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Hybrid Vehicles Toyota Prius Hybrid Prius that gets over 100 Miles per Gallon
74 messages, Last post on Mar 11, 2008 at 12:31 PM
You are in the Toyota Prius Forum. Your Host is pf_flyer
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Replying to: gagrice (Jun 28, 2006 11:47 am) The aftermarket guys add a much larger battery (something I have often wondered about). The NiMh battery was never developed by GM! It's a design done by a separate company (who have been trying to get the car manufacturerers to listen for a few years now). The NiMh battery has been improving rapidly. Just look at the capacity increase of AA batteries over the last two years. Almost doubled! As for adding an inverter, not a good idea. Most aftermarket inverters run on 12VDC. The Prius 12V battery is tiny and you'd run the risk of discharging it rapidly - and damaging it (because it's a lead acid battery it can be damaged if discharged too much). As for heat under charge, all battery technologies heat up, but both the LiI (lithium ion) and NiMh (nickle metal hydride) seem to suffer from this a little more. An easy solution is to use coolant passed though small pipes between the battery cells. There are up to 400 cells in the Prius (500 V battery), though I suspect it's closer to 333. Lots of places for improvement. There isn't actually a lot of heat energy, so a simple free air radiator would suffice with a charger that throttles back when the temp gets too high. Oh, and there are rumours that Toyota will add "plugin" capability to the Prius in 2008. We shall see. 
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Replying to: pathstar1 (Jul 02, 2006 7:57 am) I just saw this at the opening in Los Angeles last week. It's very interesting, and it also discusses to an extent the improvement over battery technology over the last few years, and also how the Automakers have not used the best battery technology available to them. The movie's been distributed by Sony Classics, and it's well worth seeing. Thanks! Tim |
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Replying to: pathstar1 (Jul 02, 2006 7:57 am) Here is a brief bit of history concerning the NiMH battery that was developed by a GM company for the EV-1. Detroit, October 10 -- Texaco (NYSE:TX) and General Motors (NYSE:GM) today announced Texaco's intent to acquire GM's share of a joint venture that has developed an advanced battery technology for the automotive market. Under the terms of the memorandum of understanding, Texaco will acquire GM's 60 percent share of an existing joint venture with Energy Conversion Devices – ECD – (NASDAQ:ENER), a firm in which Texaco already holds a 20 percent interest. GM and Ovonic Battery Company, a subsidiary of ECD, formed the joint venture, GM Ovonic, in 1994 to manufacture and commercialize high-efficiency, nickel metal hydride (NiMH) automobile batteries. The joint venture, which will be re-named Texaco Ovonic, plans to fully commercialize and expand its applications to a broad range of energy markets. "ECD and Ovonic developed breakthrough advanced NiMH battery technology and General Motors has brought it to the production stage http://www.cobasys.com/news/PressReleases/20001010.htm OK, now onto the heart of the matter about Cobasys' long history of aggressively defending its comprehesive NiMH patent portfolio, which gives it exclusive control over worldwide NiMH battery production. I have not actually read the legal judgement against Panasonic in favor of Cobasys by the international court of arbitration because that decision was sealed and supposed to remain confidential by prior agreement of the parties, as you probably know. However numerous details of that judgement/settlement have emerged in the press, including some revealed by Cobasys itself. What we know is that the court levied a $30 million fine against Panasonic and Toyota which they had to pay to Cobasys for violation of Cobasys' NiMH patents and back-payment of royalties owed to Cobasys. NiMH History, why no PHEV
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Replying to: gagrice (Jul 02, 2006 1:52 pm) I stand by my statement - "The NiMh battery was never developed by GM!" Partially funded, perhaps, but that's it. This brings up an interesting point - I'm not sure there is another example of such a quick adoption of a "new invention". The development hatched the battery in 1999 and look how pervasive use of the NiMH technology has become in six short years!
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Replying to: pathstar1 (Jul 03, 2006 7:54 am) Under the terms of the memorandum of understanding, Texaco will acquire GM's 60 percent share The bottom line is the US taxpayer through Clinton's giveaway program PNGV was involved in the development of the NiMH battery. PS Texaco Cobasys (Ovonics) sued Toyota and Panasonic after GM sold their 60% to Texaco.
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Replying to: pathstar1 (Jul 02, 2006 7:57 am) I've got to remember to RTFM! The Prius battery consists of 28 modules of 6 cells each. That's 168 cells. Peak voltage will be 252 V and "average" voltage will be around 210 V. Minimum voltage would be 201.6 V, and if you measured the battery voltage and found it lower you might have some shorted or otherwise dead cells. You can estimate how many dead cells there are by dividing the difference by 1.2 V (the minimum voltage you should see across a nickle metal-hydride cell). This would be difficult unless you actually separate the 7.2 Volt modules though, as the voltage can vary depending on state of charge -of each cell-, so the battery voltage can vary more than you would think it would caused by dead cells. Bottom line of this is -if- you can buy the 7.2 V modules the battery is made of, you can "repair" a battery pack. Once it's over about 7 years of operation, this might not be a good way to go as all the cells will be getting old. Nice to know though in case there are cell failures early. As Toyota absorbs these per the warrenty, I guess they made it easy to repair. |
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Replying to: gagrice (Jul 03, 2006 4:09 pm) I guess Texaco Ovonics is the company they interviewed (with a plant visit as well) on Motorweek last year. I think the head guy they talked to was the actual inventor. They are also into using the Nickle hydride matrix to store hydrogen at "low" pressure (100 psi instead of several thousand psi) to build "practical" hydrogen storage tanks for hydrogen powered vehicles.
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Replying to: pathstar1 (Jul 05, 2006 10:56 am) I personally would rather see a simple electric vehicle for running errands with a 50 mile range. Much easier to build and maintain. Would satisfy a lot of people's needs. As long as modifying a Prius is the only option for PHEV, I don't see that as practical. There is just too many things that can go wrong and not be covered by a warranty.
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Replying to: gagrice (Jul 05, 2006 11:43 am) The electric vehicle is very clean, never needs oil changes, and has many less moving parts. When the EV1 was around, it needed very little maintenance. The auto industry relies on cars needing parts, oil changes, etc, especially dealerships. I forget what the exact percentage is, but dearlerships make a large portion of revenue from their repair shops. The EV1 was very successful and had a range of about 80 miles, and 'could have' been marketed succesfully. GM and other auto makers (and oil companies) did not want electric cars around. When GM1 ended the leases to the EV1, rather than simply selling the cars to the leasees, they forced leasees to return the cars against their will. The cars then got crushed and went into the shredder. Why not just sell the EV1s that have already been driven. Toyota finally allowed some customers to keep the RAV4 EV after consumer protest against Toyota also forcing customers to return the vehicles and then crushing them. GM and other auto makers did not want anything to do with electric vehicles even when there was customer demand for them. There is more information about this at www.whokilledtheelectriccar.com and the movie is being shown throughout hundreds of theatres across the nation over July and August.
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Replying to: timinalaska (Jul 05, 2006 4:32 pm) |
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