Why does the Gen3 hybrid battery fail more than in the Gen2?

I don't accept the premise of your entire statement.
Show me world wide figures. Actual stats...
Excuse me if...."I have noticed" in this case is simply NOT enough.

I have participated in Prius Chat a long, long time....
and "I HAVEN'T noticed...a huge discrepancy between Gen 2 Hybrid Battery failures and Gen 3 Hybrid Battery Failures."

Of course I don't have statistics or studies to back up my statement either....so I guess it's as invalid as yours.

 

This is wrong My prius is clocking 70000 kms a year. Amd its as good as new i have 2014 prius Gen 3. AUSTRALIA. This persons started wrong string .

LG-D855 using PriusChat mobile app

 

Maybe this thread should be closed? I know it's making me angry, I'm ready to bite the head off a snake, just about now.

Or at the least change the title to: "I'm alleging the Gen 3 Battery...."

 

The Gen3 is pushing higher currents, but the modules actually are more robust. I would expect that these factors may make the Gen3 somewhat more susceptible to overheating in warm climates or mountainous terrain than the Gen 2.

JeffD

 

Did Sri Lanka receive the Gen 1 Prius that was sold only in the Japanese market (NHW10 1997-2001)? What we in the USA call the Gen 1 was the second generation (NHW11 2001-2003). The original liftback (2004-2009) was the first generation sold in significant quantity. Just to play Devil's Advocate, I do believe there have been more traction battery failures in the liftback than in the sedan's generations as there are significantly more cars produced. How many sedans are still running on their original batteries? I don't know.

Toyota Prius - Wikipedia

 

Although the thread title may a bit strong, it's a topic which touches on some questions I've been pondering for some time now.

@jdenenberg touches on the relatively higher current demand placed on the Gen 3 battery and the idea that Gen 3 modules are more robust than Gen 2. This has been well discussed here and likely won't be disputed by the well-versed Priuschatter. This raises a few questions for me of which I'm ignorant and struggle to find clear answers to:

-How much greater current demand on Gen 3 vs. Gen 2, up to 30%?
-Do we know as fact Gen 3 modules are of any different chemistry than Gen 2?

Now bring the E0E recall into play but not until Feb 2014 or so... It seems this was a software play designed to lessen current demand. Assuming I'm correct, it's clear Toyota felt this was required at least to try and prevent mass IPM inverter failure. So my next questions are:

-Wouldn't this mean less aggressive current demand on the battery to in turn lower IPM temp?
-Is the E0E worldwide, Sri Lanka specifically for the sake of this thread?
-If the IPM had been up to the task with original software, does this indicate the battery chemistry would indeed have to be more robust than Gen 2 in order to yield a battery with similar or better staying power?

There are loads of early Gen 3's out there that had plenty of time to accumulate mileage and stress before the recall and there certainly have been reported IPM failures since, and to vehicles which have had the recall performed. Thankfully, we still aren't seeing the first wave of 2010 battery failures in North America. We are predominantly North American on PC, though, so who knows what's going on elsewhere.

 

I haven't heard of any chemistry differences between the GII and GIII battery. Just minor tweaks to the physical structure. We (well, the Panasonic and Toyota engineers) learn with use and over time. Size is almost identical. Note that a NiMH battery uses nickel plates, one "solid" and the other not so much, and potassium hydroxide in water as an electrolyte.
When you go from a GII to a GIII you almost immediately notice the increased use of the battery. Pearl S (GIII) will shut of the ICE if there is the lightest hint it can. Pearl (GII) not so much. I've never made current measurements so I can't comment on the statements of the GIII using higher current.
If you use the battery more often on any given drive, it will probably "wear" more. But you will also get better mileage.

Again, the only failures I recall reading about were in Taxi use. That industry is -very- sensitive to cost issues, so they became quite aggressive in their preference of GII cars. A "good thing (tm)" for those selling their GIIs.

Do keep in mind there are some who love to spread "FUD" about hybrids. Not so much recently with low fuel prices, but once upon a time it was "professional". So do your research carefully as some numbers may have been "adjusted".

 

You have 168 individual battery cells in the Prius so one fails and it's then time for HV battery replacement/repair. There is no redundancy built in.

 

Thanks, David. I mistakenly took your statement of more aggressive battery use in Gen 3 as being synonymous with higher current and will edit my previous post. Agree completely with Gen 3 battery use being obviously higher than Gen 2 with or without Techstream verification.

So this plays to my curiosity as to what effect the E0E plays on current load and if it is lower after the recall is performed. Same can be said for how aggressively the battery is used. It all makes me wonder if Gen 3 will see longer battery life post E0E and how it may relate if parts of the world don't see the recall.

I suppose it is possible the OP is a FUD troll but I'm using it to voice some curiosities I've had anyway. Probably should have started a new thread altogether...

 

I -heard- over the "grape vine" that the recall reduced the high current pulses when you used high throttle. It was causing the output transistors to heat up and expand, which was causing them to loose some contact with the heatsink. Actually I may have read that in the letter from Toyota, but I just don't remember. I didn't notice any difference in the way the car drives, but I only use full throttle when provoked by someone in a PU trying to kill me (to get out of his way). Only about once a week.

There are many "conspiracy" theories I could come up with to explain why some areas didn't have to do the recall. But not being a politician of a certain ilk I'll just say I don't know.

 

i think tesla has that, but i'm not sure how much of the $100,000. it accounts for.

 

The OP may of innocently made this statement with all good intentions.
BUT..
If you are going to make a 2 sentence thread? With that as the heart and nearly singular statement?
You need to come back and explain yourself and/or simply provide more evidence to support your argument.

Otherwise....I read..."Thanks In Advance" as "Gotch Ya!".

 

Well, one cell failing won't make the Prius NiMH battery unusable. It takes two in one module, as I recall, for the battery computer to give a warning (the 168 cells are divided into 28 modules of 6 cells each). Generally, a NIMH cell will fail to short, so the rest of the module will function normally. The battery computer monitors the modules in pairs, and won't fail a pair unless two cells have failed, as I recall. Keep in mind a cell operates at about 1.25V so in a nominal 200V battery one or two cells are not significant. Fully charged the battery -could- reach 252V, but that is avoided. Fully discharged the battery -could- reach 159.6V, and that is also avoided. Looking at that voltage range, two cells missing wouldn't have much effect. In fact, from GII reports, a "bad battery" (by Toyota's software definition) often has 7 or more cells bad.

The "fail to short" comment is caused by reverse charging. If a cell looses too much capacity it will discharge to 0 during operation and that will cause the current through the battery to reverse charge it. This causes nickel to "whisker" across the cell, shorting it.
This is why the Prius won't discharge the battery lower than about 20-30%. The limit to full charge is to reduce the chance of a low capacity cell over-charging, loosing electrolyte, and then, due to even lower capacity, becoming the cell that will "whisker" during normal operation discharge.

I can't comment on the new Lithium battery as I have no experience with it.

 

a few years ago there was a discussion of batteries failing in G3 in greek taxis around 200,000km (or was it miles?), sooner that it was expected based on G2 experience. some taxi drivers from spain confirmed that. maybe overheating in hot climate? those taxi drivers admitted not using AC, but rather driving with open windows in summer.

 

Wow, strong memory, f_j.

prius 2010 hybrid batteries dead at 126000km and up on atleast 3 taxis i know of | PriusChat

 

We have only had a rare few Gen3 batteries die here on Prius Chat (re: USA consumers).
I realize European cabbies had some batt fails.
Very few 2009 Gen2 have died yet either, by my count.

So my question would be, does it look like Prii HV batteries are lasting longer? maybe life of car in most cases in the USA?

Unfort Toyota is not talking , or maybe we should just ask. But we have no new info from Toyota on batt life in many years. So we have no clue, no real data, regarding %Gen2 or %Gen3 batt fails.

 

Since i put the new battery so far no issues.
I put my previous battery on a used item reselling website here in Srilanka,and there were so many people who called me for the battery having same issues like me.i needed to sell my previous battery for any one who need the cell modules;but most people that called me told that they also tried changing cells(removing low voltage with new ones) but it wont last even 5000km.i think here in sri lanka we r using aircondition most of the time.it draws more power from the hv battery.may be that or some other issue with HV battery smart controller software conflicting with scanner software during resetting procedure.when they checks battery with the scanner they always reset smatbox through scanner.so here we need some expert opinion.another thing here in sri lanka most people put normal lead acid 12v battery that use in normal cars when prius's original 12v dies after five years.then comes certain issues.

 

A lot of Priuschatters preach using AC throughout the summer, to cool the cabin and the battery. I've monitored battery temps (with Scangauge), with and without AC, and found little or no drop in battery temperature with AC use. Like you, I suspect the frequent use of AC just put more load on the whole system.

 

YES! THIS! Surely this is a trend! Use of regression analysis indicates that Gen 5 will be sold new with already failed batteries.

 

Most of the responses to the OP deserve an "unlike" button. He brought up a valid and correct concern and you guys jump all over him.

Bingo! The Gen III cars push the batteries harder than the Gen II does. I'll add cooling as a likely difference. Camry's and most Lexus are mean to the batteries also. My opinion is based on actual testing of Gen II and Gen III batteries. I have not been able to spot a difference in the construction of a Gen II and Gen III modules. Everyone says there is a difference.

The Gen III cars are on average 6 years newer than the Gen II. They are still too young to generate a lot of failures. The failures for taxi drivers and other hard users are the first signs of the coming storm. It will take a few years for the Gen III batteries to fail in large numbers. Rebuilding is going to be harder because all the Gen III modules are going to be worse off than a similarly aged Gen II.

Brad