euh. like , not release potassium hydroxide or anything else ? Isn't that what a seal does : keep stuff inside the containment vessel?
I believe that, at this point, it’s clear that explaining how an alkaline battery works is necessary. I avoided that so far, as chemistry is not my thing, but it seems unavoidable now.
Alkaline battery operation is described on Wikipedia and I will just sum it up. Zinc reacts with manganese dioxide, with potassium hydroxide acting as the electrolyte. Potassium hydroxide is dissolved in water, forming K
+ and OH
- ions, and the negative ions participate in the reaction. Theoretically the reaction is perfectly balanced.
Reality is, however, not perfect. Reactions do not happen instantenously, molecules are not everywhere in perfect proportions all the time and the entire process does not happen in a vacuum away from any other substance. We have positive potassium ions dissolved in water. Potassium loves reacting with water and that’s a very
violent relationship. While in an alkaline battery the raction is not as impressive as what you get by
throwing alkali metals into water, but it still happens — slowly, over time. And the reaction is: 2K
+ + 2H
2O → 2KOH + H
2. Do you see the second product? That is hydrogen, which slowly accumulates in the battery, increasing pressure.
If you have a perfectly sealed container and pressure rises inside that container, do you know what happens? Kaboom. Do you want kaboom that spreads a strong base, a mild neurotoxin, and a gas, which
mixed with oxygen in air will happily explode on any source of ignition? I believe not. That would deal much more damage not only your devices, but also you. So alkaline batteries have a seal at the bottom, which is expected to let pressure out safely. The battery still spills its guts, but only just a bit and in relatively peaceful manner.
The problem is not the seal. The problem is chemistry of alkaline batteries. It’s a problem inherent to their operation.