Magnet (800 gauss) influence on Li - ion battery

[levnu]

What are the infuences of a magnet on such battery
can constant magnet placed near the battery damage it somhow?

if i would like to measure its influence...
what params shall i measure
for instence:
- influence on charging time
- influence on discharging time
- influence on capacitness
- infuence on ....

Thanks

 

[dick_freebird]

The main effect I imagine will be to "steer" the current
away from uniform flow. Much as I've seen trouble at
DC arc welding when using magnetic workpiece clamps.
The arc goes sideways from where you want it. In a
battery, biasing current unevenly will probably result in
some inefficiencies and conceivably cook one side and
fail to charge the other. Or something.

But I don't know whether this particular field strength
is able to exert a problematic influence, or only some
trivial one.

Perhaps you would find it interesting to put your max
charging / discharging current through a simple wire,
place the magnet of interest in proper relative position
/ orientation of field, and observe how much deflection
/ force.

 

[mtwieg]

I know there are non magnetic Li batteries specified for use in high field MRI scanners (1.5T and up). The cell chemistry isn't really different, but they are made using non-ferromagnetic materials. As far as I know, their electrical properties aren't affected by the field. I doubt a small 80mT field would cause any noticeable effect.

 

[tpetar]

What are the infuences of a magnet on such battery
can constant magnet placed near the battery damage it somhow?

if i would like to measure its influence...
what params shall i measure
for instence:
- influence on charging time
- influence on discharging time
- influence on capacitness
- infuence on ....

Thanks

Why you simple dont do an experiment, measure and monitor values? Extract Neodymium magnet from old 3,5" hard disk.

I think, if there some influence of magnetic field on battery, it will be on battery life, or faster aging process.

 

[levnu]

Thanks for all answers,
So i would take 3 new same batteries of 2100 mAh (without magnet, with 1 magnet, with 10 magnets)
and
compare them before and after around 1000 cycles of charge/discharge,
i will compare their capacitness, charging/discharging time.
would the measured params will:
- Answer the aiging process?
- 3 batteries is enough? or their natural variance may make my results be unreliable?
- should i add somthing to the test?

Thanks

 

[tpetar]

Measuring and monitoring internal resistance of batteries.

Also check and determine locations for placing magnets to batteries. I supose you dont have device or very big magnet to make big magnetic field.

After magnetic field test, test these batteries on vibrations, with specialized device for this purposes with adjustable freqeuncies of vibrations.

On end first try to make high current drain test and compare with declared maximum current, then recharge and try capacity test.

- - - Updated - - -

How long you will keep batteries near magnets ?

 

[levnu]

i will repeat cycles of charge/discharge for about 1 month

 

[tpetar]

Also it will be good to measure or to know strength of magnetic field.

 

[levnu]

The magnetic feild of each magnet is 80mT

 

[tpetar]

The magnetic feild of each magnet is 80mT

Few Teslas more and you can make CT or MRI.

Its around 800Gs it will be interesting, I hope You will not forget to post results on EDABoard.


Additional to this its interesting to monitor battery during charging/discharging with FLIR camera. I have somewhere tests with this camera, its very interesting to see thermal spreading and in what part of battery.


Best regards,
Peter

 

[levnu]

Yes thermal test sounds interesting
Hh if I put 20 magnets it will be 1.6 T

 

[mtwieg]

Doing the tests at a higher discharge current will probably most interesting. Orientation of the magnet with respect to the field should also be a degree of freedom.

Yes thermal test sounds interesting
Hh if I put 20 magnets it will be 1.6 T

Doubtful, pretty much all rare earth magnets saturate at around 1.2T, and even that will only be extremely close to the surface.

 

[tpetar]

Who knows maybe you will discover new way to upgrade batteries to super hybrid battery, but with separate selling of crowbar to owners for removing batteries from device. :smile:

 

[levnu]

i thought to draw current of 0.3C becasue i want to be ok w/ the battery spec
i want that the only parameter on capacity change will be the magnets and not due to the reason that i draw more than 0.3C currrent

 

[tpetar]

Yes this is ok and reasonable.



See this:

Magnetically Aligned Nickel Micro-particles for Lithium Ion Battery Anode Stress/Strain Detection
**broken link removed**

 

[levnu]

looks interesting