Lithium-Ion Battery Safety

Why lithium-ion gets its own section#

While the robot runs on SLA, your team is surrounded by lithium-ion cells — laptops, cordless drills, camera batteries, and phone power banks. The Safety Manual warns that misuse, physical abuse, or improper handling can force lithium-ion cells into thermal runaway, a failure mode that can cause fires or explosions. Thermal runaway is self-sustaining: once a cell overheats, it heats neighboring cells, and the reaction accelerates.

The manual's rules to prevent thermal runaway#

• Use UL Solutions–certified batteries or battery packs.
• Buy from the original equipment manufacturer or a reputable source. Suspiciously cheap internet batteries with minimal packaging, no branding, or no documentation may be counterfeit — avoid them.
• Avoid crushing, bending, or severe impact to cells, packs, and battery-operated devices, and avoid excessive vibration — a real concern on a robot.
• Do not expose lithium-ion batteries to high temperatures (don't leave them in a hot car or near heat sources).
• Always use the correct, compatible charger for the battery.
• Avoid excessive or prolonged charging. Overcharging causes irreversible changes that reduce life or lead to failure; it's best to recharge only when the charge is low and then bring it to 100%.
• Do not use or charge devices surrounded by materials that block normal airflow — cells need to shed heat.
• During storage and transport, keep spare batteries from shorting: loose batteries or pack terminals can contact metal items (like a spiral notebook binding) and short. Tape terminals or use cases.
• Keep batteries away from small children — they are a choking hazard, and ingested button/coin cells cause serious internal chemical-burn injuries.

Fire response#

The manual specifies having a Class C fire extinguisher on hand for electrical/lithium fires (an ABC extinguisher also covers Class C). But it adds a critical caution: lithium fires produce toxic smoke, and extinguishing should not be attempted unless the fire is very small and the person is trained in extinguisher use. If the fire is not small, or you are not trained, reach out to local emergency authorities — your safety comes before the equipment.

Putting it together#

For a beginner, the practical takeaways are: buy reputable, certified cells; charge with the right charger on a hard, non-flammable surface with airflow; never charge a swollen, dented, or damaged pack; store spares with terminals protected; and know where your Class C extinguisher is and when not to use it. A swollen or hot battery is an emergency — isolate it and ventilate the area.