Dropped 18650 - Keep or Discard?

Oops… :person_facepalming:
Dropped a rather new Panasonic 3400mAh on the tile floor here today from about 3½ feet high…
Ugly dent in tail…
It’s doing the NOR test in my Liitokala charger as we speak.
Reading 2173 mAh at 3.52 Volts now, so it seems to be okay…

I don’t know what the separator is and where it would be located…
And how do i find out if it’s prone to fail?
High current discharging?

Small dents on the bottom are not too critical as there is a small gap between the foil pack and bottom

On the side its a lot more dangerous

I hoped someone was going to say that ! :+1: :smiley:

Any idea how much of a gap that is?
Does it mean you can solder on it? (Just curious)

this is a picture from a cell before assembly
You can see that the seperator is longer than the lithium foils

I am not sure but that contact is most likely welded at factory to the bottom of the cell

Seen OK for me.
I will keep it except it look danger to continues use. :wink:

When you drop a cell and make a dint you are making the cell smaller and that means you get less capacity lol :stuck_out_tongue:

According to INR18650-35E specification paper

Drop Test
Test method: Each fully charged cell or battery is dropped three times from a height of 1.0 m onto a concrete floor. The cells or batteries are dropped so as to obtain impacts in random orientations. After the test, the sample shall be put on rest for a minimum of one hour and then a visual inspection shall be performed.
Criteria: No fire, no explosion (Test shall be performed with the following criteria IEC 62133)

Heating Test
Test method: To heat the standard charged cell at heating rate of 5°C per minute up to 130°C and keep the cell in oven for 10 minutes.
Criteria: No fire, and no explosion.

Overcharge Test
Test method: To charge the standard charged cell with 12V and 3C(10.2A) at 23°C for 7 hours.
Criteria: No fire, and no explosion. Overcharge test shall be performed with the UL1642 standard

Vibration Test
Test method: As to the UN transportation regulation(UN38.3), for each axis (X and Y axis with cylindrical cells) 7Hz→200Hz→7Hz for 15min, repetition 12 times totally 3hours, the acceleration 1g during 7 to 18Hz and 8g (amplitude 1.6mm) up to 200Hz.
Criteria: No leakage, with less than 10mV of OCV drop

External Short-circuit Test
Test method: To short-circuit the standard charged cell by connecting positive and negative terminal by less than 80 ± 20mΩ wire for 3 hours.
Criteria: No fire, and no explosion.