Lee Wrote:
It only works if you get every single detail right. That's expensive. You
can afford it for luxury cars where there is enough money to do it right.
But I have serious doubts that it can be scaled to mass-produce cheap EVs.
They'll get beat by the first company to figure out the best way to use far
smaller numbers of much bigger cells.
Complex solutions always come first. Simple solutions take longer to
perfect; but usually win out in the end.
>
Exactly Lee! So probably the real reason I wont buy a Tesla is I cant
afford one (because of the thousands of itty bitty cells that make it
expensive to manufacturer). Im still concerned about the long term
reliability and business model of a lower cost (aprox $30K) car that cant
afford to have Tesla Rangers field service guys running out to your house
when the battery burps like they do now on the high priced Teslas to cover
up the issues. As far as I know they havent shipped any lower priced Tesla
3s and would be surprised if they could turn a profit *without going to
large format cells like all other EV manufacturers*. Not sure if Elon
Musks Ego will let him make that change though, like Edison with DC who
had to be forced out of GE (When Tesla had a better idea with AC) Déjà Vu
Mark
Message: 6
Date: Fri, 12 Oct 2018 13:22:45 -0500 (GMT-05:00)
From: Lee Hart <leeah...@earthlink.net>
To: Electric Vehicle Discussion List <ev@lists.evdl.org>
Subject: Re: [EVDL] Why I Won't Buy a Tesla
Message-ID:
<20404926.1563.1539368565...@wamui-sassy.atl.sa.earthlink.net>
Content-Type: text/plain; charset=UTF-8
Rod Hower via EV wrote:
>>> You probably shouldn't use microcontrollers because they have
>>> millions of transistors with the potential of failure...
David Roden wrote:
>> I don't think it's quite the same. The microcontroller has lots
>> of semiconductors, but they're all formed at one go on one
>> substrate. OTOH, the lithium cells are individual units,
>> manufactured individually, with individually welded connections.
>>
>> I too was skeptical about the Tesla ant colony battery construction
>> -- which IIRC actually was used in earlier EVs with much less
>> publicity and far lower production numbers. I believe the T-Zero
>> Roadster was one of them.
Paul Dove wrote
> It?s called sarcasm!
(smiles) so true... but it's hard to recognize sarcasm when folks aren't
familiar with the actual situation.
Putting lots of parts on the same chip means the reliability of each part is
closely related to the rest. If one part is good, they're all good. If one
transistor is weak, or one resistor has a resistance too low, they are ALL
are weak or low resistance. And when one part fails, they all likely to
fail.
Same for batteries. Yes, a big cell is really a lot of small cells inside.
It may have multiple plates wired in parallel, or one big plate folded or
rolled into a cylinder (any piece of which would have been a fine cell in
its own right). All these little cells were manufactured at the same time,
and are "identical twins". Then they all get put in one big case, which
seals the whole lot of them. This means they will all be kept together, at
the same temperature, and experience the same charging and discharging
regimen.
Contrast that with individual cells. When they started mass-producing cheap
18650 lithium cells for laptops, many people independently came up with the
idea of using thousands of them to build an EV pack. The initial attempts
were failures, because there were too many differences between cells. Lots
of failures and fires. Alan Cocconi is the first person I heard of that
succeeded with them in his tZero. It required carefully matched cells, and a
BMS to individually monitor them. The tZero inspired the Tesla Roadster, and
led to their subsequent EVs.
It only works if you get every single detail right. That's expensive. You
can afford it for luxury cars where there is enough money to do it right.
But I have serious doubts that it can be scaled to mass-produce cheap EVs.
They'll get beat by the first company to figure out the best way to use far
smaller numbers of much bigger cells.
Complex solutions always come first. Simple solutions take longer to
perfect; but usually win out in the end.
--
Excellence does not require perfection. -- Henry James
--
Lee A. Hart http://www.sunrise-ev.com
Have a renewable energy day,
Mark
Mark E. Hanson
184 Vista Lane
Fincastle, VA 24090
540-473-1248 phone & FAX, 540-816-0812 cell
REEVA: community service RE & EV project club
Website: www.REEVAdiy.org (See Project Gallery)
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My RE&EV Circuits: www.EVDL.org/lib/mh
FREE Solar EV Charging! ; http://www.WeatherLink.com/user/MarkHansonREEVA
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