Author Topic: What went wrong.  (Read 2826 times)

0 Members and 1 Guest are viewing this topic.

Offline G7PSK

  • Super Contributor
  • ***
  • Posts: 3698
  • Country: gb
  • It is hot until proved not.
What went wrong.
« on: October 17, 2015, 02:04:15 pm »
Hi I was talking with my sisters about the dangers of Lithium batteries and how they can catch fire, so I thought a demonstration would be in order.
 I took this cell outside and stabbed it with a screw driver, nothing happened so I put some water on it and it blew a few bubbles so next I tried a blow lamp and still nothing happened other than the blow lamp melted the aluminium foil cover a bit.
Did I stumble across the only non flammable LiPo. or what.
 

Offline zapta

  • Super Contributor
  • ***
  • Posts: 6004
  • Country: us
Re: What went wrong.
« Reply #1 on: October 17, 2015, 02:09:20 pm »
Obviously you got a bad one.

;-)
Drain the swamp.
 

Offline hayatepilot

  • Frequent Contributor
  • **
  • Posts: 262
  • Country: ch
Re: What went wrong.
« Reply #2 on: October 17, 2015, 02:16:08 pm »
The cell was probably empty.
Fully charged cells react quite violently if stabbed with a screwdriver.  ;)

Greetings
 

Offline Galenbo

  • Super Contributor
  • ***
  • Posts: 1474
  • Country: be
Re: What went wrong.
« Reply #3 on: October 17, 2015, 02:53:43 pm »
Hi I was talking with my sisters about the dangers of Lithium batteries and how they can catch fire, so I thought a demonstration would be in order.
 I took this cell outside and stabbed it with a screw driver, nothing happened so I put some water on it and it blew a few bubbles so next I tried a blow lamp and still nothing happened other than the blow lamp melted the aluminium foil cover a bit.
Did I stumble across the only non flammable LiPo. or what.

Lithium batteries aren't dangerous, people (like you) are.
:-) :-) :-)
If you try and take a cat apart to see how it works, the first thing you have on your hands is a nonworking cat.
 

Offline Stonent

  • Super Contributor
  • ***
  • Posts: 3824
  • Country: us
Re: What went wrong.
« Reply #4 on: October 17, 2015, 02:59:25 pm »
The answer is reverse connect to a car battery charger
The larger the government, the smaller the citizen.
 

Offline amyk

  • Super Contributor
  • ***
  • Posts: 6848
Re: What went wrong.
« Reply #5 on: October 17, 2015, 03:54:51 pm »
The cell was probably empty.
Fully charged cells react quite violently if stabbed with a screwdriver.  ;)

Greetings
This. What voltage was it at before the abuse? If it was already dead, it won't do much.

The fire comes from all the energy released by the cell when it gets short-circuited.
 

Offline bktemp

  • Super Contributor
  • ***
  • Posts: 1623
  • Country: de
Re: What went wrong.
« Reply #6 on: October 17, 2015, 04:34:25 pm »
If you want to do a nice demonstration, remove the protection circuit and apply 12V limited to a couple of amps to the battery and wait.
I did this once. As soon as the battery gets overcharges gases are beeing produced, inflating the battery. Those gases are highly flammable. Suddenly the battery popped open and the gas ignited, rocketing the battery about 5 meters away while producing sounds like a rocket.
 

Offline zapta

  • Super Contributor
  • ***
  • Posts: 6004
  • Country: us
Re: What went wrong.
« Reply #7 on: October 17, 2015, 04:51:21 pm »
If you are interested in lipo mayhem, you can find examples here

https://www.youtube.com/results?search_query=lipo+fire

(don't try it at home, it can be extremely dangerous).
« Last Edit: October 17, 2015, 04:55:22 pm by zapta »
Drain the swamp.
 

Offline IanB

  • Super Contributor
  • ***
  • Posts: 9668
  • Country: us
Re: What went wrong.
« Reply #8 on: October 17, 2015, 08:24:57 pm »
The cell was probably empty.
Fully charged cells react quite violently if stabbed with a screwdriver.  ;)

Greetings
This. What voltage was it at before the abuse? If it was already dead, it won't do much.

The fire comes from all the energy released by the cell when it gets short-circuited.

Precisely. Also the fire comes from the flammable organic solvent used for the electrolyte.

When you stab a charged battery you create a short circuit between the layers. The large short circuit current that results heats the metal parts to red hot, which ignites the electrolyte. In contact with air the solvent burns vigorously, accelerated by the heat from the shorted battery.
I'm not an EE--what am I doing here?
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf