Battery Temperature Management

[jkk_]

such as not having full time 3G/LTE connectivity (maybe offering it as an option/upgrade/subscription), reducing or eliminating over the air software updates/enhancements and getting them during the yearly service checkups

That'll end up people driving in outdated cars, i.e., cars that have potential exploits in them. Not really a good direction to take things.

 

[Booga]

I am very curious to learn if other aspects of the 3 will have similar "make it cheaper" aspects, such as not having full time 3G/LTE connectivity (maybe offering it as an option/upgrade/subscription), reducing or eliminating over the air software updates/enhancements and getting them during the yearly service checkups, lower warranty periods (6 year / 100k for the battery), etc. I would love to have an S, as I feel it is a technology playground for the user, having full control and information for just about everything within the vehicle. I really hope the 3 will be similar and not locked down / limited because it is mass produced.

Thoughts?

I expect the 3G/LTE connection will remain included in the base price - they're going to use our driving data and that requires a connection. If they charged for it and had people without it, they would lose the data source.

 

[scaesare]

AFAIK, Nissan added a heater to the battery pack (in 2012) for dealing with sub-zero temperatures, but they did not add any additional cooling capabilities.

Ah, looks like I mis-remembered which vehicle they adopted that for... it was the e_NV200:
Does Nissan e-NV200 Show Change of Policy on Battery Heating, Cooling?

Thanks for the correction.

As an aside, here's the heat degradation issue I was referring to, which supports the premise that active cooling is not strictly for power capacity efficiencies, but also longevity reasons (long-ish thread outlining history of issue):

Lost Battery Capacity and Range / Autonomy, Page 2 - My Nissan Leaf Forum

Note that I suspect that the active cooling on the Tesla may be required moreso for heat buildup during supercharging than typical environmental heat management, but nonetheless cooling during high C-rate charging should help with longevity...

 

[Frank99]

I expect the 3G/LTE connection will remain included in the base price - they're going to use our driving data and that requires a connection. If they charged for it and had people without it, they would lose the data source.

It depends on the value they place on the individual's data. If they cut the LTE and used WiFi instead, and simply encouraged people to connect the car to their home wireless, they could collect just as much information from the 90% of people who'd do that, at the loss of the data from the 10% who won't. Heck, they could do a deal with Starbucks and have the car auto-connect to every Starbucks it passes by and dump it's data. Might be cheaper than the LTE data plan...

 

[JeffK]

Might be cheaper than the LTE data plan...

I know loads of people who couldn't input a wifi password if their life depended on it.
A combination of LTE and Wifi is the best approach for everyone. Lifetime cell access is not that expensive (relatively speaking).

 

[Booga]

It depends on the value they place on the individual's data. If they cut the LTE and used WiFi instead, and simply encouraged people to connect the car to their home wireless, they could collect just as much information from the 90% of people who'd do that, at the loss of the data from the 10% who won't. Heck, they could do a deal with Starbucks and have the car auto-connect to every Starbucks it passes by and dump it's data. Might be cheaper than the LTE data plan...

Yeah - I think there are enough instances to collect data if needed. I don't know how much data Autopilot needs (road conditions, known construction zones, etc.), but that might be an overriding factor. It could sync with a phone and use the data connection from that.

I'm hoping the cost of this is already baked into the car for a number of years (8 years for example to match the drivetrain). I don't mind paying a little bit after that, but would hope it's not outrageous.

 

[jerry33]

AFAIK, Nissan added a heater to the battery pack (in 2012) for dealing with sub-zero temperatures, but they did not add any additional cooling capabilities.

Correct. They did change the chemistry to reduce heat degradation.

 

[Electroman]

But the jury is still out if that really helped or not. Early reports are not very encouraging. Lizard battery is more like a penguin battery.

 

[int32_t]

That'll end up people driving in outdated cars, i.e., cars that have potential exploits in them. Not really a good direction to take things.

Outdated, maybe, but without a data connection -- unexploitable.

 

[jerry33]

But the jury is still out if that really helped or not. Early reports are not very encouraging. Lizard battery is more like a penguin battery.

True. I have one but am concerned that it can only charge to 100%, which probably nullifies any gains.

 

[SageBrush]

What fraction of the waste heat from the battery and electronics can be diverted to the cabin for heating ?

 

[JeffK]

What fraction of the waste heat from the battery and electronics can be diverted to the cabin for heating ?

What fraction? I mean it depends on the thermodynamic properties of the materials used, the heat capacity of the coolant, radiative losses, etc... It's question is nearly impossible to answer accurately.

Would you be satisfied if I lied and said "all of it" in the layman sense?

 

[SageBrush]

What fraction? I mean it depends on the thermodynamic properties of the materials used, the heat capacity of the coolant, radiative losses, etc... It's question is nearly impossible to answer accurately.

LOL

ok,...we cannot model it accurately.

How about empiric observations ? Changes of Wh/mile at steady state driving with cabin heating on or off would be interesting at different ambient temperatures.

I was just thinking that about 1000 - 2000 watts of waste heat are generated at highway driving speeds, and I'd like a ballpark idea of how much of that that be diverted to the cabin. Estimates with some explanations would be great. Presume Tesla insulated where it was reasonable to do so, and that they did not choose a crappy refrigerant ;-)

 

[JeffK]

LOL

ok,...we cannot model it accurately.

How about empiric observations ? Changes of Wh/mile at steady state driving with cabin heating on or off would be interesting at different ambient temperatures.

I was just thinking that about 1000 - 2000 watts of waste heat are generated at highway driving speeds, and I'd like a ballpark idea of how much of that that be diverted to the cabin.

The Model 3 is supposed to have a "revolutionary" new HVAC system so unfortunately Model S/X observations won't hold.

 

[SageBrush]

The Model 3 is supposed to have a "revolutionary" new HVAC system so unfortunately Model S/X observations won't hold.

How well does the Model S/X perform ?

 

[AZ Desert Driver]

Yeah - I think there are enough instances to collect data if needed. I don't know how much data Autopilot needs (road conditions, known construction zones, etc.), but that might be an overriding factor. It could sync with a phone and use the data connection from that.

I'm hoping the cost of this is already baked into the car for a number of years (8 years for example to match the drivetrain). I don't mind paying a little bit after that, but would hope it's not outrageous.

If you watch the Mobileye lectures, they intend to update the "maps" with 10k of uploads every few microseconds. Nightly updates, or baton pass updates, would delete the core of the advanced piloting systems. Full time connection is baked in.

 

[Genshi]

I'm not so sure this is true. Other EV's , such as the Leaf, had premature batter degradation in hot climates due to lack of thermal management. They subsequently added such to later models precisely for pack longevity reasons.

Exactly what he said... The Leaf problems in the early models was primarily related to both battery chemistry differences and the use of air cooling when liquid cooling should have been used. It was cheaper to do air though...
Are Air-Cooled Batteries Hurting Nissan Leaf Range?

I only scanned this next article, but I'm pretty sure they've since fixed some/most of those problems.
Nissan Testing New Battery Pack to Address Problems with LEAF in Hot Weather

Edited to add:
Apparently there's some irony to be had here, too. Elon Musk derided the Nissan Leaf packs before problems had even emerged for... exactly the reason the problems emerged. "As a result, the LEAF pack will have temperatures “all over the place,” claimed Musk, causing it to suffer “huge degradation” in cold environments and basically “shut off” in hot environments."
Gigaom | Electric Car 101: Liquid vs. Air Battery Cooling Systems

And edited again to add this:
BMW and LG Chem Trump Tesla in Battery Thermal Management - HybridCars.com
Recently it was reported Tesla were in talks with Samsung and LG, ostensibly for their addition to the supply chain. It seems possible, between the "revolutionary HVAC" system for the Model ≡ and those talks, that it might also have something to do with LG's patent of a potentially simpler/cheaper cooling solution?

I'd rate that as unlikely because the simpler explanation is redundancy in their supply chain during the ramp up to 500k vehicles/year, but it might be part of the reason they're looking to work with partners besides Panasonic.

 

[Reeler]

Perhaps the Model 3 will forgo active cooling like the LEAF to keep costs down. The Bolt apparently goes to a design where each cell is passively cooled, which is different from the Volt and Spark where coolant was pumped between each cell.

It would affect battery life for sure, but would reduce the cost of the battery unit significantly. If you want less degradation, you could buy a luxury model (i.e., the S or X).

 

[jkk_]

Perhaps the Model 3 will forgo active cooling like the LEAF to keep costs down. The Bolt apparently goes to a design where each cell is passively cooled, which is different from the Volt and Spark where coolant was pumped between each cell.

It would affect battery life for sure, but would reduce the cost of the battery unit significantly. If you want less degradation, you could buy a luxury model (i.e., the S or X).

So... in order to save a few bucks let's push people to continue driving ICE. I respectfully disagree.

 

[SageBrush]

Perhaps the Model 3 will forgo active cooling like the LEAF to keep costs down. The Bolt apparently goes to a design where each cell is passively cooled, which is different from the Volt and Spark where coolant was pumped between each cell.

Tesla != GM