Cell internal resistance strongly depends on the temperature of the cell. The lower the temperature the higher the resistance.

Ballpark cell internal resistance values at 25°C: 1-5 mΩ (see chart below), but increases significantly at low temperatures. Also, resistance depends greatly on the size of the cell and chemistry: Large cells have a lower internal resistance.

Both cell internal resistance $R_0$ and the resistor-capacitor parallel resistance (see Cell diffusion voltage) decrease exponentially with temperature:


Resistance also depends on the applied current and the State-of-charge of the cell [2]. The discharge resistance is relatively constant at SOC above 50 %, and increases with decreased SOC at low-SOC range [3]. Charge resistance is smaller than discharge resistance.



This result agrees with this from [4]:


In the following chart, the instantaneous voltage change is due to cell internal resistance $R_0$, and the exponentially slowing Cell diffusion voltage change is due to diffusion processes.


Cell internal resistance affects the Cell overpotential after periods of charge or discharge.

Example of resistances $R_0$:

These internal resistances lead to Joule heating losses from 1% to 3% of the cell energy capacity when a cell is charged at 1C.

Estimating cell internal resistance using current jumps

Internal resistance rises slower with calendar storage in LFP cells than in NMC cells

See also: