Kingsong s20 Cut out FIRE (New York)

[Forwardnbak]

New company “BEGONG” announces s22 dragon LT

[Tawpie]

3 hours ago, BatteryMooch said:

If the nickel is pressing against the top of the cell then it could easily melt the plastic wrap and top ring insulator (if plastic, not paper) and directly short-circuit the cell. Perhaps unlikely but it’s not impossible.

I believe you're correct here.

It's kind of bad that the plastic 'sleeve' is the only insulator and the cell's positive and negative electrode are that close together, but this is how these cells are manufactured. I'm no battery pack builder, but I don't think it's common to add insulation because under no circumstances should the nickel strip ever get "hot". If you did add insulation, you'd want to use fiberglass or asbestos or some other fireproof material.

 

 

 

(just kidding about the asbestos BTW, you wouldn't be able to import it into the US with that stuff in it)

[Hellkitten]

@Tawpie https://www.mcmaster.com/fishpaper

[Tawpie]

2 minutes ago, Hellkitten said:

@Tawpie https://www.mcmaster.com/fishpaper

says 235F max temperature? I thought you would be above 750F to get visible red in not-darkness. But I'm not a pack builder so I shouldn't talk.

[goatman]

those packs are built like crap, noone builds like that anymore, not even cell holders. atleast the 900wh begode packs cell holders had built in protection where the nickel couldnt short out the cell

 

[Tawpie]

9 minutes ago, goatman said:

those packs are built like crap, noone builds like that anymore, not even cell holders.

If we're lucky, the third party review will flag this deficiency and if we're very lucky KS will do something to fix it. I kind of doubt it though, they'd need a new aluminum case cuz the battery size would grow.

Edited April 3, 2022 by Tawpie

[Paul A]

Maybe have suggestions passed on to KS for consideration via E-wheels.

No KS rep here anymore.

[Planemo]

'Install the PVC fireproof protective cover' 

Tbf, I think the overall construction looks pretty good.

[Paul A]

Portable contents insurance, also known as personal effects insurance, can provide a level of financial cover for personal items that regularly leave your address with you such as handbags, laptops, musical instruments, sporting equipment, or items on you such as spectacles, jewellery or clothing.

 

[Forwardnbak]

So as it stands has anyone decided to cancel? 
Are KS due to provide any further info or just send them S22’s?

 

[Robse]

3 hours ago, Planemo said:

'Install the PVC fireproof protective cover' 

Tbf, I think the overall construction looks pretty good.

Its ok :-)

[BatteryMooch]

8 hours ago, supercurio said:

…good thing we have a battery assembly videos! It's like they shared it with us for review 

LOL…I completely forgot about that video, thanks!

Looks like I was wrong. At 0:15 in the video that looks like green fishpaper rings were added to the cells. But as @Tawpie and @Hellkitten noted the temp rating for at least one type of fishpaper is 235F, wayyyyy below the temp of red hot nickel (several hundred degrees-F in my opinion).

Sooooo….they added additional insulation but we don’t know if it can hold up to the hot nickel or not. 😔

Edited April 3, 2022 by BatteryMooch

[Planemo]

17 minutes ago, Robse said:

Its ok :-)

The point I was making is that you could cover 4 sides of the battery in space shuttle re-entry tiles if you wanted, it's all a bit futile if the battery still expels it's guts out of the top or bottom. And even if you could confine the fire to the footprint of the pack, I imagine it would then turn into a bomb if the pressure can't escape.

[Robse]

19 minutes ago, Planemo said:

The point I was making is that you could cover 4 sides of the battery in space shuttle re-entry tiles if you wanted, it's all a bit futile if the battery still expels it's guts out of the top or bottom. And even if you could confine the fire to the footprint of the pack, I imagine it would then turn into a bomb if the pressure can't escape.

I see it more as a kind of protection against a fire spreading from one side of the package to the other. 
In addition, fire can also occur in the components and not only in the batteries. But I can see what you mean :-)

[Chriull]

9 hours ago, BatteryMooch said:

Wouldn’t happen though IMO if paper rings were added when the pack was built.

 

9 hours ago, supercurio said:

@BatteryMooch good thing we have a battery assembly videos! It's like they shared it with us for review

Seems they have insulators, as normally used for li ion battery packs

https://imgur.com/a/anZd0Bs.jpg

12 hours ago, BatteryMooch said:

While a continuous short can definitely happen I think intermittent shorts are a very real possibility and also need to be thoroughly tested for.

"Intermittent shorts" happen "all the time" during riding. Was a problem in the very beginning of euc riding - wheels were frying mosfets at and around standstill!

Neither wires, mosfets, connectors, nickel strips nor li ion cells will survive currents the motor could draw at lower speeds.

So, afair @RagingGrandpa had some 200A measured as current limit from one modern wheel? This is regulated in firmware by switching off the mosfet - "shorting the pwm duty cycle".

A couple of years ago Gotway stated to limit phase currents to some 120A.

This pulses are delivered from the battery - in average presumably some half, third or even less of this phase current values. But still values the wheels components can not survive for longer periods of time.

From the beginning on it was a competition between motor wires and mosfets - what will fry first. Once one component was beefed up the other one died first...

The know how of the manufacturers lies in the delicate mixture how much power they allow by firmware and the let the components survive without making the wheel to "boring".

As it seems the nickel strips now (?and with begodes 900Wh packs?) started to become a limiting factor, too - but this time not only leading to a failed wheel but annihilated by flames...

Ewheels step to own litech batteries with reinforced nickel strips for begode wheels seems to be the right direction.

Nickel strips definitely have to be taken out of the "possible failing components" - this hardware component has to be changed and be made fail safe!

The rest has to be in first place regulated in firmware - how much power is allowed for how long at which speeds, so that the wheel survives as much use cases as possible.

BMS fuses are just

10 hours ago, Tawpie said:

A fuse as a last resort makes sense

 

Edited April 3, 2022 by Chriull

[BatteryMooch]

1 hour ago, Chriull said:

Seems they have insulators, as normally used for li ion battery packs

https://imgur.com/a/anZd0Bs.jpg

Yup, noted that in my post earlier. 🙂

Whether the fishpaper, with its fairly low temp rating (235°F for one type), can still provide protection while being press against by nickel strip at hundreds of degrees above its rating is still unknown though. The fishpaper would probably have to be vibrated out of the way after decomposing (or whatever) so it probably still provides protection even with red hot nickel but testing would certainly be needed if any possible failure scenarios resulted in hot nickel.

It’s easily argued though that the pack’s design has failed if the nickel can ever get hot.

I’m still leaning towards heat conduction (from the hot nickel) to the cells forcing them into runaway with short-circuit current being my #2 choice. All guesses and just my personal opinion though.

 

1 hour ago, Chriull said:

Nickel strips definitely have to be taken out of the "possible failing components" - this hardware component has to be changed and be made fail safe!

Agreed! Nothing short of a crushed pack should ever result in hot nickel.

 

1 hour ago, Chriull said:

From the beginning on it was a competition between motor wires and mosfets - what will fry first. Once one component was beefed up the other one died first...

Properly sizing the wiring and selecting an appropriate insulation type is pretty easy. The failures probably came from cost-cutting or unreasonable requirements for size, bending radius, connector choice, etc. 

IMHO the FET failures were because many of these companies either don’t know how to properly select their MOSFETs (and other components), don’t test thoroughly enough, or make too many compromises in reliability for the sake of lower parts costs and/or smaller size. They can be set up to be incredibly robust but that takes time and money, something not easily given by many companies.

I guess what I’m saying is that the wiring/MOSFET competition you mentioned never needed to happen. 🙂

Edited April 3, 2022 by BatteryMooch

[Chriull]

10 minutes ago, BatteryMooch said:

Properly sizing the wiring and selecting an appropriate insulation type is pretty easy. The failures probably came from cost-cutting or unreasonable requirements for size, bending radius, connector choice, etc. 

These was in the times with small diameter axles, which tended to break by the burdens...

So phase wires were thin and people exchanged tipps on how to seperate them witg zip ties so the copper won't touch through the melting insulation...

10 minutes ago, BatteryMooch said:

I guess what I’m saying is that the wiring/MOSFET competition you mentioned never needed to happen. 

Yes. With proper planning, design and testing all this could gave been avoided.

But as "history shows" euc development/evolution is driven by trial and error..

[techyiam]

25 minutes ago, Chriull said:

But as "history shows" euc development/evolution is driven by trial and error..

I can understand that they probably don't have many mechanical engineers, so there would be a lot of trial an error in that department. If you look at inMotion or Kingsong's history, one may not be surprised by this. After all, for non-suspended wheels, there are only the wheel bearings and the wheel and motor assembly.

But on the electrical front. I was expecting more. But here we are. Astonishing! 

[Paul A]

Some of the personnel of KS.

 

King Song Production and Quality Control video

Aug 11, 2017

King Song International

3.61K subscribers

 

There are about 20 firms manufacture and selling EUC in a large scale, only about 10 of them have R & D ability for a motherboard.

King Song has become the top company which owns the core technology of Independent R&D on both mainboard and appearance.

In the last 5 years, self-balancing vehicle sales kept increasing, as more and more people accept this way of transportation and recreation, the demand will grow rapidly.

So it’s your time to grasp the opportunity to cooperate with King Song, let’s create miracles together!

Edited April 3, 2022 by Paul A
Addition of video description

[Robse]

1 hour ago, Paul A said:

Some of the personnel of KS.

 

King Song Production and Quality Control video

Aug 11, 2017

King Song International

3.61K subscribers

 

There are about 20 firms manufacture and selling EUC in a large scale, only about 10 of them have R & D ability for a motherboard.

King Song has become the top company which owns the core technology of Independent R&D on both mainboard and appearance.

In the last 5 years, self-balancing vehicle sales kept increasing, as more and more people accept this way of transportation and recreation, the demand will grow rapidly.

So it’s your time to grasp the opportunity to cooperate with King Song, let’s create miracles together!

Nice video - wonder how it looks today (its nearly 5 years old)   Whats the name of these 20 firms?