Automotive Science and Engineering

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With respect to the limitations of fossil energy resources, different types of electric vehicles (EVs) are developed as suitable alternatives. Lithium-ion (Li-ion) battery cells play an extremely important role in EVs due to their unique features. But they need a thermal management system (TMS) to maintain their surface temperature uniformity and avoid them from thermal runaways. In the current study a phase change material (PCM) based TMS is introduced and applied to provide a uniform temperature distribution on a Li-ion battery cell surface. This PCM based TMS declines the final maximum temperature difference to (1/5) and (2/3) at 1 C and 2 C discharge rate respectively.
 

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In recent years, the automotive industry has experienced a dramatic mutation in the develop ment of electric vehicles. One of the most important aspects of this type of vehicle is its thermal management. Among the various parts of an electric vehicle that are subjected to thermal management, the battery is of particular importance. Battery cell temperatures may exceed the allowable range due to continuous and high-pressure operation and various weather conditions, and this, in addition to performance, severely affects battery life. Therefore, the appropriate cooling system is essential. In this research, the most common methods of battery cooling are investigated. First, three-dimensional thermal analysis on the battery is performed using the computational fluid dynamics method in transient and steady-state phases.  Then, the effect of changing the cooling flow rate on the maximum temperature of the battery cell as well as the temperature difference of the cells in the battery pack is investigated. The effect of changing inlet coolant temperature change on battery cell temperature distribution is also investigated. The results show that by increasing the flow rate from 0.5 to 1.2 liter per minute, the maximum temperature in the battery pack and the temperature difference between the cells decrease to 44.4 and 2.51 ° C, respectively. Also, by changing the temperature of the inlet coolant from 15 to 30 ° C, the maximum temperature in the battery pack increases up to 42.2 ° C and the temperature difference is negligible.

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The transition from traditional internal combustion engine vehicles to electric vehicles is in progress. With their high energy density, low self-discharge rates, long cycle life, and absence of memory effects, lithium-ion batteries have become the primary power source for alternative vehicles. Throughout the battery's lifespan, its performance or health gradually deteriorates due to irreversible physical and chemical changes. Depending on the specific aging mechanisms, a battery may lose capacity or face increased internal resistance. Growing awareness of the importance of environmental protection and the potential implications associated with products and services has spurred interest in developing methods to better understand and address these impacts. Life cycle assessment is a method used to examine the environmental effects associated with all stages of product production. This study compares the operational conditions of an electric vehicle equipped with both new and old battery packs. The performance difference indicates that the vehicle with the aged battery has 17% less capacity, operates over 20% weaker in range, and its ohmic resistance increases by up to 150%. From a well-to-wheel perspective, using an electric vehicle with an old battery could result in a 2% increase in carbon dioxide emissions, reaching 56.638 g CO₂ equivalent per kilometer.