#15 The Engineering of Tesla's Structural Battery Pack

This video covers how the Tesla Structural Battery Pack works - the key points. The following video will cover how I think the battery pack is manufactured from the cell up.

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*Timeline*
00:00 Intro
00:58 Vehicle Structure
02:21 Conventional Pack
03:22 Structural Pack
06:53 Polar Moment of Inertia
07:51 General Layout
10:12 Modularity
11:01 Recycling
11:42 Negative Mass
13:24 Summary

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Intro Music by Dyalla: Homer Said

[andrewbuck]

I still occasionally hear about people having battery pack failures. With a structural pack, would a battery pack failure mean they'd have to throw the whole car away?

[richard]

Anyone else find it amazing that we are now on PART FIFTEEN of the videos explaining battery day? I'm not sure if that shows just how much Elon wants to innovate or how incredibly deep your videos are able to explain the finer details. I'm sure is a combination of both. Kudos to both of you!

[Sekir]

Engineer here. That's why I commented on your latest video that I can hardly wait this one! Shear force explanation: it was very well done, I don't think an in depth explanation would be needed for this video. Another note: structural battery pack and front/rear castings integration will happen with bolts. I base my conjecture on these: the casings are made of aluminium, and the battery pack housing seems to be steel, those two are very hard to weld together. Second: if servicability(?) is important any damage to these parts will result in throwing away the whole car! Bolts makes a much more reasonable choice here.

[cwmaguire]

Okay, you win. I want to ensure you can keep doing this so I'm supporting you on Patreon and voting with my wallet.

[madhusudhan]

As a mechanical engineer, this was the most awaited video for me. This is awesome channel.

[ZachMeador]

This channel is one of my favorite ones to support on Patreon. Jordan’s the GOAT

[MrRickyw]

Your description is very good. The key point that you make is in conveying that the battery shell is in intimate contact with the battery immediately adjacent to the next battery. The same concept is explained when you compare the breaking of a single straw versus the force required to break dozens of straws while each straw is in intimate contact with the next straw. However, in a micro analysis sense, all failures described as 'shear' failures are really failures in compression/tension. However, we use the word 'shear' failure as a generic expression of failure modality.

[kschleic]

I agree with your assessment that coolant will go under the cells... Not only does it lower the CG, but the coolant channels could be designed to provide a crush structure to protect against underbody levering or spearing impacts.

[FutureAzA]

Fascinating as always. I always wondered what sort of cascade we'll see as weight comes down. Lighter pack means we need fewer batteries to get the same range, but that could also mean lighter wheels, tires, brakes, and other components. Reduce that weight, now we need an even smaller battery, which reduces weight again.

[oisiaa]

Other manufacturers claim they have "structural battery packs", but that just means they have beefy battery cases and transmit some load through them. Tesla is actually using the individual cells themselves as structure and is transferring 100% of the load through the battery.

[quietbydayYT]

Also interesting are the implications for electric flight. Developing the technology and fine-tuning manufacturing to make batteries structural could really reduce weight for flight applications (similar to the wing-as-fuel-tank design of modern planes mentioned during Battery Day).

[timellemeet]

If I understand correctly the new charging curve will be improved by:

1. More Silicon
2. Tabless (less resistance/heat)
3. The better cooling system from the new pack design

[oooChickenatorXooo]

Your videos are the best, and I find that when I see one in my Notifications, I usually pause my YouTube queue and watch the new TLF instead.

One small note: I found the milk jug example a tad cumbersome.

People intuitively understand polar moment of inertia almost without explanation, no matter how daunting the phrase "polar moment of inertia" may at first seem.

The image that I have seen others use to create that Eureka moment in the learner's mind, is to mention the phenomenon where a figure skater who is in a spin speeds up when she pulls her arms in close to her body.
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[JesbaamSanchez]

Thank you so much Limiting Factor!

I'm actually watching your videos to understand more about the battery since I've been offered a position in battery manufacturing for Tesla!

Your videos is helpful (even if you are not an expert)

[JanneWolterbeek]

Thank you. Jordan can do a deep dive and still be good to follow for those who are less informed.

[JoshuaPolier]

Great point about convection. 🔋 🚀 great video !

[jamesowens]

Another excellent analysis. I'm an aerospace/mechanical engineer, and I think your explanation of the advantages of the cells bonded to the face sheet is dead on. This set up is essentially the same as the composite sandwich structures that we use in aricraft and spacecraft to keep the mass low. A typical sandwich construction would use carbon fiber composites with aluminum honeycomb core. The aluminum walls are very thin (a little thicker than aluminum foil), yet they're excellent at tying the load paths of the face sheets together. Great stiffness for the weight.

[alexvoigt]

Great video, as an Engineer I agree with the vast majority of your points. A couple of other forces for instance and effects on rigidity and driving behavior come into play too but nothing that conflicts with the overall message of your video. The new design of the 4680 and the new structural design in the vehicle allows further improvements on the castings that have another positive impact on weight as well. In addition this new design opens the door for further improvements Tesla won't start with at version one but for future iterations.

[jooptablet]

Been looking forward to this one for so long!

[danielcarlson]

thank you for good quality information it's hard to find it without manipulation.