Compression vs restriction

[fatjay]

With my configuration and space constraints active compression is going to be very difficult. However, I have rolls of kapton tape. I was going to wrap them in packs of 4, then wrap the entire thing. Will that be enough?

They are lf280k cells, the tape is 2" wide, I was thinking a strap on the top and bottom of each 4 pack then around the middle for the entire pack.

Has anyone done this? And can share their experience?

 

[AntronX]

You could place Poron foam between cells and some kind of rigid end plates like treated particle board for the corners. Just wrapping cells on their own would place bending force on corner cells as the cells swell and expand over time. If you going to restrain them you need to do it uniformly across entire cell side to prevent force concentration over small area.

 

[Brucey]

You could place Poron foam between cells and some kind of rigid end plates like treated particle board for the corners. Just wrapping cells on their own would place bending force on corner cells. If you going to restrain them you need to do it uniformly across entire cell side to prevent force concentration over small area.

Yes better to leave the cells freestanding than botch the compression job.

 

[Drunkin Solar]

Did it this way on a small 24v pack I put together using strapping material and fr4 board

 

[Suijkerbuijk]

With my configuration and space constraints active compression is going to be very difficult. However, I have rolls of kapton tape. I was going to wrap them in packs of 4, then wrap the entire thing. Will that be enough?

They are lf280k cells, the tape is 2" wide, I was thinking a strap on the top and bottom of each 4 pack then around the middle for the entire pack.

Has anyone done this? And can share their experience?

It do not need it
It have really no point for it .
Just tape them or use a nice plastic containers to drop them and vull op the space.

Wy ?
The lifepo4 battery that are sealt in a lead battery house do not have them
Its just tape nothing more .
So you use some Foam foil between the cells .
Tape it with ducttape and done

 

[AntronX]

I can't stand that fking guy ^

 

[Zwy]

It do not need it
It have really no point for it .
Just tape them or use a nice plastic containers to drop them and vull op the space.

Wy ?
The lifepo4 battery that are sealt in a lead battery house do not have them
Its just tape nothing more .
So you use some Foam foil between the cells .
Tape it with ducttape and done

Time will tell who the winners and losers are when it comes to compression and cell life.

Start here with this thread.

Then watch this. As he said, "This is no good".

 

[DPC]

I can't stand that fking guy ^

The accent?

 

[AntronX]

The accent?

Ignorant know it all. Also that dumb OMG youtube face.

 

[DPC]

Ignorant know it all. Also that dumb OMG youtube face.

I don't know him or have ever listened to him.
Is he right however I did watch most of the first video.
What he said makes sense.
I know I am not an expert on those batteries so I cant comment

Dum faces get clicks.
click get money.
would a smart mane pretend to be stupid if it makes him money?

 

[AntronX]

Dum faces get clicks.

Tells you something about his audience, doesn't it?

 

[Suijkerbuijk]

Time will tell who the winners and losers are when it comes to compression and cell life.

Start here with this thread.

Then watch this. As he said, "This is no good".

I think how the cells / battery are use .
If you use them 1c charge and discharge or even more than that.
See like a electric car with fast charging
You need that compression against it .
For normal use just to use a fridge in a garage or some lights.
I do not think you need it .
Special if you slow charge C 0.25/0.50 to that battery .

Even the first lifepo4 battery had a plastic house and not aluminium like today .
The plastic house set out and go back normal again
The aluminium house set out and stay out .
And think that is the problem

3.2V LiFePO4 Cell with Plastic Case - Poweroad Renewable Energy Co., Ltd.

As an industry-leading battery systems integrator, over the past decade, POWEROAD has cooperated with selected lithium ion battery cell producers, to develop battery solutions for a wide range of applications.

www.poweroad.com

Vs
Aluminium case

CALB 3.2v 100ah lifepo4 cells L160F100

CALB L160F100 3.2V 100Ah Lithium iron phosphate lifepo4 battery prismatic cells with more than 2000 life cycles.

www.evlithium.com

 

[littleharbor2]

click get money.
would a smart mane pretend to be stupid if it makes him money?

Is this forum not a product of that money?

 

[DPC]

Is this forum not a product of that money?

I've watched a lot of Wills videos.
They are slick and well done.
He smiles, he's up beat. speaks to the audience and not down to them.
I think he gets enough traffic he does not need to make goofy faces or use gimmicks to get you to come back.

This guy uses lots of gimmicks.
But hes not stupid, selling a different product to a different audience.
Still effective not hard to watch and he knows his stuff.

I don't like this guy.
He's french as a three dollar bill ( accent is a turn off, sounds like a pepsi )
Some of his methods and ideas are questionable compared to the first guy.
And hes not fun to watch.

 

[Zwy]

I think how the cells / battery are use .
If you use them 1c charge and discharge or even more than that.
See like a electric car with fast charging
You need that compression against it .
For normal use just to use a fridge in a garage or some lights.
I do not think you need it .
Special if you slow charge C 0.25/0.50 to that battery .

Time will be the judge.

As for Andy, I said this,

"If he was serious about actual testing, it would have 2 sets of cells, one in compression and one set loose. Both in parallel and both at the same date/ batch of manufacture plus also entered into service at the same date. Then capacity test at one year intervals."

Anything else is not based upon factual data.

 

[HRTKD]

My cells are deployed in my RV which sees some rough roads. Compression is not optional for me. Compression keeps the cells from moving and ensures that there is no stress on the cell terminals.

Some compression is better than no compression.

 

[Rednecktek]

Don't tape over the vents, they need to be available to open in an emergency.

Some people will say you have to have everything built into steel plates with spring pressure down to 0.001 newton meters of compression and so on and so on.

I'm not one of those. When I tape my cells together

 

[fatjay]

I'm fairly space contrained. I'm putting 6 packs in this battery room. The plan was to have it in a 8x2 conffiguration against the wall to the left. To have them all lined up 16x1 I'd have to use the back wall and it would be nearly the length of the room.

 

[sunshine_eggo]

Let's go to the manufacturer's datasheet for the cell (not sure if you have V3):

Resource icon

EVE LF280K V3 PBRI-LF280K-D06-01 datasheet

Oct 17, 2023

EVE LF280K V3 PBRI-LF280K-D06-01 datasheet

• Sleeper85
• Battery Cell Data Sheets

This is explicitly telling you to compress the cells. The expectation is that if you don't, you will not attain the claimed cycle life.

 

[robbob2112]

Let's go to the manufacturer's datasheet for the cell (not sure if you have V3):

Resource icon

EVE LF280K V3 PBRI-LF280K-D06-01 datasheet

Oct 17, 2023

EVE LF280K V3 PBRI-LF280K-D06-01 datasheet

• Sleeper85
• Battery Cell Data Sheets

View attachment 255283

This is explicitly telling you to compress the cells. The expectation is that if you don't, you will not attain the claimed cycle life.

Question from the peanut gallery - at what SOC do you do the compression? or does it need to be springs so the compression stays even through the cycle?

 

[fatjay]

I have hte v3's which claim 8000 cycles. That's 21 years of daily cycling. I also hear a lot about calendar aging and degrading. Will they start to degrade from calendar age before they start to degrade from cycles? If so, at what point?

 

[sunshine_eggo]

Question from the peanut gallery - at what SOC do you do the compression? or does it need to be springs so the compression stays even through the cycle?

I'd compromise with a shortcut:

Given that they expand and contract, 7000N at 100% SoC and see what you get when you discharge and get shrinkage.

 

[sunshine_eggo]

I have hte v3's which claim 8000 cycles. That's 21 years of daily cycling. I also hear a lot about calendar aging and degrading. Will they start to degrade from calendar age before they start to degrade from cycles? If so, at what point?

Not quite. Not age before cycles. The claim is that they will fail due to calendar degradation before they fail due to cycles. They will degrade from age and cycles. Capacity degradation has been demonstrated many times. It's impossible to state what portion is due to age and what portion is due to cycles.

These questions can't be answered with hard evidence. IMHO, the 8000 cycle claims are B.S.

The only thing you can be certain of is if you fail to operate the cells in accordance with the manufacturer's instructions, you will experience accelerated degradation in both cycle and calendar life. Do you need to construct an elaborate compression scheme? Not necessarily. Should you devise some reasonable and convenient method to constrain the cells? Probably. Simply wrapping them in Kapton tape probably is no better than leaving them unrestrained.

They're your cells. Do what you want. You already know what the manufacturer recommends. Do it, come up with a compromise, or don't. I'm not judging you.

 

[fatjay]

Not quite. Not age before cycles. The claim is that they will fail due to calendar degradation before they fail due to cycles. They will degrade from age and cycles. Capacity degradation has been demonstrated many times. It's impossible to state what portion is due to age and what portion is due to cycles.

These questions can't be answered with hard evidence. IMHO, the 8000 cycle claims are B.S.

The only thing you can be certain of is if you fail to operate the cells in accordance with the manufacturer's instructions, you will experience accelerated degradation in both cycle and calendar life. Do you need to construct an elaborate compression scheme? Not necessarily. Should you devise some reasonable and convenient method to constrain the cells? Probably. Simply wrapping them in Kapton tape probably is no better than leaving them unrestrained.

They're your cells. Do what you want. You already know what the manufacturer recommends. Do it, come up with a compromise, or don't. I'm not judging you.

I am just looking for a better undersatnding to make an informed decision. 7000 newtons is 1573 pounds, which is pretty serious compression. I'm not even sure how to measure that.

So it looks like i'm back to the drawing board for my battery room. I'm going to need to start looking up examples of what people have done.

Just out of curiosity I see people opening battery boxes with lifepo4, and they don't appear to be compressed. Is there something I'm missing?

 

[Suijkerbuijk]

Let's go to the manufacturer's datasheet for the cell (not sure if you have V3):

Resource icon

EVE LF280K V3 PBRI-LF280K-D06-01 datasheet

Oct 17, 2023

EVE LF280K V3 PBRI-LF280K-D06-01 datasheet

• Sleeper85
• Battery Cell Data Sheets

View attachment 255283

This is explicitly telling you to compress the cells. The expectation is that if you don't, you will not attain the claimed cycle life.

Lol.
You do know the kilo that will be lol.
No this bull shit from that company.
Reason not responsible if the battery do not make that cycle.