 Ergebnis 6.3.3 Sensitivitätsanalyse 6.3.4 Fazit der simulativen Untersuchung des Kompensationsalgorithmus 6.4 Umsetzung und Verifikation des Kompensationsalgorithmus 6.4.1 Untersuchte Proben 6.4.2 Emissionsgradmessung 6.4.3 Ergebnisqualität 6.4.4 Grenzen des Algorithmus 7 Zusammenfassung 8 Ausblick

Avec le développement des véhicules électriques, la question de la valorisation des batteries lithium-ion (BLI) se pose pour diverses raisons. Pourtant, une filière de valorisation structurée n’existe pas aujourd’hui. Notre travail académique a pour objet l’étude de cette dernière. La filière de valorisation des BLIs est définie comme un système sociotechnique, complexe en émergence. Notre problématique consiste alors à l’étudier d’un point de vue technico-économique, organisationnel et prospectif et ce en tenant compte des différentes complexités. Cette problématique soulève trois questions de recherche : Comment modéliser la filière de valorisation des BLIs comme un système organisationnel complexe en émergence ? Comment faire de la prospective sur la filière de valorisation des BLIs ? Comment analyser la gouvernance de la filière de valorisation des BLIs ?Pour modéliser la filière de valorisation des BLIs, nous mettons en œuvre d’une manière combinée trois méthodes de modélisation systémiques : SCOS’M (Systemics for Complex Organisational Systems’ Modelling), la cartographie cognitive et la dynamique des systèmes. La modélisation a pour objectif la caractérisation de la filière (parties prenantes, sous-systèmes …), la compréhension de ses dynamiques d’évolution et l’identification des variables clés dans ces dynamiques. Cette modélisation est une base pour la suite.Pour faire de la prospective sur la filière de valorisation des BLIs, nous préconisons l’utilisation des scénarios. Ces derniers sont définis à l’aide de la matrice SRI (Stranford Research Institute), en exploitant les variables clés qui interviennent dans les dynamiques d’évolution de la filière. La prospective est permise en simulant le modèle dynamique des systèmes avec différents scénarios, afin d’analyser les aspects technico-économiques. Pour l’étude de la gouvernance de la filière de valorisation des BLIs, le périmètre a été restreint à l’activité de reconditionnement. Dans ce cas, l’étude de la gouvernance revient à analyser des combinaisons de répartition (application 2nde vie, partie prenante). Une méthodologie d’aide à la décision a été développée pour cette fin. D’une manière générale, cette thèse a identifié les enjeux et questions qui se posent lors de l’étude de la valorisation des batteries lithium-ion des véhicules électriques. A travers notre modélisation, nous avons établi une base d’analyse utile à l’aide à la décision. Nous avons répondu à certaines questions (aspects technico-économiques et organisationnels) et ouvert la voie pour d’autres (aspects logistiques et environnementaux). / With the development of electric vehicles, the recovery of lithium-ion batteries (LIB) arises for various reasons. However, a structured recovery network does not exist today. Our academic work aims to study this latter. The LIBs recovery network is defined as a socio-technical complex emerging system. Our problematic is then to study it from a technical-economic, organizational and prospective perspective, taking into account the different complexities. This problematic raises three research questions: How to model the LIBs recovery network as a complex organizational emerging system? How to foresight on the LIBs recovery network? How to analyze the LIBs recovery network governance?To model the LIBs recovery network, we apply with combination three systemic modeling methods: SCOS'M (Systemics for Complex Organisational Systems' Modelling), cognitive mapping and system dynamics. The modeling aims to characterize the recovery network (stakeholders, subsystems ...), understand its dynamics and identify the key variables in these dynamics. This model is the basis for the following research questions.To Foresight on the LIBs recovery network, we recommend the use of scenarios. These are defined using the SRI matrix (Stranford Research Institute), exploiting the key variables. Foresight is permitted by simulating the system dynamics model with different scenarios to analyze the technical-economic aspects. For the study of the LIBs recovery network governance, the scope was restricted to the repurposing activity. In this case, the study of the governance comes down to analyzing the combinations (2nd life application, stakeholder). A decision aid methodology has been developed for this purpose. In general, this thesis identified the questions that arise when considering the recovery of LIBs. Through our modeling, we have established a useful basis for decision aid. We answered some questions (technical-economic and organizational aspects) and paved the way for others (logistical and environmental aspects).

Indiana University-Purdue University Indianapolis (IUPUI) / With the exponential rise in manufacturing and usage of Li-ion batteries (LIBs) in the last decade, a huge quantity of spent LIBs is getting scrapped every year. Along with the efforts to making more capable and safer batteries over the last three decades, there is an immediate need for recycling these scrapped batteries. Most of these batteries typically use lithium manganese oxide (LMO), lithium cobalt oxide (LCO), lithium iron phosphate (LFP), and lithium nickel manganese cobalt oxide (NMC) cathode chemistries, and developing a technique towards regenerating these cathodes can ensure huge economic and environmental benefits for the present and future. This research focuses on a set of direct regeneration techniques with the goal of regenerating used cathode materials to be reused in LIBs. Used Apple iPad2 batteries with LCO chemistry and Nissan LEAF batteries with a combination of LMO-NMC chemistry are selected for this research. The scope of research can be divided into two parts as liberation/separation of cathode material and regeneration of liberated cathode. The liberation/separation process is carried out with the aid of ultrasonication and organic solvents with the objective being keeping the morphology and chemical composition intact for a better quality of the material. The regeneration process uses a hydrothermal technique with variations of parameters. 1:1 and 1:5 molar ratios between cathode material and a lithium lithiation agent are chosen to understand the effects of the molar ratio on cathode regeneration. In addition, the effects of processing solution (water vs. a solvent) are examined by replacing water with TEG. The effects of heat treatment on cathode regeneration are also investigated by observing phase changes of materials at different temperatures.

This diploma thesis deals with lithium-ion batteries. It is focused on negative electrode on grafit based. The goal of this thesis is to show the problematics of lithium-ion batteries together with possibilities for improvement of their basic parametres as capacity and current elektricity loadability. The first part is focused on the description of functionality of lithiumion battery. The second part is practical and it is focused on production of negative electrodes from natural graphite 280H which has different thickness and compression pressure. The third part describes preparation of negative electrodes from natural graphite 280H and also includes results of measurement. In the last part are different types of negative electrodes from natural graphite 280H compared and evaluated including the determination of conclusions. This comparison and evaluation based on obtained data.

No description available.

E-bikes, often known as electric bicycles, are becoming more and more well-liked as green modes of mobility. High-capacity lithium-ion (Li-ion) batteries are utilised to power these e-bikes because of their extended cycle life, high energy density, and low self-discharge rate. The performance and longevity of these batteries may be impacted by temperature fluctuations, however. To guarantee the safe and dependable functioning of Li-ion batteries used in e-bikes, it is crucial to do temperature analysis on the batteries. In this dissertation, the thermal behaviour of a 48V 60AH Li-ion battery used in an e-bike will be studied under various cooling scenarios. The research specifically contrasts forced convection cooling using fans with broad and limited outlet ports to natural air convection cooling with large and reduced outlet ports. The study sheds light on the ideal cooling setups that might increase battery longevity and performance. The results of this study have important ramifications for e-bike producers and designers, battery producers, and energy storage system researchers. Simulations based on computational fluid dynamics (CFD) are used to simulate the thermal behaviour of the Li-ion battery under various cooling settings for the investigation. 25°C has been selected as the ambient temperature. For forced convection, the airflow rate is set at 3.5 m/s, whereas the airflow rate for natural convection is set at 0.1 m/s. The study's findings demonstrate that both natural and forced convection cooling methods may successfully lower the temperature of a Li-ion battery. However, forced air convection cooling using fans is more efficient than natural air convection at dispersing heat. These findings suggest that, owing to the higher air velocity, shrinking the outlet ports in both cooling approaches improves thermal performance.

The automotive market is currently undergoing a historical change where stricter emission legislations and ever increasing fuel costs have intensified the search for effective alternatives to the conventional internal combustion engine, which has resulted in a substantial trend towards electrification of powertrains. Storage of electrical energy is the fundamental component in this technology where the lithium-ion batteries are currently considered as the most appropriate solution. Lithium-ion batteries, however, as other types of batteries, can only be used efficiently and durably within a specific temperature range.This Master thesis has been carried out in collaboration with Electroengine in Sweden AB, situated in Uppsala, which has an ongoing project regarding development of a modular battery system for electric powertrains. The project is at a stage where an initial prototype has been developed which provides the foundation for this thesis. The study has addressed the battery system performance from a thermal perspective, in order to validate the ability of the system to create a thermally serviceable environment for the lithium-ion battery cells. The work has therefore been focused on verifying whether the existing structure provides sufficient heating and cooling functions. Based on the validation review, the current prototype's performance is presented and suggestions for improvements are submitted.Knowledge in the relevant area has been acquired through an extensive pre study concerning competing temperature management systems, basic thermodynamics, potential pathways for heat transfer and temperature-related characteristics for battery cells. Further, testing was conducted to obtain cell-generated heat power at varying load, state of charge and temperature. Henceforth the test data was used for the creation of simulation models in (COMSOL, 2012) and numerical analysis in (MATLAB, 2011) regarding the battery system's thermal behavior for various operating conditions in order to verify the system's temperature-regulating sustainability and to design the required cooling and heating functions.The conclusion of the study indicates that the existing design possesses acceptable dimensioning of cooling and heating properties. For further development of the battery system's temperature regulatory functions, a number of system improvement measures are necessary. Prioritized improvements are adaptive cooling which is only activated when needed, and cooling through the connecting plates of the battery cells. Implementation of improvement measures will result in an extended lifespan of the battery cells, and higher overall efficiency of the battery system. / Fordonsmarknaden genomgår idag en historisk förändring där striktare utsläppslagstiftningar och ständigt ökande bränslekostander har intensifierat sökandet efter effektiva alternativ till den konventionella förbränningsmotorn, vilket medfört en omfattande trend mot elektrifiering av drivlinor. Lagring av elektrisk energi utgör den fundamentala komponenten inom denna teknologi där litium-jon-batterier idag anses som den mest adekvata lösningen. Litium-jon-batterier är dock, såsom andra typer av batterier, temperatursensibla och kan endast brukas effektivt och durabelt inom ett specifikt temperaturområde.Detta examensarbete har genomförts i samarbete med Electroengine in Sweden AB i Uppsala som har ett pågående projekt där ett modulärt batterisystem för elektriska drivlinor utvecklas. Projektet befinner sig i ett stadie där en initial prototyp framtagits vilken utgör fundamentet för ifrågavarande examensarbete. Genomförd studie har behandlat batterisystemets prestanda ur ett termiskt perspektiv med syfte att validera systemets förmåga att skapa en termiskt tjänlig miljö för ingående litium-jon-battericeller. Arbetet har följaktligen fokuserats på att verifiera huruvida den befintliga konstruktionen tillgodoser satisfierande värmnings- och kylningsfunktioner. Utifrån valideringsgranskningen har den befintliga prototypens prestanda presenterats och förbättringsförslag framlagts.Via en omfattande förstudie berörande konkurrerande temperaturhanteringsystem, grundläggande termodynamik, potentiella vägar för värmetransport och battericellernas temperaturrelaterade egenskaper inhämtades en solid kunskapsbas inom berört område. Vidare genomfördes tester för erhållande av cellgenererad värmeeffekt vid varierande last, laddningsstatus och temperatur. Fortsättningsvis brukades testdata för upprättande av simuleringsmodeller i (COMSOL, 2012) och numerisk analys i (MATLAB, 2011) gällande batterisystemets termiska beteende för olika driftförhållanden för att därigenom verifiera systemets temperaturreglerande bärkraftighet och dimensionera erforderlig kylning och värmning.Slutsaten av genomförd studie är att den befintliga konstruktionen innehar godtagbar dimensionering av kyl- respektive värmningsfunktion för tilltänkt applikation. För vidareutveckling av batterisystemets temperaturreglerande funktion återfinns ett flertal systemförbättrande åtgärder där prioriterade förbättringar utgörs av adaptiv kylning som endast aktiveras vid behov och kylning via battericellernas kontaktbleck. Implementering av förbättringsförslag resulterar i förlängd livslängd för battericellerna samt högre total verkningsgrad för batterisystemet.

Examensarbetet gjordes på Volvo Group Trucks Technology. Målet med arbetet var att studeravärmeutveckling i Li-jon cell för hybrid- och elbilar, HEV och EV. Battericeller undersöktesunder sina normala arbetsförhållanden och vid förstörande prov. Undersökningen baserades påcellernas yttemperatur. Arbetet beskrev cellernas beteende och syftade att vara ett underlag förkonstruktörer av batterisystem.En litteraturstudie gjordes för att studera faktorer som påverkar värmeutvecklingen. Sedananalyserades källor till samtliga faktorer. En moduleringsmetod för analys av cellensvärmeeffektivitet togs fram. Miljöpåverkan och ekonomiska aspekter av batterier undersöktes.Tre tester togs fram för att undersöka värmeutvecklingsfaktorer på fem celler. De flestafaktorerna var externa såsom laddning och urladdning, puls och kontinuerlig ström ochomgivningstemperatur. En infraröd kamera användes vid experimenten.Testerna visade hur olika faktorer påverkade cellernas temperatur. Vidare analys av källor visadekritiska områden i cellernas konstruktion.Förstörande värmeprov gjordes på tre par av celler. Dessa värmdes upp till 300°C vilketorsakade ”thermal runaway”. I vissa fall gick temperaturen över 600°C och celler fattade eld.Olika kemiska sammansättningar och uppbyggnad av cellerna gjorde att de betedde sig olika vidgenomförda tester.Testerna visade att olika celler presterade olika vid liknande testförhållanden. Därför är detviktigt att ta fram specifikationer för användningsförhållanden för att välja ut en cell för ettbatterisystem. Sedan kan prestandan av olika celler jämföras och effektivitet kan utvärderas församma belastningscyklar.Thermal Management System kan förhöja batteriets effektivitet och måste designas medanvändningsförhållanden i åtanke. Batteriernas säkerhet är väldigt viktig och människor får inteskadas av batterier. Därför måste säkerheten finnas i åtanke i alla steg av batteridesign.Arbetets resultat blev en sammanfattning av viktiga faktorer och specifikationer för batteridesignsom baserades på värmeutvecklingen. Samtliga riktlinjer sammanfattades i Appendix 5. / Master thesis work was done at Volvo Group Trucks Technology. Aim of the project was tostudy thermal behaviour of Li-ion battery for hybrid and electric vehicles, HEVs and EVs.Battery cells were tested in regular working conditions and abuse conditions. Surfacetemperature of cells was chosen for studying heat evolution.A literature study was conducted to research factors that influence cell temperature. Analysis ofsources of these factors was then performed. A modelling method for analyzing cell thermalefficiency was designed. Sustainability and economics aspects of batteries were also studied.When factors were established three tests were designed to study their effects. Five cells werestudied. Tests mainly examined external factors such as charge and discharge, pulse andcontinuous current, ambient temperature to name a few. An infrared camera was used.Study showed how different factors influenced cell temperature. Further analysis of sourcespointed out some hot spots of cell designs.Thermal abuse test were performed on three pairs of cells. Cells were heated up to 300°C andwent through thermal runaway which in some cases increased temperatures up to 660°C in lessthan a second and caused fire. Different cell chemistries and cell designs reacted differently tothe abuse conditions.A conclusion was reached that cells performed differently in similar test conditions. Whendesigning a battery system a set of specifications for usage conditions is crucial for choosing acell. When conditions and load cycles are known cells can be tested and their thermal andelectrical efficiency evaluated.Thermal Management System TMS can largely enhance cell efficiency and lifecycle. Suchsystem must also be designed according to usage conditions and particular cell’s performance.Battery safety showed to be a very important factor of designing a battery system. Humans shallnot be injured by systems with batteries which must be kept in mind during design.Work resulted in summary of important factors and specifications for designing a battery systembased on cell thermal behaviour. These guidelines are presented in Appendix 5.

Miljöpåverkan från konventionella förbränningsmotorer har bidragit till en övergång till elmotorer. I denna övergång spelar litiumjonbatterier en viktig roll som energilagringssystem, men på grund av sin reaktiva kemi kan de utgöra en säkerhetsrisk. I likhet med civilsamhället står Försvarsmakten inför ett skifte där förbränningsmotorer ska bytas ut mot el- och hybridmotorer. För en säker militär tillämpning är det därför viktigt att förstå hur litiumjonbatterier beter sig vid åldrande och bortom ramen för normal användning. Detta projekt syftar till att identifiera batteriparametrar (impedans, resistans, kapacitet och yttemperatur) att använda för bedömning av batteriets hälsotillstånd. Vidare syftar projektet till att värdera de identifierade batteriparametrarnas lämplighet för militära applikationer. Som en del av syftet undersöker detta projekt omgivningstemperaturens effekt på batteriparametrarna, samt använder batteriparametrarna för att uppskatta när ett batteri kan klassas som förbrukat. Kommersiella NMC/grafit-litiumjonbatterier åldrades genom full upp- och urladdning. Varje batteri utsattes för maximalt 250 upp- och urladdningscykler vid laddningsströmmar om 4 A och urladdningsströmmar om 10 A. Åldrandet övervakades genom regelbunden mätning av impedans, resistans, kapacitet och yttemperatur. Batterierna cyklades vid antingen 52 ± 3 °C, 21 ± 3 °C eller −15 ± 3 °C för att studera omgivningstemperaturens effekt på de undersökta batteriparametrarna. Impedansmätningar vid 980 Hz var stabilast med avseende på variationer i omgivningstemperatur samt batteriets laddningsnivå, och ansågs därför vara den lämpligaste batteriparametern att använda för uppskattning av batteriets hälsotillstånd när tillämpningen kräver stor flexibilitet. Förändringar i resistans och kapacitet vid givna omgivningstemperaturer ansågs å andra sidan bättre återspegla batteriets åldringsgrad. Därför ansågs resistans och kapacitet vara de lämpligaste batteriparametrarna för uppskattning av batteriets hälsotillstånd med avseende på precision. Mätning av yttemperatur gav otillräcklig information för att uppskatta batteriernas hälsotillstånd med precision. En sänkning av omgivningstemperaturen från 21 °C till −15 °C hade en stor påverkan på resistans och kapacitet; resistansen ökade medan kapaciteten minskade, vilket motsvarar en reducerad batteriprestanda. Med avseende på kapacitetsförlust så förbrukades inget av batterierna som förvarades i 21 °C under cyklingen. Batterier som förvarades i 52 °C och −15 °C var förbrukade efter 150–200 cyklingar. Med avseende på resistansökning var ett av batterierna som förvarades vid 21 °C förbrukat efter 200 cyklingar. Samtliga batterier förvarade vid 52 °C var förbrukade efter 150–200 cyklingar, medan batterier förvarade vid −15 °C var förbrukade efter 200–250 cyklingar. Slutligen, med avseende på impedansmätning vid 980 Hz så tog det 200 cyklingar tills dess att ett av batterierna som förvarades i 21 °C var förbrukat. Ett av batterierna som förvarades i 52 °C var förbrukat efter 150 cyklingar. Batterier förvarade vid −15 °C var förbrukade efter 200–250 cyklingar. / Environmental concerns associated with greenhouse gas emissions from conventional combustion engines have contributed to a transition towards electric mobility. In this transition, lithium-ion (Li-ion) batteries play an important part as an energy storage system. However, Li-ion batteries can pose a safety risk due to their reactive chemistry. The Swedish Armed Forces are approaching a transition towards electric mobility, therefore, understanding Li-ion battery behavior with regard to non-normal use and ageing is critical for safe military applications. This project aimed to identify and evaluate battery parameters (impedance, resistance, capacity and surface temperature) suitable for State of Health (SOH) estimation of Li-ion batteries in military applications. Furthermore, this project aimed to investigate the ambient temperature’s effect on battery parameters, and identify the battery’s end of life (EOL) based on battery parameter tracking. Commercial NMC/graphite Li-ion batteries were exposed to ageing through repeated charge and discharge cycles. A critical application was mimicked, where the batteries operated at 1C charge rate (4 A) and 2.5C discharge rate (10 A) between 100 % and 0 % state of charge, for up to 250 charge/discharge cycles. The ageing process was tracked through regular measurements of impedance, resistance, capacity and surface temperature. In order to investigate the ambient temperature’s effect on the investigated battery parameters, the batteries were aged at either 52 ± 3 °C, 21 ± 3 °C or −15 ± 3 °C. Impedance measured at 980 Hz was the most stable battery parameter with respect to variations in state of charge and temperature, and was therefore regarded as the most suitable parameter for SOH estimation with respect to flexibility. Measurements of resistance and capacity at given temperatures were likely reflecting electrochemical ageing phenomena more accurately, hence the most suitable battery parameters for SOH estimation with respect to accuracy. Tracking of surface temperature provided insufficient information for accurate estimation of the batteries SOH. Decreasing the ambient temperature from 21 °C to −15 °C had a major effect on capacity and resistance; the resistance increased and the capacity decreased, corresponding to a decrease in battery performance. With respect to capacity fade, neither of the batteries aged at 21 °C reached their EOL within 250 cycles, while batteries aged at 52 °C or −15 °C reached their EOL after 150–200 cycles. With respect to resistance, one battery kept at 21 °C reached their EOL after 200 cycles, all batteries kept at 52 °C reached their EOL after 150–200 cycles, and batteries kept at −15 °C reached their EOL between 200–250 cycles. Finally, with respect to impedance measured at 980 Hz, one battery kept at 21 °C reached their EOL after 200 cycles, one battery kept at 52 °C reached their EOL after 150 cycles, and batteries kept at −15 °C reached their EOL between 200–250 cycles.