Traction battery Cooler

Weehah...


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On my 3rd gen hybrid battery cooling air exits the car through baffles in the rear corners, below the hatch floor. In other words: to the outside.

 

Liquid is better in terms of temperature control, but it adds cost and weight. They appear to be a must on BEVs and larger battery PHEVs, but on PHEVs with packs along the Prime's size, the cons could out weight the pros for the car design.

 

Where's the wood chipper?

 

Well.......it's been since November 30, 2016 and today I saw the Traction Battery Cooler Question, piece o cake, I selected yes. Turns out every time you turn the car on then off you get the question asked again.

 

Yeah, I've noticed that too, although it tends to only show very briefly and fleetingly. Also, it seems to not be a "sticky" setting: If you say "yes," it still defaults to "no" the next time, best I can tell.

Last night I saw it and am pretty sure I successfully told it yes. I checked in on it once while charging this morning and I didn't hear the AC going, FWIW. Maybe it wasn't hot enough to be concerned.


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There are trade-offs, yes.

Ah, a better way to put it: "if I lived in Austin, Minnesota, instead of Austin, Texas, then I'd probably be grateful for it exhausting into the cabin!"


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The passive air cooling of the leaf also vents into cabin. Another reason to pass on one in a hot state.

The Prime venting into the cabin is odd in light of past Prii designs. The gen1 has a visible vent on the outside C pillar. But thinking about it along side the the Leaf, there might be passive cooling in the design for a little efficiency gain.

The gen1 vent is higher than the pack, so heated air can rise out. Following generations had the vent hidden lower, which is also true of the cabin vent in most cars. The intake for the gen2 is higher than that vent. So air flow over the pack powered by convection wouldn't be possible, or it would flow opposite the direction of the cooling fan, which be an obstruction in the way.

Dumping hot air into the space where the cooling air came through seems strange, but the intake and vents aren't next to each other, and a high exterior vent might compromise the exterior design, simply not be possible with the chassis. So it might be done for some passive cooling. Or the gen4 also simple vents into the cabin, and this is just carry over.

This raises a question. If the air conditioning is set to driver or front passenger only, will the system start cooling the rear in the event of high battery temperatures?

 

where is the 'battery cooling exhaust is dumping into the cabin' info coming from?

 

outer space?

 

I agree, the manual says the two vents in the bottom of the seat are intake vents not exhaust.

Also, the vents on the side of the seat are intake also for the battery, but those existed in my '14 Prius also.

So where are the exhaust vents?

 

probably in the fender, as it has always been. but a simple opening the the back area should show the venting, or if someone has service manual access.

 

As an "onlooker" (a terrific name coined by Mendel earlier in this thread) I can only go by what the owner's manual says, which seems to make it pretty clear that the only time traction battery cooling would ever operate is during charging. And my guess is the feature is mainly designed for situations where you immediately charge after driving, because the battery will already be warm, and if it's a hot day even if you were using AC the cabin temperature will rise pretty quickly after you leave the car especially if parked in the sun. I base my theory on the fact that the system asks you during shutdown if you think traction battery cooling will be needed.

That being the case, I would assume it ignores the front seat/rear seat climate control setting

 

An observation from the last 5 days. Temps 73°, 82°, 97°, 100° and 98°. I had EV miles left when I got to work. I had the windows closed all day and full sun for the first 3 days (no tint) and when I left work I lost half of the EV miles. The past two days (again full sun) I left the windows cracked and aired the car for a few minutes before I started. I was able to get very close to the miles remaining. Makes me think the battery cooler works when it is too hot on its own. The battery cooler pop up on the MFD is for charging. IMHO

 

Traction Battery cooling screen popped up again this morning when I charging my PP. I kept on looking at Multifunction display to see where I can change it to yes. I totally forgot (not used to) about the buttons on the right side of the steering wheels. I am going to try it after car is fully charged.

 

Traction battery cooling message didn't pop up when I plugged in ChargePoint cable this morning. I can't set it to "yes". Was it because ambient temperature is @ 60 F?

 

OK, I have to comment on this. While doing a Timer Charge a week or two ago, I opened the back door to put something into the car for later, and heard the sound of a fan coming from behind the vents in the back seat while it was Timer-charging (I assume it was the Traction Battery Cooler going on?)

But what's strange is, the conditions wouldn't seem to need the use of the Battery cooler: (a) I hadn't driven the car for hours. (b) the weather was quite cool (maybe 62F outside, and even cooler in the garage where this was -- even on hot days the garage is the coolest place of the house, and this was on a cool day). (c) It wasn't hot at all in the car's cabin, as (d) even two of the windows were partially open (I always leave a couple windows open when I park, because I usually drive with those windows open a bit -- every time I turn off the engine I get the "WINDOW OPEN" warning).

It had been Timer-charging for a while -- but under no other conditions that one would think would cause the Cooler to come on -- unless it comes on for ALL Timer Charges after a while, just because the simple act of charging it makes it hot (even if it's cold outside).

The sound of the fan/cooler is soft enough to where you don't hear it unless you open up a door... so maybe that's why I never noticed it before (that, and because I usually do Timer Charging in the middle of the night when I'm asleep, otherwise I just do a Charge Now).

The next time I Timer-charge it where I'm up during some part of it, I'm going to try to see if it indeed goes on again, but I'm wondering what others have observed. Even if the conditions are cool where the car is, with good ventilation in the cabin, does the cooler come on when you're Time-Charging it each time? (And no, the vents weren't covered, blocked, or anything like that).

 

Did you turn on the cooler? Otherwise I believe it's just the charger fan not the AC cooler.

Upon further review if you had the AC cooler working it would have stopped if you opened a door automatically.

 

It may very well be just a charging fan. I didn't realize there was one, though.. is there? (Because it was just the sound of a fan while charging).
Yes, I noticed too in the manual, that opening a door should stop the traction cooler... I wasn't sure if it had a short delay or anything... I just listened to it for a second or two before closing the door again. But it was just the sound of a fan -- though I have no idea if it's just a fan or the cooler. Is it normal for this charging fan to come on after the traction battery's been charging for a while? Just curious, I had never really opened the door and listened while the car was charging before then..

 

I believe all Prii have had a fan for cooling the battery. They are packed into a tight space, and the flow of current, charging or discharging, generates heat in that space. This fan is always available for venting that battery space with cabin air.

My understanding is that the supplemental battery cooler on the Prime is just the use of cabin cooling in the event the cabin air becomes too warm to properly cool the battery.

 

I came back to a cool car with AC blasting which is apparently what the battery cooler is. However, I did press yes when it asked me if it could when I powered off the car. What I don't know is if it will do that even I don't say yes. Does it default to Yes, unless I press no? I would hope so, because I can spare a few KWhs to prolong the life of my batteries.


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