Life modeling of a lithium ion cell with a spinel-based cathode

In this paper we introduce a pseudo two-dimensional (P2D) model for a common lithium-nickel-cobalt-manganese-oxide versus graphite (NCM/graphite) cell with solid electrolyte interphase (SEI) growth as the dominating capacity fade mechanism on the anode and active material dissolution as the main aging mechanism on the cathode. The SEI implementation considers a growth due to non-ideal insulation properties during calendar as well as cyclic aging and a re-formation after cyclic cracking of the layer during graphite expansion. Additionally, our approach distinguishes between an electronic (σ SEI ) and an ionic (κ SEI ) conductivity of the SEI. This approach introduces the possibility to adapt the model to capacity as well as power fade. Simulation data show good agreement with an experimental aging study for NCM/graphite cells at different temperatures introduced in literature. © The Author Lithium-ion batteries are one of the most promising candidates for energy storage in future stationary storage systems and electric vehicles.1-3 Enormous research efforts have been conducted to get a thorough understanding of the system "lithium-ion cell" and to further develop it for higher energy and power density, higher safety standards as well as longer cycle life. 4 The aging behavior of lithium-ion batteries has been a focus issue of battery research since the introduction of lithium-ion cells by Sony in 1991. 5 Reviews by Agubra et al., 6,7 Arora et al., 8 Aurbach et al., 9,10 Birkl et al., 11 Broussely et al., 12 Verma et al. 13 and Vetter et al. 14 are just a few examples of the extensive literature regarding aging behavior. Commonly accepted and experimentally verified aging phenomena as mentioned in the previously cited literature are electrolyte decomposition leading to solid electrolyte interphase (SEI) and cathode electrolyte interphase (CEI) growth, solvent co-intercalation, gas evolution with subsequent cracking of particles, a decrease of accessible surface area and porosity due to SEI growth, contact loss of active material particles due to volume changes during cycling, binder decomposition, current collector corrosion, metallic lithium plating and transition-metal dissolution from the cathode. The listed aging mechanisms can be assigned to three different categories that are a loss of lithium-ions (LLI), an impedance increase and a loss of active material (LAM). 12,[15][16][17][18] The LLI is synonymous to a decrease in the amount of cyclable lithium-ions as they are trapped in a passivating film on either of the electrodes or in plated metallic lithium. Due to the growth of the passivating layers and/or the formation of rock-salt in the cathode (residue of the cathode active material after transition-metal dissolution), kinetic transport of lithium-ions through those inactive areas is limited and results in an impedance rise. An LAM can be caused by the dissolution of transition-metal-ions from the cathode bulk material, changes in the electrode composition and/or changes in crystal structure of the a...

Section: Model Developmentmentioning

confidence: 99%

“…Lawder et al 46 studied the influence of different driving cycle profiles on the capacity fade of electric vehicle batteries and ascribed the total capacity fade to SEI growth. The effects of gas evolution due to SEI growth were modeled by Rashid et al 47 On the cathode side, Cai et al 48 implemented an SOC independent manganese disproportionation which …”

mentioning

confidence: 99%

A SEI Modeling Approach Distinguishing between Capacity and Power Fade

Kindermann

Keil

Frank

et al. 2017

“…10 Life-time simulations of lithium-ion batteries are commonly performed using physics-based models, and by estimation of relevant parameters such models have been able to narrow down the number of possible degradation mechanisms. [10][11][12][13][14][15][16][17][18][19] Typically these models contain expressions based on the physical model assumptions, sometimes z E-mail: heek@kth.se mixed with some empirical expressions, and in some cases the models have been reduced to solely a number of empirical expressions. The aim of the physics-based model presented in this paper is to be able to predict aging of the battery using a minimum of parameters.…”

Section: Model and Simulationsmentioning

confidence: 99%

A Model for Predicting Capacity Fade due to SEI Formation in a Commercial Graphite/LiFePO₄Cell

Ekström¹,

Lindbergh²

2015

157

An aging model for a negative graphite electrode in a lithium-ion battery, for moderate currents up to 1C, is derived and fitted to capacity fade experimental data. The predictive capabilities of the model, using only four fitted parameters, are demonstrated at both 25 • C and 45 • C. The model is based on a linear combination of two current contributions: one stemming from parts of the graphite particles covered by an intact microporous solid-electrolyte-interface (SEI) layer, and one contribution from parts of the particles were the SEI layer has cracked due to graphite expansion. Mixed kinetic and transport control is used to describe the electrode kinetics. © The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. [DOI: 10.1149/2.0641506jes] All rights reserved.Manuscript submitted December 19, 2014; revised manuscript received February 6, 2015. Published March 10, 2015 Lithium-ion batteries are used in all sorts of electric devices such as mobile phones, lawn mowers, electrical scooters and electric cars. Common for all lithium-ion battery chemistries is that they suffer from aging phenomena over time. Degradation occurs during storage, but is further induced by battery cycling and higher temperatures. Life time degradation generally occurs due to various processes such as electrolyte decomposition, loss of active material and loss of cycleable lithium due to parasitic reactions. 1The most common negative electrode material in lithium-ion batteries is graphite. For cells deploying negative graphite electrodes, significant amounts of cycleable lithium is lost into forming the solidelectrolyte-interface (SEI) layer on the graphite surface. The initial SEI formation during the first "formation" cycles of the battery is most pronounced, but, depending on operation conditions, the SEI layer formation will continue during the whole lifetime of the battery. The SEI layer is not homogeneous, neither with regards to morphology nor composition. Cracks are known to form upon battery cycling, 2 and various chemical compounds have been observed.2,3 Experimental work has shown that for low currents (≤C/10) the long term capacity loss usually follows a t 1/2 dependence, and models in literature usually ascribes this dependence to a diffusion limitation through the SEI layer of a reacting species in the electrolyte that participates in forming the SEI layer. [4][5][6] This paper focuses on SEI formation on graphite at moderate load currents (≤1C) at both 25• C and 45• C. For these conditions it has been shown that the SEI formation is the main cause of battery degradation. 7Although not treated explicitly, the positive electrode material is assumed to be LiFePO 4 (LFP) since it has been seen that this positive electrode material does not suffer from nor cause significant degrada...

“…Recently, a more complete model was developed by Cai et al, 20 which takes the decrease of radius of the active material into account by using a shrinking core model to describe the solid phase diffusion in the cathode. Also, the formation of an inactive material layer which causes a resistance increase in the cathode was included in the model.…”

mentioning

confidence: 99%

Capacity Fade Model for Spinel LiMn₂O₄Electrode

Dai

Cai

White

2012

Self Cite

126

A mathematical model for the capacity fade of a LiMn2O4 (LMO) electrode is developed in this paper by including the acid attack on the active material and the solid electrolyte interphase (SEI) film formation on the LMO particle surface. The acid generated by the LiPF6 and the solvent decompositions are coupled to the manganese (Mn) dissolution. The decrease of the Li ion diffusion coefficient is involved as another contribution to the capacity fade, which is caused by the passive film formation on the active material surface. The effects of cell practical operation/fabrication conditions and kinetics of side reactions on battery life are also investigated by utilizing the developed mathematical model.