Better sooner than later on the clean of the battery cooling

Cooking a battery is expensive

 

Have you looked at the air filter on the front of the rear passenger seat? Be sure it is clean. They are inexpensive and easy to replace.

 

I opened and vacuumed it , looks clean.

But previous owner had a dog in the car, it might be that inside the fan is dirty, I might need to service it, summer is coming.

 

Hello,
I just bought a 2020 RAV4 hybrid, with 66k km, and it seems that I have same problem, hv battery getting over 45 degrees some times, and loosing ev mode

@SmellyTofu , do you still own the car? Did you notice any issue in long term because of this overheating?
Thanks

 

My RAV4 is a NiMH variant. Like your's, my car sits in the garage so starts out at 19-23C in its sweet spot but heats up as I live near a hill enough to add 10% to SoC to high 60% / low 70%, I know it'd reach high 30C / low 40C by driving 4km and parking the car.

The Li-Ion version I have in my Prius v wagon I've only seen as max 36C at worse but on average sits at a very comfortable high 20C / low 30C. But fortunately I've not had to intervene to trigger the fan but with the Prius, I can with Scangauge.

 

No it won’t get dirty enough to warrant a replacement unless you’ve driven in really dusty conditions (talking dust storms etc) with the window open. In any case, even regular foam would do.

Further to this, I plugged in Techstream to check out why one trip with the battery at 50C after parking it for an hour at high SoC meant my 20-30min trip home had zero time of EV (even when shifter is in Park). This was a code it threw so I don’t know what else dealers can do other than tell me I should have used AC (but it’s not plumbed directly into the battery intake) when it wasn’t even a warm day to warrant using AC.

The error on the 2nd row but also X055E registered with higher temps (52C)

X055E error below

 

Having designed a lithium ion cell battery pack the cells don’t like to be charged or discharged above 50 C, this heats the cells up even more and can cause thermal runaway. Also below 0 C discharging or fast charging is not recommended. I’m not sure how pure EVs handle this since the battery pack can easily exceed these limits on very hot or cold days. Since my wife’s RAV4 is keep in a garage that’s partially underground the temperature varies between 45F on the coldest of days and 75 on the hottest, so the battery always starts off in the sweet spot of the operating temperature. Once the heat or AC is turned on it should remain at a good operating temperature.

 

Speaking of Traction Battery Airflow. The dealer I purchased the car from is sending me emails to have the 6 months service done. The car only has 1700 miles on it and will not need an oil change. Everything else I can do myself. I looked up the maintenance schedule in the manual and it mentions vacuuming the air intake for the traction battery. I did some investigation and removed the vent cover and found what looks like two filters as shown in the pictures. My question is do they every become dirty enough to replace, or is just an occasional vacuuming sufficient?

 

Checked mine after almost two years and 30,000 KM. Frequently carry kids and small dogs. Did not require cleaning.

 

I don't suspect. I'm seeing and experiencing it but not trying to be a smart arse about it but why not a dealer? Coz our dealers acknowledged it and said there's nothing they can do about it. So yeah, I'm on my own on this one.

 

if you suspect you have an issue with your hybrid battery not cooling, why are you trying to solve the problem yourself? take it to the dealer

 

Today I had my 24m service, raised my heat soak issue, noted the code and unsurprisingly, "No fault found" as they were trying to trigger it using very spirited driving & then EV mode after reviewing the dash cam. I think at some point they said during their drive that I might be looking at the wrong data + LOL. Plus they offered to go on the test drive but it's a cold 12C so of course it isn't going to overheat easily. It's an autumn, spring and summer problem!

So I will DIY a ventilation fan (undecided if I use a USB battery pack or 12V) and pump air from the back directly into the back of the HV traction battery casing.

 

Thanks for the info.

 

The1door. Thank you. It appears your one is the same as mine then. I'm looking casually for a left side lower seat trim of a wrecked RAV4 that I can hack a fan that pushes air out from under the seat into the cabin. The gap to the rear between the rear seat backrest and seat base doesn't seem to have any airflow.

I have as an experiment driven without the rear seat base (seat back up) and even lightly driving in suburban situations when temps are below 20C, as long as I can charge to 70% SoC perhaps twice, I can lift the HV temps above the threshold. The tops of the battery is also warm to the touch.

As for how I determine this, I monitor it using Scangauge 2 through the OBD that I monitor for temp in the middle of the HV battery. The hybrid characteristics change once it hits 45C where you get zero ability to move the car with any throttle application without ICE kicking in. So a dead flat carpark with any throttle input will kick start the ICE as if you cross the half way of the powermeter in normal circumstances.

Whilst there's no Scangauge command that can kick start the fan unlike there is on the Prius thanks to some genius on Prisuchat forums, there isn't one for RAV4 and Scangauge folks couldn't help me so I'm resorting to plugging in a BT OBD with the DrPrius app that I can trigger fan to go to 6 as opposed to 3 in normal programming when it's crossed the threshold (again Scangauge tells you the fan speed)

Yes I also raised it with the dealers but they can do nothing. Techstream can't adjust the target temps for the battery. If I could program it so that the fan starts at 27C instead of 35C I would and tampering the HV fan to be hard wired to always be on would void my warranty so I'm not doing that. But if heat was really an issue, then perhaps Toyota should have implemented a change by now.

Maybe everyday folks don't feel it but having been a geeky hybrid owner for >10yrs, you tend to notice these things and this is aside from the roof rail design is one of the biggest engineering annoyance of an otherwise good A to B car.

 

Note from The Car Care Nut's video, that after the fan blows air over the battery, the exhaust tubes that direct the air under the car are INSIDE the cover for the battery.
Therefore you can't see them by just lifting up the seat.

 

I remove the plastic on the side to give you a better view.

 

Here's The Car Care Nut's video on the hybrid battery.
If you scroll down below the video you can directly go to important chapters on air flow: (edit - I see that this video link does not show the chapter options that you see if you watch the video on The Car Care Nut's YouTube page)
8:45 min Fan Operation
14:32 min Aerial View

 

Does your vehicle have the cooling ducts installed on the battery?

BATTERY & BATTERY CABLE. 2021 Toyota RAV4 | Toyota Parts Center Online

2021 Toyota RAV4 BATTERY & BATTERY CABLE

parts.toyota.com

 

No one can spare me literally a minute to pull the rear seat and take a photo of the left side?

 

no vents on mine, 2020 XSE NiMH battery. The seat bottom is tight, it is on top of the battery with no space that I can see. My guess is that the hot air flows alone the left side panel where the seatbealt attaches. there seems to be a large gap between the paneling and the sheet metal that probably goes back to the rear vent by the side of the bumper.

 

All passenger vehicles have shutter vents located in rear of vehicle to provide exit of cabin air being pushed in by A/C fan. When vehicle windows are shut clean air is drawn in from vents in front of windshield, filtered, heated or cooled and circulated through vehicle and out the rear shutter vents. In hybrids a portion of this temperature controlled air passes through battery compartment to provide cooling and out rear vents even when battery cooling fan is stopped. Highly unlikely battery cooling air is just recirculated through cabin.
Note: Any obstructions to these rear vents could cause reduced or stop air circulation and adversely affect passenger air quality.

 

Post 8...

 

Can you post a photo of your situation as well?

 

Can someone please pull out their rear seat base (No tools required to do this) and take a photo of the left side coz either you have something I don't or they've designed a hot air vent that has nowhere to exit freely.

 

Only on the Prime. Not the regular garden variety hybrid.

 

Not what I saw, it was a regular hybrid, they did not even have the Primes when the video was made.

 

Bumping this thread back up, it seems this issue won’t go away. Currently I’ve been driving with the rear seat base out to allow the battery to cool off.

Anyway, what I know is one thing, the hot air exhaust from the battery just circulates under the rear seat with no easy way for heat to dissipate anywhere. Quickest way I think is to create an exhaust fan on the left side of the rear seat and pump it back into the cabin. Shouldn’t affect warranty as I’m nowhere near the battery and pulling air out of the closed area.

The other thing I suspect, is the material under the rear seat when fitted is covering the top of the traction battery like a blanket this heating up though the whole top plate area is about right from a temp accuracy perspective being warm to the touch.

Can someone please pop their rear seat out and check if the material under the seat is tight against the seat base or slightly loose that could fall ever so slightly? Thanks!

 

I saw the video from the Car Care Nut, he shows the hole where the warm air from the battery fan is pushed out down under the vehicle.

 

Correct. Into the wheel well. Go video what happens to that vent whilst you’re opening and closing the door.

 

That vent you’ve circled should be a series of shutters (like a house) that just allowed air to pass when the doors are closing and open/close freely. It’s got nothing to do with the air flow output of the traction battery.

 

So here are the pics. The vent is covered by duct tape as I try to prevent the mice from getting in, so far unsuccessful. I'm not worried about blocking the vent because I've removed the cargo area floor, so there is plenty of room for the warm air to dissipate.

 

Use a screen so air flows but mice don't.

 

To answer my own question (maybe) I took the rear seat out and it appears the air flows out the top of the left side of the traction battery and not plumbed anywhere else trapping the air under the seat with a very little bit leaking into the rear luggage compartment. Anyone else know of any other idea of other vent outlet?

 

To answer my own question (maybe) I took the rear seat out and it appears the air flows out the top of the left side of the traction battery and not plumbed anywhere else trapping the air under the seat with a very little bit leaking into the rear luggage compartment. Anyone else know of any other idea of other vent outlet?

I can tell you how it works in a Prius. Maybe the Rav is similar. With the Prius the warm air from the battery flows into the spare tire well area (under the floor of the cargo area, then out a vent on the left side just behind the left rear wheel. There is no ducting to bring the air to that vent but air has to go that way because the cargo floor prevents it from going out any other way.

Believe it or not, I found this out because mice have been getting into the spare tire area. I found the vent and think the mice have been getting in through it.

One thing you might try is completely taking out the cargo area floor and getting a sense of air flow there when the vehicle is in ready mode.

I'll try to post a pic of the vent later today.