Batteries crash simulation with LS-DYNA. Lithium-Ion cell. In collaboration with J. Marcicki et al, Ford Research and Innovation Center, Dearborn, MI

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1 Batteries crash simulation with LS-DYNA Lithium-Ion cell In collaboration with J. Marcicki et al, Ford esearch and Innovation Center, Dearborn, MI

2 Battery crash simulation (general) Car crash Mechanical EM Thermal CPM => Battery crush => local internal short => large localized current densities => Joule heating => temperature increase => thermal runaway => fire, explosion

3 Distributed Equivalent Circuit (1st Order andle) Cu Current Collector Page 3 Al Current Collector x (Macro Scale) Negative (Anode) Separator Positive (Cathode) Li + Discharge y x (into page) z Current collectors transport electrons to/from tabs; modeled by resistive elements Jelly roll (anode separator cathode) transports Li+ ions; modeled with andle circuit r 0 : Ohmic & kinetic r 10 & c 10 : Diffusion u: Equilibrium voltage (OCV) r m : Current collectors

4 Page 4 Standard EM resistive solver ϕ : potential E = - grad(ϕ) : electric field V = ϕ 2 ϕ 1 : voltage J = σ E : current density (σ = electric conductivity) div (J) = 0 => Δ ϕ = 0 + boundary conditions (Δ ϕ) 1 current flowing out at N 1 V= ϕ 2 ϕ 1 : voltage between nodes 1 and 2 - (Δ ϕ) 2 current flowing out at N 2

5 Introduction of randle circuits in resistive solver ϕ 2 ϕ 1 = u - r 0 *I V c r 0 *i + ϕ 2 ϕ 1 = u - V c i + (ϕ 2 ϕ 1 ) / r 0 = (u - V c ) / r 0 u r 0 i V c Page 5 FEM solve: (S 0 + D) * ϕ = b Where S 0 is the Laplacian operator (nds x nds) D has 1/r 0 at (N 1,N 1 ) and (N 2,N 2 ) -1/r 0 at (N 1,N 2 ) and (N 2,N 1 ) 0 elsewhere b has 1/r 0 (u-v c ) at N 1-1/r 0 (u-v c ) at N 2 0 elsewhere ϕ 2 ϕ 1 Actualization of randle circuits: andle circuit Page 5 i= (S 0 * ϕ)(n 1 ) V c (t+dt)=v c (t)+dt*(i/c 0 -V c (t)/r 10 /c 10 ) soc(t+dt)=soc(t)-dt*i*c Q /Q u=u(soc)

6 Page 6 Isopotentials Isopotentials can be defined and connected: The connectors do not need to be meshed. Enables alignment of cell simulations with experimental conditions (low rate cycling, HPPC, continuous discharge, ). short resistance voltage current

7 Page 7 andle circuits energy balance The different parts of the energy are tracked down E available = randle (u(t)*i(t) dt = randle u dq = randle Q/cQ u(soc) d SOC E delivered by u E delivered to load E joule heating in r0 = randle u*i dt = randle u load *i load dt = randle r 0 *i 2 dt E c10 = randle 1/2 C 10 * V c 2 Typical discharge of unit cell in a resistance

8 Page 8 EM/thermal connection T from thermal for r 0, r 10, c 10 vs T andle circuit Cu collector : EM+Thermal Al collector : EM+Thermal Anode : cathode : Thermal Thermal Separator: Thermal r 0 * i 2 added to thermal ITdU/dT added to thermal Allow correct material mass, heat capacity and thermal conductivity

9 T from thermal for r 0, r 10, c 10 vs T andle circuit Cu collector : EM+Thermal Al collector : EM+Thermal Anode : cathode : Thermal Thermal Separator: Thermal r 0 * i 2 added to thermal ITdU/dT added to thermal Allow correct material mass, heat capacity and thermal conductivity

10 Contact for Internal Short Models r s r s eplace randle circuit by resistance r s s * i 2 added to thermal Experiment + simulation (voltage, current, temperature) should give good models

11 andle circuits in LS-PEPOST Scalar potential Current density andle r0 andle SOC

12 Page 12 Contact illustration (1) Mechanical models for cells with very thin layers of materials of very different stiffnesses are still under investigation. In the meanwhile, in order to avoid the dificulties of the small thicknesses, model where the thickness was * 100, as proof of principle od crushes cell with 22 unit cells

13 Page 13 Contact illustration (2) Voltage vs time

14 Page 14 Contact illustration (3) Current density Temperature

15 Page 15 More at the 14 th International LS-DYNA User s Conference Dearborn, MI, June 12-14, 2016 A Distributed andle Circuit Model for Battery Abuse Simulations Using LS-DYNA Pierre L Eplattenier 1, Iñaki Çaldichoury 1 James Marcicki 2, Alexander Bartlett 2, Xiao Guang Yang 2, Valentina Mejia 2, Min Zhu 2, Yijung Chen 2 1 LSTC, Livermore, CA, USA 2 Ford esearch and Innovation Center, Dearborn, MI, USA Battery Abuse Case Study Analysis Using LS-DYNA James Marcicki 1, Alexander Bartlett 1, Xiao Guang Yang 1, Valentina Mejia 1, Min Zhu 1, Yijung Chen 1, Pierre L Eplattenier 2, Iñaki Çaldichoury 2 1 Ford esearch and Innovation Center, Dearborn, MI, USA 2 LSTC, Livermore, CA, USA