Sponsored

Rivian battery overheating during charging in cool weather

electruck

Well-Known Member
Joined
Oct 6, 2019
Threads
69
Messages
3,496
Reaction score
6,460
Location
Dallas, TX
Vehicles
2023 Rivian R1S
With Rivian's inaugural pack, they are using a sandwiched cooling plate to warm/cool the pack. This is of course going to have nowhere near the ability to wick away heat that Tesla's in-pack cooling has, so heat throttling is going to happen. The reason cold weather does not help this much is the fact that the center of the packs (they are stacked) are well insulated from the outside temperature, so the main way for the heat to escape remains that single sandwiched cold plate. This is a physical thermal bottle-neck that is designed into the system and cannot be helped.

Why did they not put cooling ribbons between the cylinders the way Tesla does? Cost, and manufacturing difficulty. I expect Rivian's packs to evolve and get better at thermal management, but this is a good way to get decent cooling without breaking the bank as they try to ramp up. It is similar to how Ford & GM are doing it, except Rivian is using Tesla style cylindrical cells.

For those watching the pack tech closely as I am, I will add that the sandwiched cold plate design has another characteristic that could easily cause problems down the road. Because there are vertical banks of 2170s both above and below the cold plate, both cooling and heating will potentially be quite different between the upper and lower packs. When attempting to cool the pack during DCFC, the pack under the cold plate will get the bulk of the cooling due to thermal dynamics. Keeping the _whole_ pack at an ideal temperature becomes impossible, the pack on top of the plate will always be much hotter.

Heating the pack will have the reverse problem, but since heating is not as critical as cooling, that should have less of an impact on the life of the packs. Just based on common sense, one would expect the packs sitting on top of the cooling plate to fail before the lower ones.

Time will tell, and I am certain that the design will evolve.
Lots of misnfo there, not going to try to address it all. As for cold-plate vs tesla's cooling ribbons, even tesla has admitted that axial cooling is more effective than radial (to the extent that they are moving from radial to axial cooling in newer designs). Heat conduction between the cells and cold plate is not a function of gravity so no difference between top/bottom cells. Rivian has stated that cell temps are extremely consistent across all cells in their packs (RJ has quoted the variance somewhere, don't have that reference handy).
Sponsored

 

R.I.P.

Well-Known Member
First Name
Sean
Joined
Jan 2, 2023
Threads
11
Messages
1,129
Reaction score
1,494
Location
San Carlos, Mexico
Vehicles
Tesla Y, Cadillac ELR, Rivian R1T, Jeep TJ, F250
Occupation
Electrical Engineer
Lots of misnfo there, not going to try to address it all. As for cold-plate vs tesla's cooling ribbons, even tesla has admitted that axial cooling is more effective than radial (to the extent that they are moving from radial to axial cooling in newer designs). Heat conduction between the cells and cold plate is not a function of gravity so no difference between top/bottom cells. Rivian has stated that cell temps are extremely consistent across all cells in their packs (RJ has quoted the variance somewhere, don't have that reference handy).
Oh. My. "Gravity...?"
🤦

No, it has nothing to do with gravity lol. It has to do with thermal dynamics, but to simplify that, heat rises.

Because heat rises, if you apply a heating Force to a mass, the top of the mass will end up significantly hotter than the base of the mass. Because of these laws of thermodynamics, a cooling effect to the top of the mass is going to be far more significant and effective than to the bottom of the mass. The opposite is true if trying to warm the mass.

Because of these laws of nature, the lower pack in the rivian has the cooling effect where it needs it most; on top. The top pack ends up with the cooling forces where it needs it the least; on the bottom.

I will just leave it at that, because there is plenty of information to be had on thermal dynamics elsewhere.
 

electruck

Well-Known Member
Joined
Oct 6, 2019
Threads
69
Messages
3,496
Reaction score
6,460
Location
Dallas, TX
Vehicles
2023 Rivian R1S
Oh. My. "Gravity...?"
🤦

No, it has nothing to do with gravity lol. It has to do with thermal dynamics, but to simplify that, heat rises.

Because heat rises, if you apply a heating Force to a mass, the top of the mass will end up significantly hotter than the base of the mass. Because of these laws of thermodynamics, a cooling effect to the top of the mass is going to be far more significant and effective than to the bottom of the mass. The opposite is true if trying to warm the mass.

Because of these laws of nature, the lower pack in the rivian has the cooling effect where it needs it most; on top. The top pack ends up with the cooling forces where it needs it the least; on the bottom.

I will just leave it at that, because there is plenty of information to be had on thermal dynamics elsewhere.
Sorry, but no. What the laws of thermodynamics tell us is that heat moves from areas of higher temperature to areas of lower temperature. When considering heat transfer by conduction, as between the cell and cold plate, the heat will conduct down the same as it will conduct up. Yes, hot air does rise but that is due to factors that are not relevant to heat conduction between solids.
 

Dark-Fx

Well-Known Member
First Name
Brian
Joined
Jul 15, 2020
Threads
96
Messages
9,361
Reaction score
17,751
Location
Michigan
Vehicles
Polestar 2, R1T, R1S, Livewire One, Fisker Ocean
Occupation
Engineering
Clubs
 
but to simplify that, heat rises.
Heat rises because of.... gravity! Exciting, I know! Go read up on how they have to deal with heat on the ISS and other satellites that don't have natural gravity. Not truly relevant here but any (wo)man of science will appreciate it.
 

R.I.P.

Well-Known Member
First Name
Sean
Joined
Jan 2, 2023
Threads
11
Messages
1,129
Reaction score
1,494
Location
San Carlos, Mexico
Vehicles
Tesla Y, Cadillac ELR, Rivian R1T, Jeep TJ, F250
Occupation
Electrical Engineer
Sorry, but no. What the laws of thermodynamics tell us is that heat moves from areas of higher temperature to areas of lower temperature. When considering heat transfer by conduction, as between the cell and cold plate, the heat will conduct down the same as it will conduct up. Yes, hot air does rise but that is due to factors that are not relevant to heat conduction between solids.
Welp, the purpose of my post was to shed light on why we are seeing the dcfc throttling due to heat. I understand that there are those that want do debate absolutely everything, and cry "misinformation" if there is the slightest challenge to their belief set, but that post was not for those people.

That post was for those (like me) that are seeing the heat-related throttling and would like to go do their own due diligence to understand better why. The issue is very well documented (it is being referred to as "Rapidgate" in some circles), and I am experiencing it.

Does it mean I hate the truck? Relax, no, it does not. It does mean I am aware of ways it might be improved in future models (it is what I did prior to retirement), and I am looking forward to those improvements.

Side note:
Interesting if thermal dynamics actually is gravity related lol, I did not know that.
 

Sponsored

zefram47

Well-Known Member
First Name
Aaron
Joined
Feb 6, 2022
Threads
13
Messages
2,019
Reaction score
3,159
Location
Denver, CO
Vehicles
R1T, C6 Corvette GS
Occupation
Software Engineer
Clubs
 
Oh. My. "Gravity...?"
🤦

No, it has nothing to do with gravity lol. It has to do with thermal dynamics, but to simplify that, heat rises.

Because heat rises, if you apply a heating Force to a mass, the top of the mass will end up significantly hotter than the base of the mass. Because of these laws of thermodynamics, a cooling effect to the top of the mass is going to be far more significant and effective than to the bottom of the mass. The opposite is true if trying to warm the mass.

Because of these laws of nature, the lower pack in the rivian has the cooling effect where it needs it most; on top. The top pack ends up with the cooling forces where it needs it the least; on the bottom.

I will just leave it at that, because there is plenty of information to be had on thermal dynamics elsewhere.
Conduction will be far more relevant than convection/buoyancy in the pack. That cold plate is quite effective with a high temperature gradient.
 

R.I.P.

Well-Known Member
First Name
Sean
Joined
Jan 2, 2023
Threads
11
Messages
1,129
Reaction score
1,494
Location
San Carlos, Mexico
Vehicles
Tesla Y, Cadillac ELR, Rivian R1T, Jeep TJ, F250
Occupation
Electrical Engineer
Conduction will be far more relevant than convection/buoyancy in the pack. That cold plate is quite effective with a high temperature gradient.
Then you are not seeing the overheat throttling the way so many of us are?

Wierd it would affect some of us but not others. Do you DCFC heavily?
 

MountainBikeDude

Well-Known Member
First Name
Adam
Joined
Jun 20, 2019
Threads
40
Messages
1,878
Reaction score
3,845
Location
Vancouver
Vehicles
2023 El Cap Quad Motor R1T (Selling the Xterra)
Clubs
 

WSea

Well-Known Member
First Name
Patrick
Joined
Mar 6, 2022
Threads
39
Messages
1,589
Reaction score
1,898
Location
West seattle
Vehicles
R1T, Outback
Occupation
Architect
Then you are not seeing the overheat throttling the way so many of us are?

Wierd it would affect some of us but not others. Do you DCFC heavily?
I thought you sold your truck
 

manitou202

Well-Known Member
Joined
Nov 21, 2020
Threads
19
Messages
703
Reaction score
1,905
Location
Manitou Springs, CO
Vehicles
R1T LE, Mercedes EQS SUV
My guess is the pack has plenty of cooling, but Rivian hasn't fully optimized their charging curve and how to precondition effectively. It seems most EVs go through 12 months of suboptimal charging until the OEM gets enough data. Then improvements are made through software updates.

Tesla, Polestar, Ford, Hyundai, and VW have all improved their charging curves over time on several of their EVs. Not uncommon.
 

Sponsored

R.I.P.

Well-Known Member
First Name
Sean
Joined
Jan 2, 2023
Threads
11
Messages
1,129
Reaction score
1,494
Location
San Carlos, Mexico
Vehicles
Tesla Y, Cadillac ELR, Rivian R1T, Jeep TJ, F250
Occupation
Electrical Engineer
I believe that's what's being addressed in this coming OTA

"Addressed a rare case where Direct Current Fast Charger (DCFC) was slowed due to insufficient battery cooling."

Direct forum thread below
https://www.rivianforums.com/forum/...notification-steering-improvement-more.12056/
That is correct.

On the Ford F-150 Lightning, they fixed an air damn fault issue with an over-the-air update recently. The problems on the air dam are a less-than-optimal system for raising and lowering it.

The less-than-optimal system of course was not corrected with an over-the-air update. The parameters for when the warning light comes on was adjusted, so that people see those warnings far less frequently, if ever. There, customer not complaining, problem solved. Did it change the behavior of the air dam? No lol.

Since Rivian cannot change the actual physical cooling characteristics of the battery pack over the air, a similar fix can be expected. Instead of telling you why your dcfc is being throttled, they will remove that information and remove a lot of complaints in the process. There is precious little a manufacturer can do over the air to improve cooling while dcfc, except for possibly moving the entry and exit parameters.

Do I know for certain that is going to be the fix? No, I don't work for Rivian. But I was in the industry for 30 plus years, so I'm pretty familiar with how these things work.
😏
 

WSea

Well-Known Member
First Name
Patrick
Joined
Mar 6, 2022
Threads
39
Messages
1,589
Reaction score
1,898
Location
West seattle
Vehicles
R1T, Outback
Occupation
Architect
I think it was an OOS video where he mentioned an EA charger was delivering more kw than the vehicle was requesting. I suppose that could throw off the BMS cooling.
 

R.I.P.

Well-Known Member
First Name
Sean
Joined
Jan 2, 2023
Threads
11
Messages
1,129
Reaction score
1,494
Location
San Carlos, Mexico
Vehicles
Tesla Y, Cadillac ELR, Rivian R1T, Jeep TJ, F250
Occupation
Electrical Engineer
I thought you sold your truck
Yes, I have. But I put a lot of miles on it while I had it, including a trip into Mexico. I got quite familiar with it.
 

R.I.P.

Well-Known Member
First Name
Sean
Joined
Jan 2, 2023
Threads
11
Messages
1,129
Reaction score
1,494
Location
San Carlos, Mexico
Vehicles
Tesla Y, Cadillac ELR, Rivian R1T, Jeep TJ, F250
Occupation
Electrical Engineer
I think it was an OOS video where he mentioned an EA charger was delivering more kw than the vehicle was requesting. I suppose that could throw off the BMS cooling.
Wow. The only instance I am aware of where this allegedly happened was with a Ford lightning, and it destroyed the vehicle. This is a massive failure of how the system is designed to work, and should really never happen.
 

R.I.P.

Well-Known Member
First Name
Sean
Joined
Jan 2, 2023
Threads
11
Messages
1,129
Reaction score
1,494
Location
San Carlos, Mexico
Vehicles
Tesla Y, Cadillac ELR, Rivian R1T, Jeep TJ, F250
Occupation
Electrical Engineer
My guess is the pack has plenty of cooling, but Rivian hasn't fully optimized their charging curve and how to precondition effectively. It seems most EVs go through 12 months of suboptimal charging until the OEM gets enough data. Then improvements are made through software updates.

Tesla, Polestar, Ford, Hyundai, and VW have all improved their charging curves over time on several of their EVs. Not uncommon.
Except that in all the instances you refer to, the manufacturer started out conservatively, and ramped up the ability of the vehicle as enough data was gathered.

In this case, the vehicle is overheating during dcfc, so it's the opposite case of all your other examples.
Sponsored

 
 




Top