True? Toyo loses $5k per Prius on battery?

The Telsa Roadster is based on a stretched Elise. Lotus also has a car based on a stretched Elise called the Evora. I suspect the Telsa Roadster shares much more than airbags with the Evora.

 

The chassis is unique. All the body panels are unique. Everything in the drivetrain is unique. The dash and instrumentation is unique. There really is very little left that could be shared. The airbags were retained since an airbag company was not going to create and certify a new design for a low volume production car. This detail was discussed in:

http://www.teslamotors.com/blog3/?p=74

 

Your link doesn't discuss the Lotus EVORA at all. All it says is that shares less than 7% of it's part content with the Lotus ELISE.

From Telsa:
"One of the more common misconceptions about the Tesla Roadster is that it is an electrified Lotus Elise. This has been an interesting problem to deal with because the Tesla is vastly different from an Elise and it is important that people are aware of this. In fact, we recently counted how many parts the two cars shared and the total number was under 7% by parts count. If you were to analyze it by parts value, the number would be even smaller."

I would be amazed if a company as small as Lotus developed a completely new car for Telsa and a completely different new car for themselves at the same time. I'm sure that it is just a coincidence that the Telsa and Evora were introduced in 2008.

From Lotus:
"And when it comes to creating niche sports cars, Lotus is in an enviable position - the platforms of our own products can quickly and cost-effectively become the underpinnings for our clients' vehicles."
» Services & Technologies » Niche Vehicles » Lotus Platforms

 

The Prius battery is 1.3 kWh, and Toyota are paying Panasonic EV about $500 per kWh for their current batch of NiMH batteries, which comes to about $650 at cost per Prius battery.

It would be lower than this, but high nickel prices have prevented the greater fall in NiMH battery costs Toyota were anticipating. This is partly why they are flat out at Panasonic EV trying to develop a workable lithium-ion battery, as these are currently CHEAPER than NiMH on a $ per kWh basis (ie around $300 per kWh in volume). They are currently a long way behind the competition in this respect because they were trying to make cobalt oxide based electrodes work (high energy density but poor safety and cycle life).

 

I invite everyone to post a comment to the following - Set 'em straight people...

Dueling Views on Hybrids in Today's Detroit News | Hybrid Cars

 

If that's true, Toyota can make 4kWh battery pack for under $2,000. The recent billout has the tax credit of $2,500 for a plug-in car with 4kWh. If that cost estimate is true, Toyota can make $500 on every battery pack sold AND the buyer get it for FREE.

Ok, the retail price is double the cost normally. So 4kWh pack will retail at $4,000. This means if the 2010 Prius were to have 4kWh battery pack, it would cost the consumer $1,500 for the battery pack (after tax credit). Bring it on!

 

I fully concur that the Lotus EVORA and Tesla Sportster could share a lot of external parts. It would be common sense having Lotus design conventional body panels and other generic parts while Tesla focused their engineering on the drive train. The original point was who paid for the development and how much developing a new car cost. I suspect that Lotus and Telsa have both cross licensed and cross developed components as a smart way of leveraging designs and components across different cars. (e.g. An electric Lotus with a Lotus Motor and a Tesla battery for example.) This would mean that some Evora components were part of a joint effort. I would be hard pressed to belive that Lotus developed Evora components compatable for Tesla with no compensation on Tesla's part (at the exact same time they were needed for the Sportster?).

 

I think NiMH is ill-suited for PHEV. If you drain it completely, you get too short a lifetime, maybe 1000 cycles or so (3 years' use). And draining the battery is pretty much the point of PHEV. So, yes, they could do it, you've got a fair point there. But if they wanted the battery to last the life of the car, they'd have to treat it as they treat the traction battery now, and you'd only get a few PHEV miles out of it. I think the absolute max range of charge the Prius allows now is about 30%. The NRL trials of the Hymotion and other plugins yielded just under 4 mi/KWH average.
The upshot would be (30% of 4 KWH*4 mi/KWH) = 5 miles PHEV range, for a maybe an additional 300 lbs of battery weight.

Actually, I changed my mind. That's not too bad. Five miles for a net $1500 and a 10% increase in vehicle weight. Shoot, it's a deal relative to the Hymotion pack (20 electric miles or so for $11K installed). If they can sell the Hymotion pack, Toyota ought to be able to sell this. (The retrofits do not qualify for the tax credit.) Probably too late for Toyota to consider it but it's a good point.

 

Clett, I love your posts, but say hello to the next Great Depression. Metals prices are back to where they were five years ago. And I'd say it's better than an even money bet that they'll be there a while as the global economy tanks. Spot (immediate delivery) nickel's now about one-fifth of the May '07 peak. And that's in $US (so the decline is somewhat buffered by the fall in the value of the dollar internationally.) See the five-year chart here:

Kitco - Spot Nickel Historical Charts and Graphs - Nickel charts - Industrial metals

 

Ok, then how do you explain the RAV4EV, still going strong with 100,000 miles and a 100 mile range?

 

I suspect that Telsa outsourced the entire vehicle design to Lotus and concentrated their own efforts on the drivetrain. Lotus is a very well respected engineering company and there would be no reason for a bunch of computer guys to try to tell a company like Lotus how to design a chassis. Well respected automotive manufacturers with decades of automotive design experience still go to Lotus for chassis development.

The Lotus platform is incredibly flexible and requires a minimal amount of hard tooling. Lotus uses bonded and riveted aluminum instead of the more common stamped and welded steel unibodies used in large volume production. They then put a composite body over the chassis. It is an excellent way to make light cars as long as you don't want high volume.

I suspect that Telsa paid Lotus to do the design and development work but paid for very little in actual tooling. Instead Telsa is paying for Telsa specific tooling in a higher piece price. This would allow a small startup like Telsa with low cash reserves to get into the car business.

 

David Hermance, who unfortunately died in a plane crash some years ago, gave a presentation to a Prius meeting about the differences between the Prius and RAV-4 batteries. There was a big difference between optimizing batteries for 1) limited SOC variations, but wide swings in current (Prius) vs 2) batteries for deep cycling, but limited maximum discharge rates. One number I retained was that the Prius battery was rated at 1300W/kg and the EVRAV-4 battery was rated at 120W/kg max power.

 

Good reading. Now is it my turn or your turn to make a controversial post?

 

Your turn.

I don't see any controversy though, just my opinion.

Lotus does chassis design
Telsa does powertrain design
Each does what they know best.

 

Same reason the Prius NiMH batteries last the life of the car: the drivers rarely discharge the battery fully. If they did that daily (100 miles/day), it would have taken under 3 years to get 100,000 miles, and those batteries would be dead. Even with partial discharge being typical, the Cal Edison tests of the early RAV4 EVs showed some wear on the packs by 100,000 miles with, I think, a few cell failures.


Here's a 2004 document from Cobasys that states that pretty clearly. If you kill their NiMH batteries flat, you get 1000 cycles. But if you're talking about shallow charge/discharge cycles, you can do far more (page 14).

http://www.cobasys.com/pdf/tutorial/inside_nimh_battery_technology.pdf

You can do PHEV with a very large NiMH battery, use it gently (shallow discharge cycles), get few miles per charge out of it, and it'll last a long time. But if you try to use the full capacity of the battery, you'll kill it in a few years. So PHEV is going to be done with the new formula lithium-ion batteries that can withstand daily deep discharge and still produce 3000 cycles or so. That's the promise of the A123 batteries and similar.

 

So can any RAV4EV drivers confirm that they rarely deeply discharge their batteries? I'd rather believe the RAV4EV battery is actually superior to the Prius battery in some ways.

Also, if lithium ion batteries are so good, why is the Volt only going to use half of it's 16KWhs?

Maybe, once the batteries are more proven, a firmware upgrade/hack will be made available to allow a deeper discharge.

 

Li battery only has a 100% discharged cycle life of 500-1000, worst than NIMH. By using 50% of the capacity or shallow discharge , cycle life is increase to 2000-3000.

 

That first statement is true of old lithium chemistries, not the new ones from A123 and others. That's why you are seeing the interest in PHEV -- the new lithium chemistries have neither the shelf-life problem of traditional lithium batteries not the limited number of discharge cycles.

If what you assert were true of all lithium batteries, you'd never have seen the hymotion PHEV conversions hit the street. The A123 batteries have gone >3000 full discharges cycles in testing.

Shoot, the ones A123 sells to DeWalt tool are rated for 2000 discharges. See an ad here:

DeWalt Launches 14.4v XRP Lithium Ion Battery | Tools Rule! | Toologics.com | Professional Tool News

 

So how do you explain Hymotion leaving 2 out of 5 kWh and GM's Volt leaving 8 of 16kWh unused in the pack?

 

The DeWalt web page only said over 2000 recharges, not 100% cycles.

The A123 web page on 25650 cells only offer 1000 cycles for 100% DOD.

A123Systems :: Products

Cycle life at 10C discharge, 100% DOD: over 1,000 cycles

Edit: According to DoE, the Hymotion pack installed on a PHEV Prius only allow 2.96kWh available from the 4.7kWh. That is a 62.9% of discharge.