Author Topic: Problem Li-Po battery  (Read 484 times)

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Offline tiago1986

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Problem Li-Po battery
« on: June 11, 2021, 10:11:12 am »
I have a handheld handheld console but something strange happened to me twice, I kept the device turned off with the xiaomi BM20 battery inserted and both times after a period of non-use (maximum 2 months) when I went to use the device the battery was swollen swollen, what could be happening? if I store the BM20 outside the device it does not swell in the stove but it is very annoying to keep putting and removing the battery from the device
 

Offline evb149

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Re: Problem Li-Po battery
« Reply #1 on: June 11, 2021, 10:44:37 am »
It means you should never leave the battery in that device again when you aren't using it.

Maybe even when the device is "off" there is significant leakage current drawn from the battery enough so that the
battery gets over-discharged past its maximum limit in that time.

Or if you had the charger connected but the device "off" then maybe the battery was over-charged by that device.

Or even if the device clamps the battery physically somehow too tightly when the device has the battery installed then that puts a bad stress on the battery.

In any case you really must not store the cells in that device.  And if you are going to store them anywhere long term
you should consider something like a closed metal paint can or other closed metal case filled with sand around the stored batteries and located in a safe place away from anything that could be damaged if the battery has a problem.
 

Offline tiago1986

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Re: Problem Li-Po battery
« Reply #2 on: June 11, 2021, 10:45:37 am »
I bought several BM20 batteries on Aliexpress the same from the same seller but they only swell if they are inserted in the device for a long time without use he said they are original and their value is high, they had a voltage of 4.1v
 

Offline tiago1986

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Re: Problem Li-Po battery
« Reply #3 on: June 11, 2021, 10:46:37 am »
device is handheld Powkiddy Q80
 

Offline Siwastaja

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Re: Problem Li-Po battery
« Reply #4 on: June 11, 2021, 10:52:39 am »
The aliexpress cells are just crap and possibly dangerous. Don't waste your money on them.
 

Offline tiago1986

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Re: Problem Li-Po battery
« Reply #5 on: June 11, 2021, 10:59:05 am »
Where can I buy the original BM20?

the strange thing is that this battery swells only inside the device turned off and not plugged into electrical power
 

Offline evb149

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Re: Problem Li-Po battery
« Reply #6 on: June 11, 2021, 11:40:24 am »
Pouch lithium secondary cells normally swell a modest amount in time, when used, as they age, and vs. temperature.

When there is excessive swelling like I assume you're talking about, it means one thing -- the cell is destroyed and no longer safe to keep / use.

When a cell fails and is damaged due to various cause it may swell excessively.

When a cell is over-charged, over-discharged, or mechanically damaged that can happen.

Cells typically are used in equipment, packs, or or are used in conjunction with a safety circuit / circuit board that prevents over-discharge and over-charge, over-current, and over/under temperature usage.

If the pack and equipment has an absent or incorrect safety circuit then there is generally insufficient protection and assurance that the cell cannot be over-charged, over-discharged, over-current discharged, or used at incorrect temperatures.

Typically some equipment continues to draw some current from installed cells even when some parts of the equipment is "off".  Over time (e.g. days / weeks / months) even a little discharge current if it is maintained without stopping when the cell voltage goes down to its minimum allowed value (typically around 3.0-3.2V) then the battery is over-discharged and will usually be damaged and may swell like that.

There is nothing you can do to prevent the problems except possibly:
1: ensure the equipment or the battery pack has the proper safety circuit to protect the battery from misuse.
2: don't store the battery in the equipment if it can be over-discharged by doing so.
3: don't charge the battery with chargers that don't protect the battery correctly during charging.
4: use high quality batteries of a correct type for the use and equipment.

 

Offline tiago1986

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Re: Problem Li-Po battery
« Reply #7 on: June 11, 2021, 12:11:29 pm »
I do not know the protection circuit of the device is a handheld handheld Powkiddy Q80 console but it was purchased with the battery already installed and it did not swell but the original batteries I bought both bulged inside the console with it turned off

I just updated the console firmware
 

Offline tiago1986

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Re: Problem Li-Po battery
« Reply #8 on: June 12, 2021, 10:22:19 am »
I'm thinking about purchasing an imax B6 mini universal charger to charge/discharge/storage mode some Li-Po mobile phone batteries BM20 and BP-5L models but I don't know which adapter I can buy to make this operation possible, there is an adapter for do that? I think about buying on Aliexpress
 


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