Innovative Business Models (BMs) are essential in commercialising new technologies that are initially seen as inferior. Battery second use (B2U) brings used batteries from an electric vehicle (EV) into a secondary storage application and holds the potential to improve the sustainability of EVs while generating value for stakeholders across the automotive and energy sectors, as well as for the environment and society (Gohla-Neudecker et al. 2015; Neubauer et al. 2015). However, important knowledge gaps exist as the potential value of second-life batteries and how to better extract that value are still poorly understood by both practitioners and researchers. To fill the knowledge gap, this study explores the BMs of repurposing a second life for the retired EV batteries through rich empirical case studies. The main outcomes of the research are firstly, a deeper understanding of the sustainable value of second-life batteries as is currently being achieved by industry, which also provides a comprehensive view of the potential value of B2U. Secondly, the critical B2U challenges are identified from a multi-stakeholder’s perspective across the value chain that present a fresh overview of the key factors that might impair the potential value of B2U. Thirdly, an empirically-generated typology of existing B2U business models is proposed that shows how B2U stakeholders are interacting in different ways to create and capture value from B2U. Fourthly, three critical BM design elements, namely, lifecycle thinking, system-level design and the shift to services are proposed as helpful aspects for B2U stakeholders to consider to better design their B2U business models. Fifthly, Business Model of a Technology (BMoT) is proposed as a new perspective to understand the value potential of second-life batteries and how to maximise the total value creation from B2U at the system level. The research has filled a literature gap, has met an industrial need, and has made contributions to knowledge on sustainability and BMs in the specific context of B2U. Practically, the findings have the potential to inspire practitioners toward better understanding the potential value of second-life batteries and improve their BMs to better extract value from B2U.

The effects of climate change along with shifts in social demands have opened up commercial possibilities for new and innovative green technology. At the head of this trend is research into new technologies for Hybrid Electric Vehicles (HEVs) and Battery Electric Vehicles (BEVs). These technologies would provide for more environmentally friendly transportation; however their current performance when compared to Internal Combustion Engine (ICE) Vehicles has led to slow adoption rates. One of the key factors that could help to increase the performance of HEVs and BEVs lies in improvement of the battery systems. Through proper thermal management of the batteries the range and performance of these vehicles can be improved, helping to increase the performance of the vehicles. This study looks at improving the thermal management of the battery system by generating more efficient cooling plates. These cooling plates are set between battery cells and contain channels that coolant is pumped through. Through optimization of these cooling channels, the efficiency of the cooling plates with regards to the average temperature and standard deviation of temperature of the battery cell can both be increased. The power required to run the cooling system can also be reduced by reducing the pressure losses associated with the cooling plate. Numerical optimization on three models of cooling plates was performed. The models were based on multi-inlet and outlet curved channel systems, with one model constructed using arcs and the other two using 90 degree angles. Results showed that improvements of up to 80% could be made depending on the objective functions when compared to an initial design through optimization, with straight channels providing 8% more efficient designs in terms of pressure losses over curved designs, and curved designs providing 6% more efficient designs in terms of average temperature. Analysis on the effects of varying the mass flow rate, heat flux and inlet temperature was also conducted to evaluate their effects on the optimized geometries. This study has practical applications in helping to develop new cooling plates for commercial use through implementation of the generated design features and optimization algorithms. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2012-09-27 15:09:12.261

Background: Due to the escalated environmental concerns and the requirement of Paris Agreement, restraining the carbon emission is aimed on a global scale. Being a solution, the electrification of vehicles is inevitable whilst the problematization to the batteries continues. Many strategies, from improving the battery default as a product, to servitizing the batteries in the light of servitization, has been attempted by both battery suppliers and car manufacturers. In connection to sustainability concerns, which refers to the battery End-of-Life (EoL) Management, however, not many scholars believe that circular economy for electric vehicle batteries can shape itself. Deeming the massive adoption of electric vehicle as the foundation of circular economy, some scholars advocate, that servitization can propel the execution of sustainable goal when it changes the ownership of batteries from customers to manufacturers.  Purpose: The proposed relationship of battery servitization and sustainability is standing alone shortly since 2020 without much evidence support. Hence, it is put on the list of examination to identify the motives and interest of manufacturers by offering battery servitization. Moreover, owing to the fact that the literature of battery servitization is seen segmented for only single dimensioned service type, it is also aimed by this thesis to coin the status-of-art of battery servitization from the empirical study, with customers’ perspective included.  Methodology: This thesis is designed based on a mixed method including qualitative interviews and quantitative surveys to answer the research questions that none of the methods could answer alone. Both inductive and deductive approaches were adopted due to the discrepant results from the empirics. Particularly, triangulation design, obtaining different yet complementary data to study the same topic, is followed to structure the discussion.  Findings & Conclusion: Generally, the findings answer the purpose of writing this thesis well. From qualitative study, battery servitization is more of a marketing strategy and not after a goal of building the circularity. However, sustainability is deployed by manufacturers of all levels in the supply chain. Additionally, Battery-as-a-Service (BaaS) as an all-round service solution is enlarging the content to servitize. Further, not being much aware of though, battery servitization is enabling the circularity of batteries owing to the respective battery strategies of each manufacturer. This is to say, sustainability is considered in combination of battery servitization, as the theoretical base of this thesis suggests. From quantitative study, customers’ satisfaction level proves that the manufacturers’ aimed goal is partly achieved. However, to use battery servitization as a marketing strategy for electric vehicle adoption, which indirectly facilitate sustainability, it should be invested more efforts to help more potential customers accept it.

The current stimuli of climate change and rising oil prices have spurred the development of hybrid electric (HEV), and battery electric vehicles (BEV): collectively termed EVs. However, the battery technology needs much development: at the time of writing, the range of a BEV is too low to be practical in many situations. A critical limitation is the sensitivity of batteries to temperature: the heat generated during operation affects their performance and reduces the lifetime. This study investigates battery cooling using cooling plates: thin rectangular fabrications inserted between battery cells. A coolant pumped through internal channels absorbs heat and transports it away from the battery. Previous studies of liquid heat exchangers have indicated that the geometry of the channels plays a significant role in the performance; however, there is a lack of rigorous numerical optimization applied to EV cooling plates. By developing a numerical optimization framework utilizing parametric geometry generation and computational fluid dynamics, this research has investigated the characteristics of optimum cooling plate geometry with respect to three objectives: average temperature, temperature uniformity, and coolant pressure drop. By applying each objective separately, improvements of up to 70% have been made compared to a reference design. The influence of boundary conditions on performance and optimum design has been assessed, and multi-objective optimization has investigated the trade-off between competing objective functions. Although care should be taken when extrapolating the results beyond the geometry and conditions in the study, some general design principles can be proposed. Objectives of average temperature and pressure drop can both be satisfied by a common design with wide cooling channels, but different characteristics are needed for temperature uniformity. Additional assessments have revealed that optimizations of temperature uniformity are especially sensitive to the boundary conditions, whereas the other objective functions are largely insensitive. The optimization process developed in this work can be applied to any potential cooling plate design and will lead to gains in the targeted performance measure. In doing so, the performance of the EV will be incrementally improved, thereby advancing the day when an EV is not only an environmental choice, but also a practical choice. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2011-09-07 16:24:14.6

<p dir="ltr">Vehicle electrification has been proposed as one of the most important technologies for the future of sustainable energy and climate change mitigation. These electric vehicles (EVs) are predominantly powered by lithium-ion batteries (LIBs) which contain critical materials — lithium (Li), cobalt (Co), nickel (Ni), manganese (Mn), and graphite — that are in short supply. Maximizing resource efficiency through material recovery is crucial for a circular economy and the long-term financial, environmental, and social sustainability of the EV industry.</p><p><br></p><p dir="ltr">Heavily influenced by technology, business, and policy, the EV ecosystem must balance the interests of multiple stakeholders. There is a system-of-systems dependency between the circular business model employed; the process, scale, and impact of operations; and the overall economy of the operating environment. However, these linkages are highly dependent on the technological process for material recovery. Given that proof-of-concept research methodologies in the academy are typically low-complexity technologies (low-tech) and at a low technological readiness level (TRL), economies of scale, environmental impacts, and policy implications are not readily deduced.</p><p><br></p><p dir="ltr">Two practical low-tech and low TRL methods for cathode material recovery and cell reattachment for extended battery usage were developed as proofs-of-concept. One theoretical approach for cell removal using heat application was also explored. Given that artisanal mining plays a significant role in the upstream battery material supply chain and is often carried out on a small scale with common tools, safe manual disassembly processes through low-tech, low TRL methods for environmentally friendly battery material recovery could be influential in the downstream management of end-of-life (EOL) EVs.</p><p><br></p><p dir="ltr">Another recommendation is to treat lithium-ion batteries and current recycling methods as transitory technologies, thus encouraging investments in low-tech methods as part of effective business practices today. Vertical integration and supply chain partnerships by companies to recover legacy batteries could be more beneficial in the short term than investing large amounts of capital in new recycling facilities of whose features they are unsure. Higher-complexity and TRL methods can be developed as part of new growth engines for future businesses.</p><p dir="ltr">Finally, the major policy observation is the recognition that state level involvement in setting up appealing environments for private companies is a major contributor to attracting investments for local economic growth, thus necessitating the need for stronger multistakeholder engagement and collaboration in workforce development and environmental safety. Without adequate workforce development and retention programs, companies will struggle to meet and keep the labor requirements necessary to take advantage of tax credits, which could hinder their desire to set up shop in certain states.</p>

The battery charger plays an important role in the development of electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs).This thesis focuses on the DC-DC converter for high voltage battery charger and is divided into four chapters. The background related to EV battery charger is introduced, and the topologies of isolated DC-DC converter possibly applied in battery charge are sketched in Chapter 1. Since the EV battery charger is high voltage high power, the phase-shifted full bridge and LLC converters, which are popularly used in high power applications, are discussed in detail in Chapter 2. They are generally considered as high efficiency, high power density and high reliability, but their prominent features are also limited in certain range of operation. To make full use of the advantages and to avoid the limitation of the phase-shifted full bridge and LLC converters, a novel hybrid resonant and PWM converter combining resonant LLC half-bridge and phase shifted full-bridge topology is proposed and is described in Chapter 3. The converter achieves high efficiency and true soft switching for the entire operation range, which is very important for high voltage EV battery charger application. A 3.4 kW hardware prototype has been designed, implemented and tested to verify that the proposed hybrid converter truly avoids the disadvantages of LLC and phase-shifted full bridge converters while maintaining their advantages. In this proposed hybrid converter, the utilization efficiency of the auxiliary transformer is not that ideal. When the duty cycle is large, LLC converter charges one of the capacitors but the energy stored in the capacitor has no chance to be transferred to the output, resulting in the low utilization efficiency of the auxiliary transformer. To utilize the auxiliary transformer fully while keeping all the prominent features of the previous hybrid converter in Chapter 3, an improved hybrid resonant and PWM converter is proposed in Chapter 4. The idea has been verified with simulations. The last chapter is the conclusion which summaries the key features and findings of the two proposed hybrid converters. / Master of Science

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Quando um conversor opera com uma larga diferenÃa entre os nÃveis de tensÃo de entrada e de saÃda, normalmente à possÃvel identificar uma reduÃÃo significante no seu desempenho. A razÃo disto à o aumento da quantidade de energia processada, que primeiramente precisa ser armazenada em um elemento passivo (indutor), antes de ser entregue à carga. à possÃvel dizer que quÃo maior for a quantidade dessa energia âindiretaâ, menor serà a eficiÃncia do sistema. Tal situaÃÃo à especialmente crÃtica para inversores e retificadores com correÃÃo de fator de potÃncia (PFC), visto que a razÃo cÃclica dos interruptores abrange praticamente todos os possÃveis valores. Em casos em que a diferenÃa entre o valor de pico da tensÃo CA e o valor mÃdio da tensÃo CC à grande, o Ãndice de modulaÃÃo à desviado consideravelmente de 1 e, consequentemente, maiores perdas sÃo esperadas. Para lidar com tal situaÃÃo, à proposto um retificador com caracterÃstica abaixadora e elevadora utilizando uma funÃÃo chamada de bypass. Esta funÃÃo permite que o retificador escolha entre os dois barramentos o que melhor se adapta ao nÃvel de saÃda desejado em funÃÃo do ponto de operaÃÃo da tensÃo senoidal de entrada, maximizando a eficiÃncia. Algumas das vantagens esperadas com a utilizaÃÃo da funÃÃo bypass sÃo: reduÃÃo das perdas totais por meio da operaÃÃo parcial com estÃgio Ãnico; maior nÃmero de nÃveis de tensÃo, reduzindo a corrente de modo comum e o volume do filtro de entrada, alÃm de resultar em menores esforÃos de tensÃo sobre os semicondutores; e, finalmente, reduÃÃo de perdas adicionais e no tamanho do sistema, visto que o conversor Buck de saÃda à projetado para apenas uma fraÃÃo da potÃncia total. Em adiÃÃo, sÃo apresentadas possÃveis configuraÃÃes de conversores de potÃncia para o carregamento de baterias de veÃculos elÃtricos. Topologias de retificadores trifÃsicos com PFC com corrente de entrada senoidal e tensÃo de saÃda controlada sÃo analisadas e propostas, e suas funcionalidades e caracterÃsticas bÃsicas descritas brevemente. FÃrmulas analÃticas para o cÃlculo dos esforÃos de tensÃo e corrente sobre os semicondutores de potÃncia sÃo fornecidas. A fim de avaliar comparativamente o desempenho das topologias selecionadas, fatores adimensionais de referÃncia sÃo definidos com base nos esforÃos elÃtricos sobre os semicondutores e no volume dos indutores. As caracterÃsticas do sistema proposto, incluindo princÃpio de operaÃÃo, estratÃgia de modulaÃÃo, equaÃÃes de dimensionamento e cÃlculos de perdas e eficiÃncia, sÃo descritas em detalhes. Finalmente, a viabilidade do conceito de bypass à demonstrada por meio de resultados experimentais obtidos a partir de um protÃtipo de 22 kW. / When operating with large differences between input and output voltage levels, it is normally possible to identify a significant reduction on the performance of practically all topologies in regard of conversion efficiency. Reason for this is the increasing amount of processed energy that needs to be firstly stored in a passive element (inductor) before reaching the load. It is therefore possible to say that the higher the amount of such âindirectâ energy is; the lower will be the converter efficiency. Such situation is especially critical when considering the operation of inverters or controlled rectifiers with power factor correction (PFC) because the converter sweeps practically all the possible values of duty cycle. In the case the difference between peak AC value and DC value is large; the modulation index will strongly deviate from 1. Consequently, even higher amount of losses are expected. In order to deal with the above referred drawbacks, it is proposed a 5-level three-phase PFC rectifier with an innovative approach, named bypass concept. This function allows the converter to switch between one of the available DC-links that best matches the required output levels depending on the operating point of the sinus wave, thus maximizing the efficiency. Furthermore, the referred bypass function enables direct access to the required lower voltage level by the load, reducing significantly the amount of losses. The 5-level operation allows the voltage steps to be lower than those found in three and two-level topologies, from where lower harmonic contents, reduction of common mode current and EMI are observed. Finally, the output DC-DC converters are designed for only a fraction of the nominal power, having a rather reduced impact on additional losses and also on the converter size. In addition, possible power electronics configurations for charging of EVs are presented. Suitable three-phase PFC rectifier topologies with sinusoidal input currents and controlled output voltage are analyzed and proposed, and their functionality and basic characteristics briefly described. Analytical formulas for calculating the current stresses on the power semiconductors are provided, and in order to evaluate comparatively the performance of selected topologies, dimensionless benchmark factors are derived concerning the semiconductor stresses and the volume of the main inductive components. The characteristics of the proposed system, including the principle of operation, modulation strategy, dimensioning equations and calculated losses and efficiency, are described in detail. Finally, the feasibility of the bypass concept is demonstrated by means of experimental results obtained from a 22 kW hardware prototype.

Background: Electric vehicles have been getting increasing attention due to their possibility to deliver multiple environmental, social, and health benefits. This has started a technological shift from the traditional combustion engine towards electric vehicle batteries. Because the inherited value in reverse- flow batteries is high, aftermarket activities such as remanufacturing, repurposing, and recycling become increasingly important to take part in value-added margins. However, these activities battery manufacturing have not historically been a core business of the automotive industry. In times of technological change, firms need to evaluate how the organization can integrate, build and reconfigure both internal and external competencies to respond to the dynamic environment. The dynamic environment puts pressure on operational and dynamic capabilities for original equipment manufacturers to reorganize to be a competitive force in the evolving industry. Purpose: Make-or-buy decisions have in extant literature been investigated thoroughly. However, in the context of the aftermarket of electric vehicle batteries, underlying motives affecting original equipment manufacturers’ make-or-buy decisions has not. The purpose of this work is to explore how underlying motives are affecting the original equipment manufacturer’s make-or-buy decisions in the reverse-flow value chains of electric vehicle batteries. This thesis helps explain the varying integration alternatives that firms confront when facing external pressure, and limitations within the firms’ own capabilities. Method: A qualitative embedded single case study was conducted in the context of the Swedish vehicle manufacturer Volvo Group. The case was analyzed using an abductive approach. The three aftermarket activities remanufacturing, repurposing and recycling were investigated to find out how underlying motives affect the make-or-buy decisions. This was done by adopting a paradox view looking at external factors, through an institutional lens, and internal factors, using dynamic capability theory. Underlying motives were identified by conducting dialogue-based informal interviews, semi-structured interviews, observations, and using corporate documents which were triangulated to improve the accuracy of the findings. The underlying motives were identified by coding first- and second-order motivations and thereafter connecting these with identified make-or-buy decisions. Results: The six second-order motivations: learning, business potential, compliance, cooperation simplicity, industry competitiveness, and ambiguity were identified to affect make-or-buy decisions. These underlying motives are related to the identified decisions: make, buy, collaborate, and limbo. Besides traditional responses to make-or-buy decisions, limbo was also an identified choice, defined in this thesis as a state of not doing anything while waiting for ambiguity to be reduced. This make-or-buy choice was not anticipated and is considered to be an anomaly from the findings. Conclusions: The identified underlying motives come from both internal and external factors, which shows that the firm must use a system perspective when conducting make-or-buy decisions. Furthermore, the capabilities of the firm are crucial whether the firm has the potential of integrating the operation or collaborating. However, in an environment highly influenced by ambiguity, as the present state of the electromobility industry is, the firm may end up not committing to making, buying nor collaborating at all. Instead, they end up in a state of limbo where they organize to have flexibility in the decision by not committing to any of them. The strength in the firm’s dynamic capabilities to handle the ambiguity is proposed to determine how long the firm is stuck in limbo. Based on this, a new proposed framework for how capabilities influence the make-or-buy decision is introduced. / Bakgrund: Elfordon har fått ökad uppmärksamhet på grund av deras möjlighet att bidra med flertalet miljömässiga, sociala och hälsoassocierade fördelar. Det har lett till ett accelererande teknologiskt skifte från traditionella förbränningsmotorerna till elfordonsbatterier. Eftersom det kvarvarande värdet i batterier på eftermarknaden är hög blir eftermarknadsaktiviteter såsom fabriksrenovering, återanvändning i andra applikationer och återvinning mer och mer viktiga för att ta del av marginaler från värdeskapande i värdekedjan. Dock har dessa eftermarknadsaktiviteter, i kontexten av batterier, inte historiskt sett varit en kärnverksamhet inom fordonsindustrin. Under perioder av teknologisk förändring behöver företag bedöma hur organisationen kan integrera, bygga vidare och ställa om interna och externa kompetenser för att anpassa sig till den dynamiska omgivningen. Det här sätter press på operationella och dynamiska förmågor eftersom slutproduktsleverantörer tvingas omorganisera sin verksamhet för att bli konkurrenskraftiga i den utvecklande industrin. Syfte: Beslut gällande att göra själv, eller att köpa (make-or-buy) har i tidigare forskning utforskats grundligt. Men i kontexten av eftermarknaden av elfordonsbatteriers underliggande motiv som avgör slutproduktsleverantörers make-or-buy beslut är den bristfällig. Syftet med arbetet är att utforska hur dessa motiv påverkar slutproduktsleverantörers make-or-buy-beslut i tillbakaflöden av elfordonsbatterier. Det här arbetet bidrar med en ökad förklaring på hur företag hanterar de åtskilliga integrationsalternativ som finns tillgängliga när de påverkas av externa faktorer, men också är begränsade av egna förmågor. Metod: En kvalitativ inbäddad (embedded) enfallsstudie har utförts i kontexten av den svenska fordonstillverkaren Volvo Group. Fallstudien analyserades genom att använda ett abduktivt tillvägagångssätt. De tre eftermarknadsaktiviteterna fabriksrenovering, återanvändning i andra applikationer och återvinning undersöks för att identifiera hur underliggande motiv påverka make-or-buy besluten. Det här utfördes genom att använda ett paradoxalt synsätt och genom att undersöka både externa faktorer, genom en institutionell lens, och interna faktorer, genom att använda dynamisk kapabilitetsteori. Underliggande motiv blev identifierade genom att använda dialogbaserade informella intervjuer, semistrukturella intervjuer, observationer och företagsdokument där datakällorna triangulerades för att öka träffsäkerheten i resultaten. De underliggande motiven blev identifierade genom att koda första- och andra-ordningens motiv och därefter sattes dessa samman med de identifierade make-or-buy besluten. Resultat: De sex andra-ordningens motiv: inlärning, affärspotential, samtycke, enkelhet i samarbete marknadskonkurrens och osäkerhet blev identifierade faktorer som påverkar make-or-buy beslut. Dessa underliggande motiv kopplades ihop med de identifierade besluten: göra, köpa, samarbeta och limbo. Förutom de traditionella make-or-buy besluten identifierades även limbo som ett alternativ, där limbo i det här arbetet definierades som ett avvaktande tillstånd när man väntar på att osäkerhet ska minska. Det här make-or-buy beslutet var inte förväntat i resultatet och anses i det här arbetet vara en anomali. Slutsats: De identifierade underliggande motiven kom både från interna och externa faktorer vilket visar att ett företag måste använda ett systemperspektiv när de tar make-or-buy beslut. Därutöver är ett företagets förmågor avgörande huruvida de har en potential i att integrera operationen alternativt samarbeta. I en miljö som är starkt influerat av osäkerhet, vilket är faktumet i elektromobilitetsindustrin, kan dock företaget ta ett val att varken köpa, göra eller samarbeta i operationen. Istället kan de välja ett stadie av limbo där de organiserar sig för att ha en flexibilitet i beslutet genom att inte binda upp sig på ett alternativ över huvud taget. Styrkan i ett företags dynamiska förmågor att hantera osäkerhet föreslås i arbetet bestämma hur lång tid företaget är fast i limbo. Baserat på detta föreslås ett nytt ramverk som förklarar hur företagets förmågor influerar make-or-buy beslut.

Recently in more or all electric vehicles, higher voltage batteries are used which employ large number of cells in series. Series connection among cells may lead to single point of failures, safety and charge equalization issues that demand complex control and costly and/or lossy battery management methods. Most present day high voltage batteries use dissipative-charge balancing methods, which result in poor efficiency, additional thermal management burden and lower overall vehicle range. Furthermore, the output voltages of such batteries remain unregulated and may widely change with load and environmental conditions, complicating the overall power pass design of the electrical power system. As a step forward to address these issues, this thesis studies a fault-tolerant regulated active high voltage electric accumulator with integrated power electronics for safe charge and discharge of the high voltage energy storage system. / Thesis / Master of Applied Science (MASc)

La gestion thermique des batteries Li-ion pour le véhicule électrique est essentielle, pour assurer une autonomie et une durée de vie optimales de ces batteries. Habituellement, des circuits d'air ou de liquide de refroidissement sont utilisés comme systèmes de gestion thermique. Cependant, ces systèmes sont coûteux en termes d'investissement et d'exploitation et doivent être dimensionnés sur la puissance maximale à extraire. L'utilisation de matériaux à changement de phase (MCP) pour l’absorption sous forme de chaleur latente de la chaleur à dissiper peut représenter une alternative moins coûteuse et plus facile à utiliser. En effet, les MCP peuvent stocker passivement la chaleur excédentaire produite et être utilisés en tant que systèmes passifs. Cependant, les MCP présentent de nombreux inconvénients comme la difficulté de décharger l’énergie thermique stockée, ce qui limite l’aptitude du système au cyclage, ou encore leur conductivité thermique peu élevée qui limite les capacités d’échange. Pour résoudre le problème de la régénération des MCP, un système actif supplémentaire peut être ajouté, dimensionné sur une puissance modérée; l'ensemble devient alors un système semi-passif. Dans cette étude, un système de gestion thermique composé d'un MCP et d’air en convection forcée est évalué. Ce système permet de coupler les avantages de ces deux techniques. Une modélisation du système est développée pour une cellule de batterie. Une comparaison avec de l’air uniquement, en convection forcée, montre l'utilité du MCP. Pour augmenter la capacité d’échange du MCP, un matériau à haute conductivité thermique peut être ajouté au MCP, ce qui permet d’obtenir un composite ayant une conductivité thermique plus élevée. Des composites basés sur les MCP étudiés et des nanostructures de carbone sont élaborés, leur conductivité thermique est mesurée. Ensuite, un système expérimental simulant la dissipation d’une cellule de batterie est construit et utilisé pour évaluer le MCP seul, le MCP inclus dans une mousse métallique et le meilleur composite obtenu. Enfin, pour se rapprocher des conditions réelles, un modèle représentant un stack entier de batterie est développé, des simulations sont produites et les résultats obtenus sont commentés. / Li-ion battery thermal management is essential for electric vehicles (EVs), to ensure an optimal autonomy and lifespan of those batteries. Usually, air or coolant circuits are employed as thermal management systems. However, those systems are expensive in terms of investment and operating costs and must be dimensioned on the maximal power to be extracted. The use of phase change materials (PCMs) as latent heat storage medium allowing the absorption of the heat to be dissipated as latent heat may represent an alternative cheaper and easier to operate. In fact, PCMs can passively store the excess heat produced by a device and be used as passive systems. However, PCMs have several drawbacks like the difficulty to discharge the stored thermal load which limits the system’s cyclability or their low thermal conductivity which limits their heat transfer capacity. To solve the problem of the PCM regeneration, an additional active system can be added, dimensioned on a moderate power; the whole becomes a semi-passive system. In this study, a thermal management system composed of a PCM and forced air convection is evaluated. This system permits to combine the respective advantages of the two techniques. A model of the system is developed for one battery cell. A comparison with forced air convection only points out the usefulness of the PCM. To overcome the PCM low thermal conductivity, a highly conductive material can be added to the PCM permitting to obtain a composite with a higher thermal conductivity. Composites based on the PCMs studied and carbon nanostructures are elaborated, and their thermal conductivity is measured. Then, an experimental system permitting to simulate the dissipation of a battery cell is build and used to evaluate the PCM alone, the PCM embedded in metal foam and the better obtained composite. Finally, to be closer to the real conditions, a model representing an entire battery stack is developed, simulations are produced and the obtained results are discussed.