Li-Ion Battery Swelling: Causes and Solutions

[Studiot]

Does anyone have any experience of the swelling of lithium-ion battery packs?

Attached are photos of one that came into the workshop recently.

The first is still in its Macbook and is genuine Apple, although you can see how it has forced its way out and distorted the case.

The second shows the battery pack removed. No exudate is apparent.

I have heard it suggested that this is due to overcharging, but have not seen it before.

A camera enthusiast friend says it is common with some brands of cameras, but not all.

 

[Mike_In_Plano]

I've designed lithium cells into products, and one of the issues is cell puncture. Flat cells with a plastic cover are subject to this. After the cover loses integrity, the cell absorbs moisture, the lithium reacts with the moisture to release hydrogen and the cell swells up.
The heat of the process is always of concern, so we would remove such a cell, place it in metal can and discharge it slowly through a resistor.
I can't say whether they were safe afterwards, but they were safer.

 

[Studiot]

Thank you for that insight, Mike.