TY - JOUR
T1 - Time-dependent deformation behavior of polyvinylidene fluoride binder
T2 - Implications on the mechanics of composite electrodes
AU - Santimetaneedol, Arnuparp
AU - Tripuraneni, Rajasekhar
AU - Chester, Shawn A.
AU - Nadimpalli, Siva P.V.
N1 - Funding Information:
The corresponding author gratefully acknowledges the financial support provided by the New Jersey Institute of Technology through the faculty startup research grant.
Publisher Copyright:
© 2016 Elsevier B.V.
PY - 2016/11/15
Y1 - 2016/11/15
N2 - 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.
AB - 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.
KW - Battery degradation
KW - Binder constitutive model
KW - Composite electrode
KW - Finite element model
KW - Polyvinylidene fluoride
KW - Visco-plasticity
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U2 - 10.1016/j.jpowsour.2016.09.102
DO - 10.1016/j.jpowsour.2016.09.102
M3 - Article
AN - SCOPUS:84988905478
SN - 0378-7753
VL - 332
SP - 118
EP - 128
JO - Journal of Power Sources
JF - Journal of Power Sources
ER -