The ideal battery temperature for maximizing lifespan and usable capacity is between 15 °C to 35 °C. However, the temperature where the battery can provide most energy is around 45 °C. University research of a single cell shows the impact of temperature on available capacity of a battery in more detail.
For this blog, it's important to note that the optimum temperature for lithium-ion battery cells falls between 15 - 45 degrees Celsius. If the battery cell temperature falls outside these parameters, the battery cell can be damaged. So, how is battery cell temperature monitored in EVs, and what happens if temperatures fall outside these parameters?
However, the temperature where the battery can provide most energy is around 45 °C. University research of a single cell shows the impact of temperature on available capacity of a battery in more detail. The below data is for a single 18650 cell with 1,5 Ah capacity and a nominal voltage of 3,7V (lower cut-off 3,2V and upper cut-off 4,2V).
In the UK, winter temperatures average between 0 - 7 degrees Celsius - that’s between 8 to 15 degrees colder than a lithium battery can optimally perform. Due to the internal kinetics of the battery cell, colder temperatures slow the chemical reaction.
A sub-optimally designed battery pack reaches higher temperature fast and does not maintain temperature homogeneity. According to the best design practices in the EV industry, the temperature range should be kept below 6 degrees for a vehicle to perform efficiently. Fig 1. Cell Temperature for Case I
In the UK, winter temperatures average between 0 - 7 degrees Celsius - that’s between 8 to 15 degrees colder than a lithium battery can optimally perform. Due to the internal kinetics of the battery cell, colder temperatures slow the chemical reaction. What does this mean in real life? 10 - 15% less driving range.