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Inside a Tesla Model S Battery Pack

teslamotorsclub.com

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Re: Inside a Tesla Model S Battery Pack

#21

Post by deeviant »

clumsysmurf wrote: post #16
greglindahl wrote: post #13

Earlier quoted context omitted.

Every article I've seen about the battery says that it doesn't use the usual chemistry, and that only the form factor is standard. I figured you would have something factual to say, given that you're saying you know it's dangerous.

I'm not sure what you are trying to do - but I almost fell for it. First, I specifically stated "3100mAH NCR-18650s" which is a specific part, not a form factor which anyone who handles these batteries would know - which was your first (confused) reply. Second, from everywhere I have read, like (1) these are just standard cells. Lastly, I was originally stating that I would feel unsafe being around this technology. I…

Yeah, I would be terrified of driving around in a car that's basically a metal box around a bomb ready to go, those batteries are deadly.

I think what needs to be done is to build a car around many gallons of highly flammable liquid.

Re: Inside a Tesla Model S Battery Pack

#22

Post by clumsysmurf »

deeviant wrote: post #21
clumsysmurf wrote: post #16

Earlier quoted context omitted.

I'm not sure what you are trying to do - but I almost fell for it. First, I specifically stated "3100mAH NCR-18650s" which is a specific part, not a form factor which anyone who handles these batteries would know - which was your first (confused) reply. Second, from everywhere I have read, like (1) these are just standard cells. Lastly, I was originally stating that I would feel unsafe being around this technology. I…

Yeah, I would be terrified of driving around in a car that's basically a metal box around a bomb ready to go, those batteries are deadly. I think what needs to be done is to build a car around many gallons of highly flammable liquid.

I'm waiting for Mr Fusion.

Re: Inside a Tesla Model S Battery Pack

#24

Post by api »

Gracana wrote: post #7

Interesting to compare this to the ford fusion battery[1], which uses clever construction to prevent a technician from being exposed to high voltages during construction and teardown. [1] http://www.etotheipiplusone.net/?p=3109

"The following images depict opening up and messing with a 275 volt DC power system. It will be exposed, be unfused, and be extremely dangerous. If you touch the wrong spots, you will commit suicide instantly. If your metal tool touches the wrong spots, it will explode in a plasma cloud and deposit itself on your face."

Love that warning.

"Do not look at it funny or it will explode and you will die."

Re: Inside a Tesla Model S Battery Pack

#25

Post by jacquesm »

v13inc wrote: post #19
Gracana wrote: post #7

Interesting to compare this to the ford fusion battery[1], which uses clever construction to prevent a technician from being exposed to high voltages during construction and teardown. [1] http://www.etotheipiplusone.net/?p=3109

That almost looks like it was built by a mechanical engineer, not an electrical engineer. All the effort seems to be focused on building a sturdy case for the batteries, and the actual electrical connections are all steel screw terminals and crimping, without any spot welding anywhere. I'd be worried about the electrical resistance of all those contacts, and the heat it produces. Tesla's battery pack seems like a mor…

At these elevated voltages the currents are manageable. If this were a 24V pack then your concerns would carry far more weight.

The biggest issue is vibration loosening a connection in the longer term but there are plenty of time-tested ways to avoid that from happening.

Even fork lift battery packs (which can carry immense currents) are still built using the crimp terminal/bolt through method.

Re: Inside a Tesla Model S Battery Pack

#26

Post by jacquesm »

That was one very quick trip to the recycler, pack dates from August 2013. Crashed car?

Totally nuts to work with DC voltages this high without taking safety precautions. Anything over 50V DC is to be treated with very serious respect.

AC is different, you get a good number of opportunities to dis-engage, but with DC your muscles contract and that's that.

I'd rather mess with 2 KV AC than with 200 V DC.

Lovely engineering on that pack by the way, the number of safety features is very impressive. Sure looks a lot better on the inside than mine ever did!

( http://pics.camarades.com/d/90045-1/IM000398.JPG )

(That's only 48KWh but at 48V so much higher current)

I think I've found the source of the pack:

http://www.teslamotorsclub.com/showthread.php/32687-For-sale...

Original asking price was $29K.

Re: Inside a Tesla Model S Battery Pack

#27

Post by DanBlake »

Asides from price, why not engineer a battery that did not rely on 18650 cylindrical cells? Seems like a bit of extra weight and lost capacity/space by using tons of 18650 batteries which each have their own casing instead of just making a 'brick' style battery, similar to those found in mobile phones (but obviously much larger).

Re: Inside a Tesla Model S Battery Pack

#28

Post by bigiain »

jonah wrote: post #23
agumonkey wrote: post #3

Pictures wouldn't load so I used https://web.archive.org/web/20140910232549/http://www.teslam... thanks again archive.org

It appears he was serving them off his personal NAS. Whoops.

His copyright notice and explanatory paragraphs make it clear he's trying to keep some level of control over those photographs, while still sharing them with "his community" - which means I feel a little uneasy about having archive.org unilaterally slurp the images up like that...

I know it's kind of a losing battle, but "publicly available" does not mean "in public domain".

Re: Inside a Tesla Model S Battery Pack

#29

Post by jacquesm »

bigiain wrote: post #28
jonah wrote: post #23

Earlier quoted context omitted.

It appears he was serving them off his personal NAS. Whoops.

His copyright notice and explanatory paragraphs make it clear he's trying to keep some level of control over those photographs, while still sharing them with "his community" - which means I feel a little uneasy about having archive.org unilaterally slurp the images up like that... I know it's kind of a losing battle, but "publicly available" does not mean "in public domain".

How do you feel about google images?

Re: Inside a Tesla Model S Battery Pack

#30

Post by jacquesm »

DanBlake wrote: post #27

Asides from price, why not engineer a battery that did not rely on 18650 cylindrical cells? Seems like a bit of extra weight and lost capacity/space by using tons of 18650 batteries which each have their own casing instead of just making a 'brick' style battery, similar to those found in mobile phones (but obviously much larger).

The ability to fuse the cells individually is a huge benefit. That means that if a cell shorts out internally only that little bit of capacity will disappear.
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