Precise Electrochemical Calorimetry of LiCoO[sub 2]/Graphite Lithium-Ion Cell

Abstract

The thermal behavior of a lithium-ion cell during charge and discharge was determined using an isothermal calorimeter. In order to assign the thermal characteristics of the lithium-ion cell to the cathode false(LiCoO2false) and the anode (graphite) material, a LiCoO2/normalLi cell and a graphite/Li cell were prepared. The thermal behaviors were compared with that of a lithium-ion false(LiCoO2 /graphite) cell. The notable thermal characteristics could be attributed to the individual electrode materials. In particular, the discontinuous thermal profiles showed good agreement with the phase change of the host structure of each electrode material. The degradation factor of commercially available lithium-ion cells was determined using these discontinuous thermal profiles as an indicator of the electrode reactions. We found that the decrease in the effective active material of the graphite is the main cause of capacity fading after cycling. © 2002 The Electrochemical Society. All rights reserved.

A Critical Review of Thermal Issues in Lithium-Ion Batteries

“…For example, Thomas and Newman 49 numerically integrated a convolution integral using an approximate Dirac delta function estimated from a previous experiment and also added the 300 s time lag to the deconvoluted heat generation rate to facilitate comparison with their model results. In contrast, Kobayashi et al 60 simply discharged at slow rates ͑ Ͻ C/10͒ and neglected the 600 s time constant. Self-discharge can be important for these long discharge times and complicate the 55 Natural convection and radiation through air Experimentally determined calorimeter constant Hong et al 56 …”

“…Bang et al 57 Conduction through isothermal heat sink ͑bottom only͒ Difference between test cell and dummy cell is the heat rate Kim et al 58 Conduction through aluminum heat sink 300 s time lag correction Kobayashi et al 59 Conduction through isothermal heat sink ͑bottom only͒ Neglected 600 s instrument time lag Kobayashi et al 60 Conduction through isothermal heat sink ͑bottom only͒ None given…”

“…However, because no investigations actually report the heat rate on a volume basis, cross-study comparison requires significant manipulation of the reported data. This includes estimating the heat rate from the total cell volume, [54][55][56][59][60][61][62][63][64][65][66][67][68]70 from the thickness of the unit cell 49 or the entire battery, 69 or from standard densities of full cells. 57,58 Unfortunately, these assumptions can greatly influence the estimated volumetric heat generation rate.…”

Electrochemical-thermal modeling and microscale phase change for passive internal thermal management of lithium ion batteries.

“…The primary experimental methods are accelerated-rate calorimetry (ARC) (Al Hallaj et al, 2000a;Al Hallaj et al, 2000b;Hong et al, 1998) and isothermal heat conduction calorimetry (IHC) (Bang et al, 2005;Kim et al, 2001;Kobayashi et al, 1999;Kobayashi et al, 2002;Lu et al, 2007;Lu et al, 2006a;Lu and Prakash, 2003;Lu et al, 2006b;Onda et al, 2003;Saito et al, 1997;Saito et al, 2001;Song and Evans, 2000;Thomas and Newman, 2003a;Yang and Prakash, 2004). The ARC method consists of measuring the heat rejected by the battery during operation while encapsulated in either air or solid material (e.g., Styrofoam).…”

Thermo-electrochemical study on cathode materials for lithium ion cells

“…The commonly used calorimetric methods include isothermal microcalorimetry and accelerating rate calorimetry. Some studies coupled cell charge-discharge test equipments with different calorimeters to measure temperature change or heat generation in charge-discharge process under different current densities [8][9][10][11][12][13][14]. But most literatures took the commercialized total lithium ion cell or half lithium ion cell as the research object.…”