Analysis on a Battery Thermal Management System of an Lithium-Ion Powered Battery with Heat Sink for an Electric Vehicle

Electric vehicles (EVs) are changing the transportation business by giving an economical and sustainable option to the ecosystem in contrast to conventional vehicles with a sudden spike in demand for petroleum derivatives. The battery system that stores and disseminate electrical energy to the electric vehicles are basic to the outcome of EVs. Thermal management is basic for these batteries’ performance, safety and life span. This research article centres around the plan and examination of an EV-explicit Battery Thermal Management System (BTMS). To check the adverse consequences of high temperatures on battery cells, the BTMS integrates active and passive air-cooling strategies as well as different heat sink designs. The proposed BTMS further develops battery effectiveness, eliminate temperature-related risks and improves overall EV performance by maintaining appropriate thermal conditions. This study investigates the relevance of EV batteries, establishes defined objectives, gives numerical models and calculations, and conducts in-depth studies of various heat sink layouts. This research contributes to the growth of EV technology by empowering greener and cleaner transportation options while assuring the safety and efficiency of EV battery systems through careful examination and insightful analysis.


Introduction
Addressing 21st-century challenges, like the rising energy demand and environmental concerns, is critical.Carbon dioxide emissions have surged, with a five-fold increase in the past century.The transportation sector, responsible for over half of oil consumption, must enhance fuel economy to combat carbon emissions [1].Limited reserves, uneven distribution, and increasing energy demand drive the shift towards renewable energy to replace fossil fuels.Environmental concerns hasten this transition.By 2035, renewable electricity generation is projected to be 2.7 times greater than in 2010 [12].Renewable energy applications, including consumer electronics, vehicles, and buildings, are on the rise, aligning with the global 'green' movement.Electric and hybrid electric vehicles (EVs, HEVs, FCHEVs) are gaining global attention and swiftly replacing traditional combustion-engine vehicles as eco-friendly alternatives [2].Electric and hybrid electric vehicles (EV and HEV) offer a promising solution in the near term for reducing petroleum dependence and cutting greenhouse gas and like orderly magnified contact angles and multiple short channel designs could reduce temperature nonuniformity.Shang et al. [26] optimized the structure and operational conditions of prismatic battery packs using an orthogonal test of several design parameters.Yeow et al. [27] examined the effect of dual cold plates on the thermal behavior of indirect fin-cooling battery packs and found that the location of the cold plate and the direction of coolant flow significantly impacted the maximum temperature difference.Over recent years, both researchers and automotive manufacturers have directed their attention to the cooling of these batteries, recognizing it as a major roadblock in electric vehicle advancement.Operating these batteries at low temperatures hinders their power output by suppressing electro-chemical reactions, while high temperatures accelerate corrosion, resulting in a reduced battery lifespan.Additionally, the temperature range and uniformity within a battery pack are critical factors for achieving optimal electric vehicle battery performance.Multiple studies have demonstrated that elevated temperatures in Li-ion battery cells can hasten capacity degradation and curtail battery lifespan.The heat generated in batteries not only raises safety concerns but also leads to anomalies in the electric vehicle system.Dangers associated with this overheating issue encompass risks such as scorching and, in extreme cases, battery explosions.Therefore, the implementation of effective cooling methods is essential to establish a robust thermal management system for lithium-ion batteries in electric vehicles [4].Low temperatures typically have a substantial adverse effect on the power and energy storage capabilities of batteries, while also leading to an increase in their internal resistance [28].It has been observed that at -20°C, the rise in internal resistance results in a 60% reduction in capacity [29].Consequently, a notable challenge revolves around achieving efficient charge and discharge rates in extremely cold operational conditions.Jeffs and colleagues [30] explored a control strategy aimed at heating the battery to enhance cabin comfort, battery performance, and the overall range of the vehicle.This approach led to a notable increase of 6.2% in range and a 5.5% improvement in average cabin temperature when operating in an ambient temperature of -7°C.[31] 1.1.Objective Battery temperature management is crucial for electric vehicle (EV) battery packs, particularly for highenergy-density lithium-ion (Li-ion) batteries, which can experience thermal runaway if their temperature exceeds 70°C to 130°C.The ideal temperature range for Li-ion batteries is 25°C to 40°C, and temperatures exceeding 50°C can harm their lifespan [5] .
Heat within battery cells originates from electrochemical processes and joule heating as electrons move within the cells.To regulate battery temperature, cooling systems with heat sinks, notably fin-like structures, are employed.These fins expedite convective heat transfer, and their effectiveness depends on factors like geometry, surface properties, ambient temperature, and air velocity.
Designing cost-effective and efficient cooling systems is vital in the EV industry.Ongoing research focuses on improving heat transfer methods, particularly the use of heat sinks and fins.
Fins, or extended surfaces, play a crucial role in enhancing heat transfer not only in EVs but also in various industries, including power stations, computing, and internal combustion engines, where they contribute to efficient heat dissipation.Recent developments in EV battery cooling involve liquid cold plates to maintain specific temperature distributions, prolonging EV lifespans and reducing operational failures.
Efficient heat dissipation depends on the careful selection of suitable heat sinks and thermal management systems.The thermal performance of these systems is determined through theoretical calculations and analysis, considering factors like heat dissipation, thermal conductivity, and overall system performance.
In summary, managing battery temperature is vital for EVs, especially with high-energy-density Li-ion batteries.Cooling systems with heat sinks, including fin-like structures and innovative methods like liquid cold plates, are essential for maintaining optimal temperature ranges and extending battery life.Fins, as extended surfaces, are widely used across multiple industries to enhance heat transfer rates [6] [7].

Scope
This research paper aims to delve into the thermal management challenges associated with electric vehicle (EV) batteries.Its primary objective is to propose solutions that enhance the efficiency, reliability, and safety of EV batteries, ultimately fostering the wider adoption of electric vehicles and reducing their environmental impact.One key research objective is the development of a thermal protection system designed to prevent battery overheating and thermal runaway.This system will harness advanced technologies, including both active and passive cooling systems, phase change materials, and thermal interface materials.These technologies will work in tandem to regulate the temperature of the battery pack, safeguarding it against damage.Another crucial objective is to extend the lifespan of EV batteries by implementing appropriate thermal management practices.This encompasses maintaining the battery within an optimal temperature range, employing suitable charging and discharging protocols, and minimizing stress on the battery.To achieve these objectives, the research will focus on conducting extensive calculations and analyses of various heat sinks to identify the most efficient option for thermal management.The study will entail an evaluation of the thermal properties and performance of various heat sink designs, taking into account factors like heat dissipation, thermal conductivity, and overall system performance.
Aluminum alloys, particularly Aluminum 6061, are preferred materials for manufacturing fin components and various automobile parts due to a combination of exceptional properties.Aluminum 6061, in particular, has demonstrated superior heat transfer rates compared to other materials when certain parameters, such as length and the number of fins, are kept constant.This advantage is attributed to its significantly higher thermal conductivity, measured at 180 W/(m K).The correlation between increased velocity and a subsequent rise in the heat transfer coefficient, along with a decrease in temperature, underscores the efficiency of Aluminum 6061 in managing thermal properties.Despite this, Aluminum 204 exhibits a more favorable temperature distribution compared to the other two materials, adding a nuanced perspective to the selection of aluminum alloys for specific applications.Notably, these alloys still maintain their lightweight nature, corrosion resistance, machinability, and the balance between strength and ductility, which contribute to their widespread use in the automotive and other industries.The continual evolution of materials science continues to enhance these alloys and their manufacturing processes, driving innovation and efficiency in various engineering applications [33].
Through these calculations and analyses, the research seeks to pinpoint the most effective heat sink design capable of efficiently managing the temperature of EV batteries.The selection process will involve assessing the heat sink's ability to dissipate heat effectively and maintain the battery within the optimal temperature range.By undertaking thorough assessments of different heat sinks, the research aims to provide valuable insights into the most suitable heat sink design for achieving optimal thermal management.This, in turn, will contribute to the development of efficient and dependable EV batteries, ensuring their performance, longevity, and safety.The overarching goal of this research is to play a pivotal role in the creation of efficient, reliable, and safe EV batteries by addressing the intricate challenges associated with thermal management.By encouraging the adoption of EVs, it can help curtail our reliance on fossil fuels and mitigate the adverse environmental consequences linked to transportation.

Experiment
In this paper, we delve into the realm of thermal management , specifically focusing on the utilization of various fin designs, including Rectangle plate fins, Triangular fins, and Variable area straight fins, as heat sinks for cooling battery systems.The study entails a comprehensive exploration, combining theoretical and analytical calculations, to assess the efficacy of these distinct fin geometries in heat dissipation.By investigating parameters such as heat dissipation rate, thermal conductivity, and overall system performance, we aim to gain valuable insights into the thermal management capabilities of each fin type.The findings from this research hold the potential to significantly influence the design and development of efficient and reliable battery cooling systems, with implications for enhancing battery lifespan, performance, and safety in various applications, including electric vehicles and renewable energy storage.The theoretical formulas used are listed below and are referred from [8] and [9].Fin end temperature,

Analysis of Heat Sinks:
In the thermal analysis, the examination of heat sinks, specifically different types of fins, plays a pivotal role.When it comes to thermal management and heat dissipation, the analysis of heat sinks, such as rectangular fins, triangular fins, and variable area straight fins, is of paramount importance.These fins, with their distinct geometries, serve as essential components in diverse engineering applications, including electronics, cooling systems, and heat exchangers.By subjecting each fin type to comprehensive analysis, we aim to unravel the intricate dynamics of heat transfer and dissipation.The thermal analysis delves into the behaviour of these fins, exploring factors like heat dissipation rate, thermal conductivity, and overall system performance.This examination not only sheds light on the unique characteristics and efficiencies of each fin design but also guides the development of optimized thermal management strategies.Through a thorough understanding of how each fin type performs in terms of heat dissipation, engineers and researchers can tailor their use in various applications to enhance energy efficiency and system safety.Ultimately, the insights gained from this analysis are poised to contribute significantly to advancements in thermal engineering and the design of more efficient, reliable, and sustainable systems.The transient thermal analysis revealed a rapid temperature drop from 50 to 21.8 degrees Celsius on the rectangular plate's surface.This decrease was primarily due to forced convection and the heat flow of 300W.The forced convection velocity of 5 m/s enhanced heat transfer, resulting in efficient cooling.The temperature stabilized at a steady state, indicating a balance between heat generation and dissipation.These findings emphasize the significance of considering transient behavior and boundary conditions in heat transfer system design.The heat flux analysis conducted on the rectangular plate yielded positive results.The heat flux, determined as 300 W, indicated a substantial heat transfer rate.This finding confirms the effectiveness of the heat flow in facilitating efficient energy transfer within the system.The positive results of the heat flux analysis validate the design and performance of the rectangular plate in terms of heat dissipation capabilities.These findings are significant for optimizing heat transfer systems and ensuring effective thermal management.The meticulous examination of the total heat flux associated with the triangular fin has unveiled results that are undeniably promising and indicative of its remarkable heat dissipation capabilities.The specific heat flux measurement, clocking in at an impressive 610.53 watts, unequivocally attests to the fin's ability to efficiently transfer heat.This robust performance underlines the fin's effectiveness in facilitating the dissipation of energy, making it an invaluable component for managing thermal conditions in various applications.These results not only highlight the fin's efficacy but also confirm the soundness of its design and performance.The impressive heat transfer rate serves as a validation of the engineering principles and parameters that guided the fin's creation.It signifies that the fin is indeed fulfilling its intended purpose with excellence.This affirmation carries profound implications, particularly in the realm of thermal management.Such positive findings are essential in advancing the development and optimization of thermal management systems.They provide a solid empirical basis for the design and implementation of heat dissipation strategies, ensuring that the energy within the system is efficiently and effectively transferred, thereby preventing overheating and contributing to the overall efficiency and safety of the systems.This research outcome underscores the significance of the triangular fin and similar heat sinks in addressing the pressing need for efficient heat transfer solutions in a wide array of applications, ultimately advancing the state of the art in thermal engineering and management.The total heat flux analysis conducted on the variable area straight fins yielded positive results.The measured heat flux of 234.68 W indicated effective heat transfer within the system.This finding confirms the fin's capability to dissipate heat efficiently.The positive results of the total heat flux analysis validate the design and performance of the variable area straight fins in terms of their heat dissipation capabilities.These findings are crucial for optimizing thermal management systems and ensuring efficient heat transfer.

Overall Results
The analysis conducted on ANYS software using boundary conditions obtained from theoretical calculations revealed significant temperature reductions in the electric vehicle battery with the implementation of heat sinks.Three types of heat sinks were considered: rectangular plate fins , triangular fins and Variable area straight fins For the rectangular plate fins, the surface temperature was set at 50 degrees Celsius, with a total heat flow of 300W.The ambient temperature was 25 degrees Celsius, and the heat transfer coefficient of air was assumed to be 8.66W/m^2K.After the implementation of rectangular heat sinks, the temperature dropped from 50 degrees Celsius to 21.873 degrees Celsius.This reduction in temperature demonstrates the effectiveness of rectangular plate fins in improving thermal management.
In the case of triangular fins, the heat flow was 611W, and the other boundary conditions remained the same as for the rectangular plate fins.The temperature decreased from 50 degrees Celsius to 22.324 degrees Celsius after the introduction of triangular fins.This reduction in temperature indicates the successful application of triangular fins in enhancing heat dissipation.Additionally, variable area straight fins with a heat flow of 237W was considered, and the temperature decreased from 50 degrees Celsius to 22.08 degrees Celsius.This result confirms that heat sinks, regardless of their specific design, are effective in reducing the temperature of the electric battery.
The findings from the ANYS software analysis align with the initial theoretical calculations, providing quantitative measures of the temperature reduction achieved with the implementation of heat sinks.The chosen heat transfer coefficient of air, 8.66W/m^2K, represents typical values for natural convection and further supports the practicality of the results.The temperature reduction achieved through the use of heat sinks is of great significance as it prevents the battery from exceeding a temperature rise of 50 degrees Celsius, which could adversely affect the battery's performance and lifespan.Moreover, the improved thermal management offered by heat sinks enhances the overall efficiency and safety of the electric vehicle battery.
In conclusion, the results obtained from theoretical calculations and ANYS software analysis demonstrate the effectiveness of heat sink technology in reducing the temperature of electric vehicle batteries.This research supports the practical application of heat sink solutions in the design and development of electric vehicle battery systems, contributing to improved performance, longevity, and thermal management.
The comparison of the three types of fins, namely rectangular plate fins, triangular fins, and variable area straight fins, in terms of temperature and heat flow reveals the following trends: 1. Rectangular Plate Fins: Starting with a surface temperature of 50 degrees Celsius, the implementation of rectangular plate fins resulted in a significant reduction in temperature.The temperature dropped to 21.873 degrees Celsius after the application of rectangular plate fins.The heat flow was maintained at a total of 300W.

Triangular Fins:
Similar to the rectangular plate fins, the triangular fins also showed a considerable reduction in temperature.The temperature decreased to 22.324 degrees Celsius after the introduction of triangular fins.The heat flow for this configuration was 611W.

Variable Area Straight Fins:
In this case, the heat flow was set to 237W.The temperature dropped to 22.08 degrees Celsius after implementing the variable area straight fins.

Conclusion
The increasing prevalence of electric vehicles (EVs) as a means to curb greenhouse gas emissions and reduce dependence on non-renewable energy necessitates efficient thermal management of EV batteries.This study focuses on utilizing air cooling as an effective and practical method for safeguarding EV batteries thermally.By implementing air cooling, we address challenges related to limited range, high costs, and the necessity for reliable thermal management in EV batteries.Our calculations and analysis show that air cooling effectively manages the thermal aspects of the examined battery system, which operates with a total heat flow of 300W.Evaluation of the average convection heat transfer coefficient, heat transfer rate, and fin end temperature confirms the system's efficacy.The results demonstrate that the battery system maintains an optimal temperature range for efficient operation, validating air cooling as a robust method for thermal protection.This research contributes to developing efficient and secure thermal management systems crucial for enhancing battery performance and extending its lifespan.In addition to operational benefits, effective thermal management mitigates safety hazards associated with overheating, such as thermal runaway and fire risks, making air cooling an essential component in EV battery design.Future research could explore alternative cooling methods or materials to enhance battery efficiency and performance.Investigations into phase-change materials or thermoelectric cooling systems could offer promising avenues for improvement.Advances in materials science may yield higher thermal conductivity materials, enhancing the cooling system's effectiveness.Integration of smart technologies, including sensors and control systems, could enable real-time

Fig 2 . 2
Fig 2.2.1 (a): Transient thermal analysis of a rectangular plate fin

Fig 2 . 2
Fig 2.2.1 (b): Total heat flux analysis of a rectangular plate fin

Fig 2 . 2
Fig 2.2.2 (a): Transient thermal analysis of a Triangular fin The transient thermal analysis of the triangular fin revealed a significant temperature drop from 50 to 22.32 degrees Celsius.This drop in temperature was observed as a result of the combined effects of forced

Fig 2 .
Fig 2.2.2 (b): Total Heat Flux analysis of a Triangular fin

Fig 2 .
Fig 2.2.3 (a): Transient thermal analysis of a Variable area straight finThe transient thermal analysis of the variable area straight fins resulted in a noticeable temperature drop from 50 to 23.333 degrees Celsius.This drop in temperature was attributed to the combined effects of forced convection and a heat flow of 234.68 W. The forced convection velocity of 5 m/s contributed to efficient heat transfer, leading to effective cooling.The obtained results validate the thermal performance of the variable area straight fins in dissipating heat and highlight their potential for thermal management applications.These findings are essential for optimizing the design and functionality of heat transfer systems involving variable area straight fins.

Fig 2 . 2
Fig 2.2.3 (b): Total Heat Flux analysis of a Variable area straight fin

Fig 3 . 1
Fig 3.1(e) Temperature v/s time graph for a Variable area straight fin

Figure 3 .
Figure 3.1(e) illustrates the relationship between temperature (y-axis) and time (x-axis).The blue line represents the actual temperature variation, depicting the observed fluctuations and changes over time.The green line signifies the maximum temperature variation, indicating the highest recorded temperatures during the observed period.On the other hand, the red line represents the minimum temperature variation, indicating the lowest recorded temperatures.These lines collectively provide valuable insights into the temperature dynamics, trends, and range, enabling effective monitoring and evaluation of temperature control measures.

Fig 3 . 1
Fig 3.1(f) :Heat flux v/s Time graph for a Variable area straight fin In Figure 7.3(b), the blue line represents the actual variation of total heat flux over time.The green line indicates the maximum total heat flux variation, and the red line represents the minimum total heat flux variation.These lines offer valuable insights into the dynamic fluctuations and extreme values of the total heat flux during the observed period.