Battery Differences?

The longevity will likely be a factor of the battery protection software. Toyota has had a great track record for this in regards to the NiMH, and I would expect them to have done the same quality of work for the Li-ion pack. The 7 seater Prius v available over seas has a Li-ion pack, and there hasn't been any reports here about major issues.

I don't think you'll have to worry about -29F temps where you are at.

Well, the Prius isn't a big seller in Europe, and the NEDC test cycle is easy. So it probably Toyota some money to just use the NiMH for that market. On the EPA test cycle, the weight savings of the Li-ion pack could be a bigger benefit. Performance wise, I think any advantages in terms of charging and discharging the Li-ion would have is lost by the NiMH pack being larger, as it is with the usable capacity between the two. The likely designed the packs to be near identical in terms of that performance and capacity in order to cut down on R&D time and costs between the two packs.

 

Actually, there is something mentioned in Prius Gen. 4 Owner's Manual (USA & Japan version) but not in Gen. 3 Owner's Manual nor in European Prius Gen. 4 Owner's Manual (NiMH battery only) .
e.g. 4-2. Driving procedures (USA version)

I'm not very sure if this is mainly because of the Li-ion battery.

 

The -29F was posted earlier in the thread, but neither is likely to be a regular occurrence in the continental US. It might actually be the temperature point at which the electrolyte starts to freeze. The Leaf has a a radiant heater to prevent this from happening.

This http://www.electrochemsci.org/papers/vol6/6040860.pdf states NiMH performance rapidly degrades at -20C. Figure 2 there is of discharged curves for a 6.5 Ah NiMH prismatic battery module, recorded for a discharge rate of 0.15 C, at: room temperature (RT), -20 and -30oC.

This http://www.covalentassociates.com/Li-ion%20Battery%20Electrolytes%20Designed%20For%20a%20Wide%20Temperature%20Range.pdf has -10C as the point where average Li-ion cells start their rapid degrade, but the company that wrote the paper has electrolytes good 80C to -50C.

 

yes, it is because of the li-on battery. but we have people in minnersoter, who have not had a problem starting the pip.

 

Really, if it is cold enough to keep the car from starting, it is probably best just to stay inside. Even ICE cars will have trouble when their innards reach those temps..

 

They'll also have heating mats for the battery, and even a coolant heater too, if such low temps are going to be a regular occurrence. Nothing stopping such measures from being taken on a Prius. Some were putting the EBH on a gen2 in areas with much milder temps in order to skip the fuel 'guzzling' warm up stage.

 

Question:
Is this -29 limitation unique to Toyota Gen4 batt chemistry or more generic for Li?

 

I'd happily plug a 120v into the car to keep the hybrid battery warm, when the car was running it could warm itself, and yes, in hot weather (95+) cool. Hopefully the ice would be heated during cold weather also.

 

All batteries do poorly in such cold. NiMH does better than generic Li-ion, but there is Li-ion that can do better than NiMH. The SCiB battery available for Japanese iMiEV is good down to -30C before the major drop off in performance. Toshiba : Press Release (16 Jun, 2011): Toshiba's SCiB™ Rechargeable Battery Selected by Mitsubishi Motors for New Electric Vehicles

But don't expect any of these batteries to work as well as they do in more comfortable temperatures. Though they should warm up quickly once you get the car started.

The iMiEV has a battery heater option for freezing locations.

 

i would like to see reports of prius in 40 below locations. or even without prius. seems a silly thing to worry about.

 

Bunch of Tesla's in Norway right? ...guess they have EBH?...if so is it always on?

 

When plugged in, I think the thermal management system is on.

 

So maybe what Toyota is saying no EBH so extreme cold needs thinking...I don't think my garage gets below freezing. But going for trips up north with no garage one is exposed in the mountains etc.

 

I don't think you really have to worry if you wouldn't be worrying about an ICE car.

Coldest Places in United States - Current Results

 

I think 'minnesoter' gets a bad rap sometimes ( it looks good on the news ). Sure, it gets extremely cold in the northern part of the state. However, MN is a big state ( #12, in fact ). We live in the SE corner and the weather is vastly different than those horror stories we always hear on the national news.

Disclaimer...I'm NOT saying it is paradise here..just that the temps are generally higher than the northern reaches of the state.

 

you'll have no problem with the battery then. massachusetts gets the rap it deserves. it's cold everywhere.

 

EBH usually means Electric Block Heater. The Tesla has no B to H. Maybe the same acronym is being used to mean Electric Battery Heater? If the car were parked and plugged in to a power source, wouldn't waste heat from charging keep the battery warm, so there would be no need for a separate heater system? Just a thought.
Along the same lines, if you have a regular Prius (not plug-in) in extremely cold conditions, perhaps it would make sense to have both an EBH (to make it easier to start the ICE) AND some sort of electric battery heater?
Further, I've always wondered why somebody didn't make a programmable charger that you could input the time when you wanted the car ready to go, and the charger would bring the battery to 100% charge AND adjust the charging curve so that waste heat would warm the battery to perfect operating temperature at that time.

 

I was assuming EBH was battery heater in this thread. I assume to cope with cold -29 Tesla is heating the batt before start-up. Sounds like Gen4 does not have that, thus -29 is problematic. Otherwise my next question would be, what is different about Gen4 Li batt chemistry that cold is an issue? I assume the issue is lack of a battery heater for ultra cold.