Hi everyone...... I am wanting to know what the interval and cost for the battery replacement for the Prius is? (You know the ones that make it a hybrid) We are shopping and considering the Prius, Rav4, Matrix and a couple others. thanks, Bill
If the battery is purchased new, it is just over $3000 plus labor. Batteries are available on the wrecking yard circuit or ebay for under $1000.
The actual life of the battery is indeterminate; too few have failed to make a usable estimate. I have heard of about a dozen battery failures (mostly on the 14,000 member Yahoo! Toyota-Prius forum, suggesting the failure rate is around 0.1%) and I don't see a pattern - the failures seem pretty random. As many as half the diagnosed battery failures are suspicious in my mind, but since nearly all have eventually been paid for by Toyota - even the ones past the stated warranty period - few people complain.
I think it's safe to say few Prius owners will ever experience a main battery failure, since several early Prius cars have exceeded 200K miles without battery trouble. The Prius has been on the streets of Japan for ten years now without a lot of battery failures. The two we have (2002 models with 75K miles and 110K miles) sure haven't given us any trouble that decent gas didn't fix.
The allusion was to (irrespective of the published MTBF, which you suggest is "not in the car's lifetime" or "never") your own personal version of MTBF, a.k.a. "when and if it fails".
This is moswt often longer or shorter than the stated or theoretical MTBF.
An enormous warranty on the battery (the whole hybrid system is covered for 150k miles). And, it's an utterly reliable car with a ~100% confidence level.
A serious engineering interest in ripping the system apart and installing 2-4 more batteries from wrecks, with associated modified electronics. Even more aggressively - when I got the car\ three years ago, I did a design for about k in lithium cells with plug-in charging and 100 mile range. That modification would be half the price today. Such projects are very, very tempting.
I asked the service department before I bought mine. $4500 at the time. It was enough to scare me away for one more year. But the more I learned the more I understood; individual batteries are cheap.
There's a MTBF? Last I knew, Toyota said expect the batteries to retain 98% of their charging capacity at 200,000 miles. Normally the batteries aren't allowed to charge or discharge anywhere near full capacity and it's for this reason they last.
Not dumb. When a common cell is run until depletion, its life is predictable based upon known capacity, expressed in ampere-hours as a function of stored chemical energy.
No one has presented a reliable algorithm to predict the life of cells that are (1) operated between some non-peak charge state and some non-minimum discharge state, (2) charged by a highly optimized method that nonetheless varies based on operating conditions, (3) operated in many different environmental conditions, (4) operated with unpredictable demands, and (5) used over an unpredictable time schedule. In this case, the battery (a battery is comprised of multiple cells) consists of more than 100 nickel metal hydride cells in series, and the failure of any one of them kills the entire series system. That further complicates the equation because there is no graceful failure mode.
In short, for these batteries it may be possible to make vague predictions of nominal life under nominal conditions, but it will be a very, very flat bellcurve with huge variability.
It's less than three years for laptop Lithium ion batteries with onboard charge optimization that are rarely if ever completely discharged, albeit more deeply discharged than Prius'.
With every charge a lithium cell loses lithium. Typically, economically-useful versions of such chemistries are limited to
200-300 cycles. The number diminishes rapidly if the circuitry permits max range between charge and discharge, which is always the case in laptops because of marketing demands ("Ours runs 5 hours on a charge!"). Nickel-metal-hydride cells are good for
1000 or more cycles, and many more if kept well within those limits - that mode of operation is practical only when charge life is unimportant because the "charger" is always connected, which in this case is the ICE.
Note that the electric motor system on this vehicle is designed to operate ONLY at that point in the power delivery curve where the Miller-Cycle engine - required for high mileage - performs so poorly that it would be unacceptable.
It's a great combination: an electric motor has max torque at zero RPM, and a Miller (or Atkinson) cycle engine has terrible low end torque. On the other hand, that wonderful engine design (an adaptation of the indestructible Echo engine) delivers great efficiency once the system is moving. And, by unloading the engine during high-stress initial acceleration, its life is extended. Supporting that "marriage made in heaven" requires only a small battery comprised of good quality cells, and it can be operated in a manner that has a high probability of long life.
Actual numbers tell the story - these systems clearly have a very low failure rate, and some have been on the road (in Asia) for more than ten years. Cell technology and management electronics both continue to improve, so one can reasonably expect that today's batteries will have an average MTBF even better than that of the cars built in 1997...
Experimenters with lithium cells in cars are having problems dealing with the lifetime cycle problem, which will be very costly despite the performance:weight advantage of that battery chemistry. There are other chemistries out there with similar energy densities at lower lifetime cost - don't be surprised if one of the zinc chemistries leap to the front in the next few years.
My understanding from Toyota is that the NiMH battery was chosen over LiIon primarily because LiIon batteries have predictable lives and NiMH batteries do not. Edison cells are a good example of batteries with no predictable life span.
It's interesting that the Edison cell has lost favor in the west, but other nickel+?? technologies continue to emerge, as well as zinc+??
The cell with the highest energy density of which I'm aware (but disposable) is for hearing aids - zinc/air. There is one derivative of that chemistry that might one day become suitable for rechargeable vehicle use.
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