At around 6 p.m., a pack of lithium batteries caught fire in an after-sales service building of a battery production plant. A flame reaching heights of 3 to 4 m was created for 10 seconds. A pack consists of modules of 12 to 48 cells, individually charged to 2.3 V. The 50 employees present were evacuated, and a 100-meter safety perimeter was established around the building. A team of first responders attempted to contain the fire with fire extinguishers and a hose reel. A large amount of smoke was visible. The firefighters analysed the toxicity of the smoke before intervening. The facility was ventilated based on the results, as it was not equipped with a smoke extraction hatch. The damaged battery pack and 7 others that could have been subjected to thermal radiation were immersed in a bucket of water. A firefighter and 9 employees affected by smoke inhalation were taken to hospital. The operator conducted dust measurements at the site to check that no toxicity was present. Following cleaning, production at the plant resumed after 4 days.

The faulty pack had been sent to the after-sales service department for an insulation fault. On account of a mix-up in the diagnosis with another pack sent in for repair (with a fuse fault), the recommended actions were not taken to deal with this insulation fault properly. Believing that the necessary repairs had been performed, the pack was placed under charge and earmarked for return upon completion. At 4 p.m., with the pack having been charged to 80 V, no overheating was observed. At approximately 6 p.m., a runaway reaction ejected the pack’s blow-off valve, and a fire started.

The operator planned to implement the following actions after the accident:

• conduct systematic checks on the condition of the modules/packs when the After-Sales Service Department receives them;
• create a “secondary intervention” team to deal with emergencies pending the arrival of the fire brigade and to equip them with the appropriate personal protective equipment;
• install water tanks near the production and repair areas;
• equip the After-Sales Service building with smoke extraction hatches and sprinkler systems.