Issues with the discharge port I can see include the issues that:
- broken circuit means energy will struggle to get anywhere even if you wanted. Solving for this increases complexity substantially and non-linearly.
- maximum discharge rate of the cells could mean even at max output it could take well over 10 minutes to depower if not much longer (and discharge also has a trade off of them heating up accordingly at higher discharge rates)
Ultimately, you have a lot of embodied “loose” energy and once the reaction has left your control and the walls of the cell are breached (and enough of them), it’s more akin to a collection of little firecrackers that “combust” when they touch each other rather than a fire that can be “extinguished”. Just in slow motions because they are metals.