this post was submitted on 06 May 2024
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That’s a lot of words to say, what you said is absolutely how battery packs work to limit total failures.
Can you provide a link to a battery pack design that is one total massive cell like you’re saying instead of multiple individual? Other than some thing like a AA or AAA battery….
How much do you think a length of wire weighs compared to the weight of the pack? You’re making to seem like it will add 30% weight here or something, the weight is negligible, why are you even mentioning it?
Not sure where you're getting "one total massive cell" from anything I wrote.
Every pack is made of a bunch of smaller batteries. You can't get 400v without batteries in series, from batteries that only make ~3v.
Just saw your last paragraph edit. It's a car pack, every ounce matters, and doubly so when it only adds complexity, reduces efficiency, and reduces reliability.
And an estimate of weight of the extra interconnect.... let's say it's 8' from back to front of the pack, a 350v pack and a 250kw motor. This means minimum of 715 A. Busbar that is rated for 700-800A @30c rise has cross section of 1/4"x2". For the 8' length that means we have 48in^3 of copper. That is ~16lbs of copper alone. Not counting the contactors, insulation, etc.
So 1% of a 1600lb pack? Wow so detrimental….
It is, especially when the choice that leads to that extra weight is less reliable, less efficient, and more costly. All things you don't particularly want in a car
So let's get back to the real discussion on how the packs actually work. Can you explain how a microcontroller is supposed to put cells in and out of the circuit?