Long term effects on battery by rapid charging (ie: in 15 minutes?)

felt, i feel exactly the same way about my lithium, as you do about your nimh. granted, i only have 45,000 miles, but some pip owners have well over a hundred.

i'm not even sure you can build a phev or bev with nimh, the size and weight might be too cumbersome.

also, i'm not sure where you are getting your information on cooling, charging and longevity for the prime battery? i haven't heard, read or seen anything negative.

if anything, prime with nimh would have almost no hatch space at all. no that would be an issue.

 

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The reality is that it was most likely down 40% to 60% of original on the NiMH (Nickel Metal Hydride). However, this is exactly why adding extra batteries to a Prius (lots of experimentation done on the GenII) does not improve fuel economy. The Prius is super efficient and uses the battery as a very small buffer battery. When your screen shows 100% 8-bars, it is charged to 80%. When it shows it being low at 1-bar, it is at 40%. These percentages are "state of charge" which is measured by a combination of voltage and coulomb counting. As the car ages, the battery will charge and discharge more often and more quickly. But still work just fine. Until it reaches a point that the cells are too far apart from one another and the computer can't balance and keep them together. Then you get a red problem code.

My 2006 with a dead battery still managed to get close to 50mpg at highway speeds. It is a very well engineered vehicle.

Unless you devote the time to read the science, don't believe anything you hear. The masses are ignorant and don't know or care.

Lithium is used everywhere. There is a lithium battery in your keyfob that starts the Prius... All batteries have the potential to overheat and to catch on fire or even spontaneously combust. Still safer than driving around with a tank full of explosive dinosaur goo. Rapid charging as I already explained has no bearing on it as long as you are within the spec'd C limits. Longevity, all batteries have a life cycle count. All of them. And it depends on how you treat them.

If you want an example, look to Honda. Honda made the insight, Toyota 1-uped and made the Prius. Honda tried to fight back but could not get their IMA system to compete at all with Toyota's HSD system. Toyota made a hybrid from the ground up and got excellent results. Honda bolted on a battery and motor to an existing system and it was a kludge. But people were now used to seeing a car with 50mpg (this is 2003 with 2004 MY and the EPA testing had the Prius at 50+ mpg sticker, later reduced). Honda could not get the numbers without being really abusive to the battery. As mentioned, Toyota used 40% of the NiMH battery. Honda used close to double that. So it much more more empty when the car reported it low, and much more full when the car reported it high. Most of the Honda IMA hybrids out there have replacement NiMH packs in them. This obviously doesn't mean NiMH packs are evil. It means Honda made an engineering mistake in their pack. Honda even released a software update to limit the pack range on older vehicles to help solve this problem after a huge number of claims. And it hurt the vehicle's performance and efficiency, but now it protects the pack. It got close to the Prius originally while sacrificing itself. Now it can't touch it, but will last longer.

Lithium batteries are excellent if executed correctly. Toyota has a history of doing things properly, but we will not know if they continued this tradition for many years from now.

Keep in mind however that the batteries are being used completely differently. In a non plug in Prius, the battery is a very small buffer that allows the car to be shut off essentially when stopped or when coasting. You can do this on a non-hybrid and extreme hypermillers do it to get Prius mileage in old beaters. You lose AC and the radio and power steering, brakes, etc. But it works the same concept. When you are sitting there idle you are using like 200W to 800W of power to keep everything powered and nice. When you are accelerating you can be using 20KW (20000W) to 80KW (80000W). 100HP (horsepower) is close to 75KW (75000W). If you can't shut your engine off you are still burning copious amount of gasohol to do nothing. This lowers your average fuel economy. The actual gas burning mode of the Prius is excellent but not that far off of normal vehicles.

In a plug in vehicle the battery is the main mode of transportation. When it drops 50% of its capacity, you will notice because that's what you are using to drive around. The battery in the non-plug-in Prius will get you about 1 mile on a good day of pure EV. So a 2200% improvement to 22 miles for a similar battery to the layman is a huge achievement. You'd be hauling around a couple tons of battery instead of a small human worth.

You as the owner have a lot of say in how your battery degrades. If you charge it to 100% and drive it down to 0% everyday (closer to 96% and 4% in actual SOC at the pack) you are doing what Honda did and it will die a quicker death. If you are charging to 80% and driving it around to 60% and charging up again, the battery could do that forever. If you drive around in the Arctic where the battery never gets warm it will last a very long time compared to driving it around the Sahara where even if you just park it there, it will die fast.

Automotive Lithium batteries do not introduce more complexity than Automotive NiMH batteries. The non-PiP has cooling (fan in the back seat), charging (HV ECU/Inverter), and degradation. The pack is an extremely complex series of tubes. Or is that the internet? There are actually a complex series of tubes inside the pack to collect the off gasses. Temperature monitors (3 of them). Bus bars, isolation relays, mechanical structure to compress the cells physically to prevent warping during charge, interlocks, etc. This is the NiMH battery! It is extremely complex. A lithium battery has all the same hardware, it just functions differently.

The cooling can be nothing (like a Leaf) or even actively liquid cooled like old-school Volt's. Guess which battery lasts longer?

Charging has to change from a 180V-240V system that has huge voltage swings to a different voltage that requires different charging algorithms in a tighter range. It is all software though.

Nope, Lithium is the way forward. Why use NiMH when you could use SLA just like the 12v and early EV's did?

 

The only answer to your question is to wait longer for real-life experience, but in 2006 we were in the same boat not knowing how long NiMH (Prius) batteries would last. Now we know quite a few Gen2 NiMH batts have failed in the 8-10 year time frame - lets just say maybe 5% (we have no good recent data). Gen3 NiMH failures much less to date, unclear if that is design improvement or passage of time.

Lithium in autos has seemed more reliable to date as far as we know. We always get "a lot" of vehicle fires, maybe more electronic these days, due to wiring issues etc. but rare to be battery related. All Li batteries are flammable electrolyte-based but are engineered to manage that. Meanwhile we get 8-yr warranty from Toyota, so you are heavily protected against everything except a long term problem after the warranty expiration.

 

Thank you bisco .... you always have a reasonable reply.

I know I somewhat mixed thoughts from different concerns .... in truth .... I'm struggling with the greater question, hybrid, plug-in or EV. As I stated ... I was 100% satisfied with my hybrid, and quite frankly, i'm leaning that way.

In that thread ... I can't see any reason to change from nigh to lithium. I like the Prime .... but I don't see that this topic of quick charging is much of a factor in my situation. I reason that quick charging is only a factor in EV's ..... and an EV is way down on my list.

Second truth .... I want the Prime to be more than it seems to be. The higher cost and only 22 EV miles just is not going to work for me.

 

The NiMH (Nickel Metal-Hydride) batteries in your Prius and many others have shown extraordinary reliability over the many millions that have been produced.

Automotive lithium batteries are a little more robust but mainly still rely on some type of base Ethylene Carbonate electrolyte Which is the main reason for combustion. While not nearly as flammable as the earlier Lithium electrolytes based on diethyl carbonate which had a flash point of merely 33C, it still has a flash point of around 150C.

Well our PiPs have shown very little degradation or have not caught fire from strictly battery fire alone. They are more likely to combust from the 10.6 gallons of gasoline than from the Lithium batteries.


Unsupervised!

 

Demand is going up without EVs, and the grid needs to modernize for that and to replace aged components.

Outdoor EVSE, and even outlet covers, have provisions for locks. Fancier ones probably have a login type of security.

2k1Toaster covered much of this. I'll add that lithium batteries for cars will soon be cheaper than NiMH ones, if they aren't already.

Toyota still using HiMH in some hybrids has more to do with them squeezing every dime out of their investment. Look at their automatic transmissions in smaller classed cars. The Corolla only had a 4 speed one until the last redesign, and it is still on the base trim. The Yaris and most of the Scions still use it. The rest of upgraded to 5 speed, 6 speed, or CVT for their cars years before.

 

'needs to', and 'will', are 2 different things.

 

well, we all need to see and drive the prime, (and any other car that isn't in production yet) before we can make a decision. but keep in mind, 22 miles in a phev is different than a bev. it won't work for everybody, but more because of their desires than needs.

on price, it depends on which package you want, and which lift back package you compare it to. but after federal and possible state tax credits, it likely won't be that expensive for what you're getting. and then you have to shop. toyota has some of the most liberal discounts, if you buy at the right time, witness gen 4 pricing.

 

When the rolling brown outs start, the people will start bitching for it to be fixed.

 

Do those without a drive way have cars parked somewhere when they sleep? Where is that place?

Bob Wilson

 

unfortunately, that's what it will take. but we seem to have plenty of supply in the northeast, where are the shortages?

 

I'd have to agree with @bisco. In fact the county, among other solar projects, just put in a 1.3MW solar farm about 1/4 mile down the road from my house. Can't see it from my house because of the corn growing so tall this year.


Unsupervised!

 

With PSEG, not only have been putting up solar farms, they've been putting solar panels on the telephone poles. No brownouts around here.

 

i remember the rolling brown outs in cali. in fact, one of my manufacturers put in their own natural gas power station because it was so bad. it was cost effective and reliable. how are things today, and where are they headed?

 

The level of supply or demand doesn't have much bearing on the fact that the distribution infrastructure is aging. All the wires, transformers, and various other bits aren't immune to the wear and tear of their use and environment they are in. Plus, there is the matter of a growing population.
Energy | 2013 Report Card for America's Infrastructure

Millions in the US don't have driveways. Regulations and incentives will be needed to encourage landlords and HOAs to install chargers. Areas with on street parking may require a low cost paid charger at every spot down the line to allow EV adoption to increase. In places where such is more of a norm, perhaps charge rates like with this VW will allow people to use a BEV like an ICE for daily use, and local charge stations will be more common than home charging. Such could use batteries, capacitors, or fly wheels to reduce the peak draw on the grid.

 

the grid needs modernization. if overuse doesn'tt bring it, than it will take one or more major catastrophe's.
as always, people like cheap energy, and will not willingly pay for it.

there are plenty of garages, waiting to be filled with electric cars, before anyone needs to concern themselves with people who have no place to charge at home.

 

in the US

 

exactly. i doubt the u/k needs to worry about 15 min chargers daring the grid. if there aren't any garages, there will never be enough chargers to down the system all at once.

that's like saying, what if everyone gassed up at the same time? it's only potentially a problem if everyone is charging at home, and they all have 15 minute chargers. that isn't going to happen, even here.