Researchers in Germany are providing some insight into the low-temperature performance issues of Li-ion batteries. In a paper in the Journal of Power Sources, they report on a combined in situ high-resolution neutron powder diffraction and electrochemical study on 18650-type Li-ion cells over a temperature range from 230 K to 320 K (-43 ˚C to +47 ˚C), with a focus on the graphite anode and the low temperature performance of the cell.
Safety issues along with the substantially reduced energy and power capabilities of Li-ion cells, operated at low temperatures, pose a technical barrier limiting their use in electric vehicles and aerospace applications.
… Instead of a quasi-continuous behavior as observed at ambient temperatures, an anomalous behavior occurs upon discharge at low temperature, primarily reflected in the abrupt character of the LiC12–to–graphite phase transformation and the unusual temperature dependence of the amount of LiC6. An instability of lithiated graphite phases at temperatures below 250 K (-23 ˚C) is observed, which affects the performance of Li-ion batteries at low temperatures.—Senyshyn
A. Senyshyn, M.J. Mühlbauer, O. Dolotko, H. Ehrenberg (2015) “Low-temperature performance of Li-ion batteries: The behavior of lithiated graphite,” Journal of Power Sources, Volume 282, Pages 235-240, doi: 10.1016/j.jpowsour.2015.02.008