Guest lecture by by Dr. Rachid Yazami (Nanyang Technological University)

Innovative solutions for lithium ion batteries future development 1
When:
August 12, 2019 @ 11:00 am – 1:00 pm
2019-08-12T11:00:00+06:00
2019-08-12T13:00:00+06:00
Guest lecture by  by Dr. Rachid Yazami (Nanyang Technological University)
Topic: Innovative solutions for lithium ion batteries future development
 
Please register for the event here.
Date: August 12Monday
Time: 11.00 am
Venue: 6.105 
 
Abstract:


The thermodynamics properties of a battery full reaction such as the Gibbs free energy ∆G, entropy ∆S and  enthalpy ∆H can be determined by open‐circuit voltage measurements vs. temperature (OCV, E0 vs. T) at  different  states of charge of the  cell  (SOC)  using  equations:

It is found that ∆G, ∆S and ∆H vs. SOC profiles are characteristic of the battery’ chemistry and state of health (ageing, SOH). Also, a universal empiricallaw has been unveiled which governs all batteries tested, that is the state of charge is a linear function of entropy and enthalpy:

SOC = α + β ∆S + γ ∆H,

in which the α, β and γ variables depend on the cell’ chemistry and SOH.

Moreover, a minute analysis of the ∆S and ∆H profiles enables detection of early steps of internal short‐circuit formation, therefore reducing the risk ofthermal runaway and proving the state of safety (SOS).

We  will  also  show  how  thermodynamics  data help with the fast  and  adaptive  charging of lithium ion  batteries. Full charging        below   1h      using conventional      methods        such     as    constant current constant voltage and multi‐step constant current methods, CCCV and MSCC, respectively causes premature deterioration of the battery performances. Our non‐linear voltammetry method enables fast charging below 30 min without premature end oflife and safety issues.