[PPT] - 3D 3D-Elect Electroch ochemist emistry Designin igning g and PowerPoint Presentation

SLIDE 1

3D 3D-Elect Electroch

chemist

emistry

Designin igning g and resolving

lving the

microstru

structure

ture of an electr ctrod

de

Gaëta tan Dambla mblanc nc

SLIDE 2

Additi tion

n of a 3D electr

ctroch

chem

emist stry y mode del Applies to idealised or ‘real’ geometries

Battery Cell Battery modules/packs In Situ Increasing Length Scale

Ext xten ension sion to the Development lopment

MicroStructure Modeling Battery tery Simulation ulation Module

SLIDE 3

Motiv ivat ations ions What is a Li Li-ion ion Batt tter ery? y? Designin igning g the microst

structure:

cture: The 3D approac

ach

STAR-C

CCM+

CM+ Li Li-ion ion Batt tter ery y Cell ll Model Exam ample ple of a 3D Numeric erical al model el Future ure developments

pments and conclusion

usion Agenda da

SLIDE 4

Cost st reduc educti tion

n for the

e design ign

– Minimise the number of tests and experiments – Identify at the early stages of the development potential problems

Process cess and resear search ch speed ed up up

– Parameterisation and optimisation methods

Impr mprovem emen ent t of the e un under derst stand anding ng of the e phenome nomena na taking ing place

– Performance – Ionic and electronic transport – Ageing – Short circuit

Motiv ivat ations ions

SLIDE 5

What is a Lithium hium -ion n Batt tter ery? 𝑴𝒋𝑫𝒑𝑷𝟑 𝑴𝒋𝟐−𝒚 𝑫𝒑𝑷𝟑 + 𝒚𝑴𝒋+ + 𝒚𝒇− 𝒚𝑴𝒋+ + 𝒚𝒇− + 𝟕𝐃 𝑴𝒋𝒚𝑫𝟕

Posit itive e and d nega gativ tive half reacti tions

ns for a LiCoO

CoO2 cathode hode:

SLIDE 6

The e elec ectr trode des s are made de of porou

us

s activ tive e materi erials als placed ed in a liqui uid non-aqueo eous us electr ectroly

lyte

What is inside ide a Li Li-ion ion Electr ectrod

de?

e?

+

SLIDE 7

Geom

metrical

trically ly resol

lved electr

ectrode

de

– Interfacial surface area – Volume/porosity fraction – Tortuosity

Local cal interac eractions tions

– Voltage distribution – Li-ion pathways – Li-ion concentration – Short circuiting – Thermodynamic effects – SEI growth

Materia erial int nteractions eractions

– Active material – Liquid or Solid Electrolyte – Binders, conductive additives

Contract traction

n and Expansi

ansion

n

– During the intercalation process

Advanta ntages ges of the 3D approac

ach

SEI Tortuosity

SLIDE 8

The Li Li-ion ion Batt tter ery y Cell l model el

Section across a typical Li-ion cell

Solid particles structure is to be resolved or represented by a simpler, regular structure (e.g. cylinders, grid etc.)

Geometry-resolved model

SLIDE 9

We suggest est to discreti tize ze separat ratel ely y solid and d fluid regions

ns within

in an electr trod

de,

e, with the desired d level of comp mple lexi xity ty Within in solid struc ucture ture, one can n accou count t for acti tive and d passive e mater eria ials (e.g. activ ive e mater eria ial and condu duct cting ing aid). Chemical cal react ctions ions take e place ce at the solid-elect electrol

lyt

yte e inter erpha hase (SEI): ): standar ndard d form of equa uations tions can an be used, with special al cond nditi ition

ns at

inter erface ces. The model of a Li Li-ion n batter ery y requi uires res solution ion of the following ing equa uations: tions:

– Salt concentration in electrolyte; – Concentration of Li in solid part of electrodes; – Potential in solid; – Potential in electrolyte; – Thermal energy.

Flow will initia tiall lly y be neglect ected ed, but may y be included luded in the future ure (as well as volume me chan ange ge during ing charging rging and d discharging harging to accou

unt

nt for expansi ansion

n/c

/cont

ntra

ract ction).

n).

Crucia cial: l: cond nditions itions at the inter erfac aces.. s...

The Li Li-ion ion Batt tter ery y Cell l model el

SLIDE 10

Lith thium m (Li+) ) is transp nspor

rted

ed into

and out

ut of particles cles by diffusi sion

n:

We assume here a binary electrolyte and express the conservation equation for Li-salt in the liquid phase as follows The potential in the solid phase, Φ1, is computed from the following equation: The e pot

tenti

ential al in liqui uid, , Φ2, can be comput puted d from

m the follo

lowing wing equa uati tion

n:

The main n equati tions

ns

SLIDE 11

Interface ce Condition itions



Local l curre rrent t density ity at solid activ ive surfac face e is modelled lled as (Butt ttler ler-Vol

lmer

er relati tion

n):

cs – Site concentration of solid phase

(maximum possible value of c1). k – Rate constant Rsei – Solid-electrolyte-interface resistance Ueq – Equilibrium potential of the active material with

SLIDE 12

The 3D Numeri rical al Model l Definition nition

Cathod

hode Colle llector

r – Alumin

minum m foil 10µm m thick (δkp), ,

Cathod

hode activ ive e mater erial ial – LiMn2O4 80µm thick (δp) p), , partic ticle le diame ameter er 10µm, m, target porosity

sity 40%
Separ

arator

r - 10µm

m thick (δs) s), , porosity

sity 40%,

, Mac acMull Mullin in number ber 5

Anode
de activ

ive mater erial ial – Grap aphit hite e 96µm m thick (δn) n), , particle icle diame ameter er 20µm, m, target t porosit

sity 40%
Anode
de Colle

llector

r – Copper

er foil 10µm m thick (δkn)

Elec

ectr trolyte – et ethylene lene car arbonat

nate/e

e/eth thyl l met ethyl l car arbo bonat ate e 50:50 mix, , salt t - LiFP6

Over

erall all unit cell ell dimen mensions sions - 25 µm by 25 µm by 206 µm

15 15

SLIDE 13

16 16

Model l De Definit nition ion - Catho thode de

Polyhedral mesh 2.8 million cells Solid & electrolyte resolved STAR-CCM+ CAD tool 40% Porosity

SLIDE 14

17 17

Model l De Definit nition ion - Ano node

Polyhedral mesh 1.2 million cells Solid & electrolyte resolved STAR-CCM+ CAD tool 40% Porosity

Anode Active Material - Graphite

SLIDE 15

Mesh Det etails ails

18 18 Conf nform

rmal

l Mes esh Prism ism Layer yer at th the SEI Ac Active ive Materi erial al Ele lectroly trolyte te

SLIDE 16

The full electr ctrod

de

e to be resolv solved ed – Mesh view

Symmetrical boundaries

n all external walls

SLIDE 17

The e proper perti ties es of the e Active Material rial are defined ined in the e physics sics continu ntinua

– Electrical conductivity – Diffusion coefficient – The parameter can also account for a dependence on the Temperature and Li-Ion Concentration

The e But utler er-Volm lmer er relat elations ions parame meter ers are define ined d in a panel el un under er the e relevant ant Liquid/So uid/Soli lid d phases ses inter erface ces

The Physic sics s set et-up up and Butler tler-Volm

lmer

er relat ation

SLIDE 18

Open questions:

After setup: cell capacity (Ah / coulomb)
During simulation: State Of Charge (SOC) and

corresponding Open Circuit Voltage (OCV)

Additional: average electrode concentrations to reinitialize at different SOC / OCV

Provide only:

Initial Setup (electrode regions & initial conditions)
(Open Circuit) Voltages where cell is defined as fully

charged / discharged Report computes amount of Li+ which can be shuttled between electrodes until upper / lower voltage attained

Re Report rt for r Batt ttery ery Ce Cell ll state ate

SLIDE 19

Re Report rt for r Batt ttery ery Ce Cell ll state ate

Resu sult lts: s:

C/10 full dischar harge ge rest

SLIDE 20

Resu sults lts during ing Charge rge

Lith thium m salt conc ncentra ntrati tion

n at 3 transient

nsient points nts throu

ugh

gh a charge ge 24 24 3D model 1D model

SLIDE 21

Solid lid Phase ase Concen entr trat ation ion – Liquid uid Phase se Electric ctric Poten enti tial al

1 min 2 min 3 min

SLIDE 22

Li Li-ion ion Concen entration tration diffusion usion in solid id phase

SLIDE 23

Elect ectric ic Poten enti tial al in Elect ectrolyt

lyte

SLIDE 24

Next xt Steps ps and Conclusion clusion

Initia itial l results ts prese sent nted ed Pub ublicat cation ion of valida dati tion

n paper

Begi gin n workin king g with h externa ernal l us users s Available able in STAR AR-CC CCM+ M+ 7.06 06 Fut uture ure developme elopments nts

Impr

mprove e the e mode del bui uild ld process cess

Extend work to “real” geometries
Model

del half-elect electrod

de

e to focus on the e Catho hode de or An Anode de desi sign gn

Measure

sure SEI EI overpo poten ential tial 28 28

SLIDE 25