Swollen or deformed lithium battery: real danger and what to do

If your lithium battery has swollen, bulged or deformed: you have a serious internal fault. The pre-fire or pre-explosion sign. Here's what to do.

Why it swells

Unwanted electrolyte chemical reactions generate gas inside the cell. Typical cause: repeated overcharge, deep discharge, sustained high temp, or factory defect. The casing deforms to accommodate gas.

Real risk

LiFePO4 is chemically safer than NMC, but a swollen one can thermal-runaway: self-accelerating thermal decomposition. Result: fire burning at 1500-1800 °F, can't be extinguished with water.

What to do (strict order)

1) Power down the whole system (DC and AC breakers). 2) Do NOT touch the battery bare-handed. 3) Move flammable material 10 ft away. 4) Move to outdoors with gloves and PPE if possible without bending more. 5) Call hazmat service.

What NEVER to do

1) DON'T open the case to 'see what's happening'. 2) DON'T charge further. 3) DON'T discharge with loads. 4) DON'T water it. 5) DON'T leave inside home or closed garage. 6) DON'T throw in regular trash.

How to dispose

USA: Call2Recycle program or EPA-licensed hazmat disposer. EU: licensed e-waste handler. Cost: $35-120. Some battery brands have free take-back programs (Tesla, Enphase, BYD).

Prevention: correct configuration

BMS set for your chemistry. Charger doesn't exceed 3.65 V per cell. Discharge cut at 2.5 V per cell. Operating temperature between 32-122 °F. Inverter with active overcurrent cutoff.

To set it correctly read LiFePO4 BMS explained.