Meaning
Irreversible loss of capacity and power capability caused by operating battery cells in environments below their design temperature range. Exposure to freezing conditions during charging triggers low-temperature cell degradation through the formation of metallic lithium on the anode surface. This process permanently reduces the amount of active lithium available for energy storage.
Lithium Plating
Ion diffusion slows down considerably as the temperature drops, causing ions to accumulate at the electrode interface. Because the graphite lattice cannot accept ions quickly enough, low-temperature cell degradation results in a solid layer of lithium metal outside the anode. Dendrites may grow from this layer, potentially piercing the separator and leading to internal shorts.
Electrolyte Viscosity
Electrolyte becomes more viscous and sluggish in cold weather.
Operational Limit
Power delivery drops as the internal resistance of the cell climbs in response to the cold. Once low-temperature cell degradation has occurred, the battery will exhibit higher heat generation even after returning to room temperature. Management systems must enforce strict current limits to prevent the onset of these damaging conditions.
Procurement specifications for electric vehicles often include minimum performance standards for sub-zero operations to account for these risks. Owners see reduced range and longer charging times as the software protects the hardware from permanent failure.
