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EV batteries found with internal heating elements??

Passedyouby

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Dec 11, 2020
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Hello all!

I have purchased lithium ion batteries out of two different kinds of vehicles, and both times I had an extremely exciting find, that then turned out to just confuse me!

Both sets of batteries have an inlet and outlet port for fluids to flow through the case and cool the cells, and in both cases the cells themselves were attached to that fluid heatsink via a thermal adhesive paste. HOWEVER both actually had a thin metal plat that I was able to identify as a heating element sandwiched between the cells and the head sync!!!

I was THRILLED because up here in Michigan I had expected to need a way to keep my cells warm and this was a free little perk!. However, once I connected the two wires to my power supply set at 12v (pulled about 2 amps fyi) the heating element turned out to be directional, and sending the heat AWAY from the batteries! Crazy, right?! All I can assume is that these are designed to drain the batteries if sitting for a long time, and the thermal management system would be able to pull the heat away.

Thoughts? Ideas? Has anyone else found this in the past? Anyone have a thought of if I were to flip these pads over to then use them as true heaters for the packs?

Thanks everyone!
 
Not sure what you mean by 'sending the heat away from batteries'. The fluid piping has two purposes. Take heat away when battery gets warm during high charge or discharge rates, and provide heating via heated liquid for cold temps.

At 2 amps of charge there would be no significant battery heating. It might be possible you activated a pump but I would expect it to have independent control power. Anyway heating or cooling of liquid is externally provided.

The battery pack might have an internal electric heater so batteries can be kept warm while car parked without the fluid temp management. They would have to be pretty cold to turn it on. If there was fluid in the pipes then it could have expanded and some leaked out. Once car is being used there is rarely the need for heating since large current drain will self heat the batteries, so liquid cooling is the primary purpose.
 
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Not sure what you mean by 'sending the heat away from batteries'. The fluid piping has two purposes. Take heat away when battery gets warm during high charge or discharge rates, and provide heating via heated liquid for cold temps.

At 2 amps of charge there would be no significant battery heading. It might be possible you activated a pump but I would expect it to have independent control power. Anyway heating or cooling of liquid is externally provided.

The battery pack might have an internal electric heater so batteries can be kept warm while car parked without the fluid temp management.


Hello! Thanks for the reply.

At 2A about 25 watts, but that's assuming this is a 12v heating element. The pack is a 44v pack, so it's possible the pad can absorb much more. Even at 12v, I feel the plate getting hot to the touch, so its definitely a heating element.

As for the statement I made that the heating element is "sending the heat away from the pack" see the below pictures. I have left the adhesive on the plate to make it very obvious where the pack goes. When power is applied that plate with the adhesive stays ICE COLD, while the outside of the enclosure is hot to the touch.

Image 1 is pack "A" from the inside.
Image 2 is pack "A" from the outside of the case, where I can feel the heat.
Image 3 is pack "B" from a different brand vehicle, and works the same way, with the heat being directed OUT of the pack instead of into it. Funny that someone had sharpied it at the factory years ago!


16077318931494762912146136141527.jpg16077319420348678108794885996966.jpg20201120_125017.jpg
 
Any electric internal battery heater would likey be in common contact with battery and a fluid battery cooler. So if you pump fluid through cooler and turned on heater the fluid would get warm. Not something that would be done in normal useage.

Anyway you got the heater you needed for cold temps.
 
Agreed. It's not normal.

Question- is there a chance this was designed to cycle the battery down during extended periods of not being used? Was curious if theres a downside to storing lipo at 100%
 
Agreed. It's not normal.

Question- is there a chance this was designed to cycle the battery down during extended periods of not being used? Was curious if theres a downside to storing lipo at 100%
No need to do that.

Your next challenge is controllng the heater. It would be nice if totally self contained in battery pack but it likely just sends temp sensor info to auto main computer which controls the heater. If battery gets too low on charge it doesn't keep the heater on. For this condition, if auto's charging becomes available the computer will first pull charger power to just heat up battery before allowing charger to charge battery. Your system has to do the same thing.

Minimally you could just put a thermostat to turn on heater when it falls below 5 degs F. It will be manually up to you to ensure there is enough charge on battery to supply the heater power. Next level is a low cell cutout switch so it shuts off heater if battery gets too low on charge. Your BMS may be able to help you on this by tieing it into low cell cutout.

You can just run a low power relay on BMS output to inverter. If BMS drops the battery to inverter due to low cell, the relay cuts off the heater. If BMS has low temp cutout you get its benefit. You will have to manually heat battery if BMS trips for cold temp.

BMS's with low temp are not so common. If it has low temp cutout then question is does it only cut if reverse charging current is detected or does it totally cut power to inverter without regard to charging or discharging. Most likely is later, a total power cut.

The heater likely gets a pulse width modulation On-Off control from auto computer sensed from temp sensor for a closed loop control on amount of warming to minimize power.

And you thought the heater was a blessing ;).
 
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No need to do that.

You next challenge is controllng the heater. It would be nice if totally self contained in battery pack but it likely just sends temp sensor info to auto main computer which controls the heater. If battery gets too low on charge it doesn't keep the heater on. For this condition, if auto's charging becomes available the computer will first pull charger power to just heat up battery before allowing charger to charge battery. Your system has to do the same thing.
Okay! Thank you for letting me know, I was wondering!

Yes, I was already planning on a small coolant tank with a circulating pump and a small inline heater so I have these temp controllers already purchased. Bought 6. 1 for each battery. Figure this relay would work great to cycle the heater!

Even with that, I'm not sure why the heat is being pushed AWAY from the cells. Planning to just flip over the pad and give it a whirl.
 
Okay! Thank you for letting me know, I was wondering!

Yes, I was already planning on a small coolant tank with a circulating pump and a small inline heater so I have these temp controllers already purchased. Bought 6. 1 for each battery. Figure this relay would work great to cycle the heater!

Even with that, I'm not sure why the heat is being pushed AWAY from the cells. Planning to just flip over the pad and give it a whirl.

Whoops. Here the controllers I bought.


Screenshot_20201211-200808_Amazon Shopping.jpg
 
FIGURED IT OUT!!!!! Its Actually a ThermoElectric cooler!!! It will either heat or cool the battery depending on the direction you send electricity!!! So excited to find this built into all of my packs!!!!
 
Peltier junction devices are very inefficient. I would be surprised to fine them in an EV vehicle. They need a very good heat sink or they generate more net heating then cooling.
 
FIGURED IT OUT!!!!! Its Actually a ThermoElectric cooler!!! It will either heat or cool the battery depending on the direction you send electricity!!! So excited to find this built into all of my packs!!!!
Did you have some more time to do further testing about how this works? It seems very advanced that they added such a complex feature to the batteries.
 
Did you have some more time to do further testing about how this works? It seems very advanced that they added such a complex feature to the batteries.
Sure did! Right temp sensor is inside the case. Left readout shows temp taped to the outside of the case. Left outside forn30min to equalize readouts. Powered up and took this pic 30min later.

I have 8 of these batteries set up in a 2s 4p setup. Each battery has is own temp sensor to regulate the internal heater. If 3 or more relays are tripped it will also turn on an external heater and pump to circulate heat through the fluid passageways. Havent set that up yet, but the parts have all been delivered. Will share what j learn after that's all set up!


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Peltier junction devices are very inefficient. I would be surprised to fine them in an EV vehicle. They need a very good heat sink or they generate more net heating then cooling.
Agreed on needing a good heat sync! That is probably the main reason behind the coolant lines. To help increase efficiency some.
 
Sure did! Right temp sensor is inside the case. Left readout shows temp taped to the outside of the case. Left outside forn30min to equalize readouts. Powered up and took this pic 30min later.

I have 8 of these batteries set up in a 2s 4p setup. Each battery has is own temp sensor to regulate the internal heater. If 3 or more relays are tripped it will also turn on an external heater and pump to circulate heat through the fluid passageways. Havent set that up yet, but the parts have all been delivered. Will share what j learn after that's all set up!


View attachment 31422
Wow those batteries sound incredibly sophisticated! So basically if the battery gets too cold outside it will start heating itself up?

Just a quick question.. When you say 2s 4p does that mean you lined up to cells linearly and 4 of such in parallel? I am still very new to the forum and the whole battery world so I am unsure of the terminology.
 
Wow those batteries sound incredibly sophisticated! So basically if the battery gets too cold outside it will start heating itself up?

Just a quick question.. When you say 2s 4p does that mean you lined up to cells linearly and 4 of such in parallel? I am still very new to the forum and the whole battery world so I am unsure of the terminology.
Yes and yes!

No problem, I've been interested in batteries for a while, but not this in depth until recently, so I am right there with ya on the learning phase.

Yes. The pack will heat or cool itself electronically when needed, but also has coolant lines for external heating or cooling.

Yes- one pack is 48v with 120Amps continuous output. I put 2 in series to create a single 96v pack that can still only output 120Amps. By adding 3 more 96v packs in parallel I was able to then have 96v, and 480A power output.
 
Yes and yes!

No problem, I've been interested in batteries for a while, but not this in depth until recently, so I am right there with ya on the learning phase.

Yes. The pack will heat or cool itself electronically when needed, but also has coolant lines for external heating or cooling.

Yes- one pack is 48v with 120Amps continuous output. I put 2 in series to create a single 96v pack that can still only output 120Amps. By adding 3 more 96v packs in parallel I was able to then have 96v, and 480A power output.
96v with 480A means 46Kwh ?? Thats a lot of power!

Thanks for explaining. I just watched a YT video of someone explaining parallels and series. It seems like some sort of a witchcraft xD but there must be a good reason based in physics and chemistry as to why one increases the voltage and the other capacity.

I never heard about the battery that can regulate its own temperature. Regardless of how new I am to the battery world it still seems like something that only those batteries have. Maybe I am wrong but it just doesn't seem like a feature that a lot of batteries will have.
 
96v with 480A means 46Kwh ?? Thats a lot of power!

Thanks for explaining. I just watched a YT video of someone explaining parallels and series. It seems like some sort of a witchcraft xD but there must be a good reason based in physics and chemistry as to why one increases the voltage and the other capacity.

I never heard about the battery that can regulate its own temperature. Regardless of how new I am to the battery world it still seems like something that only those batteries have. Maybe I am wrong but it just doesn't seem like a feature that a lot of batteries will have.
Nope! Batteries have voltage, a continuous amount of power (measured in amps) that can be pulled from them, a maximum amperage that can be discharged (usually for no more than 10seconds or less), and a capacity (usually measure in Amp hours or Watt hours). For example- a AA battery cannot discharge at a rate of 100A. Power simply cannot flow put of it.

My motor can consume 400A of power nonstop. If I tried to pull that much out of a single 96v pack the battery would be destroyed. By having multiple batteries in parallel that can each 'share' that 400A load. So with my 4 packs, each battery will be drawing 100A at a time.

The packs themselves are only hold 900WH of power, so this is a 7.1kwh total bank size. Less honestly, but close enough.

There are a few mistakes in this, but close enough
 
dear @Passedyouby, thanks for posting this thread.

i read everything and was wondering if you are able to/ comfortable to share more information about the model of the battery with the thermoelectric element integrated?

cheers, 400A 96V sounds like a really nice clip.
 
dear @Passedyouby, thanks for posting this thread.

i read everything and was wondering if you are able to/ comfortable to share more information about the model of the battery with the thermoelectric element integrated?

cheers, 400A 96V sounds like a really nice clip.


No problem! Happy to share. I bought the mercedes l09-1ev battery from battery hookup. No longer available.

Where are you located? I cycled these batteries 1 time for an event, now are sitting in my garage.
 

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thank you!! ☮️? cheers

(for context, i’m studying thermoelectrics, and wanted to know the model to learn more. for now only buying LFP cells; i want to integrate active thermal management into my in progress DIY LFP build, and seeing the design on these mercedes OEM was inspiring for design.)

thank you for offering, no interest for now since the cells are not LFP ? thank you!
 
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