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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 33: Poster: Charge Effects in Soft and Biological Matter

CPP 33.1: Poster

Mittwoch, 24. März 2010, 17:30–19:00, Poster C

A Transport Model for an All Solid State Lithium Ion Battery — Stefan Funken and •Manuel Landstorfer — Institut für Numerische Mathematik, Universität Ulm, Ulm, Germany

New developed solid electrolytes indicate some big advantages for rechargeable lithium ion batteries, e.g. heat and cycling stability. These features yield benefits for cell coupled solar cell/rechargeable battery devices. A priori knowledge of some of the cell parameters is of great interest to eliminate poor material combinations and reduce experimental work.

A continuum mechanical modeling framework at cell level will be presented which takes into account the deintercalation and intercalation of lithium, transport of lithium through the solid electrolyte and electrochemical reactions on the flat phase interfaces. Furthermore the potential drop across the rigid double layer is modeled as Robin boundary condition. The derivation of the transport equation for lithium ion concentration cLi+(x,t) in the solid electrolyte is done by a free energy functional F[cLi+] which takes into account repulsive ion-ion interaction. Defining the chemical potential as Frechet derivative of the free energy with respect to concentration, µLi+ = δ F[c]/δ c, and the Flux as ΓLi+→ = D · ∇ µLi+ one obtains a diffusion equation with a concentration dependent, non-linear diffusion coefficient.

The full model is a coupled non-linear partial differential equation system which is solved with COMSOL® and own code. Numerical results for discharge behavior of an example cell will be presented.