#ESS2204: Lithium-ion batteries: measuring the internal temperature using fiber-optic sensors

Supervisor: Markus Solberg Wahl, Jacob Joseph Lamb

Overview: The most important factor for battery life is temperature. When increasing the size of lithium-ion batteries (LIBs), particularly during intense charging and discharging, large amounts of heat will be generated. The increased temperatures within the LiB accelerate the degradation processes which reduce the capacity of the batteries. This leads to shortened lifetimes of LiBs, and in extreme cases can result in thermal run-away, which is a severe safety issue. To determine the changes in the thermal profile of LiBs, temperature measurements must be taken within an operating LiB. Since traditional thermocouple sensors have electrical components, they are not suitable for inserting within a LiB cell and may also react with the chemical environment. Fiber-optic sensors provide a method for measuring internal temperatures without affecting battery operation.

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Goals and tasks: This project will work with temperature sensitive optical fibers, aimed at measuring the dynamic temperature variations inside batteries and fuel cells. This will include:

• Lab work (optical/chemical)
• An understanding of optical systems
• An understanding of light-matter interactions
• An understanding of chemical reaction kinetics

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Desired skills and competencies:

• Experience within optics/chemistry/electrochemistry always good, but everyone interested is encouraged to apply.

• Experience with plotting and analysis in Matlab/Python.

• Ability to work independently with some guidance from the supervisor,

• Enjoy working in a research environment with many other researchers.

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Important info: For questions about the summer job, contact markus.s.wahl@ntnu.no