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Bold italics mine. Counter to what some dealers are saying, toyota looks like its choosing the better lithium battery in its better trims. If they thought lithium was worse wouldn't it be gone or in the cheap trims?

Anouther reason why the volt internet ad is so bad by comparing to prius. Toyota will change it to lithium (the more advanced technology) for you if you pay for it, in a short time.

 

The secret is Prius fuel efficiency is not a function of the battery technology. It lies in the hybrid control laws that only run the engine when necessary and then long enough to replace the battery charge used. But they missed the 'power density' and 'higher charge rate.' These define how much instant torque is available to launch the car from a stop. But then there is no requirement for Car and Driver to have a clue.

Bob Wilson

 

All I can say is EV1. Stick it where the sun don't shine Govt Motors

 

Note that I am not pro-NiMH and anti Lithium.
But you asked...I've never heard of a NiMH battery fire. But there have been numerous lithium battery fires, notably on airplanes.

Mike

 

The other problem with LiON (in the past) has been the slow formation of inert compounds in the charge/discharge cycles. In contrast, NiMH does not. The NiMH issue has been loss of water from the electrolyte.

Bob Wilson

 

okay, i guess i was misunderstanding. i get the feeling that toyota is not fully convinced about battery tech, or maybe it's just because it's always improving rapidly.

 

The technology is not the battery itself, but the hybrid system that includes the battery. To this point a small NiMH battery in the Prius Liftback had little significant performance disadvantage. However in terms of cost and proven reliability, the NiMH was a plus for that system. There was probably little edge to using the slightly less, but also old Li-ion "technology".

Certainly when larger battery capacity is needed, such as in the Volt or PiP, weight and other issues become important and Li-ion was the clear choice.

With Li-ion costs improved and a few performance changes baked into the new Liftback, it would not be surprising for Toyota to work Li-ion into some trim levels. That is not an admission on the part of Toyota that they got anything wrong before. They continue to hold the latest hybrid battery system technology, even when it was only NiMH - the proof is in the MPG.

 

That says it all.

 

We have a bunch of huge corporations (GM, VW, and Toyota) that have verticle integration. Each in their own way gets slow moving, and loyalists making up stories on why their moving slow is actually an advantage.

In the case of nimh, toyota is vertically integrated. They own a lot of equipment and patents and has trained workers. in the past this was a strategic advantage, as panasonic, toyota's battery partner, had a monopoly on nimh. When toyota needed more batteries, they cranked up production, when ford needed more batteries, they were SOL, and couldn't buy enough from panasonic. Tesla is vertically integrating for the same reason in the gigafactory. But .... to switch toyota needs to build new factories or build ahead nimh for the interum, then pay for a lot of equipment, retraining, etc. Over 10 years its an easy decission, toyota makes more money with the switch, but if you only look a couple years out, it will hurt profits. So toyota is being slow for these financial reasons. The dealer network also has been selling lithium fud, some probably even believe it, but they also seem to want to not sell plug-ins and not switch to lithium for hybrids.

Toyota is not ambivalent, but to sell fcv to governments, and sell the nimh they plan to continue building they release strange statements that makes in sound like nimh has some technical advantage. They make enough other statements to let you know they know the truth, and when they switch they can point to those statements.

We don't have definite information on the gen IV, but I expect in that car the anti-lithium FUD ends. It appears to have been designed for both, but battery factories with not switch over fast.

Compare Side-by-Side
As mentioned and can be seen above in a hybrid lithium only helps a little in terms of fuel economy. No one makes a car like the prius, but in mid size sedans honda and ford do, and do a tiny bit better. The bigger issue is size and weight for the power and energy. Here toyota does a better packaging job with the camry, than ford does with the fusion, so ford was unable to take advantage of this advantage. In higher power or energy batteries, its more of an advantage. As mentioned price is probably already lower for a new design for lithium versus nimh. Ford says panasonic is selling them lithium batteries for less than nimh. Part of this could be competition, but since toyota and panasonic are partners, we can guess that toyota's cost is lower than the sales price to ford.

Yes I did mention the FUD. It is there. Like the Elevator volt pitch on range anxiety, toyota should not engage in the FUD. More damage came from smoke and fires from toyota's widnow switch than all the lithium in ford, honda, samsung, bmw, mercedes, and vw hybrid batteries. Lithium as mentioned needs proper control electronics to monitor temperatures when being used to not force in into a bad zone. No excuse for not putting in proper protection there in the aircraft fire, but again different electronics and battery chemistry. Larger format batteries have more energy and old ovonics nimh (no other nimh was larger in terms of energy) should be equally able to cause fires as a similar size lithium. Talk about battery problem fud, can only hurt hybrid sales.

 

Why do you continue to portray lithium as mutually exclusive to NiMH ?

Different chemistries for different implementations.

 

I'm not sure how you read that.

I said if you were doing a new clean sheet design for a hybrid vehicle or a plug-in today you would pick the current tech which is lithium. For a given recharge power(regen brake), supply power, energy combination they will be:

Smaller
Lighter
Slower self discharge (keep more a of charge if not driven for days).
More tolerant of SOC range.

When you are doing 0.9 kwh or larger size, today's lower price should help cover

More expensive charging and control electronics. Neither chemistry likes being charged bellow freezing or above 113 F. Try to charge the nimh too much at the high temperature and it just degrades the battery, the lithium too high and it can put it in a run away mode. Electronics should be included with either battery to prevent this, and belive toyota has had it for both since the toyota alpha was released 3 years ago. Since lithium can take a higher current for a given energy, that electronic protection is more important, but toyota sweats the details.

For toyota, its fine for them to stick with older battery tech for their hybrids.
1) packaging is good enough for the added size and weight
2) Risk of battery shortfall when switching over production. Tesla has been constantly fighting low battery supplies from panasonic, Toyota doesn't want to take that risk.
3) Current electronics and software work, doesn't need the testing a new package of electronics and software take. I believe they have done this work on the gen IV prius for packages for nimh and limh, but official statement isn't out yet, simply the leaks.

 

fortunately for toyota, they can switch if and when it's best for them, seeing that the prius has no real competition.

 

I'm seeing some interesting reviews of the Malibu hybrid and even the Accord hybrid. Of course they are probably aimed at the Camry hybrid that really needs a technology 'tune-up.'

Bob Wilson

 

Toyota cannot program prius to use trickle-charging to rebalance a Lithium battery. That's one disadvantage.

Expense is another. Lithium is used in higher trim levels because it's too costly for use in base trims.

 

Definition of trickle charging? 120v?
.

if you think the Camry Hybrid needs a tune up, what does that say for the PIP? Someone on the board recently posted a comprehensive review of the Hyundai plugin. WOW!! If the 2nd-generation PiP is going to be competition for that, Toyota better really have their $hip together. It's getting to be a really tight race. I mean jeez, Toyota might actually have to sell it in more than a handful of states.
.

 

Full details have not trickled out of toyota yet, but we do have weights and volumes of the battery packs from a Toyota video. Lithium is 76 lbs, Nimh is 108 lbs. The lithium is 6% smaller than the current pack, the Nimh is 10% smaller, which would make the lithium 4% bigger than the nimh pack. That indicates to me that the Lithium will have significantly higher capacity, but figures for power and capacity are not out yet. The added volume of the lithium pack may have to do with cooling.

 

we got 45 mpg last weekend from here to manhattan and back. no complaints, try that in a tesla.

 

The wholesale cost of lithium and NiMH are about the same per kWh now. Ford claims lithium costs them less than NiMH.

I've heard the protection circuitry for lithium bulks up the pack.

 

I thought people had already figured out that the Lithium pack is only about 750 Wh compared to 1,300 Wh for the NiMH pack. I haven't personally tried to verify those numbers but the much smaller capacity does seem surprising. The lithium pack that GM is using on the new Malibu hybrid is 1.5 kWh which roughly matches the 1.7 kWh NiMH used on the Camry (from memory).

This leads me to wonder if Toyota is using a less common chemistry like Lithium Titanate that has really good power and recharging and high cycling life but has poor energy density.

 

Here are the gen 4 battery specs:

Gen 4 Staff Manual (In Japanese) =/ Specs/Design/Other Info