First: Is It Smoking, Hissing or Hot?
If the battery is smoking, hissing loudly, smells of sweet chemicals or is visibly hot, do not handle it. Get people away, leave the building if it is indoors, and call 999. Lithium fires escalate in seconds and produce toxic gas, and London Fire Brigade attended record numbers of e-bike and e-scooter battery fires in 2025, many starting indoors on charge.
If the pack is swollen but cool, calm and quiet, you have time to do this properly. Here is how.
What to Do With a Swollen E-Bike Battery
- Stop using it, and never charge it again. Charging a damaged pack is the most common trigger for a fire. Unplug the charger at the wall before touching anything.
- Handle it gently and as little as possible. Do not press the swelling, do not puncture it, do not drop it, and do not try to force it out of a tight frame mount. If it is stuck, leave it in place and get help.
- Move it somewhere safer, if it is safe to move. Outside is best: on concrete or paving, away from the house, cars, fences and anything that burns, sheltered from rain. Indoors, choose a spot away from exits and escape routes, off carpet, on a non-combustible surface.
- Isolate it from other batteries and metal. Keep it clear of the spare pack, the toolbox and anything conductive. A metal container with a loose lid, a ceramic pot or a paving slab underneath all beat a shelf full of stock.
- Watch it and arrange collection promptly. Check it periodically for heat or smell. A swollen pack is not a keep-it-in-the-shed-for-a-year item: arrange the specialist route now, while it is calm.
What Never to Do
- Never bin it. Not general waste, not recycling, not a skip. Crushed in a lorry or a sorting plant, a damaged pack ignites, and batteries in the waste stream already cause fires across the UK: our battery fire tracker logs them month by month.
- Never post or courier it. Damaged lithium batteries are barred from post and standard parcel networks.
- Never drop it at a shop battery tube or recycling point. Those containers are for sound portable batteries. A damaged pack in a mixed container puts the shop and the collection crew at risk.
- Never try home discharge tricks. Salt water buckets and DIY discharging are internet folklore that create gas, corrosion and a still-dangerous pack. Leave discharge to the treatment facility.
- Never keep charging “to see if it settles”. It will not settle. Swelling is permanent cell damage.
Why the Disposal Route Is Stricter for Swollen Packs
A swollen pack is not just hazardous waste, it is a damaged or defective lithium battery in transport terms, and ADR Class 9 rules apply stricter provisions to it: UN-approved packaging, suitable packing media, the damage declared to the carrier, and paperwork that says exactly what is moving. Each movement travels on a hazardous waste consignment note.
That is why the right route is a specialist collection, quoted per job before anything moves, rather than tipping it in with a routine load. Declaring the damage is not bureaucracy; it is what makes sure the pack is packaged so it cannot start a fire in the van.
If You Run a Bike Shop or Workshop
Customers will bring swollen packs to you, because they do not know who else takes them. Two things keep that moment safe:
- An escalation step in your process. Damaged packs never go in the standard takeback drum. They are isolated, terminal-protected and logged, and a specialist collection is arranged. Partner-delivered battery safety training gives staff the awareness to spot and handle the risky ones.
- A standing route out. Cell Comply sets e-bike businesses up with a UN-approved drum with a fire-suppressant vermiculite layer for sound packs, flat-price collections when it fills, and per-job quotes for damaged packs. The full setup is on the e-bike and e-scooter page.
Frequently Asked Questions
Is a swollen e-bike battery dangerous?
Yes. Swelling means failed chemistry and trapped gas. The pack can vent or ignite, especially if charged, pressed or punctured. Treat it as a live fire risk until it is collected.
Can I fix a swollen e-bike battery?
No. Swelling is permanent damage. Repair attempts, opening the casing or replacing individual cells in a swollen pack are how workshop fires start. The pack needs a specialist disposal route, and the bike needs a new battery from the manufacturer or dealer.
Who collects damaged e-bike batteries in the UK?
Specialist hazardous waste routes with ADR-capable carriers. Start with the retailer or brand if the pack is under warranty. Otherwise, Cell Comply arranges damaged-pack collections, packaged and documented correctly, quoted per job before anything moves.
Got a Swollen Pack Sitting in the Corner?
Tell us what it is and where it is, and we will quote a compliant damaged-battery collection: UN-approved packaging, ADR-capable carrier and the consignment note handled.