A report from Land Transport Accident Investigation Bureau (BEA-TT) reveals that a manufacturing defect in the batteries caused the fires of two electric buses in April 2022 in Paris. The buses, manufactured by the Bolloré group and operated by RATP, had caught fire in the 5th and 13th arrondissements of the capital, without causing any injuries. After the second incident, the RATP decided to withdraw from circulation, as a precaution, the 149 vehicles in this series.
The survey highlights a “delay in defining technical regulations” for new technologies such as LMP batteries. “It appears necessary to adapt the regulations”recommends it BEA-TThighlighting in particular the absence of a warning device for the driver in the event of a thermal failure. In addition, the approval tests on fire resistance, obligatory for batteries lithium-iondo not apply to LMP batteries.
A short circuit at the origin of the disasters
The BEA-TT identifies a short circuit in the battery cells as the direct cause of the fires. “The investigations carried out showed that this cause lay in the battery manufacturing process,” the report states. The fault lies at the factory, where poorly positioned insulation sheets failed to ensure sufficient insulation between battery cells, an error that went unnoticed during quality checks.
In order to reinforce safety, the BEA-TT proposes to equip the roof of electric buses with a “thermal protection” to facilitate safe evacuation of passengers.
