Accession Number : ADA575499


Title :   Expansion of Lithium Ion Pouch Cell Batteries: Observations from Neutron Imaging


Descriptive Note : Journal article


Corporate Author : ARMY TANK AUTOMOTIVE RESEARCH DEVELOPMENT AND ENGINEERING CENTER WARREN MI


Personal Author(s) : Siegel, Jason ; Stefanopoulou, Anna ; Hagans, Patrick ; Ding, Yi ; Gorsich, David


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a575499.pdf


Report Date : 21 Dec 2012


Pagination or Media Count : 16


Abstract : The expansion of battery material during lithium intercalation is a concern for the cycle life and performance of lithium ion batteries. In this paper, the electrode expansion is quantified from in situ neutron images taken during cycling of pouch cells with lithium iron phosphate positive and graphite negative electrodes. The impact of various charging cycles and rates on electrode expansion was investigated. At low C-rates the measured battery thickness was a function of State of Charge (SOC) and independent of a small external clamping force. A 0.3 % increase in total thickness was observed when charging the battery from 0 to 30% SOC, up to the stage 4-3 transition associated with the first voltage plateau. As the battery was charged beyond 30% SOC the expansion rate was reduced and then continued again after 70% SOC. The observed 0.5% expansion is attributed to a 1.7% swelling of the carbon anode; however the expansion of the negative electrode could be larger if the iron phosphate electrode also contracted during battery charging. This result is consistent with previous dilatometer experiments on lithium ion batteries with graphite materials which show up to 4% increase in electrode thickness during charging of carbon. The charging rate was shown to have a strong influence on the observed expansion. During high-rate cycling (5C charge and discharge over a voltage range larger than the advisable 3.6V high voltage limit), the battery showed a much larger and irreversible expansion of around 1.5% which was correlated with a 4% loss in capacity over the duration of 21 cycles.


Descriptors :   *LITHIUM BATTERIES , *NEUTRONS , ELECTRODES , EXPANSION , STOICHIOMETRY , STROBOSCOPES


Subject Categories : Electrochemical Energy Storage
      Nuclear Physics & Elementary Particle Physics


Distribution Statement : APPROVED FOR PUBLIC RELEASE