Thermal management and runaway propagation prevention of lithium-ion batteries in electric vehicles

This work presents thermal runaway models consistent with EV architecture, including the array size, cell packing density, the stringent thermal requirements, boundary conditions and optimisation goals. These models bridge the gap between simulation and practical application, by considering the EV specific requirements.</div><div><br></div><div>To support model validation a low-power apparatus was designed and manufactured enabling controlled heat transfer studies.

As part of this process, a cell analogue was developed that would allow repeated non-destructive testing. This analogue closely replicated the thermophysical properties of a real cell, including the anisotropic thermal conductivity and the volumetric heat capacity.</div><div><br></div><div>The models developed showed that the parked and crash scenarios of an EV represent the highest risk states. Moreover, various individual design options and material variations were considered for the role of propagation prevention and thermal management.

Additionally, within these models and the designs generated, considerations were made to the constraints of volume and weight, which negatively impact the range and vehicle dynamics that are critical for meeting consumer demands for electric vehicles. Through these simulations the potential use of low conductivity interstitial materials alongside liquid cooling channels to prevent propagation under the most energetic scenarios was uncovered.</div><br>To support model validation a low-power apparatus was designed and manufactured enabling controlled heat transfer studies.

As part of this process, a cell analogue was developed that would allow repeated non-destructive testing. This analogue closely replicated the thermophysical properties of a real cell, including the anisotropic thermal conductivity and the volumetric heat capacity.<br><br>The models developed showed that the parked and crash scenarios of an EV represent the highest risk states. Moreover, various individual design options and material variations were considered for the role of propagation prevention and thermal management.

Additionally, within these models and the designs generated, considerations were made to the constraints of volume and weight, which negatively impact the range and vehicle dynamics that are critical for meeting consumer demands for electric vehicles. Through these simulations the potential use of low conductivity interstitial materials alongside liquid cooling channels to prevent propagation under the most energetic scenarios was uncovered.

A range of interstitial materials were applied and those with the lowest weight impact were assessed. Through these simulations a range impact of between 0.3 – 2.6 % was calculated for the application of the interstitial materials.<br><br><i>Thesis is embargoed until 31 July 2027.</i>