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Hybrids and Crashes

Are hybrids more dangerous in an accident than regular cars? While there have been some concerns about battery fires and exposure to high voltage systems, a lot of work goes into these vehicles to ensure they’re as safe as anything else on the road.

How Hybrids Work

A hybrid has a generator/drive motor. When braking, this unit is in generation mode which creates drag on the vehicle to slow it down, turning momentum into electricity. When you move from a stop or floor the gas pedal, the unit acts as a motor, propelling the vehicle using that captured energy. Plug-in hybrids like the Volt and Prius Prime also allow the battery to be charged through an electric outlet, increasing the amount of time the engine can be left off.

Audi introduced a new energy recovery system with the introduction of the 2016 SQ7: electric turbocharging. This crossover functions like a hybrid, but instead of sending power directly to the wheels, it powers an air pump that acts like an extra turbocharger, improving fuel economy while maintaining the driving feel of a traditional car. 

One Vehicle, Two Electrical Systems

Hybrids use two electrical systems: an electric drive system that runs on 48 volts and an accessory system that runs on 12 volts.

Why 48 volts? Increasing the voltage reduces the amps needed to power the electric motor, but high voltages pose an increased safety risk. Your skin acts like a resistor, preventing the flow of electricity through your body, but this resistance drops as the voltage increases. While there are a number of factors at play, anything in a direct current system like the ones used in hybrids is considered lethal at around 60 volts. A jolt from the 48-volt system can still be harmful, but it’s a lot less dangerous.

Why does the car still have a 12-volt system? There’s no advantage to using a higher voltage for accessories, and keeping the 12 volts standard makes the car compatible with existing accessories. This lets automakers use the same parts found in non-hybrids, reducing manufacturing costs. It also allows the designers to keep the drive system completely separate from the rest of the car so there’s no way for a short to let high voltage power to reach the cabin. Most hybrids even go so far as to equip the engine with an alternator or generator to provide power instead of tapping into the hybrid system. During an accident, the 48-volt system can shut off completely, while the 12-volt system operates safety systems including airbags and seatbelt pre-tensioners.

Keeping Everyone Safe

There are several ways automotive engineers ensure hybrids are as safe as possible for passengers as well as people working on the vehicle:

• 48-volt cables use a bright orange across makes and models to make them easy for first responders and auto technicians to identify them so contact can be avoided.
• The battery is placed in a remote location that is unlikely to be breached during a crash, typically under the cab, at the center of the chassis or directly behind the rear seats.
• The battery uses hundreds or thousands of small cells which are divided into segments surrounded by steel cases, so if one section fails, it can’t affect the rest of the pack.
• If a collision is detected, circuit breakers or fuses will cut the connection between the traction battery and the rest of the car. The connectors on the high voltage wiring are also designed to separate during impact.
• Companies release manuals and simplified diagrams that first responders can reference to quickly identify a hybrid and pull the main fuse, stopping any potential motor activation. Since battery removal is usually the first step when handling a wrecked car, this is just one more minor step needed when making a wrecked car safe. After that, a hybrid fire can be put out like any other vehicle fire.

Getting Your Hybrid Repaired

Merton Auto Body has helped customers with their cars for decades, and we back up that experience with continual improvement of our tools and training. We’re an I-CAR Gold Class shop and our technicians are ASE certified, so we’re able to provide collision repair with the latest technology, including hybrids.