August 9, 2021

The Hidden Cost of Rapid Electrification

As electric vehicles (EVs) and buses (BEBs) are rolled out at scale, critical safety concerns surrounding lithium-ion batteries are gaining urgency. Since 2010, at least 27 high-voltage battery fires have occurred globally in a fleet of over 250,000 BEBs. Notably, two fires involving Bluebus vehicles operated by RATP in France were traced to thermal runaway caused by a manufacturing defect .

Thermal runaway, often triggered by overcharging or internal faults, leads to rapid heat generation, fire, toxic gas release, and even explosion. A key study by Sturm et al. shows that the heat release rate (HRR) in BEBs with large battery packs (up to 80 kWh) can exceed that of internal combustion engine vehicles. This is largely due to the breakdown of the battery’s solid electrolyte interphase (SEI), exposing reactive materials and triggering an uncontrolled chain reaction.

Fire dynamics simulations confirm that poor ventilation, common in depots and public car parks, worsens fire propagation and hampers emergency response. Despite growing evidence, most infrastructures remain unadapted to lithium battery behaviour, lacking fire zoning, thermal isolation, and detection systems. Real-world facilities (incl. all types of ships, ports and terminals) are rarely equipped to contain such incidents.

The greatest risk is uncontrolled implementation

  • Training is lacking for depot staff, drivers, crew, terminal operators and first responders.
  • Awareness is low across operators and municipalities.
  • Testing and validation are insufficient, and
  • Root cause analysis after incidents is rarely standardised or shared.

This knowledge gap is dangerous. Without clear safety protocols, lithium fires can spread rapidly, re-ignite after apparent extinction, and expose people and infrastructure to severe harm. Meanwhile, pressure to electrify fleets continues to rise—often without matching safety investments.

Urgent actions are needed

  • Mandatory training and emergency protocols
  • Retrofitting of depots and parking areas
  • Large-scale testing to validate fire models
  • Standardised incident investigation and knowledge-sharing

The environmental promise of EVs and BEBs must not come at the expense of human safety. If safety measures do not keep pace with innovation, we risk trading one hazard for another—this time one we barely understand.

Further we see that the Lithium Battery industry is progressing and that older models are now being exported to new markets that are being prepared for electrification. Meaning that we move to an even much higher critical and dangerous market of used EVs and used BEBs.