Details

Autor(en) / Beteiligte

• Santimetaneedol, Arnuparp
• Tripuraneni, Rajasekhar
• Chester, Shawn A.
• Nadimpalli, Siva P.V.

Titel

Time-dependent deformation behavior of polyvinylidene fluoride binder: Implications on the mechanics of composite electrodes

Ist Teil von

• Journal of power sources, 2016-11, Vol.332, p.118-128

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2016

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The majority of existing battery models that simulate composite electrode behavior assume the binder as a linear elastic material due to lack of a thorough understanding of time-dependent mechanical behavior of binders. Here, thin films of polyvinylidene fluoride binder, prepared according to commercial battery manufacturing method, are subjected to standard monotonic, load-unload, and relaxation tests to characterize the time-dependent mechanical behavior. The strain in the binder samples is measured with the digital image correlation technique to eliminate experimental errors. The experimental data showed that for (charging/discharging) time scales of practical importance, polyvinylidene fluoride behaves more like an elastic-viscoplastic material as opposed to a visco-elastic material; based on this observation, a simple elastic-viscoplastic model, calibrated against the data is adopted to represent the deformation behavior of binder in a Si-based composite electrode; the lithiation/delithiation process of this composite was simulated at different C rates and the stress/strain behavior was monitored. It is observed that the linear elastic assumption of the binder leads to inaccurate results and the time-dependent constitutive behavior of the binder not only leads to accurate prediction of the mechanics but is an essential step towards developing advanced multi-physics models for simulating the degradation behavior of batteries. •Time-dependent mechanical behavior of PVdF was thoroughly characterized.•PVdF behaves more like an elastic-viscoplastic material for time-scales of interest.•Lithiation/delithiation of Si-PVdF composite was simulated with Abaqus FE package.•Linear elastic assumption of binder leads to inaccurate results.•Elastic-viscoplastic model predicts mechanics of composite electrode accurately.