Leaking Electrolyte from Bigbattery Powerblock

[MrGreen]

I just checked BigBattery web site and could find no information on batteries with fire extinguishers. I chatted with a tech and he said that it is only in the 12v owl max but there was no information on the web site? The youtube video with the fire in a bucket said " We've included a miniature fire extinguisher unit in every one of our LFP batteries." was that a true statement made on Jan 25 ,2021 ?? I hope Will P. opens his new batteries and looks for the fire extinguishers.

DouglasHHI:
Yes, I agree. I hope Will Prowse does open his units and check. They would be there.
They are included in every OWL, HAWK, HUSKY or LiFePO4 Battery that we provide.

Thank You,

Eric Lundgren
BigBattery, Inc.

 

[Sky-HHI]

Why is the information not on your web site or shared with your tech support? It seems that it would be a great selling feature.

 

[DerpsyDoodler]

Why is the information not on your web site or shared with your tech support? It seems that it would be a great selling feature.

Do we have any way of confirming that mr green is who he says he is?

 

[Sillyputty]

k3nny,

You are correct. I would add that the Mass-Production Models with all issues fixed are already in Will's possession in his trailer.
The battery tested in Will's last video was the Beta sent to him 4.5 months ago. If anyone has our product, they can see that the mass-production model has already had all these issues fixed prior to customer distribution. Thank you for your time.

Best Regards,
Eric Lundgren : CEO
BigBattery, Inc.

From Will's website / video on this subject:

 

[Sky-HHI]

Mr Green went quiet. ?????

 

[alfaeric]

DerpsyDoodler,
Yes, you are correct. What I was referring to is the amount that it costs to get "UL Certified" and the bureaucratic process of attaining this certification are in my mind "BS". We could not agree more.. I agree, Safety should not be a cornered monopoly that stifles fair competition and UL should not cost $250K or take (6) months to achieve for us when it only costs $25K and (2) months for larger companies.

That's kind of a simplistic way of looking at it, as the big companies have spent millions on their products to show the ability to do it for $25k and in 2 months. Instead of complaining about it, you should be in the same boat as them now for your future products.

And it's not a requirement to sell the product, it's a sign to consumers that you have gone through the process to pass a specific set of standards that are considered important for consumer safety. Unlike the industry I work in, where we are required by law to meet specific requirements.

Since you don't like it, don't do it. The fact that you are complaining on an optional marketing thing, well... thanks for saving me some time.

I would still like to know the load requirements for the cells if anyone else manages to find them.

 

[solarbot]

we do not advise anyone to puncture our raw cells with a giant metal spear.

The point is, the demonstration does away with the popular wisdom that lifepo4 is immune to thermal runaway and can't self-ignite. So the question becomes: what exactly are the conditions that cause thermal runaway or self ignition? Needs further research.

We have a lot of this out on the web: even if punctured they will not catch on fire. Directly proved false. The big iron spear is over the top to be sure. But if that's what it takes to get one point on the curve, so be it. Now that we know it is possible, surely there are other conditions that can also cause ignition. Some of these conditions may be realistic, or may be conditions we need to consciously mitigate. Can a shorted wire ignite a lifepo4 cell? Most probably yes. Not unrealistic at all.

I still believe that lifepo4 is the safest common lithium-ion battery chemistry. But is not as safe as many internet pundits seem to think. The more these dangers are studied the better. If I was in your shoes I would set up a safety lab and be testing to destruction all the time, by any and all means I could think of. And making videos of it, what could be better advertising? I never thought less of a car manufacturer because they did crash tests. Rather the opposite.

Much respect for getting on the forum and joining the debate. I can't see that as anything but good for your image.

 

[solarbot]

The electrolyte will ignite at a voltage over 4.7v I think and requires sustained heat but the plates do not burn and so only the eth[y]lene carbonate burns.

But does this take into account the effect of a sustained ignition source such as an internal or external short? Also what about the electrochemistry? I would appreciate some information about how state of charge relates to fire hazard.

 

[solarbot]

From Will's website / video on this subject:


View attachment 39413

Assuming Seth Rooney is a real person and the report is accurate... Does the box say "this side up"? It should, and that direction should be up with respect to the cells, not the case. Was it shipped by ground or air? If the latter then does pressure change plus horizontal or inverted cell orientation cause this? I'm already of the opinion that the only acceptable orientation for prismatic cells is vertical. Whether or not horizontal orientation risks leakage may depend on how much liquid happens to be in the can.

Perhaps it's hypobaric chamber time for Bigbattery's QC department.

 

[Picasso]

I've never done research in the field myself but told by a few people over the years who work in a lab testing completed packs. Thermal runaway is the bridging / burning of the separator layer. Also term used more as a pack thing with heating near cells and doing a chain reaction. Electrolyte being flammable is down to what ever different manufactures use....many none ISO mfg's dont always stick to the same formula for the electrolyte.

 

[SpongeboB Sinewave]

Can you tell by looking at the PCB for the BMS, how the BMS balances the voltage ? I expect that it is a passive (actively controlled) resistor load dump across each battery. If so, then there would be a limit to how much current can be dumped of one of the batteries are being over-voltaged during a charge cycle with high-ish current when that battery is somewhat out of balance and needs more dumping.
Kind of like AGM batteries... They plump when you cook 'em. i.e. they bulge out.

If you have a thermal imaging camera or good temperature measurement method, you can see if one or more batteries are getting hot compared to the others when charging or discharging hard.

Mr. Green does not have to be defensive because ALL electronics has problems once in a while. It is just a fact of life. Anything is possible !

 

[Gazoo]

Assuming Seth Rooney is a real person and the report is accurate... Does the box say "this side up"? It should, and that direction should be up with respect to the cells, not the case. Was it shipped by ground or air? If the latter then does pressure change plus horizontal or inverted cell orientation cause this? I'm already of the opinion that the only acceptable orientation for prismatic cells is vertical. Whether or not horizontal orientation risks leakage may depend on how much liquid happens to be in the can.

Perhaps it's hypobaric chamber time for Bigbattery's QC department.

Seth updated his comment and posted Big Batterys response to him so I am fairly certain he is real. I suggest reading the updated comment...it's interesting.

So now there have been a total of 13 cells leaking. Big Battery discovered 11, Will had one and we don't know if there was more than one in Seth's package. The manufacturer, Lishen, has told Big Battery it's ok to mount the cells on the sides. A properly sealed vent will not leak. This has me wondering if Lishen had some bad quality control. Or something else is happening but I don't know what that could be. I do find all of this very odd to say the least.

 

[Bud Martin]

I also winder if Seth's unit has the added pads installed.

 

[Hedges]

This is most likely a situation of welds that had a defect. The electrolyte would leak out only if cell tilted until it covered the defect and then temperature/pressure cycled.
Alternative possibility is corrosion, which would escape an initial test. Disassembling failed cells should show what happened, and ought to be done.

As I wrote earlier, QC could include gross leak test: pressure bomb then dunk under DI water and look for bubbles.

Leaking Electrolyte from Bigbattery Powerblock

True enough. The leak was a latent defect. Perhaps all cells are subject to the same failure after a period of time. Maybe the vent seal is the problem, but only some cells have high enough liquid level to reach that when on their side. All companies large and small, highly respected and...

diysolarforum.com

 

[solarbot]

So now there have been a total of 13 cells leaking. Big Battery discovered 11,

I wonder if "discovered" really means "got report from customer".

The manufacturer, Lishen, has told Big Battery it's ok to mount the cells on the sides.

They may need to update that guidance. One thing they can't do is stay silent on the question.

A properly sealed vent will not leak.

It can leak fluid when gas vents, or else it relies on some hitherto unknown physical principle.

This has me wondering if Lishen had some bad quality control. Or something else is happening but I don't know what that could be. I do find all of this very odd to say the least.

And it's not just Lishen and Bigbattery with a stake in this, it's the whole DIY battery scene. It is no longer possible to claim that leakage is a rare issue, so how do you build a battery that doesn't leak? Just control the cell orientation? Subject all cells to extended testing in desired orientation? Switch suppliers? That last ought to get Lishen's attention.

This is most likely a situation of welds that had a defect. The electrolyte would leak out only if cell tilted until it covered the defect and then temperature/pressure cycled.

Plausible, except that pressure would not be required, only tilting. So to expand: the can was imperfectly welded but was always shipped and stored vertically so that the leak was not discovered by assembly time. This theory should have been tested by now by Bigbattery, but apparently not or they would have said something about it.

Riddle me this: if Bigbattery found 11 leaking cells then why don't they tell us whether it is the can or the vent that leaks? Maybe because if it's the vent then it looks like Bigbattery's design flaw, which they don't want. Or if it's the can then it looks like they picked the wrong supplier and it's really hard to change, at least in part because they might not be able to get the same physical dimensions. Or they don't know, and that looks even worse. So just stay silent on that and hope it blows over, which unfortunately it did not.

Alternative possibility is corrosion, which would escape an initial test. Disassembling failed cells should show what happened, and ought to be done.

It sure should. But consider: how do you test a cell for hermetic seal after disassembly? Challenge.

As I wrote earlier, QC could include gross leak test: pressure bomb then dunk under DI water and look for bubbles.

Sounds good. Should Will give the "evidence" back to Bigbattery and trust that they will do exactly that?

Here's an off the wall idea: add an accelerometer chip to the BMS so it can know if the cells were ever inverted or dropped. Have a pressure sensor too so it can know that history, and a temperature sensor so it can know if it's on fire even without the external thermistor. If Bigbattery is willing to throw in a cute gizmo like the tiny fire extinguisher, I would value such a "black box" far more.

I dunno. The neverending saga. Given what is shaping up to be a statistically high failure rate, there should be enough DIY Lishen builds out there by now to regard the lack of problem reports as meaningful. But how many tried the sideways orientation? Every photo I've seen has the cells vertical. Bigbattery would seem to be the only product out there explicitly designed to orient prismatic cells horizontally. That's the thing about pioneering: you can end up with arrows in your back.

 

[DerpsyDoodler]

It was a risky decision to start with, orienting them on their side (IMO). Are they the only company doing this?

 

[solarbot]

It was a risky decision to start with, orienting them on their side (IMO). Are they the only company doing this?

I haven't seen another one, but that's just me. Few are using prismatic cells for that matter. I found this line by Lynx, looks like DIY in the wild, complete with Daly BMS, cells zip tied, no case. And all currently unavailable on Amazon, what does that mean? They also have prismatic builds with cases, likewise unavailable on Amazon. Well. That's it for my survey

 

[Gazoo]

It can leak fluid when gas vents, or else it relies on some hitherto unknown physical principle.

But a properly treated cell should not vent. And it should not leak under normal circumstances. Why have the vents remained closed on the bloated cells we see?

And it's not just Lishen and Bigbattery with a stake in this, it's the whole DIY battery scene. It is no longer possible to claim that leakage is a rare issue, so how do you build a battery that doesn't leak? Just control the cell orientation? Subject all cells to extended testing in desired orientation? Switch suppliers? That last ought to get Lishen's attention.

As far as I know there has not been any confirmation concerning the source of the leak. If the leak is coming from the vent or elsewhere then there is a QQ problem on Lishen's side. It could even be coming from the outer ring at the terminal for all I know.

But how many tried the sideways orientation?

As I recall a few have mounted the cells on their sides. An example of that is here. I don't recall anyone mounting the Lishen 170's on their side.

 

[solarbot]

But a properly treated cell should not vent.

An Eve representative said it is normal. "During the charge & discharge process of battery, the cell will “breath” like people does- swell & shrink effect." Never mind that this kind of breathing is nothing like respiration, they say it's normal. Granted, this does not actually say the cell vents, but if the cell has no room to swell because of the rigid case does that mean operating pressure shoots way up? Can this happen while just sitting?

I turned up some abstracts that investigate pressure valve characteristics, for example, this one. The gas pressure "correlates non-linearly with temperature." (NMC chemistry.) The investigations are out there, seems like mostly behind paywalls.

And it should not leak under normal circumstances. Why have the vents remained closed on the bloated cells we see?

How do we know the vents remained closed?

As I recall a few have mounted the cells on their sides. An example of that is here. I don't recall anyone mounting the Lishen 170's on their side.

The pressure vents on those cells look like the score type that is designed to burst permanently. Are the plastic vents on the Lishens designed to burst or reseal? I assumed reseal, maybe I assumed wrongly.

Here is a nice little scrap of information from a patent: "Lithium-ion cells may operate at pressures in the range of 5-25 pounds per square inch (psi). Such pressures are produced by gases generated during the cell's formation cycle and operation." Then they go on to describe their scheme for having the vent burst at some precise pressure.

Batteryuniversity opines that "re-sealable vents with a spring-loaded valve are the preferred design" and that's what I thought the Lishens do. Having doubts about that now.

 

[solarbot]

Seth updated his comment and posted Big Batterys response to him so I am fairly certain he is real. I suggest reading the updated comment...it's interesting.

Comment now unpinned, so harder to find. You're not kidding, Bigbattery's response is beyond tone deaf, that's being charitable. Also does Will know he is a "business partner" according to Bigbattery?