Investigation of Li-ion Battery Cell thermal conditioning

The transport sector is currently undergoing a transformation towards a CO2 emission free vehicle fleet and a key to this transition is the battery electric vehicles (BEVs) utilizing Li-ion batteries as energy storage instead of fossil fuels. In a BEV the battery performance is dictating the propulsion power, range and charging speed of the vehicle and therefore all factors influencing battery performance needs to be understood. Battery performance and lifetime is often evaluated on different system levels, the smallest unit being the Li-ion battery cell. Testing and modelling performance on different system levels introduces challenges in providing representative testing environments especially on cell level where the cell integration into the battery system plays a large role in its performance and life behavior.


Suitable background


This thesis is suitable for an engineering student studying Chemistry - Electrical - , Physics - , or Mechanical Engineering. The thesis works requires some programming or data analytics knowledge in either python, MATLAB or COMSOL. Understanding the physical, electrochemical and thermal aspects of the Li-ion battery is a merit.

Description of thesis work


The master thesis project will be performed at AB Volvo in Gothenburg in collaboration with the Div. Applied Electrochemistry at KTH and range over one semester, 30 ECTS, starting from January 2023. The project will include:
Review of existing methods for thermal modelling of Li-ion battery cells
Literature review of effect on cell performance and life from thermal conditioning
Studying existing test data from different system levels to find potential differences between thermal conditioning of the battery cells in cell level test compared to other system integration levels (for example vehicle, battery pack, battery cell module)
Perform thermal and electrochemical simulations and lab experiments on battery cells using different thermal conditioning and analyze the implications
Design a proposed test environment for a single battery cell to replicate the cell’s thermal environment in a larger system



Goals:


Insights on differences in cell thermal environment during lab tests and usage in vehicle installation and its implication on cell performance in the different scenarios.
Proposed jig or test environment to mimic a realistic vehicle-like thermal environment for the cell during lab tests.


Thesis Level: Master

Tutor
Alice Hamrin (alice.hamrin@volvo.com), Rakel Wreland Lindström (rakel2@kth.se)