Yesterday, I bought a Dji Phantom 3 4k. I loaded the battery, the controller. When I turned the aircraft on and linked it to the controller, a message appeared telling me Battery cell broken, "stop using the battery and return it to factory for repairing". I stopped the battery, loaded it, but the problem remained. The 2nd cell has a lower voltage than the others. What can I do ? Can I get a new battery ? Of course, the product is covered by warranty (I bought it yesterday and the aircraft took off 20 seconds).

OK .... first things ...

Check that all contacts are CLEAN ... it is not unusual for a bit of chaff or dirt to upset the connection.

There are two sets of contacts .......... the main ones that power the motors and you charge through ... and a smaller pair that provide the power for Telemetry / Video and pass Battery info to the link back to controller. Make sure battery and aircraft contacts are clean.

Take the battery you have and SWITCH it on .... THEN connect to charger. Because the battery is in a high state of charge - you need to switch on before connecting to charger to over-ride the default. You may be lucky to see battery charge up fully ... MAYBE !! But unlikely ... but worth a try.

If still same situation then >>>>>>>

If still under warranty .............. RETURN IT NOW !!

If you only have one battery - go get another as a second battery while waiting for DJI / Seller to replace the faulty one.

ONE battery is NOT enough !! You will want at least 2 ...

As to your post here ... once a cell is damaged - that's it. No recovery. Deep discharged runs risk of further damage ... but battery is naff already - so you can try a deep discharge ... but don't be disappointed when it fails to correct anything. You may be lucky to get one flight ... then back it comes again.
DJI have put a 'barrier' between you and individual cells ... so balancing charging is dictated by a board that will shut down before it does full balancing... unlike a regular LiPo and charger setup.

Sorry not good news for you .... GET on that Warranty trail !!

If the battery is outside warranty ... then use as it bench battery when updating FW etc. instead of wasting cycles of a good one.

Nigel

Nigel is right. Cell 2 is broken. My battery was charged more than 60 times and has no issue.

To be correct ... thanks Peter ..... Cell 2 is not dead but damaged. It is probably suffering excessive high Internal Resistance. This prevents the charger from charging up that cell fully.

To be honest all 4 cells are not showing full voltage charge.  Cells 1 & 4 are near. The small drop on those is likely due to power up and pulled the top end of the charge.

Technically full charge on a HV LiPo as the DJI should be 4.35V each cell. But because the DJI charger cuts out as soon as it sees a total of 4 x 4.35V ... it is common for the pack to show 4.32V or similar per cell once settled.
Cell 3 is also down ... and that is not so good as that will soon follow cell 2 ...

Get a replacement !!

And do yourself a favour ...

Get a second battery so you don't lose out flying time waiting to charge up your one and only !!

I also advise setting your GO to set batterys auto discharge start timer to 2 or 3 days and not leave as default 10 days.

Next ... after flying ... if your battery is anywhere from 30% and up ... Leave it alone and let it stay until next time you want it. The auto discharge will bring down any high charge state and if battery is below that .. as long as its at least 30% ... its good to store.

Nigel

Thank you for your answers, especially Nigel. I followed your instructions but it didn't work. So I went to the retailer which gave me a new battery. Thanks for all and have a good day

Excellent result.

At least my info gives you a foundation to stand on  with a seller if they try the BS line !!

Great stuff and it has made my day that you have had success.

Nigel