Munro: Tesla 4680 Battery Pack Prophecy

ajdelange

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Who's on first?
 

VI Tesla

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Don't know that I agree with his spot weld hypothesis. I understood that the tiny wires were intended to act as a fuse. Should one cell short, it's physically removed from the circuit.
 

ajdelange

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Yes, that occurred to me too. If you look at some of the YouTube videos on how to make your own battery packs you will quickly learn that there are people manufacturing nickle sheets with lots of holes each about the size of the end of cylindrical battery cell. In the center of each hole is an island of nickle sheet suspended from the main sheet by a couple of thin isthmuses - all stamped from the same sheet. The central disc is spot welded to the battery contact and the isthmuses conduct current to the main sheet thereby serving as fuses.
 
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Crissa

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Don't know that I agree with his spot weld hypothesis. I understood that the tiny wires were intended to act as a fuse. Should one cell short, it's physically removed from the circuit.
We don't want the cells to fall out of the circuit, though. That's a loss of voltage.

Welding is how the batteries are usually connected, In fact, batteries are made with a coating that resists soldering, and have to be fuse welded if you want to connect them permanently. This is oretty standard practice.

If you're at the point of needing that little wire as a fuse, you're at thermal runaway. And that's a different issue, really.

-Crissa
 

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I agree with the method of spot welding battery terminals to a type of branch terminal that includes a fusible link. Spot welding is fast and a cheap operation to perform plus its very reliable connection. I have two battery packs that are constructed this way. I disassembled one pack for a BMS failure and all the batteries in the pack were still securely connected to branch circuits. I am not sure if a multiplate conductor is going to be used to connected all the batteries together, in my mind I think about amperage load and the ability of connector to allow for slight expansion in battery pack.
 
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