Basics
What is thermal runaway?
Thermal runaway refers to an uncontrolled, self-reinforcing chain reaction within a lithium-ion cell. Triggers can include mechanical damage (drops, pressure, punctures), electrical faults (short circuits, overcharging, deep discharge), manufacturing defects, or intense external heat.
If the cell temperature rises above a critical point, internal materials decompose exothermically — generating more heat than can be dissipated. The result is gas formation, pressure build-up, the release of flammable and sometimes toxic vapours, and eventually open flames. Neighbouring cells can also be triggered by the heat, allowing the process to spread across an entire battery pack.
Particularly insidious: thermal runaway doesn't always give sufficient warning and can occur hours or even days after seemingly minor damage — for example after a device or vehicle is dropped.
Extinguishing technology
Why conventional extinguishing agents reach their limits with battery fires
Lithium-ion cells supply their own oxygen for the chemical reaction and therefore don't need atmospheric oxygen to keep burning. Conventionally smothering the flame — with a blanket or CO2, for example — often doesn't permanently stop the reaction.
Strong, sustained cooling of the cells below the critical temperature is generally more effective, combined with containing flames, heat radiation and fire gases from the surrounding area. This is exactly where active safety systems like the Li-Ion Safety Box M come in: they monitor the internal temperature, cut the power supply when anomalies occur, and automatically trigger an extinguishing medium in an event that cools the cells and contains the spread.
Operations & organisation
What businesses should pay attention to when handling lithium batteries
Many lithium-ion battery fires don't originate during actual use but during unattended charging — for example overnight in workshops, warehouses or hallways. A separate, clearly defined charging and storage location, kept away from flammable materials and escape routes, significantly reduces the risk.
Damaged, swollen or noticeably warm batteries should not be reused and should be stored separately from unremarkable batteries until they have been professionally inspected or disposed of.
Whether and which specific requirements apply (e.g. from building codes, workplace safety regulations, occupational safety rules or building insurance) depends on the industry, building and insurer. This page does not replace individual legal or insurance advice — we recommend clarifying specific requirements with the responsible occupational safety officer, fire safety officer or your insurer.
