BATTERY OPERATIONSBatteriesInternalResistanceFigure 9 Internal Resistance in a Chemical CellInternal resistance in a chemical cell is duemainly to the resistance of the electrolyte betweenelectrodes (Figure 9).Any current in the battery must flow through theinternal resistance. The internal resistance is inseries with the voltage of the battery, causing aninternal voltage drop (Figure 10).With no current flow, the voltage drop is zero;thus, the full battery voltage is developed acrossthe output terminals (V_{B}). If a load is placed onthe battery, load resistance (R_{L}) is in series withinternal resistance (R_{i}).When current flows in the circuit (I_{L}), the internal voltage drop (I_{L}R_{i}) drops the terminal voltageFigure 10 Internal Voltage Dropof the battery as shown in Equation (4-3). Thus, internal resistance reduces both the current andvoltage available to the load.V_{L} = V_{B} - I_{L}R_{i}(4-3)ES-04 Page 12 Rev. 0