Next Gen Prius to have 67% larger NiMH battery with 71 MPG (vs. 50 MPG current Gen)

[ken1784]

Originally Posted by pdhenry

Toyota doesn't make their NiMH batteries. IIRC, Matsushita (Panasonic) builds them

Toyota owns 60% of Panasonic EV Energy Co., Ltd.
TOYOTA: News Releases

Ken@Japan

[dwdean]

Originally Posted by donee

Hi dw...,

The article says "due in 2009". Which is not the same thing as the 2009 model year. Its goint to be the 2010 model year, probably being sold in October of 2009 that will have the bigger battery.

Yes, you're right, my bad.

However, I still stand by the position that this sounds like a scramble to build more, rather than bigger, NiMH batteries.

Though I do suppose that it could be someone's poor attempt at starting speculation based on lack of confidence in Toyota's (in particular) ability to deliver the lithium tech battery.

[sola]

The article is very consistent with the requirements for the next gen Prius.

The gen III will not be a PHEV at first so it needs battery POWER over battery capacity. Regen power (high charging amps) and power for acceleration (high discharging amps). The 75% increase of the anode is pretty much consistent with this. This is why it will be able to ship a 40-50% mileage improvment in the city. I doubt that the highway mileage will improve drastically.

I hope however, that the design of the III will be PHEV/EV-ready. The current model cannot operate on battery power alone for long periods even after a PHEV conversion (due to some design issues which are very hard to circumvent).

[Rybold]

Originally Posted by sola

The gen III will not be a PHEV at first so it needs battery POWER over battery capacity. Regen power (high charging amps) and power for acceleration (high discharging amps). The 75% increase of the anode is pretty much consistent with this. This is why it will be able to ship a 40-50% mileage improvment in the city. I doubt that the highway mileage will improve drastically.

This explains a lot. I was thinking to myself that if it is not a plug in, then there is a minimum battery requirement but once you go over a certain capacity, you are not gaining anything except weight. Simplified, if you need X kw-hrs to accelerate from 0 to 30mph, and regenerative braking provides X kw-hrs, then a battery that holds 10X kw-hrs would be pointless.

If I am correct, you are saying that the capacity is not being increased, but the size of the electrodes is; thus allowing the power to increase, which would allow the car to remain in EV mode longer before the engine kicks in. Am I understanding this correctly?

[drash]

Originally Posted by Rybold

This explains a lot. I was thinking to myself that if it is not a plug in, then there is a minimum battery requirement but once you go over a certain capacity, you are not gaining anything except weight. Simplified, if you need X kw-hrs to accelerate from 0 to 30mph, and regenerative braking provides X kw-hrs, then a battery that holds 10X kw-hrs would be pointless.

If I am correct, you are saying that the capacity is not being increased, but the size of the electrodes is; thus allowing the power to increase, which would allow the car to remain in EV mode longer before the engine kicks in. Am I understanding this correctly?

Ummm. You're half right, it definitely would be an increase in capacity as well as power. You would need more electrolyte, a bigger cathode, yada, yada, so on and so forth in order to balance out the bigger anode. The biggie is if it uses the same size container and thermal management. This is just a by product of further R & D that Toyota builds upon the experience they already have. You are witnessing the snowball effect of R & D building upon previous work and then applying it to mass production experience they already have.

[miscrms]

Originally Posted by dwdean

but I thought that there was a serious point of diminishing returns on NiMH batteries (weight vs. charge density.)

I didn't think so. As I recall the 85Ah units in the EV1 and RAV4 EV were at least as good as Toyota's 6.5Ah or Nilar's 9Ah.

Ovonics 9500:
12V, 85AH, 17.4kg, 6.7L
Specific Power: 250 W/kg
Specific Energy: 60 Wh/kg
Energy Density: 155 Wh/L
http://www.evbones.com/9500c.gif

Panasonic EV Plastic Prismatic NimH
7.2V, 6.5Ah, 1.04kg, 0.59L
Specific Power: 1300W/kg
Specific Energy: 46 Wh/kg
Energy Density: 79.3 Wh/L
Plastic Case Prismatic Module | Panasonic EV Energy Co., Ltd.

Nilar Membrane NimH
24V, 9Ah, 3.9kg, 1.93L
Specific Power: 277 W/kg
Specific Energy: 55 Wh/kg
Energy Density: 112 Wh/L
Nilar - a new way of packaging energy

Seems like the big ones were pretty competitive with the best available today. The Panasonic's specific power is pretty impressive though. Too bad Chevrons patents prevent anyone from actually using the big ones

Rob

[catgic]

HTTP 404 Not Found

[nyty-nyt]

I kinda hoped that the EEstor ultracapacitor diode might find its way into hybrids. Zenn claimed they were going to use it.
I don't think they have really produced a commercial product yet and haven't heard anything recently about it.

[bookrats]

GM, for example, is only trying to make an expensive niche market lithium-ion plug-in hybrid, because it, through its own shortsightedness, cannot make a Prius fighter based on NiMH technology

While I can't speak for the rest of the article, this statement is, I believe, wrong

In short, everyone -- including Toyota -- would like to start shipping hybrids with lithium-ion batteries.

This is primarily because a Lithium Ion battery (with equivalent storage capabilities to the current NiMH battery packs) would be significantly lighter than their NiMH counterparts. Which results in a lighter car, and better mileage.

However, technical problems with the Lithium Ion batteries has apparently stymied everyone for the moment. (Temperature sensitivity is usually bandied about as the biggest obstacle, but I don't know.) Remember, backed away from Lithium Ion last year, after indicating that it would be used in the next generation Prius.