Process of Investigation

The key factors are listed below: .

  1. There is significant variation in layout and equipment used in hybrid design; owner’s manuals and service manuals should be consulted for information relevant to fluid and electrical systems for fire risk.

Manufacturers provide emergency response guides that have some information about hybrid and electric vehicle configurations. Some can be found at manufacturers' websites such as the following:

Ford

https://canada.fleet.ford.com/pdfs2006/EscapeHybridEmergencyResponse.pdf

 Honda (Select "Hybrid/Emergency Response")

https://techinfo.honda.com/rjanisis/logon.asp

Toyota and Lexus (Select "Emergency Response and Hybrid Information")

http://techinfo.lexus.com/

  1. Hybrids generally contain most traditional fluids and often have an additional cooling system for the inverter/converter. As in traditional vehicle fire investigation, each fluid system should be checked for involvement in fire.
  2. Hybrid electric motors operate at voltages well above traditional vehicles increasing the risk of fire due to electrical ignition. Higher voltages result in greater tendency for arcing, higher energy arcs when they occur, and the potential for arc tracking to create conductive pathways in polymers.

For more information about arc tracking, click here.

  1. Hybrid battery packs, with multiple batteries and high voltages, may overcharge individual batteries if the batteries within a pack are not uniformly balanced. Overcharging may overheat batteries or release hydrogen, either condition bringing risk of fire.
  2. As in electric vehicles, high-voltage wiring insulation may become compromised during collision or as a result of fire.
  3. Exhaust temps may be lower on hybrid vehicles (relative to traditional vehicles) for low speed operation during which the hybrid electric motor provides most of the drive energy.
  4. Hybrid manufacturers frequently develop documents for emergency response personnel that specify battery and high-voltage wiring placement. These documents, available through manufacturer websites or customer service, can be helpful during an investigation as well.