What kind of safety measures do you take when building battery at home?

[Cyclomania]

Practice practice practice... Get some dead cells & try building a smaller pack with them first.
Your bound to make mistakes no matter how much good/bad advise your given... So get yourself some practical experience 1st & build up your confidence.

I don't think I have any bad cells laying around . Perhaps I could buy some bad cells somewhere?
What more could I train on? Besides that. The plan is to try to build my battery this coming weekend.

I have glasses and I am going to do it close to the outer door. In that room the walls are mostly stone and floor is bricks. So if it starts to burn it won't catch fire so easily. I plan on duct taping some plastic on the door and walls so if a fire would become big it won't have time to come so much darkness/blackness on the walls there.

I also have a bucket that I have described. Made in metal. I plan on having that close by to be able to throw the pack down there if it goes off. Then throw wet sand on top of it. Then open the door and lift it outside. I have no idea where the most critical part of the build will arise, but there is definitely some fear involved after all the things I have read

 

[Cyclomania]

I like to build batteries with the cells at 3.3-3.4 volts. Wear safety glasses, but a welding helmet will cause you to miss welds. It's too dark. You only want paper washers on the positive end. It keeps the nickel from contacting the negative edge of the can.

If your welder is set too high, sparks will fly up from the nickel. This may include molten metal. That's why you wear safety glasses. Also, if the welder settings are too strong, you can blow holes thru the nickel. Sometimes you could blow a hole in the metal can. The cell will squeal as hot gas escapes. Then it will leak electrolyte and the cell has to be replaced. This usually happens when you miss the nickel and contact the cell case with the welder probe.

Spot welder I have is the one in the link.

AH so that happens when you miss the nickel completely basically? I think I understand.

 

[Cyclomania]

Build outside and keep a couple fire extinguishers ready. I use these:

https://www.amazon.com/dp/B09H33LX31

They barely have enough in them to put out a burning p-group, but I like how they are small enough to fit in my cycling fanny pack the rest of the time. I also have a metal ammo can half full of dirt I dump thermal runaway packs in. For thermal runaway cells, I put them in a s and dump them in a bucket of water overnight to fully short them out.

I have a portable table I put outside the garage in the driveway. My spot welder runs on battery and any other tool that needs power can use an extension cord from inside.

I used to build in the garage, but I use high quality brand name cells that vent when damaged into a short and the black gunk got all over my garage walls, a table, and some equipment when I blasted a burning cell with an extinguisher. It's really tough to clean. Like easier to repaint your walls tough.

I am in the process of getting one of those ammo cans after reading this.

When this stuff was blasted all over your walls, was that because of the water from the extinguisher or was it the actual cell that blasted out exploding energy onto your walls?

I plan on building close to the outer door. In a room that is made mostly from stone walls and brick floor. I plan on having plastic sheets on the side of the walls after reading what happened to your walls. (Kind of like one of those that they use at a construction site when they are doing things that will produce a lot of dirt and small particles in the air to protect the walls).

Do you think it could have been avoided by throwing the bad cell into a metal bucket with sand and then thrown sand on top of it along with water to make the sand wet? Or what made the walls get so affected by the cell going bad? Mostly the water from the estinguisher after it had connected with the cell?

 

[Cyclomania]

I like to build batteries with the cells at 3.3-3.4 volts. Wear safety glasses, but a welding helmet will cause you to miss welds. It's too dark. You only want paper washers on the positive end. It keeps the nickel from contacting the negative edge of the can.

If your welder is set too high, sparks will fly up from the nickel. This may include molten metal. That's why you wear safety glasses. Also, if the welder settings are too strong, you can blow holes thru the nickel. Sometimes you could blow a hole in the metal can. The cell will squeal as hot gas escapes. Then it will leak electrolyte and the cell has to be replaced. This usually happens when you miss the nickel and contact the cell case with the welder probe.

What type of machine do you use for discharging your cells to your preferred voltage?

 

[harrisonpatm]

What type of machine do you use for discharging your cells to your preferred voltage?

Build one

Not pictured are a series of appropriately sized resistors to manually discharge 40 cells at a time. This also equalizes all the cells as well. I use this to test and balance reclaimed cells for powerwall

 

[Cyclomania]

For me the dangerous part is taking cells apart, thats when there is risk of shorting out cells. The only fire I had was when I was taking a battery pack apart and the cell shorted out causing a hole in the cell. This set off a fire.
Pouring water was enough to to keep the fire from spreading to the other cells by keeping everything cool. Water won't put the fire out because as soon as you stop pouring water it reflashes but eventually the fire goes out. The fire is like a blow torch in intensity. If you can keep the fire to 1 cell cell its manageable.
The high discharge cells are the most dangerous as far as shorting out.
It don't matter what chemistry the cells are, they all will catch on fire. The fire I had was with A123 26650 lifepo4 cells (everyone says lifepo4 is suppose to be safer) ,I never had any problems with 18650 li-ion laptop cells and I built many packs with those.
It would be good idea to work on cells that are very low voltage, so they won't be so volatile. Usually when I built packs they are usually almost fully charge, now I try and make sure they arent at max voltage.
And take your time when taking packs apart. I was rushing when I shorted the cell that caught on fire. Now I use hard plastic as a buffer between the pliers and the battery so no metal to metal contact occurs. Since that incident (about 3 years ago) havent had anymore fires or shorts, and I built/tore down several packs since then.

View attachment 332491

What type of voltage do you normally keep them at when starting the build? What type of machine/tool do you use for discharging the cells to your preferred voltage? What is the voltage that you normal build at approximately?

 

[Cyclomania]

New cells and battery packs have to be at 30% SOC to meet shipping regulations, and it's been my experience that they'll hold that voltage for months. When I build with new cells, they're usually at 3.42 volts. When I have gone with second hand cells, I'll test them first for capacity, and take the time to bring them under 30% too. Probably should short one intionally to see what happens at 3.3V.

With what tool/discharger/machine do you bring the cells down to your preferred voltage of around 3,3?

How do you short a cell at that voltage to see what happens to it? You take a metal strip from the negative to the positive or something?

 

[Cyclomania]

8. Cover any exposed part of the battery not being worked on, stiff card is handy and a bit of tape.

What type of stiff card and tape do you use? You just cover the outer parts of the battery when you are working with this, correct? That you are not working on.

 

[lnanek]

I use dry powder extinguishers, so no moisture from that. Any liquid involved was probably boiling solvent from the venting cells.

In general, adding water to a lithium battery fire is harmful because it makes the decomposition reaction worse and occur at lower temperature. There are cases where fire fighters do it intentionally, though. If drenching a pack in water gets you below the critical temperature, it can prevent more cells from joining in. A pack burning from a cell or two is manageable, a pack where every cell burns up and causes the adjacent cells to burn up is not.

I definitely wouldn't cover your walls in plastic. Plastic is flammable. I definitely would not count on being able to carry the burning pack anywhere either. About most you can do is have it on a table you can tilt to make it slide into a trash can full of sand.

I wouldn't try pack building indoors anyway. Ideal place is an old metal bbq outside you never intend to use again. If you screw up and the pack starts burning up, the fire is contained in something metal and harmful gasses are not collecting inside.

 

[Bandit1961]

I don't think I have any bad cells laying around . Perhaps I could buy some bad cells somewhere?
What more could I train on? Besides that. The plan is to try to build my battery this coming weekend.

I have glasses and I am going to do it close to the outer door. In that room the walls are mostly stone and floor is bricks. So if it starts to burn it won't catch fire so easily. I plan on duct taping some plastic on the door and walls so if a fire would become big it won't have time to come so much darkness/blackness on the walls there.

I also have a bucket that I have described. Made in metal. I plan on having that close by to be able to throw the pack down there if it goes off. Then throw wet sand on top of it. Then open the door and lift it outside. I have no idea where the most critical part of the build will arise, but there is definitely some fear involved after all the things I have read

Getting the sweet spot excuse the pun) settings with your spot welder will take a bit of getting used to as when you do a few welds you'll probly notice a difference and hence ruin a few cells in the process... Pm me & I'll send you some dead cells to practice on foc.

 

[Cyclomania]

I use dry powder extinguishers, so no moisture from that. Any liquid involved was probably boiling solvent from the venting cells.

In general, adding water to a lithium battery fire is harmful because it makes the decomposition reaction worse and occur at lower temperature. There are cases where fire fighters do it intentionally, though. If drenching a pack in water gets you below the critical temperature, it can prevent more cells from joining in. A pack burning from a cell or two is manageable, a pack where every cell burns up and causes the adjacent cells to burn up is not.

I definitely wouldn't cover your walls in plastic. Plastic is flammable. I definitely would not count on being able to carry the burning pack anywhere either. About most you can do is have it on a table you can tilt to make it slide into a trash can full of sand.

I wouldn't try pack building indoors anyway. Ideal place is an old metal bbq outside you never intend to use again. If you screw up and the pack starts burning up, the fire is contained in something metal and harmful gasses are not collecting inside.

A kind of barbecue looking like this image below? Is that what you are thinking? I think they have those here at Biltema in Scandinavia in aluminium or something for around 30 dollars.

Only thing when you go outside neighbours and the landlord(an old lady) can see that I am doing something dangerous And then all of my focus will be off and I will have to explain and stuff

This is also why I am trying to research this very carefully. So if something DOES go wrong I have a plan B.

Another problem is that it is getting quite cold here now so it will be quite cold here in a couple of weeks or so to sit outside. But perhaps it is doable?

But you don't recommend garage then? That was my original thought since a garage is kind of like "semi-outside". Hmm where else could I build it? Maybe out in nature somewhere close to like a bog/moss or small lake/creek like that. Or maybe that would make the water surface burn off or something if it is thrown in a wet moss, close to water, or something?

 

[electric_nz]

With what tool/discharger/machine do you bring the cells down to your preferred voltage of around 3,3?

How do you short a cell at that voltage to see what happens to it? You take a metal strip from the negative to the positive or something?

Some chargers have a ‘Storage’ function which discharges to a lower voltage, that’s what I use to equalise the cells at a lower voltage.

I wouldn’t short any cells as they can still give a big spark.

Strongly recommend taping up any metal parts of the battery apart from the p group you are working on. I use wide insulation tape as it’s low voltage, doesn’t need to be that thick.

 

[99t4]

I think they have those here at Biltema in Scandinavia in aluminium or something for around 30 dollars.

Aluminum would be a poor choice. A hot fire will simply melt it. AMHIK LOL.

How about something like this?

From How to Build Your Own BBQ Barrel

 

[Cyclomania]

Some chargers have a ‘Storage’ function which discharges to a lower voltage, that’s what I use to equalise the cells at a lower voltage.

I wouldn’t short any cells as they can still give a big spark.

Strongly recommend taping up any metal parts of the battery apart from the p group you are working on. I use wide insulation tape as it’s low voltage, doesn’t need to be that thick.

Is this kind of like wide electrical tape or more like duct tape? Do you have link? Trying to figure out what the name is in Scandinavia.

I have ordered some type of dischargers from Aliekspress looking like this:

https://www.aliexpress.com/item/1005005444930813.html?spm=a2g0o.order_list.order_list_main.15.b3df1802qZ4fYs

Best choice might be to discharge all of the cells to approximately 2,7 volts maybe? Then they would give out relatively smaller amounts of energy is that not right?

 

[Cyclomania]

Aluminum would be a poor choice. A hot fire will simply melt it. AMHIK LOL.

How about something like this?

From How to Build Your Own BBQ Barrel

That looks good but also expensive. Do you have a model or brand name on that thing? And is that steel then or what type of metal did you have in mind?

That would be pretty ideal. Especially if it has wheels(?). Then it would be possible to close the hatchet and then just move it around with a pair of welding gloves.

The fires I've seen on youtube of packs going bad have always been pretty contained to the actual object which is the battery pack. Even the big fires. At least if it was surrounded by stones and non flammable materials it usually did not spread. Just a big fire. Does anyone have an idea of how long a lithium battery pack of around 3,7 volts would burn for, if you just let it burn out? Without trying to extinguish it.

I guess if I am unlucky(which is often the case although I am often lucky within that unluck) the fire could be a big exploding one that could blaze around outside of the barbecue. Burning trees and storage houses on the lawn and stuff

But the idea is really good. If I find one of those.

 

[Cyclomania]

Aluminum would be a poor choice. A hot fire will simply melt it. AMHIK LOL.

How about something like this?

From How to Build Your Own BBQ Barrel

Would it be possible to smother a lithium fire in on of those if closing the lid? Or would that make it explode, melt or anything unforeseen?

 

[99t4]

That looks good but also expensive. Do you have a model or brand name on that thing? And is that steel then or what type of metal did you have in mind?

That is a common (what we call) 55 gallon steel barrel. Steel yes (there are plastic versions). Directly below the photo I posted the link to the DIY project build to make it.

Often easy to find used steel barrels cheap at salvage yards:
(example) Container exchanger

Would it be possible to smother a lithium fire in on of those if closing the lid? Or would that make it explode, melt or anything unforeseen?

Probably not smother it but would help keep it contained. Of course, depends on the size and ferocity of the fire/explosion(s).

 

[batteryGOLD]

Would it be possible to smother a lithium fire in on of those if closing the lid? Or would that make it explode, melt or anything unforeseen?

what happen if u throw ethyl alcohol inside that cylindrical container? maybe 100mL ethilic alcool,better sprayed inside container, & than use a lighter to star fire..

careful with that experiment.. first try a gallon container, spray ethilic alcohol, than put a fire.. see it like a rocket! and sometimes it explodes! limit alchhool inside and careful with that experiment

 

[docw009]

I've found that doing a battery safely takes a long long time. Don't ever jump in blind with new cells. You have to learn how your welder works and what it can do with your nickel. Welding one nickel strip to another is not the same as welding to a 18650 cell, Maybe try a flashlight battery,

You have to start with all the cells at the same voltage, or your BMS may never get them equalized if they are far apart.. If using new cells, they should have shipped at 3.42 volts. It's for safety, and the law in many areas.

When I was taking brand name cells out of used batteries to put into my ebike, I would use a capacity tester to verify the cells were worth using (90% of original capacity needed). My tester only did 4 cells a day, so it would take a month to get 52 cells.

People build batteries (me included) with cells at full charge. If you short a fully charge Samsung30Q, it will melt a narrow nickel strip. That's why I build them at 30% charge.

 

[Diggs]

I keep an empty steel ash bucket with metal lid at the end of my workbench. Thankfully I haven't needed it yet.

 

[Cyclomania]

That is a common (what we call) 55 gallon steel barrel. Steel yes (there are plastic versions). Directly below the photo I posted the link to the DIY project build to make it.

Often easy to find used steel barrels cheap at salvage yards:
(example) Container exchanger


Probably not smother it but would help keep it contained. Of course, depends on the size and ferocity of the fire/explosion(s).

What do you guys think about this one:

Grilltønne med lokk | Clas Ohlson

www.clasohlson.com

I think I can get a hold of a used one.

 

[99t4]

Sure, why not? You could also use it for outdoor cooking!

 

[Cyclomania]

Sure, why not? You could also use it for outdoor cooking!

Yeah I have other ones for that purpose Only thing I don't want to ruin them by blazing chemicals and stuff from the battery in there.

Yeah this one seems fine right? Just turn down the lid when it starts to burn, close my eyes and run?

 

[99t4]

Are you expecting to start a fire? Or are you planning to study up and implement safe practices to minimize any risks?

Just turn down the lid when it starts to burn, close my eyes and run?

I don't recommend running with your eyes closed under any conditions. A friend of mine lost a front tooth doing that. Ran into a big tree.

 

[Cyclomania]

Are you expecting to start a fire? Or are you planning to study up and implement safe practices to minimize any risks?


I don't recommend running with your eyes closed under any conditions. A friend of mine lost a front tooth doing that. Ran into a big tree.

It was a joke. Not so easy to show over text maybe

Yes I am almost going too far in my safety measures I think. But better safe than on fire.