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Discussion Starter #1
Hi folks,
Planning a Tesla Model S battery box - 8 pieces: 2 rows, 4 high. It'll be a bench to sit on top of.
Any suggestions on the box material? Is cooling fans ok to have to ventilate? Any other advice or challenge somebody faced with one?
Thanks in advance.
 

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Discussion Starter #3
Why would you use cooling fans with modules that have built-in liquid cooling?
These would be more for any heat that could be trapped inside (ex. from ambient temp. high,), or to promote general air flow. The modules themselves would definitely be liquid cooled.
 

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I could see having some circulation fans, but I wouldn't bother until the temp inside the box was shown to be the weak link in the cooling change. My guess is that it won't have much effect all.

I'm curious to see what people are building. I was gonna build my box out of aluminum angle iron and some plastic sheeting to keep out dirt and fingers, possibly with inlet and exhaust fans as described above (my pack is air-cooled Leaf modules).
 

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Discussion Starter #5
I'm
I could see having some circulation fans, but I wouldn't bother until the temp inside the box was shown to be the weak link in the cooling change. My guess is that it won't have much effect all.

I'm curious to see what people are building. I was gonna build my box out of aluminum angle iron and some plastic sheeting to keep out dirt and fingers, possibly with inlet and exhaust fans as described above (my pack is air-cooled Leaf modules).
Thinking the box needs to be a little more secure than have plastic walls?
 

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Secure from what? Fire? I have an extinguisher between my legs, and the batteries are usually at their hottest when the car is being charged and unattended...If there's a fire in that box of metal, I think the game is over anyway...

Anyone have any good resources on how to build battery boxes...?
 

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Discussion Starter #7
Secure from what? Fire? I have an extinguisher between my legs, and the batteries are usually at their hottest when the car is being charged and unattended...If there's a fire in that box of metal, I think the game is over anyway...

Anyone have any good resources on how to build battery boxes...?
I'm, like you, looking for the best practices, hence the thread. I'm just thinking if a fire in a metal box - it's contained, plastic will start to melt.
 

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Other than relief venting to handle problems in the pack as described in the excellent links provided by electro wrks (and as implemented by every manufacturer, not just Tesla), I don't see any point in ventilation, and I'm not aware of any production EV with liquid-cooled modules which provides air circulation to the pack case.
 

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I'm just thinking if a fire in a metal box - it's contained, plastic will start to melt.
True... I have yet to hear of a production EV which uses a polymer (plastic) battery pack case - although there could be one - and there is good reason for that.
 

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Tesla does have another small vent or two near the top of the battery enclosure in addition to the many pop-off side vents. I'm not sure how it works. In an ideal world, it would relieve small amounts of pressure and vacuum and keep water and dirt out at the same time. Thanks to boekel for these photos.

120172

120173


Front, top cover flipped upside down with vent in center.

120174


Close-up, inside view of valve. The part# brings this up: TA292-R Breather Valve - AGM Container Controls
 

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The modules are significant weight ~70lbs/31Kg and in a vehicle should be very secure. No thin aluminum or plastic should be used without some serious engineering (like the original model S tray). Built some DIY powerwalls and was amazed at how 6+ modules would start to deflect square steel tubing frames. Please be careful with these. Also, consider some kind of engine hoist design if you will have an 8-module + wire, contactors, battery box you plan to drop into a car.
 

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I'm, like you, looking for the best practices, hence the thread. I'm just thinking if a fire in a metal box - it's contained, plastic will start to melt.
Ever heard "died of smoke inhalation"?

Some plastics give off cyanide when they burn.

Others, chlorine gas

Odds are you are not smarter than any factory automotive engineer, so pay attention to what they've done in all your "research" vs deciding you like the idea of a watching a slow melt as your nervous system shuts off.
 

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These would be more for any heat that could be trapped inside (ex. from ambient temp. high,), or to promote general air flow. The modules themselves would definitely be liquid cooled.
Heat can't get "trapped" - it's being sunk into the liquid cooling system. It's also not "cooled better" by putting fans in the battery box.

The neat thing about the fans, though, is it increases first responder safety. If you can keep them running, the car will be a pile of ashes and metal globs by the time they arrive.
 

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Hence, I vote for metalic.
Comes to question: steel vs. aluminum? How thick?
Any suggestions?
That question can't be answered because you have not defined what the box does and what loads it has to carry. Your fabrication skills and available resources also come into the decision.
 

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You said it will be a bench, is there anything nearby that can get in the vents (assuming you still want the cooling fans)? Is this going on a vehicle, or some other application?
 

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Discussion Starter #18
You said it will be a bench, is there anything nearby that can get in the vents (assuming you still want the cooling fans)? Is this going on a vehicle, or some other application?
Going on the vehicle.nothibg should get into fans as planning on small computer fans. As mentioned most of cooling/heating is via liquid.
 

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We have a technical term we use in engineering for the kind of airflow you'll get over a traction battery with computer fans:

"fart in the wind"

You need to hone your listening skills. It's impossible to talk and listen at the same time.
 

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Discussion Starter #20
We have a technical term we use in engineering for the kind of airflow you'll get over a traction battery with computer fans:

"fart in the wind"

You need to hone your listening skills. It's impossible to talk and listen at the same time.
If you have nothing to say, please try not participate in discussions, which could be useful to other in this forum.
Thanks in advance.
 
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