Looking for DIY battery casings

[ponzatron]

I'm trying to make my own batteries. I'm an intern at a battery company and I have the equipment and materials to do so. I want to play around with different battery formulations. I'm looking for a battery case around 6.84" L x 2.84" W x 8.055" H.

The closest thing I found when looking for batteries or cases of this dimension were EVE 3.2V 304Ah LiFePO4 cells. I'm wondering how I should source a case this size? I'm having trouble finding any suppliers that sell just the empty cell.

I'm interested in finding a rack solution with a built in BMS that can hold 40 of these.

 

[Pierre]

Have you tried AliExpress or Alibaba ? I managed to buy a casing locally (ZA) for a 12v 100aH Li battery that I built as a utility battery for my off-road vehicle. Surely the company that you work for has contacts in this field ?

 

[Luk88]

These dimensions look very standard, but a case to hold 40 of them? I think it's unlikely you'll find a case that holds more than 16.

The choice of such cases(holding 16 cells) is very wide, but they are mostly clones of the same thing. Often companies that sell lifepo cells also sell DIY cases.

If you mention which part of the world you're in people will most likely suggest some sellers.

 

[ponzatron]

These dimensions look very standard, but a case to hold 40 of them? I think it's unlikely you'll find a case that holds more than 16.

The choice of such cases(holding 16 cells) is very wide, but they are mostly clones of the same thing. Often companies that sell lifepo cells also sell DIY cases.

If you mention which part of the world you're in people will most likely suggest some sellers.

What are they clones of?

I've found lots of them that hold that many cells but I'm looking for cases that can fit together in a large cabinet that can be scaled up. Do you know if there's cabinet sized racks I can buy that can fit a bunch of these?

 

[ponzatron]

Have you tried AliExpress or Alibaba ? I managed to buy a casing locally (ZA) for a 12v 100aH Li battery that I built as a utility battery for my off-road vehicle. Surely the company that you work for has contacts in this field ?

I have but the only readily available cases in this size are aluminum which we can't use as a case because it could interfere with the chemistry of the nickel iron battery. There are suppliers that can make a custom case but I was hoping to find something that is already mass produced so that I would be cheaper.

 

[Luk88]

What are they clones of?

Probably Seplos/Mason 280ah 16s battery was the first?

I've found lots of them that hold that many cells but I'm looking for cases that can fit together in a large cabinet that can be scaled up. Do you know if there's cabinet sized racks I can buy that can fit a bunch of these?

I never saw one cabinet sized case, but the 16s I mentioned are available as rackmount and are all of steel construction. So one could install one above another in a rack cabinet.

You could put 7 such cases in a 46U cabinet (with 4U to spare for ventilation etc). And that would be 80 cells.

One thing where you may find them unsuitable is the fact they all come with their own bms. If you use your own chemistry (iron nickel?) you probably plan for your own BMS. So why pay for one you don't use.

How many do you need? There are many companies that make sheet steel cabinets(even one in my town). If you need more than a couple it might make sense to have them custom made.

Edit: I'm also very much interested why anyone would use iron nickel today. With the low cost of lithium and relatively high cost of nickel... I'd love to hear more about that. What advantages do they bring? Low temp charging?

 

[OffGridForGood]

I suppose you could use a metal rack designed for large 280Ah cells, but install 100A smaller cells to try to fit 40 cells in there.
To make low cost custom-sized, non-metallic cases, 3D print them? - or find a suitable sized plastic container from another industry and repurpose them.

 

[ponzatron]

Probably Seplos/Mason 280ah 16s battery was the first?

I never saw one cabinet sized case, but the 16s I mentioned are available as rackmount and are all of steel construction. So one could install one above another in a rack cabinet.

You could put 7 such cases in a 46U cabinet (with 4U to spare for ventilation etc). And that would be 80 cells.

One thing where you may find them unsuitable is the fact they all come with their own bms. If you use your own chemistry (iron nickel?) you probably plan for your own BMS. So why pay for one you don't use.

How many do you need? There are many companies that make sheet steel cabinets(even one in my town). If you need more than a couple it might make sense to have them custom made.

Edit: I'm also very much interested why anyone would use iron nickel today. With the low cost of lithium and relatively high cost of nickel... I'd love to hear more about that. What advantages do they bring? Low temp charging?

Thank you. I'm looking into the cabinets you mentioned. The company I'm at has developed a maintenance free nickel iron battery. I can't give specs at this time but I can say it's better than lead acid batteries by every metric. It charges extremely fast and can be used at 100% DOD with no damage to cell. It's also around 90% efficient. I'm trying to figure out what sizes we should produce, dimensions wise. Currently the energy density is about the same as lead acid.

 

[740GLE]

Ohhh another nickel iron start up!!!

What’s the Wh/lbs you guys are looking at?

My guess 4x a Li options, so you’re looking at stationary ESS solution.

I’d say you’d prob want +500ah per cell to make it worth while of one battery to carry all load vs multiple smaller banks.

 

[ponzatron]

Ohhh another nickel iron start up!!!

What’s the Wh/lbs you guys are looking at?

My guess 4x a Li options, so you’re looking at stationary ESS solution.

I’d say you’d prob want +500ah per cell to make it worth while of one battery to carry all load vs multiple smaller banks.

Right now were looking at about 50Wh/kg. We are still in the product development phase and are very hopeful that we can get it even more dense. Our researchers are looking into things like coating electrodes in electroplated nanotubes or using gel based electrolytes.

We're leaning towards creating standard sized 1.25V cells with a small Ah capacity and then chaining them together in parallel or series to produce the Ah capacity we need to create "modules" of whatever voltage and capacity we want. This way we can just package them in different sized batteries for all industries. I'm currently trying to figure out the dimensions (l x w x h) of a battery that we should produce for the stationary storage or UPS market

Our actual energy density isn't all that better than lead acid at the moment, but since we can deliver 90% efficiency and use the batteries at 100% DOD, we can deliver a higher amount of usable capacity in a smaller Ah battery, allowing us to reduce size.

 

[ponzatron]

I suppose you could use a metal rack designed for large 280Ah cells, but install 100A smaller cells to try to fit 40 cells in there.
To make low cost custom-sized, non-metallic cases, 3D print them? - or find a suitable sized plastic container from another industry and repurpose them.

I haven't been able to find cases in these dimensions from any other industries unfortunately. The only cases I found are aluminum and made for prismatic cells. Should I start trying to find another size and/or try to source custom ones? Or do you have any leads on any non-lifepo4 batteries that are these dimensions i could probably source plastic cases for?

 

[Luk88]

Right now were looking at about 50Wh/kg. We are still in the product development phase and are very hopeful that we can get it even more dense. Our researchers are looking into things like coating electrodes in electroplated nanotubes or using gel based electrolytes.

We're leaning towards creating standard sized 1.25V cells with a small Ah capacity and then chaining them together in parallel or series to produce the Ah capacity we need to create "modules" of whatever voltage and capacity we want. This way we can just package them in different sized batteries for all industries. I'm currently trying to figure out the dimensions (l x w x h) of a battery that we should produce for the stationary storage or UPS market

Our actual energy density isn't all that better than lead acid at the moment, but since we can deliver 90% efficiency and use the batteries at 100% DOD, we can deliver a higher amount of usable capacity in a smaller Ah battery, allowing us to reduce size.

How is the price per kWh looking? I'm not expecting an exact answer, but just a ballpark (let's say we're at a cost of flooded lead when manufactured at scale).

I'm asking because I'm curious what the advantage of this tech is over lifepo. I believe the major reason why many UPS products are still using lead (AGM etc) is because manufacturers are still monetising old designs (or at least elements of them). The moment they have an opportunity to switch to a new battery type they will go for lifepo4. Only a person that has very specific requirements wouldn't. No doubt before your investors put down their money they thought about such things and they must have identified some market segment where only lead currently works (sub polar LTE base stations is one that comes to mind).

It would be very interesting if you could mention these market segments where lead is still king and not for legacy design reasons.

Unfortunately I don't have an answer to your question. In fact I think it is unanswerable. If there was one standard set of battery sizes we wouldn't have so many form factors for lithium batteries. The closest we get to it is the cylindrical cells like 18650 etc.

 

[ponzatron]

Since were still developing and testing different variations of the battery, I can't really give you a good ballpark figure. Some of the research we've found on using carbon nanotubes in the electrode design is really promising, so trying that is on our to-do list. There are many studies out there where researchers use nanotubes in the construction of the anode or cathode and this can easily double or triple energy density using a similar amount of material. For the battery we currently have, let's just say that cheaper than $150 per kwh is an easily attainable goal at medium production levels.

As far as the market research I've done, lead acid dominates almost every segment we've looked at. Each of these is for the North American region:

• Grid-Scale Electricity Storage Technologies
  • Lead acid - 43% market share
  • Lithium ion - 21% market share
  • Both have around the same CAGR, li-ion will not eclipse lead acid in North America anytime soon
• Microgrids (Home Scale)
  • Dominated by lead acid
• Auto starter batteries
  • Dominated by lead acid
  • Will not be eclipsed by li-ion anytime soon
• UPS batteries (includes consumer and commercial)
  • Lead acid - 92% market share
  • Lithium ion - 3.3% market share
    • Has a ridiculously high CAGR of 57%, growing very fast
  • NiMH - 3.5% market share
  • NiCd - 0.8% market share
  • 80-85% of consumer grade UPS systems use lead acid
• Aircraft starter batteries
  • NiCd and Lead acid about equal
• Marine batteries / RV batteries (includes consumer and commercial)
  • Lead acid - 55% market share
  • Lithium ion - 32% market share
• Material Handling Market (Forklifts)
  • Lead acid - 97% market share
  • Lithium ion - 2% market share
    • Has a very high CAGR of 34%, growing fast
• Mobility scooters
  • Lead acid - 65% market share
  • Small market but easy to enter and sizes are standard

There's probably a few markets I'm forgetting. For the forklift battery market, charge time is very important. Our batteries can charge ridiculously fast. The auto battery market is also very promising. They use a metric called Cold Cranking Amps and we can deliver very high cold cranking amps. Plus we can give a warranty on our batteries that is double the standard warranty on lead acid auto batteries.

I haven't done much research on the telecom market yet... But I'm definitely interested. Thanks for pointing me in the right direction!

 

[werkenklasse]

Have you considered using clear plastic ammo cans? I know its primitive but it may work for testing purposes. Also, I know most folks would be content with a 20 kw battery bank, happy with a 30kw bank and ecstatic with a 50kw bank.
Looking forward to hearing more about your project. I have some original Edison cells that are currently 94 years old and still work. They are outlasting the wooden casings they came in.