Review of Graphene Applications in Electric Vehicle Thermal Management Systems

Abstract

As electric vehicles (EVs) continue to develop, effective battery thermal management systems (BTMSs) are critical for ensuring battery safety, performance, and longevity. This review explores the application of graphene-based materials in BTMSs, focusing on graphene coatings, graphene nanofluids, and enhanced phase change materials (PCMs). Graphene’s superior thermal and electrical conductivities offer substantial benefits for improving heat dissipation, reducing temperature fluctuations, and enhancing battery performance. Despite its potential, challenges such as high production costs and complex manufacturing processes hinder large-scale adoption. This paper summarizes recent advancements and compares graphene’s performance with conventional materials. Key findings, including performance metrics from studies, are discussed to demonstrate the advantages of graphene. The review also outlines future research directions, emphasizing the development of hybrid materials, combining graphene with other advanced substances to optimize EV thermal management. The findings aim to guide future innovations in the field.

1. Introduction

As the urgency to mitigate global carbon emissions has intensified, electric vehicles have become a cornerstone of sustainable transportation [1]. Battery thermal management systems have traditionally relied on materials such as aluminum, copper, and conventional carbon-based materials, chosen for their moderate thermal conductivity and stable properties. However, with increasing energy demands and performance expectations, these materials have shown limitations in efficiently managing the heat generated during the rapid charging and discharging cycles of modern EV batteries, which can lead to overheating and compromise battery safety, performance, and lifespan [2,3,4].

BTMSs are designed to maintain optimal temperature ranges within batteries, involving both passive and active cooling strategies. While the solid materials used in the system play an important role, BTMS designs also consider other factors, such as architecture, coolants, and cooling strategies. Thus, materials are just one component of the overall BTMS design. The materials referenced here are likely to refer to the hardware components used in thermal management systems, such as cold plates, pipes, heat exchangers, or materials used for heat acquisition within the battery pack.

Graphene, a two-dimensional allotrope of carbon known for its exceptional thermal and electrical conductivity, presents a transformative potential in this context [5]. Introduced in battery research in the early 2000s, graphene’s ability to facilitate rapid heat dissipation, stabilize temperatures, and improve energy density has positioned it as a promising candidate for addressing the thermal management needs of modern EVs [6]. This shift from traditional materials to graphene-based solutions is primarily driven by the need for materials that can sustain higher charge–discharge cycles without degrading battery performance or safety. Despite its potential, graphene’s application in BTMS faces challenges, such as high production costs, scalability issues, and difficulties in integration into existing systems without significant redesign. Graphene offers several advantages over traditional coolants and metal-based phase change materials (PCMs). For instance, while traditional materials such as aluminum and copper are often used for heat dissipation due to their relatively high thermal conductivity, graphene’s thermal conductivity exceeds that of copper by a factor of more than 10, making it a more efficient material for managing heat in high-performance applications like EVs. Additionally, graphene’s flexibility and lightweight nature provide additional benefits in terms of integration into battery systems without adding significant weight. In comparison, metal-based PCMs offer effective thermal regulation, but they generally have slower response times and lower thermal conductivity than graphene-based solutions.

In addition to the importance of thermal management in EVs, there are significant structural and safety considerations, which are critical to understanding the challenges faced by BTMSs. Recent studies, such as the one by Abhishek Agarwal, Rafael Cavicchioli Batista, and Tashi have highlighted the importance of optimizing battery pack designs to improve both thermal management and structural integrity in EVs [7]. This highlights the need for innovative solutions like graphene-based materials that not only address thermal challenges but also contribute to overall battery pack safety and performance.

This review aims to fill the gap in the current literature by offering a comprehensive analysis of the applications, advantages, and limitations of graphene in BTMS for EVs. Unlike previous reviews, this paper focuses specifically on the recent advancements in graphene-based solutions for thermal management, with an emphasis on hybrid composites that combine graphene with other advanced materials to further enhance thermal conductivity and battery safety. The review also critically evaluates the challenges of manufacturing and scalability and examines the potential for cost-effective graphene synthesis methods that would make these advanced solutions more feasible for large-scale implementation.

The primary objective of this review is to provide a structured background on the role of graphene in improving thermal management in EVs, to compare it with other traditional and emerging materials, and to outline the current research trends. The review aims to answer key questions regarding graphene’s potential advantages and drawbacks in BTMS applications, offering targeted recommendations for future research and development in this rapidly evolving field.

The paper is organized as follows. Section 2 reviews the various cooling methods currently employed in BTMSs, including air cooling, liquid cooling, and phase change material (PCM) cooling. Section 3 discusses the unique properties of graphene, with a focus on its electrical and thermal conductivities, mechanical strength, and surface area, which contribute to its potential for enhancing thermal management in EVs. Section 4 compares graphene-based technologies with traditional battery systems, emphasizing the significant improvements graphene can bring to energy storage and thermal dissipation. Section 5 addresses the current challenges in graphene-based thermal management systems, as well as the prospects for future developments. Finally, Section 6 presents the conclusions and outlines the potential for graphene to revolutionize EV thermal management systems in the coming years.

2. Cooling

2.1. Air Cooling

Air cooling remains a widely employed method for battery thermal management owing to its simplicity and cost-effectiveness. In recent studies on EV battery safety, a holistic approach to thermal management has been emphasized, where both thermal efficiency and structural integrity are key to ensuring the safety and longevity of batteries. This is particularly important when considering the impact of accidents on battery performance and safety. For example, Agarwal et al. evaluated the crashworthiness of electric vehicle battery packs using honeycomb structures, demonstrating the potential of these structures to enhance the crash resistance of battery packs. This highlights the importance of integrating both thermal management and structural protection in the design of EV battery systems [8]. These systems involve the circulation of air around or through a battery pack to dissipate heat. In passive air cooling systems, natural convection is used to move air across the battery pack. This technique does not rely on an external energy source, such as fans or blowers, to circulate the air. However, the effectiveness of passive air cooling is limited, especially during high-power consumption periods or rapid charging cycles, where higher airflow is required. (This type of air cooling still relies on vehicle movement to generate airflow, similar to ram air cooling in aircraft, which consumes energy and causes drag).

In active air cooling systems, heat dissipation is enhanced by utilizing fans or blowers to increase airflow [9]. This method is more effective than passive air cooling but introduces additional complexity, higher costs, and increased energy consumption.

Figure 1 shows a typical air-cooled BTMS. Figure 1a depicts a typical Li-ion battery air-cooled BTMS without a fan, where external air enters the air inlet on one side of the battery pack through the relative motion of the EV, moves through the gap between batteries, and exits through the air outlet on the other side. The generated heat is transported away based on natural convection. However, natural convection cooling alone cannot satisfy the requirements of a high-temperature working environment and high charge–discharge cycles. To address these constraints, a forced convection technique was established. Note that passive cooling in electric vehicles (EVs) involves both natural air convection and radiation. Natural air convection requires sufficient space for airflow, while radiation is more effective under cooler ambient conditions. However, in EVs, batteries are typically enclosed (e.g., in the front or back compartments or as part of the chassis). This enclosure often limits natural air convection, making radiation the primary passive cooling mechanism. Therefore, passive cooling in EVs primarily refers to radiation, though some designs may still incorporate natural convection in cases where space permits airflow, such as in open battery configurations. As shown in Figure 1b, the basic active air-cooled BTMS with a fan consists of a battery pack, a cooling channel, an inlet and outlet, and a cooling fan. A fan or blower at the inlet or outlet generates sufficient air flow to carry excess heat or uniformly distribute the temperature. Active air cooling has some disadvantages, such as high cost, increased energy consumption, and high noise. However, active air cooling remains the mainstream solution because it can effectively dissipate heat and is more reliable.

Despite being an economical solution, air cooling struggles to maintain battery temperatures within optimal ranges for high-performance applications, particularly during fast charging or extended operations under heavy loads. The cooling capabilities of air systems are often insufficient to meet the energy-density requirements of modern EVs, leading to the need for more advanced cooling methods.

2.2. Liquid Cooling

Liquid cooling systems are often used in high-performance EVs because of their superior heat transfer capabilities [10]. In a liquid cooling system, a coolant—typically a mixture of water and glycol—circulates through channels in close contact with the battery cells. This circulation absorbs and removes heat more efficiently than air cooling systems, offering greater control over battery temperature and ensuring more uniform cooling across the entire battery pack. Figure 2 shows a typical phase change liquid cooling system, which is mainly used for battery thermal management to regulate the battery temperature through the process of coolant evaporation and condensation.

A typical liquid cooling system includes the following components: a coolant tank, coolant pump, pipes, heat sources, and a heat exchanger. The liquid coolant is circulated through the system by the pump to transfer the absorbed heat to a heat exchanger, where it is dissipated. For a liquid cooling system, the coolant is usually a non-toxic, chemically stable, and flame-retardant liquid, such as silicone oil or mineral oil, to prevent any short circuits or electrochemical reactions with the battery cells. The battery pack is immersed in the coolant to cool its entire surface, ensuring a uniform temperature and minimizing localized thermal effects.

The higher heat capacity of liquids allows them to absorb larger amounts of heat before experiencing significant temperature increases. This makes liquid cooling systems highly effective for managing the thermal requirements of large battery packs, particularly during high-power fast-charging applications. However, liquid cooling systems tend to be more complex and expensive compared to air cooling systems, and they should be carefully designed to prevent leaks and avoid reactions between the coolant and battery materials. Despite these challenges, liquid cooling remains the preferred option for many modern EVs due to its ability to maintain consistent battery temperatures.

2.3. Phase Change Material (PCM) Cooling

Phase change materials (PCMs) offer an innovative approach to battery cooling by absorbing and releasing heat as they undergo physical phase transitions, such as from solid to liquid [11]. During charging and discharging cycles, the PCM absorbs heat, causing a phase change and storing excess thermal energy. This process stabilizes the battery temperature, preventing overheating and maintaining optimal operating conditions.

The primary advantage of PCM-based cooling systems lies in their energy efficiency. They regulate temperature without requiring external power, making them a passive cooling mechanism. However, standalone PCM systems typically lack the cooling capacity needed for high-performance applications, especially during rapid charging or under continuous heavy loads. As a result, hybrid systems that combine PCMs with air or liquid cooling methods are being developed to enhance the thermal management performance of EV batteries.

3. Properties of Graphene

Graphene’s unique properties make it exceptionally attractive for battery applications, particularly for energy storage and management. As a two-dimensional material composed of a single layer of carbon atoms arranged in a hexagonal lattice, graphene exhibits extraordinary characteristics that distinguish it from conventional materials. Its exceptional electrical conductivity allows for rapid electron movement, thereby facilitating efficient energy transfer and faster charging times, which are critical factors for enhancing the performance of lithium-ion batteries and other energy storage systems [12,13,14]. In addition, the remarkable thermal conductivity of graphene ensures effective heat dissipation, a crucial feature for maintaining optimal operating temperatures and preventing overheating during high-power operations. As battery systems, especially in electric vehicles (EVs), deal with significant heat generation during rapid charging and discharging, graphene’s thermal properties are vital for managing and dissipating that heat efficiently. Enhanced thermal conductivity helps reduce the thermal resistance within the battery pack, improving the overall thermal management system (BTMS) and ensuring longer battery life and safer operation.

Moreover, graphene possesses outstanding mechanical strength—over 100 times stronger than steel—which not only enhances the durability of battery components but also contributes to the overall longevity of battery systems. Its large surface area further enhances its capabilities, providing ample space for ion storage, which improves energy density [15,16]. These combined properties make graphene a transformative material that can significantly improve the efficiency, safety, and longevity of batteries.

Figure 3 provides a visual representation of the synthesis routes for graphene, highlighting both the top-down and bottom-up methods. These synthesis methods are critical for optimizing the structural integrity and properties of graphene, such as its electrical and thermal conductivities, to meet the specific needs of battery applications. Top-down approaches, such as micromechanical cleavage and liquid-phase exfoliation, allow for the scalable production of graphene with high electrical conductivity and thermal properties, which are essential for efficient energy storage systems and thermal management in batteries. Bottom-up techniques, including chemical vapor deposition (CVD) and epitaxial growth on silicon carbide, offer controlled synthesis that optimizes the structural integrity and surface area of graphene, which is critical for enhancing the mechanical strength, energy density, and overall thermal management of batteries.

Understanding these synthesis methods is fundamental for advancing the application of graphene in battery technology and ensuring the production of high-quality graphene tailored to specific performance and thermal management requirements.

3.1. High Electrical Conductivity

Graphene is well known for its exceptional electrical conductivity, allowing electrons to move at velocities approaching the speed of light. Recently, the integration of TiO₂ into reduced graphene oxide (rGO) films has shown remarkable potential for enhancing the performance of lithium-ion batteries. For instance, such integration has been reported to significantly increase the specific capacity of lithium-ion battery anodes to approximately 400 mAh/g at a current density of 200 mAh/g after 550 cycles, whereas that of conventional TiO₂ carbon black anodes is less than 50 mAh/g [17]. This improvement suggests that rGO-TiO₂ films could serve as superior candidates for battery anodes, thereby contributing to the overall efficiency and performance of EV thermal management systems.

Recently, a three-dimensional (3D) porous graphene scaffold (2LrGO@LIG) was developed, and it achieved photothermal and electrothermal conversion efficiencies of 94.1% and 99.1%, respectively, along with high energy storage density. This composite demonstrates significant potential for application in smart building materials and wearable electronics, highlighting its versatility and efficiency in energy conversion systems [18]. The technology of 3D porous graphene scaffolds, mainly applied in smart building materials and wearable electronics, also has significant potential in electric vehicles (EVs) for thermal management and battery systems. First, their exceptional thermal conductivity makes them effective materials for battery thermal management, facilitating heat dissipation during charging and discharging, which enhances battery safety and longevity. Second, the lightweight, high-strength properties of graphene enable the creation of lightweight battery enclosures, reducing the overall weight of EVs and improving energy efficiency. Additionally, their excellent conductivity allows for effective electromagnetic shielding, mitigating interference in battery systems. Furthermore, 3D porous graphene scaffolds can serve as electrode materials in supercapacitors or lithium-ion batteries, enhancing energy storage density and enabling faster charging. Finally, integrating these scaffolds with phase change materials can produce composites with improved thermal management for EV battery packs and systems. Overall, their application in EVs highlights considerable potential across various areas, including thermal management, lightweight design, electromagnetic shielding, and energy storage. Graphene nanoribbons were introduced as a novel conductive additive in vanadium oxide and manganese oxide cathodes for zinc-ion batteries, and they significantly enhanced charge transfer and Zn²⁺; diffusion rates. The ZnxV₂O₅-GNRs electrode achieved a specific capacity of 487.0 mAh g⁻¹ at 0.1 A g⁻¹ and a capacity retention rate of 104.6% after 5000 cycles at 5 A g⁻¹, demonstrating the excellent performance of GNRs compared to traditional carbon black [19].

3.2. Thermal Conductivity

Graphene’s thermal conductivity reaches values up to 5000 W/mK, significantly exceeding that of copper, which has a value of approximately 400 W/mK [20]. A hybrid graphene aerogel (HGA) was developed to enhance the thermal conductivity and latent heat of composite PCMs, achieving over 95 wt% paraffin wax loading and reducing supercooling by 9.37%. In battery thermal management applications, the PW/HGA composite effectively minimized peak temperatures and improved temperature uniformity, highlighting its significant potential in battery systems [21].

Gao et al. developed a hierarchically structured graphene paper with a thermal conductivity (κ⊥) of 12.6 W m⁻¹ K⁻¹ after graphitization, and it demonstrated a cooling efficiency 2.2 times higher than that of commercial thermal pads. This lightweight and high-performance thermal interface material shows promise for use in electronic devices, as well as in aviation and aerospace applications [22]. In addition, Bai et al. developed a graphene/multi-walled carbon nanotube aerogel composite PCM with ionic liquid, which achieved a thermal conductivity of 0.751 W/(m·K), representing a 232% improvement over pure ionic liquid. The three-dimensional network structure facilitates efficient phonon transfer and enhances cyclic stability and heat transfer efficiency [23].

3.3. Mechanical Strength and Surface Area

Graphene exhibits remarkable mechanical strength with a tensile strength of approximately 130 GPa and a large surface area of up to 2630 m²/g, which enhances its energy storage capabilities. In a recent study, Chen developed graphene-based composites by integrating graphene with nanostructures such as TiO₂ nanodots and 2D MXene, and the approach improved the electrochemical performance of supercapacitors and metal-ion batteries by preventing the restacking of the graphene layers, thereby boosting their energy storage capabilities [24]. Similarly, Baachaoui et al. modified polyimide-based laser-induced graphene electrodes by incorporating carbon black and Prussian blue and realized a significant increase in the capacitance and energy density of microsupercapacitors, which remarkably retained over 95.8% of their initial performance even after 6000 cycles [25]. Additionally, Barakat utilized atomistic simulations and continuum mechanics to study the mechanical properties of graphene-based cis-1,4-polybutadiene nanocomposites, and her findings demonstrated that incorporating graphene not only strengthened the material but also improved its overall mechanical behavior [26].

3.4. Comparison Between Graphene-Based Batteries and Traditional Batteries

In recent years, graphene-based battery technologies have been developed to overcome the limitations of traditional lithium-ion batteries. The remarkable thermal and electrical properties of graphene render it an attractive option for improving energy storage and battery management systems. Graphene batteries present significant advantages, particularly in thermal conductivity, where they achieve values up to 5000 W/mK, greatly enhancing heat dissipation. In contrast, traditional lithium-ion batteries typically have thermal conductivities between 200 and 400 W/mK, which can lead to overheating under high-power conditions.

Graphene batteries also present high energy density and can reach 500 Wh/kg, thereby extending the driving range of EVs. Traditional lithium-ion batteries, by comparison, have an energy density of approximately 250 to 300 Wh/kg, which limits the overall range and performance. Additionally, graphene’s high electrical conductivity allows for charging speeds up to five times faster compared to conventional lithium-ion batteries, making them ideal for fast-charging applications where reduced charging times are essential.

In terms of durability, graphene-based batteries have a significantly longer lifespan, with the potential to endure up to 2000 charge–discharge cycles with minimal degradation. In comparison, traditional lithium-ion batteries typically degrade after 1000 to 1500 cycles, resulting in a gradual loss of capacity and performance. However, the high production costs and complex manufacturing processes of graphene-based batteries pose challenges for their large-scale commercialization. Despite these obstacles, traditional lithium-ion batteries benefit from established production techniques, which make them more affordable and widely available.

Environmental impacts also differ between the two types of batteries. Graphene-based batteries can potentially be produced using carbon-based materials, offering a more sustainable alternative to traditional lithium-ion batteries, which rely on finite resources such as cobalt. The extraction and processing of finite resources, such as cobalt, raise significant environmental and ethical concerns. These concerns are especially relevant in the context of electric vehicle (EV) battery production, where the demand for materials like cobalt has surged. Addressing these challenges is essential to ensuring the sustainability of EV technology. Further research is needed to explore alternatives to cobalt and improve the sustainability of battery production. As shown in

Table 1. Graphene battery performance comparison with conventional lithium-ion battery.

Feature	Graphene-Based Batteries	Traditional Lithium-Ion Batteries	Research	Reference
Thermal Conductivity	Up to 5000 W/mK, superior heat dissipation	200–400 W/mK, less effective at managing heat	Wang et al. Lad et al.	[27,28]
Energy Density	Up to 500 Wh/kg, enabling longer driving ranges	250–300 Wh/kg, providing moderate energy storage capacity	Zhou et al. Silva et al.	[29,30]
Charging Speed	Up to 5 times faster charging speeds, due to higher electron mobility	Slower charging speeds, due to higher internal resistance	Wang et al. Inamoto et al.	[31,32]
Lifespan	Lasts up to 2000 cycles with minimal degradation	Typically, 1000–1500 cycles before noticeable degradation	Ramírez et al. Kurc et al.	[33,34]
Production Cost	Higher costs due to complex and expensive manufacturing processes	Lower costs due to mature production methods	Gao et al.	[35]
Environmental Impact	Potential for sustainable production using carbon-based materials	Use of finite resources (e.g., cobalt), raising concerns	Ikram et al.	[36]

, graphene-based batteries exhibit significant differences from conventional lithium-ion batteries in several key features, including thermal conductivity, energy density, charging speed, lifespan, production cost, and environmental impact.

Graphene-based batteries demonstrate significant improvements in thermal management, energy density, charging speed, and longevity compared to traditional lithium-ion batteries. However, challenges such as higher production costs and complex manufacturing processes hinder their large-scale adoption. Despite this, graphene batteries present a promising sustainable alternative for future energy storage and thermal management applications.

This structured approach should enhance the readability and coherence of the content while maintaining the technical depth and focus on key areas.

4. Types of Graphene Batteries

Several types of graphene-based batteries are under development, each leveraging graphene’s extraordinary properties to address the limitations of conventional batteries.

4.1. Graphene Lithium-Ion Batteries

Graphene lithium-ion batteries (GLIBs) incorporate graphene in various forms, such as additives in the anode or cathode, or as a replacement for traditional materials. For instance, researchers at Samsung SDI have developed graphene batteries that charge five times faster than standard lithium-ion batteries, thus providing a longer cycle life and increased efficiency [37]. Graphene oxide (GO) enhances the mechanical strength and thermal stability of solid-state electrolytes by providing nano-reinforcement, improving interfacial adhesion with matrices, increasing thermal conductivity, reducing brittleness, creating moisture barriers, and maintaining ionic conductivity. This results in more robust and effective electrolytes for advanced energy storage applications. Notably, researchers at MIT have explored graphene-enhanced battery technologies, focusing on stability and performance in various environmental conditions, particularly for electric vehicles (EVs). These studies underscore the effectiveness of GO in making solid-state electrolytes suitable for diverse climates and long-term applications [38]. In addition, LG Chem has developed advanced battery materials that incorporate graphene to enhance efficiency and safety. Their innovations, such as temperature-responsive materials, aim to prevent thermal runaway and improve overall battery performance. These developments indicate LG Chem’s commitment to advancing the energy storage technologies for EVs [39].

4.2. Graphene Supercapacitors

Graphene supercapacitors capitalize on the large surface area and high electrical conductivity of graphene to store and release energy efficiently. For example, Shoeb et al. created a graphene-supported nanocomposite (RGO-Au-Ag₂O/PIn), initially aimed at antimony removal from wastewater. Later, this material was adapted for energy storage in supercapacitors, exhibiting a capacitance retention rate of 82% after 12,000 cycles [40]. Dywili et al. worked on synthesizing and comparing GO and reduced GO (rGO) as supercapacitor electrodes. Despite the anticipated pseudocapacitive advantages of GO, rGO demonstrated superior performance, which is attributed to its enhanced conductivity [41]. Ruman et al. utilized a green synthesis method to produce SnO₂/CuO/FeO/PVP/RGO nanocomposites, which exhibited a high specific capacity of 249 C/g and maintained 94% of their capacity after 15,000 cycles in hybrid supercapacitor devices [42].

4.3. Graphene Polymer Batteries

Graphene polymer batteries combine the lightweight and flexible characteristics of polymer materials with the high conductivity and thermal stability of graphene. Researchers at Peking University summarized the advances in graphene-based materials for energy storage and conversion, focusing on their applications in lithium batteries, supercapacitors, and fuel cells. They highlighted the high carrier mobility, fast recombination rates, and long-term stability of the materials and emphasized the need for innovative designs to overcome practical challenges [43]. Zafar et al. reviewed advancements in graphene-based polymer composites for energy applications and highlighted their use in enhancing the performance of supercapacitors, lithium-ion batteries, and fuel cells. They detailed various fabrication techniques, such as solution mixing and electrospinning, showcased the tailored properties achieved, and emphasized the role of the composites in improving energy storage and conversion efficiency [44]. Additionally, Toyota reported advances in graphene-polymer batteries that demonstrated superior cycling stability with a significant reduction in degradation over extended use, highlighting the potential of these batteries in future electric and hybrid vehicles [45]. Graphene is being increasingly integrated with other materials such as metal oxides and polymer composites to improve thermal conductivity and mechanical stability in EV battery systems. For example, graphene combined with metal oxides can significantly enhance the thermal conductivity of the composite, while maintaining lightweight and flexible properties. In polymer composites, graphene has been shown to improve mechanical strength and durability, while also contributing to enhanced thermal management. These hybrid materials offer a balanced solution that combines the benefits of graphene with other materials, enabling cost-effective production and improved performance in BTMSs.

4.4. Applications of Graphene in EV Battery Thermal Management

Graphene’s exceptional thermal and electrical properties position it as a transformative material in the thermal management of EV batteries, which is crucial for ensuring safety, performance, and longevity. The incorporation of graphene into various thermal management solutions can significantly enhance heat dissipation and temperature regulation in battery systems.

One prominent application is in thermal interface materials (TIMs). For instance, Panasonic developed graphene-enhanced TIMs that significantly improved heat dissipation in battery packs. These materials not only reduce thermal resistance but also minimize temperature fluctuations during operation, which can enhance battery safety and efficiency. By lowering the operating temperature, TIMs help mitigate the risk of thermal runaway, which is a critical concern in lithium-ion batteries [46]. Recent studies highlight the importance of optimizing electrolyte formulations for fast-charging scenarios, where graphene-enhanced TIMs could synergize with low-viscosity co-solvents and highly concentrated electrolytes to maintain thermal stability under high current densities [47].

Another application is in battery cooling systems. Ford integrated graphene coatings into battery cooling systems and demonstrated that such enhancements could lead to a reduction in operating temperatures by up to 20% [48]. This improvement is particularly beneficial during rapid charging or high-power output scenarios where heat generation is significant. By maintaining optimal temperature ranges, Ford’s graphene-enhanced systems can prolong battery life and improve overall vehicle performance. Recent advancements in electrolyte design, such as fluorinated solvents (e.g., FEC and DFEC), have shown enhanced thermal stability up to 393 °C [49]. When combined with graphene’s high thermal conductivity, these systems could further suppress thermal shrinkage and improve heat dissipation in extreme conditions [50].

Graphene nanofluids represent another innovative application. Arifutzzaman et al. developed a hybrid nanofluid (MXene/Si-oil) using MXene (Ti₃C₂Tx) and functionalized graphene nanoflakes, and it achieved a 68% enhancement in thermal conductivity at 0.02 wt% concentration. The nanofluid maintained thermal stability up to 393 °C and exhibited a 31% decrease in viscosity with increasing temperature, making it promising for cooling systems in electronic devices [51]. Similarly, Zhao et al. demonstrated that additives like LiDFOB and LiPO₂F₂ in electrolytes could stabilize cathode–electrolyte interfaces (CEI), reducing impedance during cycling [52]. Integrating graphene nanofluids with such additives may enhance both thermal and electrochemical performance in EV batteries.

The incorporation of nano-graphene platelets (NGPs) into phase change materials (PCMs) enhances their thermal properties and reduces supercooling by improving thermal conductivity, which facilitates efficient heat transfer, and by providing nucleation sites that promote crystallization during solidification. This reduces the supercooling effect, allowing the PCM to solidify closer to its melting point. Additionally, NGPs decrease thermal resistance and improve the structural stability of the PCM, ensuring consistent performance over multiple cycles. Ultimately, these enhancements enable the modified eutectic PCM mixture to achieve supercooling levels below 0.1 °C, significantly improving its efficacy in thermal management applications. The PCM demonstrated reliable thermal performance and a projected lifetime of 80 years, making it a promising material for thermal energy storage applications [53]. The ability of PCMs to absorb excess heat during charging cycles helps to maintain optimal battery temperatures, which is essential for performance and safety.

Furthermore, Yun et al. developed a multifunctional sandwich-structured TIM with a trilayer film consisting of BNNS/CNF and GNP/CNF layers, achieving an in-plane thermal conductivity of 25.5 W/m·K and an EMI shielding effectiveness of 29.0 dB. The TIM also demonstrated excellent electrical insulation, mechanical compatibility, and flame retardancy, making it suitable for advanced electronic devices and mobility platforms [54]. The mechanical strength and thermal conductivity of graphene allow for lighter and more efficient battery designs. These graphene-infused enclosures helped to dissipate heat more effectively, thereby contributing to the overall thermal stability of the battery system.

Finally, collaborations with automotive manufacturers are exploring the use of graphene in smart thermal management systems. For example, companies such as Schaeffler (Schweinfurt, Germany) and Valeo (Paris, France) integrated graphene materials to enhance the efficiency and adaptability of thermal management in EVs. Schaeffler developed modular thermal management systems that use advanced materials, including graphene, to optimize the cooling and heating processes of batteries, ensuring that the vehicle operates within an optimal temperature range to maximize the battery life and charging efficiency [55]. By utilizing the properties of graphene, these smart systems aim to optimize the cooling efficiency in real time, ensuring that batteries remain within safe temperature limits under various driving conditions.

Recent research emphasizes the role of solid-state electrolytes (SSEs) in improving battery safety and thermal stability. Graphene’s mechanical strength and thermal conductivity could address SSE challenges, such as brittleness and interfacial resistance, by reinforcing composite structures [56]. Additionally, fluorinated electrolytes with graphene additives may extend operational temperature ranges (−125 to +70 °C) while maintaining non-flammability [57]. Machine learning-driven material design, as proposed by Fu et al., could further optimize graphene hybrid composites for next-generation thermal management [58].

In summary, the applications of graphene in the thermal management of EV batteries are diverse and impactful. Graphene plays a crucial role in addressing the challenges of heat management in EVs by enhancing thermal interface materials and cooling systems to improve the efficiency of nanofluids and PCMs. These advancements not only improve battery performance and longevity but also contribute to the overall safety and reliability of EVs.

5. Development and Prospects

The development of graphene-based thermal management technologies for electric vehicles (EVs) has shown significant promise, but several challenges remain that need to be addressed before large-scale implementation. Graphene’s exceptional properties, such as high thermal conductivity and mechanical strength, make it an ideal candidate for enhancing the efficiency of thermal management systems in EV batteries. However, its potential has not yet been fully realized due to factors such as high production costs, scalability issues, and integration into existing systems.

Many studies focus on specific aspects of graphene’s performance, such as its thermal conductivity or its role in specific cooling technologies, but fail to provide a comprehensive analysis of its overall effectiveness when integrated into complex battery systems. There is also a need to explore hybrid material systems that combine graphene with other advanced materials to enhance the thermal performance of BTMSs.

To address these gaps, this review systematically analyzed existing literature by searching multiple academic databases such as Web of Science, Scopus, and Google Scholar, using keywords such as “graphene”, “battery thermal management”, and “cooling systems”. Studies were selected based on their relevance, quality, and contribution to the understanding of graphene’s role in BTMSs. The selected studies were categorized into three main areas: graphene coatings, graphene nanofluids, and graphene-enhanced phase change materials (PCMs). Each study was critically assessed for its strengths, limitations, and applicability in advancing graphene-based solutions for BTMSs. This methodology ensures that the findings presented in this review are both comprehensive and balanced, providing a clear direction for future research in this area.

Despite the numerous advantages of graphene in enhancing battery performance and thermal management, several challenges remain regarding its widespread adoption in EVs. One primary challenge is the lack of experimental validation for the theoretical benefits of graphene. Heat generation and thermal runaway are primary obstacles. The high power output during charge and discharge cycles generates significant heat, which can lead to overheating and safety risks. The high thermal conductivity of graphene mitigates these issues by facilitating efficient heat dissipation. However, empirical studies, such as by Dong, C [59], have provided experimental evidence showing graphene’s ability to enhance heat dissipation and maintain battery temperatures within safe limits. Continuous research, such as the integration of graphene composites into battery systems, exemplifies this potential by enhancing safety via the maintenance of battery temperatures within safe limits and reducing the likelihood of thermal runaway incidents. As research progresses, advanced graphene-based thermal management systems that dynamically respond to temperature fluctuations will significantly enhance overall battery safety and efficiency.

Another significant challenge is production costs. High production costs and complex manufacturing processes hinder the large-scale application of graphene. Despite advancements in production techniques, including chemical vapor deposition (CVD) and liquid-phase exfoliation, the economic scalability of graphene is still uncertain. However, advancements in manufacturing techniques, such as chemical vapor deposition (CVD) and liquid-phase exfoliation, are expected to significantly reduce costs. Market analyses project that the price of graphene could decrease by 50% within the next five years as production methods improve, making graphene more accessible for mainstream applications in battery technologies [60]. It is important to critically assess the balance between initial high costs and the long-term benefits, such as enhanced safety and battery lifespan, which could reduce maintenance costs. Collaborations between research institutions and industry leaders are actively seeking to develop cost-effective production methods, thereby paving the way for the broader adoption of graphene-enhanced technologies.

Moreover, the structural flexibility of graphene presents opportunities for new designs in battery systems. This flexibility can enable the integration of graphene into various forms, such as graphene-based composites or coatings, which could be applied to battery cells or thermal management structures. However, this design flexibility also requires careful consideration of the material’s behavior under different environmental conditions, such as temperature fluctuations and mechanical stresses.

In terms of future development trends, there is a growing focus on the hybridization of graphene with other materials. For example, combining graphene with phase change materials (PCMs) or other advanced thermal management solutions may enhance the overall efficiency of EV thermal systems. Additionally, research into graphene-based batteries is advancing, and their potential applications in electric vehicles could significantly reduce the need for external cooling solutions.

Looking ahead, the prospects for graphene in EV thermal management are promising. As research into the material continues, new techniques for manufacturing and integrating graphene into EV systems are likely to emerge. These advancements will make graphene more cost-effective and scalable, ultimately improving the thermal management efficiency of EVs. Moreover, the development of graphene-based supercapacitors and batteries may further enhance energy storage and contribute to more sustainable and efficient EVs. The key to unlocking the full potential of graphene in EV thermal management lies in continued innovation, particularly in addressing the cost, scalability, and integration challenges.

6. Conclusions

Graphene has emerged as a game-changing material for enhancing energy storage solutions, particularly in electric vehicles (EVs). With its exceptional properties—high electrical and thermal conductivity, mechanical strength, and large surface area—graphene can address many challenges in traditional battery technologies. Its integration into lithium-ion batteries, supercapacitors, and polymer batteries shows great potential in improving energy density, charging speed, and overall battery performance. Additionally, its ability to enhance thermal management by improving heat dissipation and stabilizing temperature fluctuations makes it a crucial component in ensuring battery safety, longevity, and overall vehicle efficiency.

The incorporation of graphene into EV battery systems, especially through graphene-enhanced thermal interface materials, cooling systems, and phase-change materials (PCMs), plays a critical role in mitigating heat generation and preventing thermal runaway. These innovations not only enhance battery performance but also contribute to the overall sustainability of EVs. As the research and development of graphene in energy storage technologies continue to evolve, collaborative efforts across academia, industry, and government are essential to drive forward innovation, ensuring that graphene-based technologies will contribute to the transition to more efficient and environmentally sustainable transportation.