It will be 2-3 times more costly to keep Tesla plugged at 2°F....I agree, but having the motor stators heat up to heat up the coolant flowing through them is a weird heat source, to me....
Those motors are a large mass of steel, copper, magnets, lube and aluminum.
They are just sitting out there, out in the breeze, and they are located far from the coolant inlet to the pack.
A 'half-a-shoe-box' size 2kW coolant heater tucked in somewhere makes engineering sense, to me...
Maybe a Tesla fan can explain why this the way to warm the pack.
So the octovalve is just a fancy coolant director valve?
I thought at first it had something to do with a heat pump system.
Remember you need heat and AC to defog the windows sometimes.
If a Bolt and a Model 3 are parked out in the 2°F driveway for 48 hrs, both plugged in and topped up, what would the energy cost differences be for running these TMS systems?
If you say so. what about both motors being used for heating. Is that really a thing?
Good discussion of Model 3 heat here, with links to logs of temps:
forums.tesla.com
Definitely On my Dad's model Y I can see in less than 15-20 minutes while seating still battery raises from -20°C to 50°C.... pushing almost 7 kwh on the stators....while driving and heating up battery it will never hit more than 30°C because of using cabin heater and driving...and while plugged to fast charger it will go all the way to 60°C + before it will stop heating battery and start cooling battery if it goes over 64°CGood discussion of Model 3 heat here, with links to logs of temps:
.Battery Heating explained
So most of my reference data is https://forums.tesla.com/forum/forums/temps-precondition-regen-data-graphs and Bjorn's videos.
Here is a diagram I did of the high voltage electronics loop, and the parts diagram of the heater setup. Just add the heater core at the firewall end of those long hoses #4 and #7, and you have it all.
View attachment 33587 View attachment 33588
The battery heater set up is identical, but the heater is half as big, and much closer to the front of the battery than the pump, and reservoir.
The yellow symbols are the temperature thermistors. The acronyms are GM speak for inverter, onboard charger, and accessory battery charger
50 - 60C? It sounds too hot for Li-ion battery. Wonder how much reduction in range in cold weather. It must take quite a bit of power to keep temperature this high all the time.
That is how Tesla chemistry works they love to be on hot side.... Regarding insulation of metal portions pipes yes definitely....but rubber hoses are not needed.... What would benefit is using 1/4 inches coating like they use in truck beads and coat entire bottom of the battery pack.
Not sure if truck bed coating has any R-Value. I thought the pack was built with insulation.
The insulation in the battery pack consists of white plastic sheets, think thick painter's drop cloth.
It must have some R-Value. Does the good professor at Weber show this during a teardown of the pack?
The white plastic sheets under the aluminum coolant manifolds are referred to as thermal mats by GM. While they no doubt reduce heat transfer, they are just thin plastic sheets.
Thanks for the link. I'll watch all of these videos someday...
Wow! I watched all those videos, and my brain just "saw" the pads as under the manifolds.. Amazing. So the plastic is supposed to increase the thermal conductivity, like thermal paste under mosfets, and unlike thermal relief pads which decrease heat loss when soldering.Thanks for the link. I'll watch all of these videos someday...
However, it looks like these 'mats' are on top of the 'hot plates'. It's cooling and heating, there professor....
Don't know why you wouldn't want direct cell contact to the plates to make for better heat or cool conductivity.
To me the question is: What's between the 'hot plates' and the metal bottom plate of the finished pack as installed in the car? The bottom of these hot plates is the area that needs the insulation, and I suspect it has a decent R-Value.
It has no insulation besides trapped air underneath...if insulation was done...it will definitely help a lot how fast battery is getting cooled down when car was not used.Thanks for the link. I'll watch all of these videos someday...
However, it looks like these 'mats' are on top of the 'hot plates'. It's cooling and heating, there professor....
Don't know why you wouldn't want direct cell contact to the plates to make for better heat or cool conductivity.
To me the question is: What's between the 'hot plates' and the metal bottom plate of the finished pack as installed in the car? The bottom of these hot plates is the area that needs the insulation, and I suspect it has a decent R-Value.
It also act as barrier when battery heater just starts in cold weather to prevent different rate of expansion between thermal aluminum plates and battery modules...
Really?
Yes. But make sure you see what you are looking at. I was so sure I knew what the plastic film was for, I saw it in an entirely different place.
www.ptonline.com
Very interesting....is this what we have or something else? I will try to find this conductive plastic sheets from my last teardown on Bolt HV battery..... I do remember when I was taking them out they definitely are something more than just plain plastic.This was instructive. I really had never thought about using metal oxides or other stuff as filler to make plastic thermally conductive.
Plastics That Conduct Heat
Helping electronics, lighting, and car engines keep cool are some new roles for hermoplastics that are formulated to replace metal or ceramic.
