Sandy’s Tesla Battery Day Follow-up. Plus More!

[DougSpindler]

Sandy’s Tesla Battery Day Follow-up. Plus More!
Very interesting - Nice discussion the design of cars.

[trobbins]

I was hoping for some better discussion on the changed end tab arrangement in the new cell configuration, which Elon's talk indicated was a highly tabbed roll with flattened tabs.

[DougSpindler]

Sandy has another video where he said Tesla’s new battery design is brilliant.  He goes on to say how he he just doesn’t understand why folks at battery day missed something that great.

[wraper]

which Elon's talk indicated was a highly tabbed roll with flattened tabs.

Those are not tabs but base metal foil with laser cut edge which then is flattened into shingled shape after rolling. So all of the edge is a one big contact.

[trobbins]

Yeh 'tab' was a description of the extended foil that is nicely extended and folded - no doubt based on an FEA and manufacturable optimisation of many factors.

What's not clear to me is if they do a form of solder connection to the main interconnect/heatsinking path (as per soldering a FET drain tab directing to a heatsink/current conductor), and if so then whether that temperature rise is a compromise in any way.

[wraper]

I doubt there is any solder.

[trobbins]

Yeh the patent drawings don't show any soldering, so perhaps it is just compression.

[wraper]

BTW it's also acting as a heatsink, conducting heat away from inside of the battery. Because of this they will have simplified cooling solution on the bottom. Not need to run flat tube with micro-channels in between of batteries. As of connection, it may be whatever but soldering won't happen because it will cause heat damage the the battery and overall if poor solution for mass production. I don't know any batteries where it is used.

[trobbins]

As a step increment in lower per cell bulk electrical and thermal resistances, and reduced voltage and temperature differences between the base and the most distant small active surface areas within a cell roll, then hopefully it sidelines the cell from being a significant bottleneck to total system performance from peak power aspect, through to continuous improvement in battery capacity and longer availability resulting from alleviating internal cell hot spots and degradation (especially for ludicrous type operational modes), and as you say in simplifying or removing some auxiliary processes used to constrain temperature rise.

[tom66]

I wonder if then Tesla will use the positive or negative (or both) terminals of a given battery for coolant - could require some interesting thermal system design as coolant would need to be completely non-conductive and free of contaminants.

[NiHaoMike]

I wonder if then Tesla will use the positive or negative (or both) terminals of a given battery for coolant - could require some interesting thermal system design as coolant would need to be completely non-conductive and free of contaminants.

They could use transformer oil for coolant.

[Bud]

....which ignites magnificently and will be adding to the show in case of battery fires .