TRAINING BULLETIN 99

Electric Vehicles Operations
TRAINING BULLETIN 99-05
Huntington Beach Fire Department
Applicable ( ü ) to the following personnel:
Fire Administration Fire Prevention Fire Captain Fire Paramedic
Chief Officer ü Fire Suppression Fire Engineer Firefighter

Electric Vehicles Operations/Considerations

INTENT

To provide a standard operating guideline for the following operation(s) in Huntington Beach and automatic/mutual aid regions. This bulletin shall comply with all safety practices and procedures according to department policy.

I Introduction:

The majority of rescue procedures used with electric vehicles are identical to those currently used in emergency situations involving gasoline-powered vehicles. However, noteworthy differences do exist. The remainder of this bulletin is devoted to analyzing and describing those features unique to electric vehicles. In addition, attention is given to unique factors which may affect how a rescue procedure is performed. General Motors supplied this information to assist Firefighters to perform safely! The GM EV1 will be identified throughout this bulletin. All electric Vehicles have similar precautions. Pre-planning your emergency is the best deterrent for a fatal mistake!

Vehicle design overview:

An electric vehicle will have the letters "EV1" or "electric" written on or badged on the vehicle. In a circumstance where vehicle badging is not readily distinguishable, if the vehicle underbody is visible (vehicle rollover), most electric vehicles can be distinguished from gasoline-powered vehicles by its fully enclosed, smooth underbody, i.e., there are no exhaust pipes or gas tank underneath the vehicle. "Belly pans" have closed off the vehicle’s underbody.

II. Battery modules:

Electric vehicles are powered by lead-acid battery technology, a chemistry that is prevalent in nearly all automotive applications today. Although the chemistry is not unique, the engineering of the electric vehicle batteries introduces several noteworthy features. The General Motors EV1, is powered by twenty six, 12-volt lead-acid battery modules connected in series, for a system total of 312 volts. The EV1 modules are gas-recombinant, valve-regulated, and have a higher specific energy (52 amp-hours) than standard batteries found in conventional vehicles. These battery modules are not "flooded" with electrolyte. Instead the electrolyte is trapped in an absorptive glass mat. Therefore, the amount of free electrolyte contained within the battery is actually very small. If a severe puncture was to occur the electrolyte leakage from the module is about 1 to 2 teaspoons.

Both the battery modules and the battery pack are vented to allow the removal of trace amounts of hydrogen and oxygen produced during charging or vehicle operation. Gaseous emissions have a limit of 25% of the lower flammability limit (LFL).

III. Propulsion:

The EV1 is propelled by an alternating current (AC) induction motor with integral gearing, and is capable of achieving 137 horsepower. The sealed drive unit (motor, gears and differential) contains about 56oz. Of oil which is there for the life of the vehicle. The battery direct current (DC) is converted to three-phase (AC) for the motor by insulated gate bi-polar transistors (IGBTs) in the power electronics bay (PEB).

The EV1 is charged using an off-board inductive charging system. The inductive charging system is actually a take-apart transformer with the off-board portion (the charger) acting as the primary, and the on-vehicle portion (the charge port) acting as the secondary, of the transformer. Primarily, the EV1 will be charged using a 6.6 kW charger which is hard-wired to a 220-volt/40-amp circuit.

IV. Braking and Steering:

The EV1 braking and steering systems are both unique in that they are electro-hydraulic systems. The front disk brakes are hydraulically actuated and powered by electrically driven pistons (12-volt power); the rear drums are electrically actuated (12-volt power). The brake components – including brake fluid – are the same as those typically used in other GM vehicles. An electric motor-driven pump rather than a belt-driven pump provide steering power-assist. The pump motor is a high-voltage (180 volts) component and should be approached with caution. The high-voltage carrying cables can be quickly identified by their orange color.

V. Passenger heating and cooling:

The EV1 uses a heat pump for passenger heating and cooling, rather than a conventional heating and air conditioning system. As a result, some special considerations must be given to these components. The compressor motor, located forward of the left front tire (driver’s side), operates at a higher voltage (180 volts) than other accessory systems. The high-voltage electrical wiring for the compressor is an orange cable. The refrigerant used for cooling is an industry-standard R-134a refrigerant.

When the heat pump is in heat mode or A/C (cool) mode, the heat exchanger is pressurized from 200-300 psi. The heat exchanger is located inside the passenger compartment, under the dash, just behind the radio module. Once the heat pump is turned off, the pressure bleed-down takes place within 1-2 seconds. However, to add a margin of safety, emergency personnel should wait approximately 10 seconds after turning power off to the heat pump before using any mechanical device in the area of this heat exchanger.

Vehicle body construction:

All EV1 body panels are molded from glass-reinforced plastic composites, similar to the plastic panels used on the Chevrolet Corvette. The door construction is SMC inner and outer panels using a mini-wedge door striker assembly. This design is similar to other GM vehicles; door strikers, locks, and handles are identical to existing designs. Therefore, door prying/cutting efforts, as well as procedures for defeating the locking mechanisms, will be identical to those used on other GM vehicles of that design.

The body structure of the EV1 is structurally "glued" together, this may impact the way firefighters pry through the structure during rescue procedures. Body flanges may not separate the same way welded-steel structures do.

The EV1 utilizes a magnesium alloy construction of many interior parts. The magnesium alloy is benign below 1060°F. Above this temperature, the material will burn, but it is not combustible or explosive.

The remainder of this bulletin is devoted to a more comprehensive discussion of EV1 vehicle features and the implications for emergency response personnel and procedures.

Electrical Hazards

High voltage in motor compartment (underhood)

There are several high-voltage components in the motor compartment of which firefighters need to be aware.

Power steering motor

Located in the lower right corner of the motor compartment (passenger side)
High-voltage cables are orange in color

Power electronics bay (PEB)

The power inverter/motor controller
Located underhood, in the center of the motor compartment

Heat pump compressor

Located forward of left front tire (driver’s side)
High-voltage cables are orange in color

Motor/gear assembly

Direct attachment to PEB; no high-voltage concerns

Vehicle Inlet (charge port)

Located in the "nose" of the vehicle in the front fascia
Hinged door at opening
High-voltage cables (only active during vehicle charging) located at the bottom of the charge port, near the front air inlet

The cables and connections for all of these components should NEVER be cut, punctured or handled, especially if abraded, exposed or damaged in any way.

These components are electrically isolated from the vehicle frame.

High-voltage in vehicle "tunnel"

Lead-acid battery pack

Located down center tunnel of vehicle (between driver’s and passenger’s seats) in T-shaped compartment
Length of pack extends from front-of-dash to forward trunk wall
Twenty-six, 12-volt modules are connected in series for 312 volts, total
Battery modules, cables and connections are securely attached to the battery tray, which is bolted into the vehicle’s aluminum structure.

Never cut into the battery tunnel or penetrate the battery pack compartment, in any way, even after disabling the battery service disconnect. The battery pack and all of its connections (except the services disconnect) are not accessible from any location on the vehicle, without the use of special service tools and equipment. The battery compartment is fully enclosed by underbody "belly pans".

Note: Mechanical or hydraulic extraction tools MAY be used to enter the passenger compartment of this vehicle through the door, door frame, front windshield, rear window, or roof. Extraction procedures may include:

Cutting through the roof "pillars" in the areas of the windshields and door frame. However, care must be taken not to cut into the side of the vehicle just forward of each rear wheel-well, since the battery pack runs cross-car at that location.

Cutting through the floor may be accomplished by using caution not to cut through the battery pack. Cut the floor panels directly under and forward of the driver and passenger seats.

Do NOT cut the hard plastic "T" shaped battery support tray.

The battery modules, cables and connections are electrically isolated from the vehicle frame.

Disconnecting the high-voltage system

Automatic disconnect

The vehicle has a high voltage interlock loop which passes through all high voltage components: the battery pack, power electronics bay/propulsion motor, power steering pump motor, heat pump compressor, and charge port. This interlock loop is designed to "open" in the event of a vehicle collision which has caused damage to underhood components. If the interlock loop is broken, or opened in any way, high-voltage is immediately removed from the high-voltage bus and is discharged. All of these components are disabled within a fraction of a second that the loop is broken and voltage is removed from the connectors and cables along this loop.

Even though the automatic disconnect has been tripped, this does not remove the energy stored in the battery pack. High-voltage still exists inside the battery compartment.

Firefighters can identify that the automatic disconnect has been tripped if the "WAIT" light is illuminated on the instrument panel. This can only be done if the 12-volt power has not been disabled.

Accessory power to all 12-volt systems is not disconnected by this feature.

Service disconnect

The battery pack may be disconnected manually from all high-voltage components by removing the service disconnect.

The service disconnect is located behind the driver’s seat underneath a panel of carpeting. To isolate battery voltage:

Lift the small carpet panel
Rotate the service disconnect handle and remove the pin

Power to all high-voltage components will be contained within a fraction of a second.

Firefighters should wait 10 seconds before applying force to the vehicle

The high-voltage components, including the power electronics bay, do not have any significant "capacitance," i.e., the ability to store an electric charge.

Because of the high-voltage interlock loop, it is not necessary to pull the disconnect in the event of a vehicle collision.

The service disconnect does not disable the 12-volt power system.

Even though the service disconnect is pulled, the energy contained within the battery pack is still present.

Disabling the 12-volt system

The 12-volt power system may be disconnected by removing the "maxi-fuses" located under the front of the dash at the passenger’s side of the vehicle.

Handling battery electrolyte

The electrolyte is typical in chemical composition (43% concentration, by weight) to that commonly used in lead-acid automotive batteries and should be handled using the same hazourdous material procedures.

Follow established protective clothing guidelines and procedures; full P.P.E. and self contained breathing apparatus (SCBA) when handling battery electrolyte seepage.

Securing the EV1

If the EV1 is powered-up and running, the instrument cluster will be lit and the "RUN" light (located on the lower left-hand side of the center console) will be illuminated. When the vehicle is off, the instrument cluster will be totally dark.

NEVER ASSUME THE ELECTRIC VEHICLE IS "OFF" SIMPLY BECAUSE IT IS QUIET!

Vehicle noise is virtually undetectable while the vehicle is on. Therefore, care should be taken to ensure that system power is removed through the securing procedure before vehicle handling takes place.

The procedure for securing the EV1 is:

Place the vehicle in park by moving the shift lever to the "PARK" position.

The parking brake will actuate (set) automatically.

Shut off the vehicle power by depressing the "LOCK" button located on the center console; or by depressing the "OFF/ACC" switch for 2 seconds.
If the vehicle cannot be placed in park, shut off the vehicle power by depressing the "OFF/ACC" switch, and hold it for 2 seconds until the vehicle power is turned off.

Note: The park brake can be set manually by pressing the park switch located on the left side of the dash if the vehicle is not able to be placed into park using the shifter (assuming 12-volt power is available).

Securing the electric vehicle ensures that it will not operate inadvertently.

Supplemental inflatable restraints (SIRs)

Even though handling vehicles equipped with supplemental inflatable restraints (airbags) in any emergency rescue situation should not be taken lightly, it is worth noting that the EV1 is equipped with both driver and passenger air bags.

Generally, in the event that the air bags deployed, there may be some residual smoke, which does not present any personnel risk. There may also be some residual powder residue present. Protective gloves and eye wear should be used in these rescue circumstances.

If the airbags have not deployed, battery power to the airbags should be disconnected if possible. The airbags can be disabled by cutting the "YELLOW" 12-volt cable (all airbag harnesses are distinguished by their yellow color).

Capacitors in the airbag actuators may keep the airbags energized for up to 10 minutes after disconnection. Also, static electricity can deploy the airbags. Therefore, it is advised that firefighters carry out extrication procedures, but do not place their body or any objects against or in close proximity to either airbag location. The extrication procedure should take place with care not to get in close proximity to the airbag modules.

Vehicle fires

While charging

In the event that there is a vehicle fire while charging, the following procedures should be taken:

Turn off the charge power, at its source:

With the convenience charger, pull the plug out of the wall
With the standard 6.6 kW charger, turn off the power switch on the equipment

Disconnect the main power source for the circuit

While parked and NOT charging

Treat the fire as any other vehicle fire, using extinguishing materials and procedures commonly used to fight vehicle fires.

XIII. Immersions

If the EV1 is immersed in water, either partially or completely, there will be NO electrical hazard to either vehicle occupant(s) or firefighters. When water enters the battery pack compartment the system quickly "shorts-out;" battery pack voltage is consumed in a rapid discharge process that is contained within the battery pack compartment. Because the battery pack is fully isolated from earth ground, this discharge process takes place without risk to either vehicle occupants or firefighters who may be required to enter the water for an extrication operation. Firefighters should be aware that during this rapid discharge process, the water in the battery compartment undergoes an electrolytic process, producing small amounts of hydrogen and oxygen gasses. There could be some minor popping in the battery compartment as these gas "pockets" come into contact with the dissipating battery voltage.

Note: Firefighters should not attempt to pull the service disconnect in these circumstances.

Towing the vehicle

The EV1 should be towed using a flat-bed or tilt-bed vehicle carrier.

For More Electric Vehicle Info:
General Motors
Honda
Toyota