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Takano, Kiyonami; Saito, Yoshiyasu; Kanari, Katsuhiko; Nozaki, Ken; Kato, Ken; Negishi, Akira; Kato, Tohru

doi:10.1023/a:1015547504167

Cited by 65 publications

(39 citation statements)

References 12 publications

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“…A portion of the resistance to electron flow resides in the joint formed between the current grid tabs and the terminals. In short, for a cell that has no cooling plate applied to its cathode tab, this relationship can be stated as: Q Joule =Q cell core +Q anode tab +Q cathode tab [2] The total heat generated within the cell core is the sum of all sources of heat from that assembly (resistive, polarization, and entropic). Cooling the cathode tab would have the effect of removing the last term on the RHS of Eqn.…”

Section: Theoretical Analysis: Heat Generationmentioning

confidence: 99%

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Thermal Effect of Cooling the Cathode Grid Tabs of a Lithium-Ion Pouch Cell

Bazinski

Wang

2014

J. Electrochem. Soc.

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Infrared thermography shows that the joint between the cathode grid stack and the cell tab is a source of Joule heating within a lithium-ion pouch cell. This can exacerbate thermal gradients within the cell core if the C-rate is sufficiently high. This paper studies the heat generated at the cathode tab joint of a 14Ah lithium iron phosphate (LFP) pouch cell. The heat generation was quantified by using an energy balance equation and the average heat transfer coefficient was calculated by modeling the cell as an isothermal vertical plate in natural convection. The influence of this heat on the cell's thermal gradients was studied during a 3C and 8C rate of discharge. It has been found that removal of this heat at its source can appreciably lower the overall average surface temperature of the cell. However, at a 3C rate discharge, the removal of this heat can induce a greater thermal gradient within the cell core. At an 8C rate of discharge, there is a minimal improvement in the temperature gradient. As a result, a thermal management system which incorporates cathode tab heat removal would most likely be an ineffective design feature. Maintaining uniformity of temperature between cells is an important factor in the thermal management of lithium-ion batteries. It is desirable for this variation to be in a tight range.1 Rugh et.al. stated that temperature gradients should be kept to less than 3• C to 4• C throughout the battery pack.2 Failure to meet this criterion has a direct effect on decreasing the battery pack life. In addition, they also advocate an operating temperature range of 15• C to 35• C for the pack. Excursions beyond this range have repercussions as well. It has been found that the lifespan for a lithium-ion cell is reduced by approximately 2 months for every degree of temperature rise while operating in a temperature range of 30• C to 40 • C. 3 Capacity and power degradation is also accelerated at elevated temperatures. 4-9The lithium iron phosphate (LFP) cell chemistry is gaining wide acceptance in electric vehicle applications.10 Its inherent ability to tolerate abusive conditions and resist thermal runaway is especially attractive to battery pack designers. Battery manufacturers have responded by offering high capacity cells in a pouch format. This format affords better packaging efficiency and offers a very favorable area-tovolume ratio to facilitate thermal management. As a result, this work uses a high capacity LFP pouch cell.The temperature near the cathode terminal of a pouch cell is consistently higher than that at the anode, due to differences in the thermal conductivities of the metals used as current collectors. This is true regardless of the particular lithium-based electrochemistry being used.

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Section: Theoretical Analysis: Heat Generationmentioning

confidence: 99%

“…2 Failure to meet this criterion has a direct effect on decreasing the battery pack life. In addition, they also advocate an operating temperature range of 15…”

mentioning

confidence: 99%

Thermal Effect of Cooling the Cathode Grid Tabs of a Lithium-Ion Pouch Cell

Bazinski

Wang

2014

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…As known to all, cell internal impedance consists of ohmic impedance, solid electrolyte interface impedance, charge transfer resistance and diffusion [22] . Although the V -I characteristic provides with the information of internal resistance, electrochemical impedance spectroscopy (EIS) technique can provide us with more detailed information about over potential resistance [23] . Using the EIS technique, the polarization resistance and ohmic resistance could be analyzed at different frequency.…”

Section: Determination Of Resistance By Ac Impedance Metermentioning

confidence: 99%