IS THIS SAFE? LiPo battery question

[lena_boyd]

Hi there!
I am working on a project which involves a 3.7V 2500mAh lipo battery.

I'm really starting to worry because I keep reading these horror stories about LiPo batteries being unsafe.

I have connected the positive (red) wire coming out of the battery to a switch, which connects to a jst connector, and the black wire also connects to the black wire on the jst connector.
The jst connector is attached to an adafruit 32u4 feather (microcontroller).

the battery is recharged through the adafruit feather with a USB cable, and automatically stops charging when fully charged.

I have insulated the soldered wires (my soldering is not amazing).

Is there any way that a battery of this type and size could just explode or catch fire? The project is meant to be wearable but it feels like a risk.

 

[rjenkinsgb]

That should be fine; just be sure the battery cannot be shorted, and cannot be crushed.
It's connected to a proper charge circuit, so cannot be overcharged.

Note that the charge facility on the feather is only rated 100mA - so 25 hours or more to charge from flat for a 2.5AH cell.
An 18650 or similar standard cell with a holder and separate charger, so you can swap charged cells in, may be more practical.

There are two common problems with lithium cells, and both relate to misuse in different ways.

The first is mainly related to packs that use multiple cells in series, in things that do not monitor or control every cell separately.
If one cell has a slightly different capacity to another, eventually one can be overcharged while the rest are still not full, and that one cell can burst.
(Or DIY charge circuits that have no proper voltage control).

Any overcharge can cause cells to rupture, so using a properly designed charge circuit is essential.

Properly designed packs (or pack chargers) have "balance" charge that monitors and controls the voltage on each cell.

And, simple physical damage. LiPo cells with soft cases can be damaged by being dropped or crushed, as the internal insulation can be damaged.
That can cause an internal short and massive heat build up.

Cased cells such as 18650s from major manufacturers are somewhat more resilient, but still sensitive to overcharging.