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Modelling mechanical degradation in lithium-ion battery electrodes

MACSI at the department of Mathematics and Statistics at the University of Limerick invites you to a seminar

Date: Friday, February 8, 2019, Room A2-002 @ 16.00

Speaker: Dr. Jamie Foster, School of Mathematics and Physics, University of Portsmouth.

Title: Modelling mechanical degradation in lithium-ion battery electrodes

Abstract: Lithium-ion battery electrodes are composite materials comprised of (i) electrochemically active materials, (ii) polymer binder and (iii) pore space which is filled with a liquid electrolyte during operation. One predominant form of degradation that limits their usable lifetime is mechanical pulverisation which occurs when various constituents of the electrodes swell during device assembly or during operation. This is particularly prevalent in Si-based devices, where the active materials can swell by up to 400% in volume. 

We develop a poroviscoelastic model for an electrode that is comprised of: (i) a viscoelastic material model for the polymer binder; (ii) Darcy’s equation for the flow of the electrolyte, and; (iii) solid inclusions to mimic the active materials. Owing to the complex geometry of modern-day electrodes, solution of such a model on a realistic geometry is impractical, even with sophisticated numerical methods. Multiscale techniques (that exploit the disparity in length scales between that of a typical particle of active material and the whole electrode) are therefore employed to coherently separate solution of the problem into two steps: the first for the microscopic scale, and the second for the macroscopic scale. Finally, these two problems are solved sequentially using numerical (finite-element) and analytical (asymptotic) techniques, respectively. We show that the model solutions exhibit strong qualitative agreement with microscopy images of real electrodes and we suggest ways that insights from the model could be used to carry out better educated postmortems of failed batteries.

Further Information: If you have any questions regarding this seminar, please direct them to Romina Gaburro (061 2131930, email romina.gaburro@ul.ie  or Clifford Nolan (061 202766), clifford.nolan@ul.ie).

Supported by Science Foundation Ireland funding, MACSI - the Mathematics Applications Consortium for Science and Industry (www.macsi.ul.ie), centred at the University of Limerick, is dedicated to the mathematical modelling and solution of problems which arise in science, engineering and industry in Ireland.

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