Author

Kevin Cwiok

Date of Award

12-2016

Document Type

Thesis - Open Access

Degree Name

Master of Science in Mechanical Engineering

Department

Graduate Studies

Committee Chair

Dr. Sandra Boetcher

First Committee Member

Dr. Patrick Currier

Second Committee Member

Prof. Rafael Rodriguez

Abstract

Due to the regulations on internal combustion engine vehicles, there is a large demand of hybrid and electric vehicles with large battery packs as Energy Storage Systems (ESS) capable of long ranges and decreased emissions. These battery packs output large heat loads during charge-depletion mode and currently require active cooling to keep the batteries within operating conditions. The current systems relied onto achieve this are the air and liquid cooled thermal managements systems. A recent alternative approach to current cooling for ESS thermal management is the use of phase-change materials (PCMs). PCMs regulate the temperature of the ESS by leveraging the latent heat of fusion to absorb large amounts of energy at constant temperature while changing phase from solid to liquid. While PCMs have large heat capacities, the downside is their low thermal conductivity which causes them to melt unevenly, which is a main reason PCM is not ideal for cooling systems. The study will involve fully investigating the use of PCM into a hybrid-electric vehicle battery thermal management system. The proposed methodology is to mix thermal conductivity enhancing material, loose carbon fibers, into the PCM to spread the heat absorbed more evenly throughout the entire mass. This material matrix is characterized in order to determine the necessary material and thermal properties to justify its use and implantation in the EcoEagles 2016 Chevrolet Camaro for vehicle testing and validations. Results obtained during multiple vehicle tests have demonstrated that the PCM has successfully kept the battery pack at a safe operating condition of under 45◦C. This was done passively resulting in a reduced overall vehicle energy consumption and increased vehicle battery pack efficiency. The study continues by investigating the use of a shape-stabilized phase-change material cold plate that is capable of addressing several issues that a represent with the bulk PCM plate in its current state on the vehicle.

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