Edmunds dealer partner, Bayway Leasing, is now offering transparent lease deals via these forums. Click here to see the latest vehicles!
The Great Hybrid Battery Debate
The great battery debate is on!
What is the replacement cost? Is there a replacement need? How does this impact the total cost of ownership over the lifetime of the vehicle?
What is the replacement cost? Is there a replacement need? How does this impact the total cost of ownership over the lifetime of the vehicle?
0
This discussion has been closed.
Comments
Panasonic Prismatic HV NiMH battery module.
Typical consumer electronic cylinderical NiMH battery. Note: Recharge cycle is only 500.
Dennis
Prismatic Module Spec:
Nominal Voltage: 7.2V
Nominal Capacity: 6.5Ah
Speceific Power: 1300W/kg
Speceific Energy: 46Wh/kg
Weight: 1040g
Cylindrical Module Spec:
Nominal Voltage: 7.2V
Nominal Capacity: 6.0Ah
Speceific Power: 800W/kg
Speceific Energy: 40Wh/kg
Weight: 1090g
Dennis
Ni-Mh battery used in Prius is much more environmental friendly. Nickel and Metal Hydride are not heavy metal or toxic. Nickel can be found in 5 cents literally. There is still the need to recycle Ni-Mh batteries because Nickel recovered from recycling pays for itself! This is not true for other batteries.
Dennis
Toyota Rav4 EV had 28 KWH EV NiMH battery to achieve 87 miles range when travelling at 60mph. That's more than eighteen times larger than Prius battery. In order for Rav4 EV to have the same range of hybrids(700miles), Rav4 EV will need to have 225 KWH battery! To be fair, acknowledge that Rav4 is a heavier SUV and Prius is a mid-size sedan.
Dennis
The main reason that the voltage is inverted and increaste to 500 volts is because smaller wires can be used becuase the current is less.
Powrer= current times volt times the angle between voltage and current (o for resistive, +/_ for inductive or capcitive) assume resistive.
For example if the mote is a 2.5 Kilowatthour motor thatt menas the instantaeous power is 2500 watts or 2500 amp hours. If that is deliver by 12 volts then a current of 208.3 amperes while the same motor running 500 volts would only require a current of 5 amperes. The smaller the amperes or current the smaller the wire is need and the less loss due to impedence.
P.S. - Were you awre the Prius can only go in reverse via the eletric motors. The ICE can not supply reverse power. Does that mean the Prius is a mild or soft hybrid in reverse?
Yes, I am aware. Prius ICE can not supply power to the wheel directly but it can power indirectly by generating electricity which then powers the main 50kw motor. Therefore, in reverse, Prius acts as a serial hybrid. Remember, the electricity generated from MG1 does not have to go through the battery, HSD can route power directly to the 50kw MG2.
Dennis
If Hybrid battery life is your only concern, then I wouldn't worry about it and would go ahead buy and enjoy the new hybrid technology.
YMMV,
MidCow
The settlement was reached through arbitration. As part of the agreement, Cobasys and Panasonic will cross-license each other on current and future patents to avoid litigation.
http://www.freep.com/news/statewire/sw100650_20040707.htm
Let the number increase and the price fall !!!!
Dennis
I seriously doubt the price of NiMH batteries will get significantly cheaper. Batteries of all kinds have gone up in price no matter what the rest of the Electronics market is doing. The only competition is generic batteries that have proven themselves inferior to name brand. At least in all the ones I have bought. If you are counting on the price going down by the time you need to replace the batteries, I would be real surprised if they are. Hopefully the generous warranty will take care of all your battery replacements.
Consumer electronic AA Nimh rechargable battery prices has been going down since it was introduced. Not only the price, the capacity had gone up as well. When they came out they had 1500 mah rating(higher is better). Now, they have 2400 mah batteries for less than what 1500 mah used to cost!
Dennis
Short answer: NiMH do have memory effect but at a very slow rate.
Long answer: Compared to AA NiCD batteries, AA NiMH batteries suffers much less of the memory effect. AA NiMH retains/remembers 80% of it's capacity after 500 cycles. Hybrid Electric Vehicle NiMH batteries' memory is 20 times better. They have 10,000 cycles until it is reduced to 80% of the original capacity. That is to show the rate of the memory effect. The battery is still completely functional after that point. Replacing the pack is up to the owner if he/she wants to regain efficiency of a new hybrid car.
Dennis
For example, during highway cruising, the battery is rarely used. Another extreme case is, short and hilly blocks in San Francisco with stop signs at every corner. The battery would use up plenty of recharge cycles in this situation, only if you accelerate hard enough so that the battery supply power to the main electric motor.
Dennis
Very true. More importantly, not all chargers are created equal either! It is the cheap charger that damages the battery by charging too fast and over heating the battery. Overcharging the battery when it is full also damages the battery.
The charger in the Prius is very intelligent and powered by 32-bit CPU. There are temperature sensors to protect the battery pack with active cooling system. It is also packed with the latest charging technology to prolong the battery life.
Dennis
The 30-kW Sanyo battery pack sits under the rear carpet and forms the cargo area’s load floor. Inside the thin metallic cassette sit 250 nickel-metal hydride D-cells wired in series and producing 330 volt. You read that right. D-cells,the same size as, but not interchangeable with, the ones found in flashlights. Unlike said flashlight, an external cooling vent in the driver’s side rear window is part of the forced-air thermal management system. In hot weather it draws excess heat away from the pack, while an electric heater warms the batteries when the temperature drops. Ford says the system can handle temperature extremes from -40°º F to +122°º F.
http://www.autofieldguide.com/articles/070402.html
Dennis
Because of the chemstry of the battery. The voltage varies with the state of charge of the battery but nominal voltage is commly accepted as 1.2 volts.
Dennis
Most 9V NiMH provide 8.4V. There are 7 1.2V cells connected in parallel. Some 9V NiMH use 8 cells to provide 9.6 volts. The trade off is in the capacity or the mAH.
The battery that will be in Highlander hybrid or RX400h is said to have twice the power of Prius. It is not clear if it will have 403.2 volts with 6.5 AH or 201.6 volts with 13 AH.
If you think electricity flow as a water pipe. The volt is how wide the pipe is and Amp per hour is how fast the water flows.
Dennis
3-4pm EST
noon-1pm PST
Hybrid Chat Room
Second, in your analogy, voltage would be the pressure accross the pipe while the diameter of the pipe is analogous to the impedance of the circuit. Current (amperes) is analogous to the rate of flow. In your reference to "amps per hour" I assume that you mean Ampere Hours which is the integral of current over time and is a measure of the energy delivered (at a particular voltage). Note that 1 amp for 10 hours is 10 AH, but only 1A per hour. You may be confusing battery capacity (AH) with discharge rate which is also important to a battery's rating since capacity will usually decline at high dicharge rates.
NOTE: This is a NEW time slot for this week!
Hybrid Vehicles Chat Room
Immediately following at 6-7pm PT/9-10pm ET, we keep the chat party going with the Mazda Mania chat.
Mazda Mania Chat Room
The Town Hall chats are a great place to take these message board topics LIVE. Hope to see you there this week!
PF Flyer
Host
Pickups & News & Views Message Boards
If you stick a new module in with a bunch of dated modules, the results are bad. The old modules lose capacity over time, so their charge/discharge cycle is going to be far different from a new module. Not to mention how the algorithms in the BCM (Battery control module) will be farked up by adding a new module to an old pack....
Just to clarify...when one module goes bad in a Prius HV battery pack, you will need to replace the entire pack.
FWIW, I have tested modules from Prius battery packs (2001 and 2002)
We tested this quite extensively one night in a parking lot and monitored current/voltage/SOC/temp.
The thing that I found interesting is that I could mush on the accelerator (in reverse mind you) and get going as fast as I could, and the highest current draw from the batteries we would see was around 30A. Which isn't so amazing when you convert it to HP (~24 HP). But at he time I was green and thought WOW.
There were 3 guys in the car, each weighing ~200LBS, plus our test equipment.
Oh, those were the days!!
That is a direct contradiction to everything ever published about those modules and their controlers, both technical and real-world occurences.
Please back your wild claim with a detailed explanation.
JOHN
This is not to say one CANNOT replace only the bad batteries, but I doubt that the vehicle computers are programmed for this eventuality, since the variables are enormous (one variable in the total output for each battery that is new in an old stack). Most likely there would be some unusual warning messages from the computer, the severity would be based on how many old vs new, how bad the old ones are, etc.
And I seriously doubt that you will ever get a Toyota engineer to say replacing some batteries in an old pack is acceptable. They will tell you to replace the whole pack...
And I also doubt that you will ever get anyone at Toyota to say replacing some batteries in an old pack is good enough. They want all the money they can get.
It has *ALREADY* been proven that bad modules can completely (and automatically) be ignored without any negative affect on the pack itself. Then rather than multi-state support, you would have new-only support... which is another method of module replacement without the need for the entire pack.
Now you have two examples to disprove.
JOHN
I don't doubt that the battery software controls account for gradual depeletion of the battery pack capabilities. If they didn't account for this, they would be idiots, because the packs are going to deplete over time.
However, that doesn't mean the algorythm accounts for mixed old and new batteries. Maybe it does, maybe it doesn't. But (as was pointed out above), Toyota also would have no reason to want users to be able to replace a single battery, since they would get the return business of a new battery pack.
The Prius depends on those battery packs. I have no doubt that there is capability to run with some battery modules out, but it is intended as a short term use, until the pack can be fixed. In general, the concept of messing around (in any fashion) with the batteries is unsound in a car that requires electricity to run.
Considering the 8 year, 150K warranty, I bet they are correct.
This was part of the debate that forced Toyota to warranty the Hybrid batteries for 8 years 150k miles. You may find it interesting as I did. This has been my skepticism from the start. Although with 8 years and 150k miles I would not fret over buying a hybrid.
http://solstice.crest.org/discussion/ev/current/msg00392.html
If your cell-phone shutdown at 40% and refused to power back up until you plugged it in, the battery would last dramatically longer. But instead, users drain the thing to totally dead on a regular basis. That's a huge difference from the way a system like HSD in Prius works.
JOHN
JOHN
While that is true for a "mild" hybrid, it is not for a "full" hybrid like Prius. In fact, 100% of the time the engine is providing thrust to the wheels it is also powering the generator-motor. The resulting electricity is immediately used by the thrust-motor.
Preventing the battery-pack from being used as much obviously helps to extend the life of it.
JOHN
04 Prius battery ECU will not let the battery discharge below 40% SOC. The rest of 60% of the 1.31 kWH battery can provide 28 hp for 135 seconds. If you climb the hill at 60mph and the hill is so steep that the battery provides all 28hp for 135 seconds, Prius can trouble 2.25 miles before the battery SOC get to 40%. It is when the turtle icon appears.
If the hill is not as steep and Prius main ECU request only 14hp from the battery, Prius can go up 4.5 mile long hill. That's a very long hill!
I know you had bad experience with batteries. Let me give you another graph which shows the Cylinder D-shape batteries(Used in Japanese Prius) and Prismatic batteries(Used in US Classic Prius). They tested over 180,000 miles for Cylinder and 150,000 miles for Prismatic. Note that 04 Prius batteries has less Internal Resistence than last generation Prismatic modules. Basically, these batteries can keep going and going and going .....
Dennis
It uses the plain old batteries, several years old technology...
The NiMH itself within the Prius battery-pack is record-breaking "technology". The energy-density is significantly higher than just "plain old batteries". Other NiMH simply cannot compare.
JOHN