Possible Widespread 2018-19 Traction Battery Quick Charge Problems

[IssacZachary]

Isn't there a space above and below the battery for cooling purposes? I don't recall that heat has to travel through the chasis to exit the battery.

You need to know how the battery is attached to the chassis.

I've never taken one out so my guess would be along the edges.

But I'm trying to understand what you are saying. It sounds like I'm missing something here.

Also doesn't the electric NV 200 can also use the same battery yet has a fan that blows air over it for better cooling?

 

[LeftieBiker]

There is a cooling tunnel under the floor - we know that much from the Gen I Leaf, and the so-called Leaf 2 uses the same midsection. The battery isn't cooled through the chassis - that's silly. When you drive, air passes over the top of the battery case from the nose of the car, and exits where the rear diffuser is located. There should also still be a flap in the cabin, by the emergency power cutoff, that sends cabin air into the tunnel when the blower is on and the fresh air intake open. This flap might be of use when the car is parked in a garage, if you can force cool air into the cabin without running the car's climate control, which exhausts heat into the front of the car.

 

[IssacZachary]

The battery isn't cooled through the chassis - that's silly.

Maybe it depends on what you define as the chasis? Anyhow, this is an air cooled battery isn't it. Not a chasis cooled battery.

When you drive, air passes over the top of the battery case from the nose of the car, and exits where the rear diffuser is located.

Isn't there a bit if space under the battery case between it and the plastic under tray where air flow too?

There should also still be a flap in the cabin, by the emergency power cutoff, that sends cabin air into the tunnel when the blower is on and the fresh air intake open.

I once was tempted to open the cover of the emergency disconnect and pour water down in there to cool the battery but decided against it.

But yes, the idea to cool the battery through there sounds like it could be possible with air. It might even work with the A/C in if you had a way of plugging the hot air from the condenser from going down into the battery space.

Now I'm wondering if I could put a heater over that hole and heat the battery (it's snowing right now). But now I'm straying off topic.

 

[Evoforce]

The NV 200 will not work well in hot climates either. We are already seeing many Kia Soul failures in Arizona. We also anticipate the Hyundai Ioniq will do poorly as well. All vehicles mentioned use air blown over the pack while it is moving or charging but not when it is parked or sitting in a hot garage. Compound that with charging in a already hot garage or initially trying to cool with a hot interior. Cars are most of the time parked, and they are parked over hot concrete or asphalt.

 

[cwerdna]

It sounds like all Leafs from all years and battery sizes thus far would be much better cars if someone would just figure out a way to install a fan that blows fresh air over the traction battery. It might not be enough cooling for those that live in extremely hot areas but it would be better than nothing and might be sufficient in most areas due to the overall thermal stability Nissan designed into all Leaf batteries. The battery fan could even be left on for extended periods by means of a 12V solar panel on the roof.

A fan will do nothing other than possibly help accelerate the pack reaching ambient temperature. It will not help it get cooler than ambient temp. In some cases, like if it's blazing hot outside and the pack is cooler than ambient, I would NOT want the fan running. I'd want it to take longer for the large thermal mass of the battery to reach ambient temp.

There should be a LOT of airflow at least under and possibly around the pack at freeway speeds. However, as has already been pointed out, you need to find the sweet spot of pack temperature increasing due to resistance in the pack vs. cooling (if any) provided by high ambient temp airflow.

Heck, when I'm at work, on a hot day, if I'm able to park in the slightly underground area which is cooler than outside temp at ground level, when I bring my car out of there, my battery temps begin to rise. And, as I drive home, they continue to rise. I've posted about this a few times like at http://www.mynissanleaf.com/viewtopic.php?p=509210#p509210.

Also doesn't the electric NV 200 can also use the same battery yet has a fan that blows air over it for better cooling?

I'm pretty sure the e-NV200 doesn't just have a fan but rather cooled air thanks to the HVAC system.

Side note: Not sure if I've posted this before, but the title of this thread irks me. It doesn't sound like there are widespread problems w/quick charging on the '18. There are alleged issues with "quick charging" speed and throttling, esp. after multiple quick charges. The title by itself makes it sound like the car has widespread compatibility problems or widespread REFUSAL to CHAdeMO charge, which I don't think is the case. (Sorry, not following this thread closely as I have little time and not much interest.)

 

[lorenfb]

The battery isn't cooled through the chassis - that's silly. When you drive, air passes over the top of the battery case from the nose of the car, and exits where the rear diffuser is located.

Then the chassis can't act as a heat sink when charging or parked, i.e. the battery case can have a higher temp than the vehicle's chassis which results in even higher cells' temperatures.

 

[lorenfb]

A fan will do nothing other than possibly help accelerate the pack reaching ambient temperature. It will not help it get cooler than ambient temp. In some cases, like if it's blazing hot outside and the pack is cooler than ambient, I would NOT want the fan running. I'd want it to take longer for the large thermal mass of the battery to reach ambient.

That's it. Good summary.

 

[IssacZachary]

A fan will do nothing other than possibly help accelerate the pack reaching ambient temperature. It will not help it get cooler than ambient temp.

I totally agree.

But one good thing about a fan is that it can be controlled. Add flaps that can also be controlled by an actuator and you can have more control over air cooling. And another good thing is that at least you can get temps closer to ambient instead of letting it cook at several degrees above that. Maybe you could plug the fan in all night and get your battery temps down as low as possible before venturing into the heat of the day. I don't know, it's just an idea.

So if this quick charging is heating up the battery past ambient temps and causing problems at least you could combat this problem a little with use of a blower or fan. You could also perhaps add some sort of cooling system to cool the air being blown too.

Of course none of this is a perfect solution. But some of us can't afford a Tesla just yet. I'm just throwing my two cents out there is all.

 

[IssacZachary]

The battery isn't cooled through the chassis - that's silly. When you drive, air passes over the top of the battery case from the nose of the car, and exits where the rear diffuser is located.

Then the chassis can't act as a heat sink when charging or parked, i.e. the battery case can have a higher temp than the vehicle's chassis which results in even higher cells' temperatures.

Hence why a fan blowing while parked at say a CHAdeMO station would help cool the battery.

 

[cwerdna]

In the past, we've already joked about having these at CHAdeMO stations. Skip to 0:17.
https://www.youtube.com/watch?v=nvp6pc9D2sU (was probably a different video URL but of the same test)

If that were very chilled water and not just at ambient temp...

We actually have an "Active cooling your leaf" thread before: http://www.mynissanleaf.com/viewtopic.php?f=34&t=21651.

Also, within the past 2 years, I recall seeing a kit (unclear if it was real and really for sale) marketed in Japan for racer(s)? that was basically a duct that ran from the passenger side HVAC vent over the front passenger seat into the hole for the service plug (plastic cover is on top of the hump/tunnel in the back seat area). Nobody would be able to sit in the front passenger seat.

I wish I could find the URL or a pic. My Google-fu wasn't good enough and FB's search sucks.

 

[arnis]

40kWh Leafs have "battery protection logic" that doesn't allow rapid charging if battery is above 40*C.
Theoretically, this reduces battery degradation. But it definitely locks out long-trip (300+ miles) travelling
as battery will not cool down enough during travelling or rapid charging for next rapid charge.
22kW charging is not rapid charging (check my signature, it's there since like 2016 :lol: )

Now we need to wait and see, can new chemistry deal with constant 30-35*C temperature.
We should see results this fall already.
If it does handle that temperature without degrading more than 2-3% annually, I'll give "thumbs up"

I'm very sure it is not necessary to have active cooling for any vehicle that charges at 50kW max.
But it is extremely important to have chemistry that is not afraid of 45*C (like Tesla).
Because if Leaf1 had active cooling, it would degrade almost as fast as it did without active cooling.
Tesla does NOT COOL the pack when it reaches 30*C. Nor 40*C. And it doesn't cool while parked (up to around 50*C).

And this is why 60kWh Leaf will have active cooling - it will charge faster than 50kW.

 

[LeftieBiker]

You don't absolutely have to have a dedicated duct running to the air exhaust flap. All you need to do is run the A/C, with fresh air or partial recirculate as much as possible, with a higher blower speed. This may be why my car still has 12 bars after just about 5 years: I ALWAYS use the A/C if it's hot, or even warm outside. OTOH, with the heat from the A/C also running down that tunnel, it could be a zero sum game under many conditions. I suspect it isn't usually, though, because that air gets 'diluted' with lots of ambient air.

A fan will do nothing other than possibly help accelerate the pack reaching ambient temperature. It will not help it get cooler than ambient temp. In some cases, like if it's blazing hot outside and the pack is cooler than ambient, I would NOT want the fan running. I'd want it to take longer for the large thermal mass of the battery to reach ambient temp.

This is the dilemma faced by the gentleman who converted my Vectrix VX-1 to Leaf cells. The bike came with two large blowers to cool the OEM NiMH pack, but he decided to remove them, and instead use plywood to actually insulate the pack, instead. This was because he (and I, to a lesser extent) cools the garage in which the bike resided/resides, so the pack would start out cool, and stay cool for quite a while, even in Hot weather. The pack surface temp sensor I rigged up shows that this is effective for most rides. In my case, since I usually ride from late afternoon until very late at night, by the end of many rides the pack is actually cooling down before I arrive home, despite the insulation. That's because the pack is bolted to the bike's aluminum frame.

 

[arnis]

Cabin air is evacuated at the rear bumper.

Here we can see those one-way flaps:

So somewhat cooled air (there is not a lot of chilliness left after passing the trunk) never
touches the pack walls. On the other hand, if AC is activated, air is blown through front bumper
intake and over the battery (at least some of it should be) EVEN IF vehicle is stationary.
If car is driving at medium or high speed, AFAIK, exterior fans are switched off, but there is
enough air circulation happening.
What is definitely true is that in case of stationary vehicle (traffic jam, or DC charging etc).
having AC activated (but not pumping lots of cold) will result in "more windchill" for battery case.

 

[LeftieBiker]

That definitely means that a portable A/C unit would have to be connected to the front of the car, not the rear.

 

[ElectricEddy]

Cabin air is evacuated at the rear bumper.

Here we can see those one-way flaps:

So somewhat cooled air (there is not a lot of chilliness left after passing the trunk) never
touches the pack walls. On the other hand, if AC is activated, air is blown through front bumper
intake and over the battery (at least some of it should be) EVEN IF vehicle is stationary.
If car is driving at medium or high speed, AFAIK, exterior fans are switched off, but there is
enough air circulation happening.
What is definitely true is that in case of stationary vehicle (traffic jam, or DC charging etc).
having AC activated (but not pumping lots of cold) will result in "more windchill" for battery case.

Great...another way for the rats to get in.

 

[LeftieBiker]

It should be possible to replace the flaps with metal screen or even hardware cloth.

 

[arnis]

Pretty much every vehicle on the road has had those flaps. For decades.
There is a reasonable mesh/grill on the other side.
One should not remove those flaps. These flaps have been there for years.

 

[hill]

......snip......
Tesla does NOT COOL the pack when it reaches 30*C. Nor 40*C. And it doesn't cool while parked

oh boy - sorry, but "very sure" doesn't really make it so. Far from it. We've been out on the road during 38°C temps - and when we stopped, the fans were blazing. you can hear them humming along loudly in this very short video - how loud they sound, even prior to the 1st couple minutes of charging.

https://youtu.be/bljd3M_1iNw

and during the next 40 minutes of charging the chiller fans ramped up almost twice as loud. additionally - even when we are in our garage at home, even charging at just 40 amps, the fans will kick on - even during a 78°f day. i have no idea where the 30°C cooling notion comes from. But yea- most people have no clue how important keeping a traction pack cool actually is (nor does Nissan) while it's just sitting there passively or charging.
obviously Tesla knows more about keeping tracction packs at the best temperature for longevity, because many of the early model S's have clocked over 250k & even 300K miles, losing on average less than 10%. very unlike our Nissan Leaf, with just over 80k miles, down well over 30%. sadly, the poor slobs who have purchased the larger packs will get diminished capacity even quicker than ours. Who knew. Probably Nissan
.

 

[Evoforce]

Yes, Tesla has very aggressive cooling . For those who haven't experienced it, they may have doubts.

 

[arnis]

......snip......
Tesla does NOT COOL the pack when it reaches 30*C. Nor 40*C. And it doesn't cool while parked

oh boy - sorry, but "very sure" doesn't really make it so. Far from it. We've been out on the road during 38°C temps....

I clearly stated when pack reaches. I wasn't talking about ambient temperature. Though we can be sure when that if it is 38*C outside, pack is higher than 38*C. And like I stated, it doesn't cool the pack at 40*C. But I didn't state that it doesn't cool the pack when it reaches 55*C.
And those fans are not specifically for battery cooling. Those are condenser fans (two condensers two fans). And if HVAC is activated and blowing chilly air into the cabin, those fans are on. Even if battery is dead frozen :lol:

PS: And when I say "parked" I don't mean stationary. I mean parked vehicle. Like.. It's doing nothing. Vehicle that is idling.

Going back to Leaf. It's very hard to heat the pack over 50*C with 30*C ambient and maximum charge rate of 50kW.
Though it is possible to heat the pack to 50*C while it is 38*C outside and charging happens at 50kW
Therefore, battery cooling for vehicles that charge up to 50kW is far from "imporant thing to have",
especially considering 50kW charge rate as not optimal for long distance travel in the first place.

Like my signature estimates, Leaf 2.0 wit 40kWh pack is mid-range EV. Not suitable for long-distance travelling.
And Nissan agrees with me