The cell cooling coefficient: A standard to define heat rejection from lithium-ion batteries

Alastair Hales, Laura Bravo Diaz, Mohamed Waseem Marzook, Yan Zhao, Yatish Patel, Gregory Offer*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

20 Citations (Scopus)

Abstract

Lithium-ion battery development is conventionally driven by energy and power density targets, yet the performance of a lithium-ion battery pack is often restricted by its heat rejection capabilities. It is therefore common to observe elevated cell temperatures and large internal thermal gradients which, given that impedance is a function of temperature, induce large current inhomogeneities and accelerate cell-level degradation. Battery thermal performance must be better quantified to resolve this limitation, but anisotropic thermal conductivity and uneven internal heat generation rates render conventional heat rejection measures, such as the Biot number, unsuitable. The Cell Cooling Coefficient (CCC) is introduced as a new metric which quantifies the rate of heat rejection. The CCC (units W.K-1) is constant for a given cell and thermal management method and is therefore ideal for comparing the thermal performance of different cell designs and form factors. By enhancing knowledge of pack-wide heat rejection, uptake of the CCC will also reduce the risk of thermal runaway. The CCC is presented as an essential tool to inform the cell down-selection process in the initial design phases, based solely on their thermal bottlenecks. This simple methodology has the potential to revolutionise the lithium-ion battery industry.

Original languageEnglish
Pages (from-to)A2383-A2395
JournalJournal of the Electrochemical Society
Volume166
Issue number12
DOIs
Publication statusPublished - 2019

Bibliographical note

Funding Information:
This work was supported by the Faraday Institution (grant number EP/S003053/1, FIRG003), the Innovate UK THT project (grant number 133377), the Innovate UK BATMAN project (grant number 104180), the Innovate UK CoRuBa project (133369), and the EPSRC TRENDS project (grant number EP/R020973/1).

Publisher Copyright:
© The Author(s) 2019.

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