Baltimore County Fire Department

Hybrid Vehicles

Objectives

• To help responders identify Hybrid Vehicles currently on the market

• Introduction to special hazards associated with Hybrid Vehicles

• Provide safety information for fire and rescue situations

What is a “Hybrid Vehicle”?

• Combines a smaller internal combustion gasoline engine with an electric, battery powered motor

• Two types: Series Hybrid System Vehicle switches between gasoline and

electric power sources

Parallel Hybrid System Electric motor supplements gasoline motor

High-Voltage Battery Pack

• High-Voltage nickel-metal hydride(Ni-MH)• Comprised of individual battery cells that

contain potassium hydroxide (KOH)• KOH has a pH of 13.5, highly alkaline• KOH liquid is absorbed in each cell by a

thin membrane paper• This results in a gel, or a Dry Cell Battery

Toyota Prius

• Four door, five passenger sedan

• High voltage cable runs under body, within the frame to the engine compartment. Covered with BRIGHT ORANGE sheathing

Toyota Prius

• DC-DC Converter, Inverter, and transaxle (not visible) with electric motor in the engine compartment

Toyota Prius series hybrid system

• Gasoline engine will automatically stop and start as the vehicle is running

• Gasoline engine will stop when the vehicle comes to a stop, i.e. at a traffic light

• Pressing the accelerator pedal will restart the gasoline engine

• The gasoline engine may run to recharge the battery pack

Toyota Prius Battery Pack

• 38 individual battery modules

• 276.3 Volt output• weighs 110 lbs.• Located above the rear

axle

Honda Insight

• Two door, two passenger coupe

• First hybrid electric on U.S. market, more than 5,000 on the road today

• Like the Prius, high voltage components have Bright ORANGE sheathing

Honda Insight Battery pack

• 120 D-cell battery sized cells

• Weighs 48 lbs.• 144 Volt• Located in the rear of

vehicle near the rear axle, accessible through the floor covering

Honda Insight parallel hybrid system

• Electric motor runs in conjunction with the gasoline engine

• Vehicle does not operate on the electric motor alone

• Gasoline engine only shuts down when the vehicle is at a complete stop

Honda Civic

• Introduced with the 2003 model year

• Four door, five passenger sedan

• High voltage system, and battery pack the same as the Insight

Special considerations

• Primary concern is the High Voltage System. Remember: BRIGHT ORANGE

Do not touch bare cable that could be part of the high voltage system

If any of the hybrid vehicles are submerged in water, electrocution danger exists from the service plug and high voltage system components

Special considerations

• Both Honda and Toyota battery packs are well insulated and protected from impact damage during a collision due to their location above the rear axle

• potassium hydroxide (KOH), will react violently if it comes in contact with metals such as aluminum, zinc and tin.

• Hydrogen gas is the byproduct of KOH contact with aluminum

Special considerations

• When the gasoline engine shuts down, such as at a traffic light, there will be no noise from the engine compartment.

• This does not mean that the vehicle is turned off, simply depressing the accelerator may cause the gasoline engine to come to life.

• Chocking the wheels is important to avoid the possibility of the vehicle moving forward prior to shutting it down

Hybrid vehicle “on” indicators

• Toyota Prius console: Green LED “READY”

light means the vehicle can move under it’s own power

• Honda Insight has an illuminated green “AUTO STOP” that appears when the vehicle is still running

Emergency scene considerations

• Identification of a hybrid vehicle Name: Prius, Insight, and Civic Vent in the “C” post may be a clue, as this

is where the high voltage battery vent is located

On the Prius, a tag identifying it as a “Toyota Hybrid”, Honda has similar tags

Emergency scene considerations

• Vehicle stabilization Both the Prius and

Insight sit low to the ground, about 5 inch clearance

Consider having to use large stepchocks turned upside down as a wedge in extreme cases

Emergency scene considerations

• Hybrid vehicles have a 12volt battery system to operate accessories:

Prius- Located on the driver’s side in the trunk near the wheel well

Insight- Located under the hood like most vehicles

Emergency scene considerations

• Access to the passenger compartment* Look for visual clues of the vehicle

“sleeping” meaning the gasoline engine is in a shut-off mode. Green LED “READY” or green illuminated “AUTO STOP”

* Honda: place shift level into Neutral to avoid sudden forward movement

* Toyota: gear selector must be in Park (P)

Prius, release button for gear selector

• Manual release button can be pushed if gear selector cannot or will not move

• Remove plastic cover, push and hold red button, then move gear selector into (P) park

Emergency scene considerations

• Lock out tag out,

Remove keys from the ignition, ensure any green indicators go out, an added safety measure to ensure the vehicle is completely shut down

Prius, further safety shut off

• Should the ignition key not turn to the off position, it is possible to pull the high voltage relay.

• Under the hood, midway along the firewall, look for a plastic black box.

• This box contains four components, the driver’s side relay “IGCT” breaks the power circuit from the high voltage battery

Prius, further safety shut off, cont.

• IGCT relay

Safety shutoff Toyota and Honda

• In the event the listed procedures do not work for the Prius, and you cannot turn off the Insight or Civic ignition.

• Remove the 20Amp HV fuse located in the fuse panel

Prius fuse panel is under the hood driver’s side

Special considerations

• Prius has thicker insulation especially in the “C” post to help make the air conditioner more efficient.

• Usually styrofoam and foam rubber

Special considerations

• The exterior latch on the Insight’s hatchback does not mechanically control the hatch release.

• It activates a relay which operates the hatch release motor.

• Will need to be opened manually with the key if 12-Volt system disconnected (located in the right rear taillight assembly)

• Rapid extrication, if needed may be accomplished through the Insight’s rear hatchback

More considerations

• Frontal and rear impact collisions pose several problems.

May loose vehicle name plates as well as any hybrid vehicle markings making positive identification of a hybrid vehicle difficult

Possibility of damage to HV battery pack if impact in rear is significant

Inability to access under the hood for alternative shut-off methods should key not work

Safety Considerations

• Remember if vehicle is partially or more submerged do not touch any High Voltage components due to electrocution hazard

• Keep in mind that components of the High Voltage System have

BRIGHT ORANGE color or sheathing

Review

• Hybrid vehicles combine electric motor with gasoline for fuel efficiency and reduced emission gases

• Three models on the road in the U.S. now, Toyota Prius Honda Insight and Civic

• High Voltage battery system poses electrocution hazard

Review

• Vehicle will be silent when running on electric motor, which is usually at a stop.

• Look for indicators, green LED or illumination of “READY” or “AUTO STOP”

• Always remember BRIGHT ORANGE in conjunction with the High Voltage System

References

• Moore, Ronald (July, 2001) Firehouse.com University of Extrication Part 1, 2, 3 http://www.firehouse.com/extrication/archives/2001/july01.html

• Toyota Motor Corporation Prius Emergency Response Guide