Extreme Li-Ion testing: Request for Tests

OK, I got to thinking that maybe if I can figure out a way to do these tests safely, it might be nice to document what happens to a Li-Ion cell when it is exposed to extreme conditions. At this point I’m open to suggestions on tests that people would like to see done.
Don’t hold back, any suggestion will be fine; we can decide later if the test can be performed safely.

Depending on the test, I will use new cells or laptop pulls that are performing close to their capacity.
If anyone has specific cell types they would like to order/donate for testing, PM me to arrange that.

Here is a list of tests and results. Pictures have been added where applicable.

1. Over Discharge
Updated 02/19/2013: Preliminary results using a laptop pull; already had reduced capacity and higher internal resistance.
Cell over discharged to 1.4 volts for four cycles. Cell slowly rebounds to 3.2V once load is removed. Charging indicated increased internal resistance with each pass, although minor. Each pass produced very slightly higher capacity (about +100mAh after four cycles).
I will eventually perform this test on a cell with better initial conditions.

2. Over Charge
Test not performed yet

3. Short Circuit for 90 seconds
Updated 02/19/2013: Preliminary results using laptop pull; already had reduced capacity and higher internal resistance.
Cell was shorted for 90 seconds using 20ga wire. Circuit resistance was approx. 0.12 Ohm. Cell was already discharged before shorting.
Short was removed when cell reached an external temperature of 60C (fatal test to be performed later on a fully charged cell).
Cooling, charging, and discharging after this produced a minor reduction in capacity and a notable increase in internal resistance. One 90 second short produced much more internal resistance than four cycles of over discharge (Test 1).

4. Short circuit until cell failure
Test not performed yet

5. Reverse Charge
Test not performed yet

6. Discharge at 0C
Test not performed yet

7. Discharge at –20C
Test not performed yet

8. Discharge at +50C
Test not performed yet

9. Extreme Overheating Without a Load
Test not performed yet

10. Overheating With a Load
Test not performed yet

11. Two Unbalanced Cells Placed in Parallel
Tests performed. Results posted here

12. Cell left in non-terminating charger for long period (up to six months)
Test Not performed yet.

For starters, we can overcharge it until it vents… and explodes.
Then we can discharge it to 0V and even reverse charge it.

Thanks for doing this!

I would do what Ryan already said along with a shprt through thick wire. Thanks for doing these tests! I've alwabrew anted to do these but chickened out. Just make sure you have some filters for your mask that are rated for hcl. Also a body suit would be a good idea, for short exposures a paint suit may do the trick.

Capacity at various temperatures from –30C to 40C would be interesting.

Some preliminary results have been added above. More to come, including some of the more interesting tests J)

I’m still open to test suggestions, however, I’m trying to keep it related to flashlights. I would not expect punctures or crushing when using a flashlight, so I will not be performing those tests.

I am adding ‘cooking’ though. This will be raising the temperature to well above the recommendations without a load. This would simulate a situation where a cell or flashlight was left in a hot area like an engine compartment. I’ll probably limit it to 100C or 125C.

submerged during discharge :slight_smile:

+ a million to you having some serious safety gear (or not doing the tests at all!)

I don’t want to see anyone with long term health problems caused by this sort of thing.

lick on a fully charged battery

Fully charged battery into salt water

I’ve seen this in fresh water; the positive end rusts/corrodes in a few minutes. otherwise it seems fine. Saltwater would probably make things move along quicker.

Not a problem, you barely feel anything. Lick a 9V battery for a more interesting sensation :wink:

Thanks for the concern ruffles, scaru you too. Much appreciated.
All tests with any risk of venting or explosion are conducted outside in open air, behind a shield.
Longer term tests with minimal risk (i.e. overdischarge) are placed inside a surplus .50cal ammo box on a cement floor in my garage. I painted it a nice glossy blue instead of camo green. :slight_smile:
In general, Lithium Ion cells do not contain seriously toxic chemicals. Breathing the vent fumes from a cell would be harmless (mostly a small amount of hydrogen gas). The only risk is formation of toxic compounds when a cell overheats. For small cells this is negligible (also, these will be outdoor tests). The current industry concern is for large batteries in electric vehicles.
I’ll also try to avoid eating any cell material that may be exposed during a test :wink:

try charging it at 10C

My power supply tops out at 6.3A, about 2-3C for most cells. I’ll consider this test if I can gain access to a higher current supply. Thanks!

Whats missing is tests on old cells, ones that have lost capacity due to age or many cycles.

Put a cell direct on the ac power socket…

that is genius! :smiley:

Fully charged battery into various bodily orifices… J)

Submerge it, freeze it, you know, and all the other unsafe stuff.

There is no safe way coming close to any battery :wink:
It’s just guidelines for safer use. Be careful.