Battery Chiller

[ph2]

Has anyone ever checked out the chiller for the battery? I am trying to determine if mine is functioning properly; whenever parked with the hood open, I have always noticed that the refrigerant line to the chiller is never cold like the line to the cabin evap coil. Has anyone noticed this on a hot day?

 

[jimbo69ny]

Has anyone ever checked out the chiller for the battery? I am trying to determine if mine is functioning properly; whenever parked with the hood open, I have always noticed that the refrigerant line to the chiller is never cold like the line to the cabin evap coil. Has anyone noticed this on a hot day?

The battery is cooled using the same AC compressor as the cabin air. So if you have cold cabin air, your battery is getting cold fluid too. I could be wrong but I am pretty sure thats right.

 

[rayray]

not 100% accurate.
You have to be in none Eco modes .
So, always put it on auto or normal to ensure battery is getting chilled ..

 

[ph2]

Thanks for the replies so far; I suppose I should clarify my question.

The battery chiller and cabin evap coil are supplied by the same compressor. However there is an actuator on the chiller that controls the flow of refrigerant.

Does anyone know when this actuator should be open/closed?
Is it simply controlled by battery temp when set to 'AUTO' or are there other control variables such as the car needs to be moving, etc?
I have observed that my chiller does not receive refrigerant when the AC is set to 'AUTO', the battery temp is high and the car is parked; has anyone else observed this or can replicate/confirm?

 

[miimura]

There is a "Thermal ECU" that controls this stuff based on actual battery temps. However, its behavior is not publicly documented. The batteries actually like to be a little warm, so in reality they don't need cooling unless it's over 90F outside and you are driving fast or fast charging. In order for it to do active cooling, either with the radiator or the A/C, the car needs to be ON in READY, or charging. If you hear the fans running during charging, it still may not be cooling the battery, it may just be getting the heat out that was generated by the on-board charger.

 

[ph2]

There is a "Thermal ECU" that controls this stuff based on actual battery temps. However, its behavior is not publicly documented. The batteries actually like to be a little warm, so in reality they don't need cooling unless it's over 90F outside and you are driving fast or fast charging. In order for it to do active cooling, either with the radiator or the A/C, the car needs to be ON in READY, or charging. If you hear the fans running during charging, it still may not be cooling the battery, it may just be getting the heat out that was generated by the on-board charger.

Hi all, dead thread but wanted to follow up with what I found now with Tesla diagnostics setup. The chiller was in fact not working. I had observed this years ago but not being able to easily test, it was hard to know with certainty. I was measuring battery coolant temps >110F when charging in the summer (>90F) with Jdemo. I simply stopped using fast charging in the summer because I knew it was cooking the battery.

Now with diagnostics available it fails the chiller test every attempt. It will not ‘click’ during the test. Ordered a used one online and was able to get it to open its valve with voltage applied. With the spare solenoid, it ‘clicks’ on the original chiller indicating that the valve should be open indicating perhaps a bad solenoid. More troubleshooting and testing to come; battery temp is a little too low to test right now.

 

[alflash]

When the electric vehicle battery assembly temperature is high, the thermal controlECU sends a thermal expansion valve (TXV) and magnet valve operation request tothe power management control ECU. At the same time, the thermal control ECUregulates the switching valve way to open the passage to the battery coolant cooler.When the power management control ECU receives a signal from the thermal controlECU, it controls opening the thermal expansion valve (TXV). In addition, the powermanagement control ECU closes the magnet valve when the air conditioning is off orwhen the electric vehicle battery assembly needs to be cooled immediately. As aresult, the refrigerant flows through the chiller and exchanges heat with the coolantin order to further cool the electric vehicle battery assembly

https://alflash.com.ua/2019/to_rav4ev/bat_high_temp.png
This car has undergone the Coolant Air Purge procedure?

https://alflash.com.ua/2019/to_rav4ev/coolant_air_purge.png

 

[ph2]

https://alflash.com.ua/2019/to_rav4ev/bat_high_temp.png
This car has undergone the Coolant Air Purge procedure?

https://alflash.com.ua/2019/to_rav4ev/coolant_air_purge.png

https://alflash.com.ua/2019/to_rav4ev/bat_high_temp.png
This car has undergone the Coolant Air Purge procedure?

https://alflash.com.ua/2019/to_rav4ev/coolant_air_purge.png

At the time, everything was still factory (except Jdemo) and without TPDS, my method of changing coolant was with two buckets and let the pump do the work. No air in system at all.
One other thing now that I have TPDS and CAN data, I noticed that the reported active cooling setpoint on the battery is 158F. This could be an artifact of using an app not originally intended for our vehicles.
On other reported setpoints, Tesla systems seem to respond based on what CAN is reporting. If this is the case, I can’t see the chiller being of much use at all in stock condition…

 

[n3ckf]

I remember talking to an older engineer who worked on the Toyota/Tesla integration of the vehicle (at a demo where they had one, i had just bought mine at the time). He said they took one to Death Valley and finally got the battery cooling circuit to work property but that he thought it was complete overkill to have it on the vehicle. However if you operate someplace like Phoenix (at the time Phoenix was killing Prius batteries which are only air cooled), it might be useful. I doubt it gets hot enough in (most of ) california that you ever need it?

 

[alflash]

...
One other thing now that I have TPDS and CAN data, I noticed that the reported active cooling setpoint on the battery is 158F. This could be an artifact of using an app not originally intended for our vehicles...

Do you mean this data in the top line?

 

[ph2]

Do you mean this data in the top line?View attachment 56

Yes, but mine shows 158F and hasn’t changed in differing conditions.

 

[alflash]

Yes, but mine shows 158F and hasn’t changed in differing conditions.

I assume that in the context of this parameter, the word "target" means a certain threshold that sets the condition for a particular action. I don’t know whether the cooling of HV battery should actually turn on if its temperature is more than 158°F, since I don't find this data in the repair manuals and others descriptions for the RAV4EV...
For RAV4 EV, the numerical value of this parameter may be different.