These have to be 50 years old. Was the chemistry different back then? 50 year old Duracell’s would be completely covered in white chemicals.
Thoughts?
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Yeah, I’m thinking the chemistry used was different back then.
Newer technology is most likely cheaper to produce, but leaks.
“They don’t make 'em like they used to.” 
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I think the cans were probably a whole lot more robust also. I’ve watched a LOT of products be OK when they first come out. Then the material and construction is pared down, trimmed, weakened and generally compromised until it starts breaking routinely.
Remember when fridges lasted decades? Now the plastic parts are junk and breaking within 5 years-pretty much most models.
I’ve got a Maytag washer that is over 40 years old, used routinely, and doing fine. THAT doesn’t happen anymore.
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Good point, we all have had an appliance that just did not want to die.
Growing up we had a Norge refrigerator. Damn thing lasted 50 years. What do you think went bad? The rubber seal around the door got all sticky and fell apart.
Thicker metal walls, most likely. Takes longer for the electrolyte to eat through them. Possibly the electrolyte became neutralised by age before it managed it, because it’s not going to last forever due to impurities in the manufacturing process (IIRC, impurities are also the main reason along with heat accelerating the corrosion process that alkaleaks tend to leak as often as they do, so it sort of works both ways though). The electrolyte will degrade over time, which is the reason alkaleaks generally have an expiry date, normally 5-10 years out. The electrolyte available 50 years ago was probably also less pure so likely would degrade faster.
(edit: clarified what I meant)
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I’d expect these are zinc carbon batteries which don’t leak like alkalines, but have lower capacity and voltage under load.
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I recall reading that batteries used to have mercury in them, that prevented leaking and bulking.
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Those are zinc chloride cells, not alkaline cells. The physical designs and failure modes are not the same for those cell chemistries. They also had mercury in them, which prevented corrosion reactions and internal production of hydrogen gas. They have almost certainly dried out completely by this point, and are incapable of leaking now.
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Interesting, if they dont leak how come they never cought on? They are superior no?
Zinc-carbon (or “heavy duty cells” nowadays) predate alkaline cells. As far as I know alkaline cells broadly outperform them: superior energy density, power density, shelf life.
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Idleprocess is correct. Alkaline cells are higher in energy density, current capability, voltage stability under load, and shelf life.
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Shelf life? The batteries in the picture are 50 years old? I don’t think 10 year old alkalines would look as good.
Lower performance and energy density and higher cost, in addition to releasing mercury into the environment when people inevitably chuck them into landfills and incinerators.
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That makes sense.
I didn’t know this but have wondered why on occasion (mainly the occasion right after discovering a leak).
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Just because the exterior of the can still looks good after 50 years doesn’t mean they still actually work.
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Yes but the question was why haven’t they leaked, not why dont they still work. I think its mutually agreed upon that they stopped working many years ago.
They were listed in a 1949 ad for “only” 10 cents each. That would be about $1.27 in today’s money.
I have a Toshiba zinc-carbon cell (AA) from 1984 or somethin. (expiry date was 1986 stamped)
It still works great in an old calculator from same era, voltage should be around 1.3 volt or so. Maybe I can take a picture of it later.
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I have two maxell zinc carbon batteries which I got in aiwa vhs remote controller and it’s expiry date was in 1987. Batteries don’t have any sight of leak and voltage is about 1.35 volts.
I have some alkaline AA older than 30 years without leaking and voltage of more than 1.5 volts.
Only batteries which never leaks from my experience are maxell AA.