2021-2023 cold weather performance fix

[GarageWarrior2023]

I thought I remembered seeing they took one of their existing cooling systems and just modded it, who knows how true that is.

Well if that is the case, then that would make a lot more sense from a production standpoint. reusing existing parts wherever possible is definitely a reasonable and cost effective angle.

I haven't heard that about the system, but would be very curious to find out if it's true and if it is, what did they borrow the system from and what were the details of the system as implemented on the other machine. might help us understand selections, choices, and expectations of Ford with the system

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[Billyk24]

I thought I remembered seeing they took one of their existing cooling systems and just modded it, who knows how true that is.

Was it Donna? on a Muro video that stated they borrowed the Escape design and she stated something about future modifications.

 

[Billyk24]

Well, I'm pretty confident the battery was supposed to have a thermally non-conductive insulator pad under each cold plate so they could function efficiently. very little added cost or complexity. I believe a later management decision or supply chain issue (products of that nature from 3M and other during the pandemic became back ordered) caused it to be omitted late in pre-production. That's my theory.

As for the heating/cooling loop. Most manufacturers aren't insulating these (but I wish they would), and the rubber does have a low R-value. Where Ford went wrong, was making it unnecessarily long. This added cost, complexity and created an issue with keeping the coolant warm or cool efficiently while traveling through a lengthy maze of thermal loss.

When you look under the hood and think about the routing for a few seconds, you start to wonder how anyone would have approved the design in the first place. It costs more, it's more parts, more hose, more everything. It's not even smart from a manufacturing or cost perspective, let alone function and efficiency.

My simplest take on the Mach-E is "doing less with more".

No more pandemic supply chain issues. Let's search for something that can work. Find a service center/garage that can lift the vehicle and start adding such. It has to be a simple peel and stick procedure on the inside of the what I refer to as the skid plates.

 

[GarageWarrior2023]

No more pandemic supply chain issues. Let's search for something that can work. Find a service center/garage that can lift the vehicle and start adding such. It has to be a simple peel and stick procedure on the inside of the what I refer to as the skid plates.

I agree, definitely time for solutions.

Yes, the material required is minimal and inexpensive. The challenge is the battery tray is a top down access, rather than a bottom up access. To install it inside would require taking the entire battery out and stripping it to the shell. Kind of labor intensive.

Here's a Weberauto video showing a teardown of the mach-e battery for cooling system servicing. skip to 19 minutes in roughly and watch him lift out one of the battery modules. under which you can see the area where the thin thermal barrier material would go. There even appears to be spacing/offset present (pins and supporting edges) that makes me believe that something was designed to be there but isn't.


For comparison here's a weber auto video of a bolt ev battery teardown by weber auto. skip to 1 hour 30 minutes and 40 seconds in and you'll here him talking about the thermal pads that are under the cooling plate before he removes them. this is the component that's missing from the mach-e. the battery design is otherwise fundamentally the same. Functionally though, the Bolt EUV I had worked to -40c, had consistent winter range and not once did I get a battery cold message while driving. (Before anyone gets at me about the bolt battery fires, that was an LG battery pouch tab defect in some batteries. Nothing to do with the battery design or thermal management. and FYI Ford uses LG batteries too!)


The easier retroactive solution would be a thin thermal barrier on the outside bottom of the battery. Even something as simple as a non-conductive composite plastic adhered to the bottom would greatly improve thermal efficiency. Or a composite plastic with a thin foam double sided adhesive pad between it and the bottom of the battery.

As you can see from the bolt battery, it really doesn't take very much to create an appropriate barrier.

I really think a simple external solution could work and be very cost effective.

 

[GarageWarrior2023]

Just to add another bonus video to the topic. Sandy Munro talking about the Mach-e battery and the thermal aspects/properties of it and what you do and don't want in an EV battery enclosure for thermal efficiency. Skip to 22 minutes in and listen/watch for a minute.

 

[Jimrpa]

My opinion is it would only save a minimal amount of heat loss, probably less than 5%. EDIT: more like 10% loss. Due to the large number of bends and turns it would be very difficult to insulate. The loop temp is about 120°F. This is the cabin heating loop:

Insulating the bottom of the battery pack would probably do far more because of the large surface area.

Interesting. I did not know they used a liquid loop for cabin heating. I thought they just blew air across a resistive strip like home heating.

 

[Billyk24]

I agree, definitely time for solutions.

Yes, the material required is minimal and inexpensive. The challenge is the battery tray is a top down access, rather than a bottom up access. To install it inside would require taking the entire battery out and stripping it to the shell. Kind of labor intensive.

Here's a Weberauto video showing a teardown of the mach-e battery for cooling system servicing. skip to 19 minutes in roughly and watch him lift out one of the battery modules. under which you can see the area where the thin thermal barrier material would go. There even appears to be spacing/offset present (pins and supporting edges) that makes me believe that something was designed to be there but isn't.


For comparison here's a weber auto video of a bolt ev battery teardown by weber auto. skip to 1 hour 30 minutes and 40 seconds in and you'll here him talking about the thermal pads that are under the cooling plate before he removes them. this is the component that's missing from the mach-e. the battery design is otherwise fundamentally the same. Functionally though, the Bolt EUV I had worked to -40c, had consistent winter range and not once did I get a battery cold message while driving. (Before anyone gets at me about the bolt battery fires, that was an LG battery pouch tab defect in some batteries. Nothing to do with the battery design or thermal management. and FYI Ford uses LG batteries too!)


The easier retroactive solution would be a thin thermal barrier on the outside bottom of the battery. Even something as simple as a non-conductive composite plastic adhered to the bottom would greatly improve thermal efficiency. Or a composite plastic with a thin foam double sided adhesive pad between it and the bottom of the battery.

As you can see from the bolt battery, it really doesn't take very much to create an appropriate barrier.

I really think a simple external solution could work and be very cost effective.

Dropping the battery pack top down isn't going to work for Jane and Joe Sixpack. Your external application seems possible. Exactly what to use is going to be beyond Jane and Joe's ability to secure. Need mechanics/engineers to apply for such a needed job.

 

[Billyk24]

Dropping the battery pack top down isn't going to work for Jane and Joe Sixpack. Your external application seems possible. Exactly what to use is going to be beyond Jane and Joe's ability to secure. Need mechanics/engineers to apply for such a needed job.

Heck, can someone make an appointment with Sandy in the Detroit area and obtain a solution?

 

[GarageWarrior2023]

Heck, can someone make an appointment with Sandy in the Detroit area and obtain a solution?

I would love to see that!!

Also waiting to see if @Mach-Lee does a test with the heating loop insulation. I love his testing, does an amazing job capturing and presenting the data. A true professional.

 

[Mach-Lee]

Basically all this points to the bottom of the pack being where the significant heat loss occurs. And from teardowns we know it's not insulated, so it makes sense.

Just to expand on the battery pack bottom heat loss, I did some additional calculations. First we have to understand the construction of the bottom of the battery pack. The cell pouches themselves are heatsinked to the coolant cold plates with thermal interface material (TIM). I'm going to assume the thermal resistivity of this assembly is fairly low since it is designed for heat extraction. The aluminum cold plates have a dimpled underside and sit on standoffs. There is a small air gap (~5 mm) between the bottom of the cold plates and the bottom of the tray (which is where insulation SHOULD be, but there is none). The battery tray is also made of thin aluminum, coated black.

Battery cell module removed, TIM on cold plate:

Bottom of cold plate:

Empty battery tray:

The primary heat loss mechanism is convective loss, with radiative loss as a minor component. The following analysis assumes the battery temperature is +15ºC (departure time battery temperature) and the exterior temperature is -25ºC. The area of the bottom of the pack is approximately 2.5 m². We can assume the bottom of the battery tray is at ambient temperature (-25ºC) because there is no insulation and aluminum is a good conductor of heat. The bottom of the cold plates has a relatively low emissivity since they are shiny (assume ε = 0.17). The result of the Stefan–Boltzmann calculation is approximately 75W of radiative loss. For convective loss, we can assume a convective heat transfer coefficient of about 15 W/m²·K for free convection inside the pack with negligible flow. For a 40ºC temperature differential, the convective loss is 1500 W.

Therefore, the total heat loss through the bottom of the battery pack with no insulation is about 1575 watts. My previous experiments have determined the heat capacity of the battery is about 175 Wh/ºC. That means the pack will lose about 9ºC per hour and would cool down from 15ºC to 0ºC in only about 100 minutes, which almost matches a previous test I did (it only took 82 minutes, so there might be even more loss than I've predicted here).

If a 1/2" insulating foam with an R-value of 2.0 (0.352 m²·°C/W) is applied to the bottom of the pack, the rate of heat loss drops to only 240W, a savings of 1335W. Instead of cooling off in less than two hours of driving, the battery will now take approximately 11 hours to cool down. If driving in cold conditions, the battery will only lose about 3ºC of temperature between DC charging stops instead of 15+ degrees.

This shows the dramatic improvement in battery heat retention that is possible with insulating the battery. If you combine this with insulating the hoses, you're up to almost 2 kW of heat savings, or about 40% more heat available in the cabin.

Ford really should have put SOME insulation in the bottom of the tray like the Bolt, even a 1/4" sheet would have been WAY better than nothing.


Table 1 - Estimated heat loss of the battery (in watts) vs. outdoor temperature and insulation thickness. Assumes battery has been preconditioned (15ºC).

Thickness	R-Value	5ºC/41ºF	-5ºC/23ºF	-15ºC/5ºF	-25ºC/-13ºF	-35ºC/-31ºF	-45ºC/-49ºF
No Insulation		188	500	938	1500	2190	3000
1/8"	0.5	113	266	446	646	861	1090
1/4"	1.0	81	181	293	412	536	663
3/8"	1.5	63	137	218	302	389	477
1/2"	2.0	51	111	174	239	305	373
3/4"	3.0	38	80	123	168	214	259

I suggest choosing an insulation thickness to reduce heat loss below approximately 300W based on cold temps you regularly experience.

 

[GarageWarrior2023]

Just to expand on the battery pack bottom heat loss, I did some additional calculations. First we have to understand the construction of the bottom of the battery pack. The cell pouches themselves are heatsinked to the coolant cold plates with thermal interface material (TIM). I'm going to assume the thermal resistivity of this assembly is fairly low since it is designed for heat extraction. The aluminum cold plates have a dimpled underside and sit on standoffs. There is a small air gap (~5 mm) between the bottom of the cold plates and the bottom of the tray (which is where insulation SHOULD be, but there is none). The battery tray is also made of thin aluminum, coated black.

Battery cell module removed, TIM on cold plate:

Bottom of cold plate:

Empty battery tray:

The primary heat loss mechanism is convective loss, with radiative loss as a minor component. The following analysis assumes the battery temperature is +15ºC (departure time battery temperature) and the exterior temperature is -25ºC. The area of the bottom of the pack is approximately 2.5 m². We can assume the bottom of the battery tray is at ambient temperature (-25ºC) because there is no insulation and aluminum is a good conductor of heat. The bottom of the cold plates has a relatively low emissivity since they are shiny (assume ε = 0.17). The result of the Stefan–Boltzmann calculation is approximately 75W of radiative loss. For convective loss, we can assume a convective heat transfer coefficient of about 15 W/m²·K for free convection inside the pack with negligible flow. For a 40ºC temperature differential, the convective loss is 1500 W.

Therefore, the total heat loss through the bottom of the battery pack with no insulation is about 1575 watts. My previous experiments have determined the heat capacity of the battery is about 175 Wh/ºC. That means the pack will lose about 9ºC per hour and would cool down from 15ºC to 0ºC in only about 100 minutes, which almost matches a previous test I did (it only took 82 minutes, so there might be even more loss than I've predicted here).

If a 1/2" insulating foam with an R-value of 2.0 (0.352 m²·°C/W) is applied to the bottom of the pack, the rate of heat loss drops to only 240W, a savings of 1335W. Instead of cooling off in less than two hours of driving, the battery will now take approximately 11 hours to cool down. If driving in cold conditions, the battery will only lose about 3ºC of temperature between DC charging stops instead of 15+ degrees.

This shows the dramatic improvement in battery heat retention that is possible with insulating the battery. If you combine this with insulating the hoses, you're up to almost 2 kW of heat savings, or about 40% more heat available in the cabin.

Ford really should have put SOME insulation in the bottom of the tray like the Bolt, even a 1/4" sheet would have been WAY better than nothing.

Thanks @Mach-Lee this is awesome! Based on your calculations I would say you are right on the money.

With the math in place it aligns with the claims the Ford engineering team has of the battery's heat retention over time (because their calculations are probably based on there being thermal insulator pads in the original design). It also aligns with them putting a 7kw heater in the 23.5 and 24 models to add the required 2kw to compensate for the thermal losses you calculated. My theory is they went this route to avoid attention being put on the missing thermal insulators in the battery enclosure....also to avoid angry customers pushing them to fix that issue. I think the same thing happened with the coolant/heating loop redesign, to turn attention away from the shortcomings of the existing loop and how easily those shortcomings are mitigated with simple insulation of the lines....something people would have also pushed for in existing models.

This is definitely painting a clear picture now.

This all tells me, that in theory, insulating the battery and the cabin/battery heating loop would equate to the same/similar performance as having a 7KW heater, but it would be much more efficient (better range) because it would be doing it with a 5KW heater rather than a 7KW heater that's fighting against inefficient losses.

 

[Billyk24]

Thanks @Mach-Lee this is awesome! Based on your calculations I would say you are right on the money.

With the math in place it aligns with the claims the Ford engineering team has of the battery's heat retention over time (because their calculations are probably based on there being thermal insulator pads in the original design). It also aligns with them putting a 7kw heater in the 23.5 and 24 models to add the required 2kw to compensate for the thermal losses you calculated. My theory is they went this route to avoid attention being put on the missing thermal insulators in the battery enclosure....also to avoid angry customers pushing them to fix that issue. I think the same thing happened with the coolant/heating loop redesign, to turn attention away from the shortcomings of the existing loop and how easily those shortcomings are mitigated with simple insulation of the lines....something people would have also pushed for in existing models.

This is definitely painting a clear picture now.

This all tells me, that in theory, insulating the battery and the cabin/battery heating loop would equate to the same/similar performance as having a 7KW heater, but it would be much more efficient (better range) because it would be doing it with a 5KW heater rather than a 7KW heater that's fighting against inefficient losses.

The last two posts were priceless. Can someone actually meet with an independent engineer/auto mechanic shop such as Sandy's in Detroit and create a needed product?

 

[Tom L]

Just to expand on the battery pack bottom heat loss, I did some additional calculations. First we have to understand the construction of the bottom of the battery pack. The cell pouches themselves are heatsinked to the coolant cold plates with thermal interface material (TIM). I'm going to assume the thermal resistivity of this assembly is fairly low since it is designed for heat extraction. The aluminum cold plates have a dimpled underside and sit on standoffs. There is a small air gap (~5 mm) between the bottom of the cold plates and the bottom of the tray (which is where insulation SHOULD be, but there is none). The battery tray is also made of thin aluminum, coated black.

Battery cell module removed, TIM on cold plate:

Bottom of cold plate:

Empty battery tray:

The primary heat loss mechanism is convective loss, with radiative loss as a minor component. The following analysis assumes the battery temperature is +15ºC (departure time battery temperature) and the exterior temperature is -25ºC. The area of the bottom of the pack is approximately 2.5 m². We can assume the bottom of the battery tray is at ambient temperature (-25ºC) because there is no insulation and aluminum is a good conductor of heat. The bottom of the cold plates has a relatively low emissivity since they are shiny (assume ε = 0.17). The result of the Stefan–Boltzmann calculation is approximately 75W of radiative loss. For convective loss, we can assume a convective heat transfer coefficient of about 15 W/m²·K for free convection inside the pack with negligible flow. For a 40ºC temperature differential, the convective loss is 1500 W.

Therefore, the total heat loss through the bottom of the battery pack with no insulation is about 1575 watts. My previous experiments have determined the heat capacity of the battery is about 175 Wh/ºC. That means the pack will lose about 9ºC per hour and would cool down from 15ºC to 0ºC in only about 100 minutes, which almost matches a previous test I did (it only took 82 minutes, so there might be even more loss than I've predicted here).

If a 1/2" insulating foam with an R-value of 2.0 (0.352 m²·°C/W) is applied to the bottom of the pack, the rate of heat loss drops to only 240W, a savings of 1335W. Instead of cooling off in less than two hours of driving, the battery will now take approximately 11 hours to cool down. If driving in cold conditions, the battery will only lose about 3ºC of temperature between DC charging stops instead of 15+ degrees.

This shows the dramatic improvement in battery heat retention that is possible with insulating the battery. If you combine this with insulating the hoses, you're up to almost 2 kW of heat savings, or about 40% more heat available in the cabin.

Ford really should have put SOME insulation in the bottom of the tray like the Bolt, even a 1/4" sheet would have been WAY better than nothing.


Table 1 - Estimated heat loss of the battery (in watts) vs. outdoor temperature and insulation thickness. Assumes battery has been preconditioned (15ºC).

Thickness	R-Value	5ºC/41ºF	-5ºC/23ºF	-15ºC/5ºF	-25ºC/-13ºF	-35ºC/-31ºF	-45ºC/-49ºF
No Insulation		188	500	938	1500	2190	3000
1/8"	0.5	113	266	446	646	861	1090
1/4"	1.0	81	181	293	412	536	663
3/8"	1.5	63	137	218	302	389	477
1/2"	2.0	51	111	174	239	305	373
3/4"	3.0	38	80	123	168	214	259

I suggest choosing an insulation thickness to reduce heat loss below approximately 300W based on cold temps you regularly experience.

Emissivity? Resistivity? Stefan–Boltzmann calcu-what? Come on, you’re pulling our leg. You’re really a retired scriptwriter for 1960’s sci-fi movies, aren’t you?

 

[dpnelson]

Thanks @Mach-Lee this is awesome! Based on your calculations I would say you are right on the money.

With the math in place it aligns with the claims the Ford engineering team has of the battery's heat retention over time (because their calculations are probably based on there being thermal insulator pads in the original design). It also aligns with them putting a 7kw heater in the 23.5 and 24 models to add the required 2kw to compensate for the thermal losses you calculated. My theory is they went this route to avoid attention being put on the missing thermal insulators in the battery enclosure....also to avoid angry customers pushing them to fix that issue. I think the same thing happened with the coolant/heating loop redesign, to turn attention away from the shortcomings of the existing loop and how easily those shortcomings are mitigated with simple insulation of the lines....something people would have also pushed for in existing models.

This is definitely painting a clear picture now.

This all tells me, that in theory, insulating the battery and the cabin/battery heating loop would equate to the same/similar performance as having a 7KW heater, but it would be much more efficient (better range) because it would be doing it with a 5KW heater rather than a 7KW heater that's fighting against inefficient losses.

If they could have stayed at 5kW by adding insulation, that's a really bad example of bean counters and marketers triumphing over engineers. Keep in mind that the LFP pack is a different cell form factor, so that pack may not be as easy to add insulation to.

They could offer a cold weather package that adds pack insulation, but they may not want to have multiple variants of the same pack. They could also quietly add it for 2025 alongside the heat pump and let the heat pump take credit for all cold weather improvements. It would probably make quite a difference in extremely cold weather where heat pumps can start to lose efficiency.

 

[GarageWarrior2023]

If they could have stayed at 5kW by adding insulation, that's a really bad example of bean counters and marketers triumphing over engineers. Keep in mind that the LFP pack is a different cell form factor, so that pack may not be as easy to add insulation to.

They could offer a cold weather package that adds pack insulation, but they may not want to have multiple variants of the same pack. They could also quietly add it for 2025 alongside the heat pump and let the heat pump take credit for all cold weather improvements. It would probably make quite a difference in extremely cold weather where heat pumps can start to lose efficiency.

Yep, seems to be the ongoing issue with Ford that I'm finding. The engineers create something viable, and the higher ups trim it into something riddled with shortsighted issues. And then the Higher ups perpetuate the issue and create a long term customer retention problem.

I really think it's as simple as releasing an extreme weather kit for cold climates. something that's added by the dealership and is external. nothing inside the battery. An EV version of a block heater. That's all it has to be. Simple, straight forward, paid for option that gets added. No one would have an issue with that. I'd buy the kit tomorrow if they had it. even if the kit was $1000 installed.

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