Sugar itself is not more energy dense than a battery, is it? You need an oxidizer to get energy out of something like sugar. In theory, sugar, gasoline, etc. are much more energy dense, but they need to be very carefully mixed with oxygen to release it all at once. That's why cars aren't generally bombs on wheels even though they theoretically contain sufficient energy to meet that description.
The thing with batteries isn't just the amount of energy that they contain, but that it comes entirely pre-mixed and ready for instantaneous release.
As far as normal batteries withstanding physical abuse, I don't know. I certainly wouldn't try puncturing or badly overheating a regular battery, and wouldn't be surprised if such treatment caused it to release what it has. I could, of course, be wrong.
Alkaline batteries can explode however it is quite different than the failure of Lithium batteries. If shorted out or exposed to current they can produce heat and hydrogen gas and because they are in a sealed metal canister they pop, sometimes violently. Note that this is different than Li-ion which can short out internally.
Considering how much more common standard batteries are, you can assume it is indeed pretty rare.
As for the energy density of sugar you're right that they're not really directly comparable but yeah I think it is more energy dense. Actually, wikipedia has a nice table for it:
I think we're actually in agreement here. My whole point was that the chemistry of how the energy is released is more important than the energy density.
Yeah, just some quibbling over details. My point is just that any battery that's as energy dense as a modern Li-ion battery will have similar potential to cause havoc if abused, and the problem will get worse as the tech improves because we'll be packing more and more energy into our pockets and backpacks. Maybe it is the chemistry more than the density, but I'm going to bet that any chemistry with comparable density would share the same problem. So, mildly different perspectives on the same ultimate effect, I think.
The thing with batteries isn't just the amount of energy that they contain, but that it comes entirely pre-mixed and ready for instantaneous release.
As far as normal batteries withstanding physical abuse, I don't know. I certainly wouldn't try puncturing or badly overheating a regular battery, and wouldn't be surprised if such treatment caused it to release what it has. I could, of course, be wrong.