How long till a thermal battery management mod?

Since the Nissan Ariya will have active battery management, how likely is it that someone will attempt to mod a Leaf with the Ariya battery pack or battery cooling components?

Does anyone have any idea on how similar the two platforms might be?

Or alternatively, do we expect that the Ariya tech will eventually trickle down, and Nissan will someday add it to future Leaf models?

Predictions?

Just a prediction.

Battery technology advances to the point where a thermal management system is not necessary for the average commuter EV. That seems the path that Nissan is trying to take anyway.
TMS might still be needed for the high end EV, but if the current development of batteries is to be believed, future batteries will be able to operate at much higher temperatures without capacity damage and the passive air cooling design that Nissan is using will become the standard for all but the high end EV that are working with power levels in the upper half-to-one million watt range.

Imagine if the battery in your Leaf could be replaced with one that works at 140F without any issues, it would make road trips easy as the time between quick charges would be more than enough to cool it down below whatever extra high "danger" level it has. Would also make the systems simpler to do maintenance on if the TMS is one less thing to worry about.

knightmb said:

Just a prediction.

Battery technology advances to the point where a thermal management system is not necessary for the average commuter EV. That seems the path that Nissan is trying to take anyway.

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I bet it isn't needed for 90% or more of the current leaf owners with the way they use their car. I know I don't need it.

Adding all the plumbing needed to a Leaf does not seem feasible.

It's not just the "plumbing", the whole controller system would have to be modified: it would require a complete "transplant" of one platform to the other.
The Leaf always was/is/will be an EV platform without an (active) cooling system...and I'm OK with that. I much prefer the ability to "drop in" a larger (40 kWh) battery pack instead.

BAsrican said:

Or alternatively, do we expect that the Ariya tech will eventually trickle down, and Nissan will someday add it to future Leaf models?

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I don't believe there are future LEAF models (I think 2022 is the last model year, in the U.S. at least).

Stanton said:

The Leaf always was/is/will be an EV platform without an (active) cooling system...and I'm OK with that.

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Agree and me too (being ok with that and all)...

IMHO, I liken the LEAF to the VW Beetle of the gone era... Air-cooled and lacking many comfort amenities that became the norm along the way while it remained for the most part unchanged from its initial post-war form to final retired form in year 2000... Beetle was revolutionary when introduced, reliable & relatively low cost and led its company to develop newer platforms meeting expectations of the modern day.

I predict same will happen to the LEAF. Nissan will keep it alive for a few more years with modest improvements (if at all) and will keep positioning it as a lower cost entry point alternative to the Ariya and then eventually retire it as other brands come in sweeping the lower cost segment away (thinking of the Chinese brands here)...

I predict same will happen to the LEAF. Nissan will keep it alive for a few more years with modest improvements (if at all) and will keep positioning it as a lower cost entry point alternative to the Ariya and then eventually retire it as other brands come in sweeping the lower cost segment away (thinking of the Chinese brands here)...

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Fair prediction but I seriously hope that they will install CCS in the next Leafs, that is IMO the biggest fault that new Leafs have...... otherwise, super little EVs.

knightmb said:

Just a prediction.

Battery technology advances to the point where a thermal management system is not necessary for the average commuter EV. ...

Imagine if the battery in your Leaf could be replaced with one that works at 140F without any issues...

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I like this prediction!

OldManCan said:

I predict ... Nissan will keep it alive for a few more years with modest improvements (if at all) and will keep positioning it as a lower cost entry point alternative to the Ariya and then eventually retire it as other brands come in

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I suppose this is a reasonable prediction.

I hope they keep producing the LEAF for many more years though. At least so that there will still be replacement battery packs available down the road, because sooner or later they will degrade... :?

BAsrican said:

I hope they keep producing the LEAF for many more years though. At least so that there will still be replacement battery packs available down the road, because sooner or later they will degrade... :?

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Me too. I also hope that battery packs with higher energy density might become available down the road.

OldManCan said:

Me too. I also hope that battery packs with higher energy density might become available down the road.

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Yeah, that's why I wonder about the Ariya packs. Even if the Leaf disappears someday, hopefully something out there could still fit.

So evsenhanced are doing this. A new 16 blade battery for the leaf with tms included. Hopefully available worldwide via specialist installers. New Zealand first though.

As Leaf drivers are not generally doing 85 down the highway, even an 80kWh pack would largely remove what little thermal issues most of us are seeing (outside of the southwest).

whereswally606 said:

So evsenhanced are doing this. A new 16 blade battery for the leaf with tms included. Hopefully available worldwide via specialist installers. New Zealand first though.

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It would be interesting to see where they would put the radiator. Their video didn't show or tell.

Honestly, even just a little better airflow over the top of the pack would do quite a bit.

DougWantsALeaf said:

Honestly, even just a little better airflow over the top of the pack would do quite a bit.

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Is there documentation on the improved battery cooling design in 2018 and later models with 62 kWh batteries? In particular, I'm interested in how the battery is thermally bonded to the exterior or bottom of the car.

(By analogy, the silicon inside a CPU is hermetically sealed inside the chip under the metal "lid" of the CPU. There is no liquid or air cooling inside the CPU, but an external heat sink with a fan can dissipate heat fast enough to avoid damage.)

In this video of a Leaf battery disassembly, there does not seem to be any significant thermal bonding between the cells and the bottom of the battery case; in fact, it looks like there are contours for structural rigidity that form air gaps, and the yellow adhesive on the bottom of the battery case (when it's flipped over at the end of the video) might form another big air pocket when adhered to a bottom panel under the car:

https://www.youtube.com/watch?v=gXC75TdQnlw

For fun, has anyone experimented with something like carpet blower fans under the car after driving home in rush hour on the highway in hot weather, using LeafSpy to chart the difference? Is there anything designed for airflow cooling of the battery, like through the front grill?

There was, in the Gen I cars, a cooling tunnel of sorts, with air entering the front of the car and exiting the rear. People have tried powerful fans aimed at either the front underside, or the rear underside. I'm not sure that we know how effective that was, but with the reduction in clearance between the top of the pack and the battery in the Gen II (which is mostly a modified Gen I midsection), another obstacle to cooling has appeared. People have also tried blowing chilled air down into the area under the EV Emergency fuse cover, and some have even put ice - yes, ICE - in there. Improvement in cooling is claimed in those cases.

AlexDarcy said:

DougWantsALeaf said:

Honestly, even just a little better airflow over the top of the pack would do quite a bit.

Click to expand...

Is there documentation on the improved battery cooling design in 2018 and later models with 62 kWh batteries? In particular, I'm interested in how the battery is thermally bonded to the exterior or bottom of the car.

(By analogy, the silicon inside a CPU is hermetically sealed inside the chip under the metal "lid" of the CPU. There is no liquid or air cooling inside the CPU, but an external heat sink with a fan can dissipate heat fast enough to avoid damage.)

In this video of a Leaf battery disassembly, there does not seem to be any significant thermal bonding between the cells and the bottom of the battery case; in fact, it looks like there are contours for structural rigidity that form air gaps, and the yellow adhesive on the bottom of the battery case (when it's flipped over at the end of the video) might form another big air pocket when adhered to a bottom panel under the car:

For fun, has anyone experimented with something like carpet blower fans under the car after driving home in rush hour on the highway in hot weather, using LeafSpy to chart the difference? Is there anything designed for airflow cooling of the battery, like through the front grill?

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There's a similar analogy, but poor. The semiconductor die (the CPU chip) is bonded to the semiconductor package substrate,
which provides relatively high thermal conduction path to the semiconductor package. So cooling the package cools the semiconductor
die (chip). Just as there is a thermal resistance between the semiconductor die and package, there's thermal resistance between the
Leaf's battery and the Leaf's body. The thermal resistance determines the thermal time constant, relatively high for battery cooling
or heating, via the Leaf's body. So that results in a good and bad situation for the Leaf battery, e.g. bad when ambient is cooler and
good when the Leaf has been parked in a cool garage before driving in a hot ambient.

Muxan.com do a ccs plug conversion for leafs