A reaction that has reached chemical equilibrium no longer shows changes in reactant and product concentrations, but forward and reverse reactions are still going on. I'm confused whether a completely discharged battery is in a state of equilibrium.
Argument that an equilibrium has been reached
If I measure the cell potential, it will be zero. That means that the Gibbs free energy of reaction is zero, which is a property of a chemical equilibrium. When I discharge a battery by shorting it, there are concentration changes in the battery that cease when the battery is discharged, which looks like a reaction going toward and then attaining equilibrium.
Argument that this is not an equilibrium state
One property of a chemical equilibrium is that it is dynamic, i.e. the forward and reverse reactions are ongoing but occur at the same rate. For the battery, the reaction does not happen unless I close the circuit by electrically connecting the electrodes (e.g. shorting the battery with a wire). Even if I connect the electrodes with a wire, no current will flow because the battery is dead. So I don't see forward and reverse reactions going on. This would be like placing two beakers with 1 M aqueous salt solutions next to each other and saying they are at equilibrium. However, if the solutions were both contacting a dialysis membrane, ions would flow in either direction (at the same rate) so it would be fair to call this a state of dynamic equilibrium.
Which argument wins?
Is the discharged battery at a state of equilibrium or not? Does it matter whether the electrodes are connected electrically to decide on the answer? Does it make sense to discuss a state of equilibrium in the context of electrochemistry in the first place?