Lithium Battery Safety, Charging and Storage

This web copy is a reference version for members. The controlled copy is the signed document held by the team; in a conflict, the signed document governs. Reading it does not replace induction, training or per-activity clearance.

1 Scope and Applicability

This SOP applies to every lithium polymer (LiPo) and lithium-ion pack SFU Racerbot uses whenever they are inspected, charged, stored, transported or disposed of. All charging takes place in ASB 9819.

• Everyone completes the battery briefing during Stage 1 onboarding before entering the workspace.
• Only members the Tech Team Lead has cleared may start or attend a charge. An uncleared member may watch a cleared member charge, but may not start, adjust or attend a charge themselves.
• This SOP does not apply to sealed consumer devices — laptops, phones, cordless tool packs with integral protection circuitry — brought in for personal use.
• It does not apply to large-format packs, modules, EV batteries or systems above 60 V. Racerbot does not use these. Introducing one requires a new risk assessment and FAS review first.

Anyone present may stop battery work at any time if they believe it is unsafe. Work stays stopped until the Team Lead or Operations Coordinator has heard the person who called the stop and resolved the concern. Calling a stop in good faith never counts against anyone.

1.1 Purpose

This SOP defines how Racerbot members inspect, charge, store, transport and dispose of lithium battery packs. It ensures that Racerbot members use and maintain our LiPo batteries in a safe manner.

1.2 Keywords

LiPo; lithium polymer; lithium-ion; balance charge; parallel charging; storage voltage; cell drift; C rate; thermal runaway; venting; swelling; fireproof charging bag; isolation container; F1TENTH; RoboRacer; SOP-TECH-02; SOP-ADM-09.

1.3 Contact

Questions about this document or the equipment it covers go to the Tech Team Lead. Questions about the workspace go to the Operations Coordinator. Questions about safety go to the FAS Safety Officer. Contact details are available to members through the team’s internal channels.

2 Introduction

Racerbot builds and races 1/10-scale autonomous vehicles on the F1TENTH/RoboRacer platform. The vehicles run on high-discharge lithium polymer packs, typically 2S to 4S, which hold a large amount of energy in a soft-sided pouch with no mechanical protection and no way of arresting an internal short once it starts.

A lithium cell in thermal runaway supplies its own oxidiser. An extinguisher will not stop the reaction inside the cell; it only controls what the fire spreads to. The cell burns hot enough to ignite anything near it and vents smoke containing hydrogen fluoride and carbon monoxide. The correct response is distance, containment of the surroundings and evacuation.

Almost every documented LiPo fire traces back to a short list of causes: charging a physically damaged pack, charging unattended, charging at the wrong cell count or chemistry, parallel charging, or storing a pack at full charge. This SOP is built around removing those causes. Section 11 covers the response for when something goes wrong anyway.

3 Equipment and Apparatus

The following is kept at the charging station in ASB 9819. The Operations Coordinator checks the list at the start of each semester and after any incident.

4 Materials and Supplies

• Lithium polymer packs, 3S (11.1 V nominal), high-discharge hobby grade. Nominal 3.7 V per cell; maximum 4.2 V per cell; storage 3.8 V per cell; minimum safe resting 3.0 V per cell.
• Lithium-ion packs where used for transmitters or tools, handled to the same rules.
• No chemical reagents are consumed by this procedure.

Packs, chargers and protective components are bought from reputable manufacturers or authorised suppliers. Anything that plugs into a wall outlet carries a certification mark accepted in British Columbia.

5 Hazard Assessment

6 Hazard Control Measures

6.1 Mandatory engineering controls and PPE

Engineering controls

Fireproof LiPo bag for every charge; non-combustible charging surface; charging area clear of paper, cardboard, solvents and soft furnishings; ABC extinguisher within reach; closed non-combustible storage; separate isolation container for suspect packs; room ventilation.

Required PPE

Impact-rated safety glasses, worn during any intervention on a suspect pack; heat-resistant gloves for moving a hot pack; nitrile gloves and vented goggles for a leaking pack; closed-toe, closed-heel footwear at all times in the workspace.

PPE change-out

Nitrile gloves are single-use and are changed immediately on any contact with electrolyte, then disposed of with the contaminated material. Heat-resistant gloves showing charring, stiffening or a damaged liner are withdrawn and replaced.

6.2 GHS labels and safety data sheets

Assembled battery packs are articles and are not supplied with a GHS label. Where a manufacturer supplies a product safety data sheet or transport document for a pack in service, the Tech Team Lead files it in Appendix A against the pack identifier. No other GHS-labelled substance is used in this procedure.

6.3 Handling and storage

• Incompatibilities: do not store or charge packs next to flammable liquids, solvents, isopropyl alcohol, aerosols, paper or textiles, and do not store packs in the same container as loose metal tools or hardware.
• Service life: packs have no fixed expiry date. A pack is withdrawn from service on any of visible swelling or degradation (such as reduced capacity, cell drift, or rise in internal resistance).
• Storage conditions: 3.8 V per cell; cool, dry and out of direct sunlight; inside a fireproof bag inside closed non-combustible storage.

6.4 Waste disposal

• Lithium packs are only disposed of through specialized waste streams.
• End-of-life packs are cooled, stable and have their terminals taped before they leave the workspace. The Operations Coordinator sends them through the SFU Facilities Services battery-recycling route and records the disposal.
• For a leaking, severely damaged, fire-involved or otherwise unstable pack, contact FAS Safety for disposal instructions. Do not discharge it, and do not seal a hot or venting pack in a bag or closed container.
• Burnt residue, sand used to contain a fire and material contaminated by electrolyte are bagged, labelled and sent through the hazardous waste route, not the general bins.

7 Pre-Use Inspection Checklist

Complete before every charge. If any item fails, stop, isolate the pack under §8.5, and tell the Tech Team Lead before going any further. Place checklist in Lab.

• Charging area clear of paper, cardboard, solvents and soft furnishings Visual
• ABC extinguisher present, in date and unobstructed; exit route clear Visual
• Charger cord, leads and connectors undamaged; no exposed conductor Visual
• Pack free of swelling, dents, punctures, cuts and crushing Visual
• Pack wrapper, wiring, connectors and heat-shrink intact Visual
• No leaking, and no sweet or chemical smell Visual and smell
• Pack at room temperature, not warm from use Touch — cool to the hand
• Pack not involved in a drop, crash or deep discharge since its last inspection Pack record
• Every cell within 0.1 V of its neighbours Cell checker
• No cell below 3.0 V Cell checker
• Charger set to the correct chemistry, cell count and current Charger display
• Safety glasses and heat-resistant gloves at the station Visual

8 Procedure

8.1 Set up

1. Clear the charging area of anything that will burn.
2. Confirm the extinguisher is in place and your exit is clear.
3. Inspect the pack against Section 7 and check every cell voltage.
4. Place the pack inside a fireproof bag on the non-combustible surface.
5. Connect the balance lead, then the main lead.
6. Set the charger to the pack’s chemistry and cell count, and to 1C unless the Tech Team Lead has approved a different rate for that pack.

8.2 Charge — the five rules

These five are not subject to local variation, exception or hurry.

1. Fireproof containment. Charge only inside a fireproof bag or container on a non-combustible surface — concrete or metal. Never on wood, carpet, a bench mat or a chair.
2. Balance charge only. Every charge is a balance charge. Parallel charging is prohibited outright.
3. Never unattended. Someone stays with the pack for the whole charge, and a second person is present. When leaving, stop the charge.
4. Room temperature. Keep room temperature within the manufacturer’s range. Never charge a pack still warm from use, and never below freezing.
5. Correct settings. Confirm chemistry, cell count and current on the charger before you press start.

6. Disconnect the pack as soon as the charge completes. Do not leave a finished pack on the charger, and never leave a charge running overnight.

8.3 Store

• A pack that will not be used within 48 hours is brought to storage charge at 3.8 V per cell, before it is put away.
• Store in a fireproof bag inside the closed non-combustible storage, away from heat, sunlight, liquids and anything flammable, with terminals covered.
• Never store a pack fully charged, and never store one fully discharged.
• Never leave a pack in a vehicle, a backpack or a car overnight.
• The Tech Team Lead checks stored packs at least monthly for voltage drift and swelling, and before and after any extended pause including examination periods. Battery storage obligations do not pause during exams.

8.4 Identity, pairing and records

• Every pack carries a durable identifier. Cycle count, date of first use and any anomaly are tracked against that identifier by the Tech Team Lead.
• Where packs are dedicated to a vehicle, the pairing is recorded in that vehicle’s build record under SOP-TECH-02. Changing the pairing is a build change and is recorded there; it changes nothing in this SOP.
• A pack withdrawn from service is marked as withdrawn in the pack record and in the build record of any vehicle it was paired with, so nobody returns it to service without knowing its history.

8.5 Damaged, swollen or suspect packs

1. Do not charge it. Do not use it. Do not put it in a bag or container with good packs.
2. If the pack is stable, cool enough to approach and showing no smoke, hissing, venting or odour, move it by its body, never by the leads, wearing heat-resistant gloves and safety glasses, and use the long-handled tongs from the FAS response kit rather than your hands.
3. Place it in the FAS response kit pail on a shallow layer of dry sand, or in the isolation container, in a ventilated area away from anything flammable. Leave the lid off or resting loose. Never clamp, latch or seal the lid.
4. Label it with the date and what happened.
5. Monitor it from a safe distance. If it gets hotter or starts hissing, venting, smoking or smelling, stop handling it and go to Section 11.
6. Tell the Tech Team Lead and Operations Coordinator, notify the FAS Safety Officer, and file a report under SOP-ADM-09. The pack does not go back into service.

8.6 Transport

• Transport packs at storage voltage, in fireproof bags, inside a rigid container, with terminals insulated against short circuit.
• Never in a passenger footwell, and never in a closed car in the sun.
• Never move a hot, smoking, venting or failing pack through a corridor, an elevator or any occupied area. Evacuate and call for help instead.
• Off-campus transport and shipping must meet Transportation of Dangerous Goods requirements. Contact FAS Safety or EHS before transporting any damaged, defective, recalled or fire-involved pack off campus.
• Airline and carrier rules on lithium batteries are strict and vary. The travel lead checks them before any trip. Where carriage is not permitted, packs are sourced at the destination. Racerbot does not carry batteries in breach of a carrier’s rules.

8.7 Troubleshooting

9 Accidental Exposure and First Aid

A lithium pack is not a pourable liquid, so the realistic exposure is a punctured or venting pack releasing electrolyte or fumes.

Every exposure is reported the same day under SOP-ADM-09, however minor it looked at the time.

10 Decontamination and Housekeeping

• Do not start any clean-up after a vent, fire or leak until the pack is inert and cool and FAS Safety or EHS has confirmed the cleanup method, PPE and waste route.
• Wearing nitrile gloves and vented goggles, collect residue and contaminated absorbent into a sealed, labelled bag for hazardous waste disposal.
• Wipe affected surfaces with water and a mild detergent. Never use isopropyl alcohol or any solvent on residue from a thermal event.
• Inspect the bag, charging surface, sand and isolation container used in the event. Any bag that has contained a fire is destroyed and replaced, never reused. A used extinguisher is replaced and the FAS Safety Officer is notified. A used FAS response kit is restocked before it goes back into service.
• At the end of every session the charging station is left clear, packs are at storage voltage in their bags, and nothing is left connected to the charger.
• The charging station does not go back into service after an incident until the Operations Coordinator has confirmed the Section 3 equipment list is complete and serviceable.

11 Emergency Procedures

Match what you can see to one of the four cases below and do what that case says. If you are unsure which case you are in, treat it as the more serious one.

11.1 Hot or damaged pack: no smoke, flame, hissing or venting

1. Stop the charge. Disconnect the charger or power source only if it is safe and does not delay you leaving.
2. Move people and anything flammable away from the area.
3. If the pack is stable and can be moved safely a short distance, put on goggles, a face shield and heat-resistant gloves, and use the long-handled tongs.
4. Place it on a shallow layer of dry sand in the metal pail. Do not bury, puncture, crush or tightly cover it. Leave the lid off or loose. Never seal it.
5. Keep the pail on a non-combustible surface in a ventilated, controlled area and watch it continuously from a safe distance.
6. Tell the Team Lead and the FAS Safety Officer. The pack does not go back into service.

11.2 Hissing, popping, unusual odour, venting or smoke

1. Do not approach, touch, move or cover the pack.
2. Warn everyone, leave the room and close the door behind you if it is safe.
3. Pull the fire alarm, evacuate and call 911. Then call Campus Public Safety on 778-782-4500.
4. Do not re-enter, and do not rely on a dust mask or particulate respirator for protection — they do not stop battery gases.
5. Tell responders the pack type, size, quantity and location if you know them.

11.3 Flames

1. Pull the fire alarm, evacuate and call 911. Then call Campus Public Safety on 778-782-4500.
2. Do not pick up, move or cover a burning pack or device.
3. Only someone trained in extinguisher use may attempt a very small, early-stage fire with an ABC extinguisher, and only once the alarm is pulled, the exit is clear and there is no unsafe electrical condition. Never use a Class D extinguisher on a LiPo or Li-ion fire.
4. Even if the flames go out, evacuate and keep the area restricted. The pack can reignite.

11.4 Fire spreading, heavy smoke, multiple packs or an explosion

1. Do not attempt to control the fire.
2. Pull the alarm, evacuate by the nearest safe exit and close doors behind you if safe.
3. From a safe place, call 911 and Campus Public Safety on 778-782-4500.
4. Go to the assembly area and do not re-enter until the fire department or Campus Public Safety authorises it.

11.5 Afterwards

Do not return the room or the equipment to service until it has been assessed and cleared. Nobody is ever penalised for evacuating early or for calling emergency services.

• Injuries, fires, smoke, property damage, extinguisher use and near misses are reported the same day to the Team Lead and the Operations Coordinator, and to the FAS Safety Officer.
• An SFU incident report is filed for any injury, fire, exposure, property damage or significant near miss.
• The full process — what counts, who is told, how the review runs — is SOP-ADM-09, Incident Reporting and Post-Incident Review. Reporting in good faith is never penalised, including when the person reporting caused the problem.

Emergency contacts:

Assembly area for the Applied Sciences Building is the point shown on the evacuation map posted in ASB 9819. Do not re-enter the building until emergency or safety personnel authorise re-entry.

12 References

• SOP-004-FAS — Lithium-Ion and Lithium Polymer Battery Safety and Emergency Response, Faculty of Applied Sciences, Version 1.0, August 2026. This SOP is written to be consistent with it; where the two differ, the FAS document governs.
• SFU Racerbot POL-03 — Operations: Safety, Facilities and Property, §5.
• SOP-TECH-02 — Autonomous Vehicle Testing and Configuration Management.
• SOP-TECH-06 — Day-to-Day Lab Operations and Housekeeping.
• SOP-ADM-09 — Incident Reporting and Post-Incident Review.
• SFU Racerbot Student Team Risk Assessment, 2026-09-10.
• SFU Racerbot Student Team Lab Safety Plan, 2026-09-10.
• Health Canada — Battery Safety: Lithium-Ion Batteries.
• Transport Canada — Transporting Batteries.
• SFU Burnaby Campus Assembly Areas map, Safety & Risk Services.
• FAS-SOP-01 (LiPo Battery Handling) — withdrawn and superseded by this SOP.

Appendix A — Attachments

Attachments are listed in the order they are referenced and filed behind this page.