As the title says, this doesn't really belong here, but I thought it could be interesting to see what can happen if you overcharge li-ion cells.
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I actually watch one of those. The one with the Disney car. The thing is from the 1930’s for god sake and was designed for golf cart batteries. The guy dumped TWO Tesla battery packs into it without modifying the thing much simply because there was room. I was predicting this one. You do not mix pre and post li-ion technologies without thoroughly exploring the entire electrical system. He didn’t.
There are more than 7000 18650s in a Model S or X, and something like 5000 21700s in a Model 3...
Does anyone know why Tesla uses 'canned' cells, surely all that additional metal is unnecessary weight? Surely a larger form factor arrangement would be more efficient and lighter.
I don’t know why, but Tesla is famous for having more car battery experience than basically everyone and their battery packs are famous for being the best out there. They’re particularly good at cooling which may also have something to do with it. Also something me flamebuggy didn’t pay attention to. Heat pipes are great for cooling but they actually have to be attached to something
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Yes, he did install two battery packs, but a Model S has something like 14 of these, so two doesn’t seem excessive. From what I know (as seen in a subsequent video) someone who doesn’t know anything about li-ion batteries and charging hooked the batteries up to a 45 V charger, whereas the batteries had a voltage of 42.
I think it's just to bridge the time until they have their own battery factory. They wouldn't have any batteries to put in cars if they waited for that to be finished.
Personally I think the can weight is less of a problem than the wasted space inside a 18650/2X700 pack.
What's the weight of a can in comparison to the entrails? A LGHG2 weighs 49g all in all, I would assume the can is less than 5% (at max) of that, times 7000 would be about 17kg - not that much weight, that's around the weight of a spare tire, and I consider that the upper bound of the total can weight.
Good point, the wasted space is as much of an issue. This is why mobile phones are now shifting to built in non-user replaceable batteries. The space you save on additional casing, connections and enclosure walls makes a big difference in overall size in the context of a phone. The additional benefit for the manufacturer is that the user has to replace the phone every two years.
I thought their Gigafactory is already up and running. It’s going to be much larger still, but it’s producing battery packs for Tesla cars right now, I’m pretty sure about that.
As for the form factor, it doesn’t seem to be a problem, since apparently the Tesla cells are ahead of the pack in the relevant categories (Tesla claims that their cells perform better than anything else on the market, and some ‘experts’ agree).
I’ve read something as to why Tesla prefers the 18650/21700 format over larger, ‘custom’ made cells for individual car models: With these little cells, it’s possible to create any kind of larger batteries, just by combining them into larger modules. It allows them to produce batteries for all of their cars, their semi truck and even the power wall with the same basic cell, and if they manage to improve the chemistry of the cell, all of their products will benefit immediately, without any retooling or anything like that.
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