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It's the Batteries, Stupid!

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"dependence on imported batteries"

Are there any potential hardline battery exporting nations??? And anyway, what's stopping the US building up it's own manufacturing base. Again?

That's true, but I think what one of the commenters mentioned is true too, that the battery pack is more like an engine, a part that isn't replaced for the car's lifecycle. Electricity is the fuel. Foreign made batteries are as much a threat to national security as foreign made consumer goods; these things we could always build at home if the situation calls for it, but for resources like oil we really have no choice. Yes it's probably bad for the job market in the US, but it doesn't directly related to security, esp since the countries they listed as primary battery producing nations are Japan and Germany, both strong allies to us.
 
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Nice little primer on battery technology and who is using what today:

Market for Electric Vehicle Batteries Is Heating Up - Seeking Alpha
The big breakthrough was NiMH (nickel-metal hydride) batteries. This technology was developed by a very bright and energetic older gentleman named Stanford Ovshinsky. It was truly a game changer. NiMH batteries were first tried in the electric vehicles used in California several years ago. In 1999, General Motors used NiMH batteries in the EV-1 electric vehicle, giving the car a range of 140 miles. Southern California Edison put a combined 7 million miles on 320 electric Toyota RAV4’s, and concluded that the NiMH battery would last 130,000 to 150,000 miles. Ovonics was acquired by Energy Conversion Devices (NASDAQ: ENER). In 1994, GM bought 60% of ECD, and then in 2000 Texaco bought GM’s share of ECD, and in a 50/50 partnership with ECD, created a spinoff battery company called Cobasys (which owns the patent to NiMH technology). Shortly thereafter, Texaco was acquired by Chevron (NYSE: CVX).

Carmakers today are mostly focused on lithium batteries. In the past several years lithium batteries have become the standard for laptops and cell phones, because they hold the most charge of commonly available batteries. Tesla Motors, which started shipping it’s first electric car this year, leveraged the existing battery technology by making a battery pack out of 6800 lithium batteries, each of which are about the size of a standard “AA” penlight battery.
 
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...lithium batteries, each of which are about the size of a standard “AA” penlight battery...

I just took this photo comparing 18650 cells (from a flashlight) to more common AA, C and D sizes.

2996406708_c2137d60eb_o.jpg


Is that like a bad joke that the Li-Ions are called "UltraFire" with a logo of a burning fire?!
 
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I just took this photo comparing 18650 cells (from a flashlight) to more common AA, C and D sizes.
Thanks, for that. I figure people often make that comparison primarily because the aspect ratio is so similar to that of AAs.
Is that like a bad joke that the Li-Ions are called "UltraFire" with a logo of a burning fire?!
:eek:

Someone else worried about lithium:
Swapping Peak Oil for Peak Lithium? - Future of Lithium Auto Batteries | Hybrid Cars
 
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Bill Arnett (Tesla Customer) posted this photos of a real Tesla 18650 next to consumer cells:
display_data.php


Based on the pattern on the positive terminal of the battery, I am guessing Sanyo...
sanyo_ur18650fh-2000mah_03.jpg

China_ANCOO_TECHNOLOGIES_HK_CO_LIMITED20088222114285.jpg
 
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What do the Matsushita cells look like?

The guy from Asahi Shimbun asked me for my best guess as which supplier Tesla uses, and I pulled Matsushita out of my err... hat. I said likely Sanyo or Matsu, but ultimately came down on the side of Panny for no particular reason.




.
 
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Thanks David

Panasonic seem to prefer the "It" symbol instead of C Rate, which

Represents "Current" and is defined as follows It(A)= Rated Capacity (Ah) / 1(h).

Looks like it's the same value.

They seem to recommend 0.7 It for charging http://industrial.panasonic.com/www-data/pdf/ACA4000/ACA4000PE4.pdf

So for a 2900mAh cell that would be about 4.1 A for about 40 minutes (I think in practice you have to charge in pulses with cell balancing stuff in between)

Can't find an acceptable discharge rate range.
 
Yeah, I couldn't find that either, but the discharge curves available in this old PPT http://download.intel.com/idf/us/docs/PS_EBLS003.pdf give pretty good performance, but only list 0.5C and 1C discharge rates. Something of a mystery battery, since other than that Asus, I haven't seen mention of it used anywhere else. Increasing battery capacity has got to be the easiest way to cut weight and increase performance available to Tesla. With prices so much lower than where they were two years ago, its almost a no brainer. And it would help neutralize those "fat elise" comments that the reviewers like throwing around.
 
Well I think the Roadster may be stuck with the "fat Elise" taunt. Reducing battery weight would mean re-designing the pack which would require redoing all the crash tests etc etc. When there's Model S and Bluestar (Model T?) to roll out then maybe Tesla will revisit the Roadster if they reach their 25th Anniversary.

Here's hoping - on both counts.