BY DAVE DALRYMPLE
Hybrids. That word can provoke an electrifying discussion among emergency responders. “Did you hear about this? Read about that? Well, if it’s this car, we need to do this to make the vehicle safe, but if it’s this other vehicle make, then we need to turn this, twist that, and then it will be safe to work around.” Couple this confusion with misinformation and it’s a mess-similar to the hype when frontal airbags were introduced in the late 1980s and early 1990s.
Hybrid vehicles have been available here in North America since late 1999 and in Japan since 1997. Hybrids are currently powered by a drivetrain combining an electric motor with a gasoline engine, though that will change in the near future with the use of alternative fuels. The electric drivetrain is direct-current (DC) power; however, all the current SUV and pickup truck hybrids also generate 110-volt alternating current (AC) power. The high-voltage (HV) drivetrain power can vary from 144 to 675 volts at this time and run up to 125 amps as well. The HV battery pack is not plugged in to external power to charge; it is charged through normal drivetrain operation.
The cable that runs power from the HV battery pack to the HV motor in the drivetrain is bright orange, though that, too, will change a bit in the near future. The cable is visible wherever it runs, including under the vehicle (photo 1).
 Photo 1 |
The drivetrain is heavily managed if not completely controlled by a computer. Each hybrid model has a specific emergency response guide that tells emergency responders how to manage the vehicle if it’s involved in a collision, catches fire, or needs to be towed. Except for the drivetrain, these vehicles are otherwise no different to manage at the emergency scene than their conventionally powered kin. Electric power in the drivetrain is easily managed if we just observe a few simple concepts.
However, all the “normal” concerns we have with today’s vehicles still apply-supplemental restraint systems (SRS), construction concerns, and material/component issues (photo 2). However, depending on the emergency, those material/component factors may be more of a problem with a hybrid vehicle.
 Photo 2 |
VEHICLE IDENTIFICATION
Early hybrids were visually unique, but today hybrids may simply just have a different drivetrain and look no different from the outside than their nonhybrid counterparts. Depending on crash damage, they may be difficult to identify visually at the scene. Space limits a detailed description of all models and features, so I will focus on what we as responders will likely observe in the field. Many hybrid vehicles will display a label on various high-voltage components (photo 3).
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Honda Insight, Civic, and Accord hybrids. Honda hybrids display a “Hybrid” badge on the right rear of the vehicle (photo 4). Although the Insight is visually distinct (photo 5), the Civic first and second generation (photos 6, 7) and Accord hybrids (photo 8) are similar in appearance to their conventional counterparts. Note the orange cable in the Accord engine compartment.
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Toyota Highlander SUV, Camry, and Prius hybrids. The Highlander hybrid has a chrome grille, whereas the conventional model has vehicle color grille (photo 9, left). The Camry hybrid appears similar to the nonhybrid model (photo 9, center) but is distinguished by the hybrid badging. The Prius second generation is visually unique (photo 9, right); the first generation is more conventional in appearance (photo 10). All of the Toyota hybrid models have hybrid badging on the rear; the 2006 models of each of the above vehicles also have badges on the fenders (photos 11, 12).
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Lexus Rx400h SUV, GS450h, and LS600h. Lexus hybrids have simple badging on the rear of the vehicle (the letter “h” added to the vehicle model logo) (photo 13) and on the side rub rail molding (photo 14).
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Ford Escape SUV and Mercury Mariner SUV hybrids. The Escape Hybrid has a badge on the rear of the vehicle as well as on each front door (photo 15).
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General Motors: Chevy/GMC pickup truck hybrid. The GM pickup truck has a badge on the tailgate and on each front door (photo 16). This vehicle also has standard 110-volt plugs, much like a power strip on the passenger side of the pickup bed (photo 17).
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GM Saturn VUE Green Line hybrid. The VUE Green Line has this badge on each front door and rear lift gate (photo 18).
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HV battery air assist. In addition to hybrid badging, these vehicles also need air to assist in cooling the HV battery pack and aid its operation when cold. Some of the vehicles have visible external air intakes in the vehicle body (e.g., Ford Escape and Toyota Prius first generation). Some have these air intakes in the passenger compartment (e.g., Honda Civic and Accord and Toyota Prius second generation).
OPERATION
Primary securing of the vehicle. As with every other vehicle we encounter today, we need to secure the vehicle’s power and power it down, which factors into our providing a safe working environment at the incident, whether it’s a motor vehicle accident, vehicle fire, or even a sick vehicle occupant. Powering down the vehicle discharges the energy storage capacitors in the SRS system in all vehicles and shuts the HV system down at the HV battery pack in a hybrid vehicle.
First, switch the ignition to OFF and remove the key and secure it in your fire apparatus (photo 19). Why? With the advent of proximity card/keyless ignition switches, this “wireless” key does not need to be inserted into the ignition switch to start the vehicle- it may be on the person; in a purse, briefcase, or backpack; or somewhere in the vehicle. The ignition switch is very similar to the ones in our fire apparatus, a push button. These “wireless” keys must be kept a distance from the vehicle to ensure the vehicle is not able to “power up” and facilitate the ability to start if the ignition switch is pressed.
 Photo 19 |
After securing the vehicle key, we need to locate the 12-volt battery and remove the positive and negative cables, either by disconnecting or cutting (photo 20). However, this is sometimes easier said than done. In approximately 40 percent of today’s vehicles, the primary 12-volt battery is located outside of the engine compartment. Consider that alone, apart from how the vehicle is damaged and how to access it.
 Photo 20 |
Stay away from the bright orange cable (photo 21)! Bright orange cable is the industry standard for HV power in a motor vehicle, which runs from the HV battery pack to the electric motor in the hybrid drivetrain. Keep in mind that as technology has progressed, not all hybrid vehicles use high-voltage power. The newest GM hybrids, such as the Chevy Tahoe and Saturn Green Line VUE hybrids, use what GM calls “intermediate voltage”; their hybrid drivetrain power uses bright blue cable.
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Secondary securing. Although removing the ignition key and disconnecting the 12-volt battery from the system to disarm the HV circuit and SRS systems should be your primary way of securing a vehicle, there are secondary ways to secure the HV power in a hybrid vehicle. Unfortunately for first responders, the secondary ways vary from vehicle to vehicle and even model year; the best way to utilize this methodology is to use the vehicle’s emergency response guide (ERG) (photo 22). Knowing the secondary method used to disarm the HV circuit can be important, depending on the crash, subsequent damage to the vehicle, and access to the 12-volt battery. These options include removing fuses and relays and something as simple as turning a rotary switch to shut off HV power.
 Photo 22 |
HV battery pack. The HV battery pack in these vehicles is comprised of individual nickel metal hydride (NiMH) battery cells arranged into groups. Depending on the vehicle, voltage is directly related to the number of cells and groups in the battery pack. The electrolyte in an HV battery is not like that of a conventional 12-volt battery; it is a solid material or heavy gel. The chance of a leak of this fluid from a damaged battery is highly unlikely and would be minimal at the worst. Also remember that even when we properly shut down and secure the vehicle’s power, there will always be power in the HV battery pack (photo 23).
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Safety systems. Hybrids can have all the safety systems on the market today with the exception of rollover protective structures (ROPS), so the issues relating to SRS (frontal, side, side curtain, and knee air bags) and seat belt pretensioners all are present. Use the same methodology/procedures you employ to manage these issues. Best practices include power shutdown; stripping interior trim prior to vehicle structural cutting/displacement; and observing the space between you, victims, and SRS components (photo 24).
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STABILIZATION
Now that we have the vehicle powered down, we can proceed just as in a “normal” motor vehicle accident (what’s normal today?). Make victim contact, and begin stabilizing the vehicle. If the vehicle is upright and on its wheels, you can use the same procedure/methodology you use now. With a vehicle on its side or upside down, remember not to crush/pinch or damage the orange cable or its connectors where it runs underneath the vehicle, especially if you have to raise the vehicle with lifting bags or a jack.
Tool evolutions. The tool evolutions we have already learned to make a pathway so we can disentangle our patient generally work well with these vehicles. However, make a mental note for three vehicles: the Honda Civic and Accord Hybrids (first and second generation) HV battery pack is vertically mounted in the rear seatback, so a trunk-tunneling maneuver is not advised (photo 25). Also, the GM pickup truck hybrid has an HV cable running down the inside of the rocker panel from the HV battery pack to the step-up transformer (photo 26). Those are the vehicles with specific tool evolution concerns. Otherwise, extrication is straightforward as in any other vehicle, still keeping in mind the securing of the vehicle’s power and stabilization.
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Firefighting issues. Hybrid vehicles pose most of the same concerns as any of today’s vehicles. Safety systems are in various places in the vehicle, and their properties deploy at a certain temperature range. Various types of plastics throughout the vehicle, interior and exterior, add to the vehicle’s fire load. The variety of vehicle construction materials, such as alloys or composites, used in components or structural members are also present, as are gas struts that raise the hood or hatch, and fuels and fluids.
With hybrids, we also have a HV battery pack and an increased use of alloys such as mag-aluminum. All these concerns warrant a higher degree of caution when approaching a fire in a hybrid vehicle. For example, the ERG for most hybrids states that you may need copious amounts of water to effectively extinguish a fire in such a vehicle, especially one involving a HV battery pack. Again as in all vehicle emergencies today, strive to ensure securing the vehicle’s power systems.
In terms of hazards, hybrid vehicles are really no different from other modern vehicles. We can resolve many of our concerns using the same procedures and methodology used for conventional vehicles. Although there is a high-voltage power hazard present, the vehicle’s inherent and internal safety components greatly minimize the risk, and we can further enhance our safety by using simple commonsense safety procedures at the scene. We actually deal with a greater number of potential hazards overall with all vehicles today because of SRS systems, vehicle materials and construction, and our limited operational pathways.
Many of the methods we were taught to employ in a situation involving an entrapped victim or a vehicle on fire may no longer work well with today’s vehicles. They do not take into account some of the common current vehicle hazards. Think of the hazards in vehicles back in 1995, and compare them with the hazards in vehicles of 2006. Is it the same creature?
Author note: For more information on hybrids, visit the following Web sites:
- Toyota: www.techinfo.toyota.com/public/main/erg.
- Honda: www.serviceexpress.honda.com/rjansis/logon
- Ford: www.motorcraftservice.com/vdirs/retail/default
- GM pickup hybrid: www.gmstc.com/home.asp
- National Alternative Fuels Training Consortium: www.naftc.wvu.edu
DAVE DALRYMPLE is a career EMS provider for Robert Wood Johnson University Hospital/St. Peter’s University Hospital Emergency Services in New Brunswick, New Jersey. He is also a firefighter/EMT/rescue technician and former rescue services captain of the Clinton (NJ) Rescue Squad. Dalrymple is the education chair of the Transportation Emergency Rescue Committee-US and serves on the Expert Technical Advisory Board of the International Emergency Technical Rescue Institute as the road traffic accident advisor.
