3 ms·
I wonder what phenomenon is driving this. A spent battery weighs more?
by iancmceachern 5y ago
I wonder what phenomenon is driving this. A spent battery weighs more?
- dragontamer 5y agoThe physical chemistry changes as a battery is spent. The internal chemicals are being converted from one molecule into another. Its not surprising to me that the two different chemicals have different physical properties. (Elasticity, density, who knows? They're a fully different chemical once the electrons move around)
- ChrisLomont 5y agoAlmost all the mass of a molecule is in atom nuclei, and these masses do not change under any battery chemistry I've ever seen. The only way to change mass appreciably is to add or remove atoms from the interior of the battery.
- thescriptkiddie 5y agoIIRC alkaline batteries produce some kind of gas while being discharged. When the battery is dead it is probably inflated like an unopened soda can, assuming it hasn't leaked.
- jandrese 5y agoIsn't that what the vents holes are for?
- thescriptkiddie 5y agoI'm not sure about alkaline cells, but NiMH and lithium cells have burst discs or some other type of pressure relief valve rather than just a hole. My assumption is that when alkaline cells leak they have over pressurized and blown the pressure relief valve.
- icodestuff 5y agoIIRC, new batteries contain a semi-liquid electrolyte, which damps the bounce. When discharged, it becomes much more rigid, so the battery bounces. Compare dropping a gallon jug with ~a cup of water in it vs a cup frozen into ice to see what i mean.
- ztakeo 5y agoHere's a good reference https://pubs.rsc.org/en/content/articlelanding/2015/ta/c5ta01576f/unauth https://pubs.rsc.org/en/content/articlelanding/2015/ta/c5ta0...
- exhilaration 5y agoPreviously discussed on HN: https://news.ycombinator.com/item?id=21693423 https://news.ycombinator.com/item?id=21693423