Modern vehicles contain dozens of sensors that do everything from measuring temperature and speed to preventing collisions. Sensors make cars safer and more reliable, but they aren’t without energy costs.
In 2024, manufacturers are expected to produce around 11 billion automotive sensors; collectively, these sensors will use a lifetime total of between 780 and 1,150 petajoules of electricity. That’s the equivalent of 217 to 320 billion kilowatt hours, or enough to power 20 to 30 million American homes for one year.
Researchers at Dalian Maritime University in Dalian, China, have developed a new type of automotive safety sensor: a self-powered noncontact triboelectric nanogenerator (SNC-TENG), which they say is both energy-saving and better at detecting objects at longer ranges.
The researchers hope their technology will help make vehicles both safer and more energy efficient. Their paper was published in Advanced Functional Materials in September.
A self-powered sensor
Ying-Chih Lai, who co-authored the paper, said modern vehicles are typically equipped with cameras that help monitor their surroundings, but these cameras can be unreliable in low light, darkness, and poor weather conditions.
Alternatively, light detection and ranging systems (LiDAR) use lasers to help map the surroundings, but they’re also less reliable in poor weather. LiDAR systems are expensive, too, and not likely to see widespread use on typical vehicles.
The other problem with both of these safety strategies, said Lai, is that they need continuous power input. “The SNC-TENG, as a self-powered active sensor, does not require any power from the vehicle,” he said. “It can actively perceive the surrounding objects with no need of continuous electricity.”
Instead of drawing power from the car’s battery, the sensor is powered by electrostatic induction, which means it gets its electrical charge from the electrical fields of nearby objects. Nanosheets made from a titanium-based 2D material called MXene help increase the device’s charge-trapping capacity, while a conductive sponge increases the number of particles that can carry an electric charge.
This design not only powers the device, it also gives it the ability to detect objects at ultra-long distances of up to two meters. The nanogenerator can even detect very slight movement of around 1 mm.
The researchers tested their device on a real vehicle and found that it could provide accurate blind spot detection as well as parking lot monitoring and theft and vandalism protection.
For the latter, it “can detect the approaching persons via the electrostatic induction with no need for physical contact,” Lai said. “Then, the generated electrical signals can activate the onboard surveillance camera to monitor the surrounding circumstances.”
If the approaching person touches the sensor, Lai said, it will trigger an alarm. Ultimately, the researchers envision a system that will send an immediate warning to the owner’s mobile phone when the device senses a theft attempt.
Similarly, the researchers said their device can be used to monitor nearby cars while the vehicle is parked. When the sensor detects a vehicle that’s too close, it will trigger a surveillance recording so if there’s a parking lot collision, the offending driver can be held accountable.
In their paper, the researchers said their sensor is not only highly sensitive and energy-smart but also cheaper and easier to make than many conventional sensors. This is an important point since the energy requirements of traditional sensors contribute to increased vehicle manufacturing costs and environmental pollution.
Self-powered sensors, they said, could help offset both the financial and environmental costs of modern vehicles, making them more carbon-friendly. A less expensive, simpler sensor could also help “accelerate the development of smart and secure vehicles,” they wrote, and “promote advances in a wide range of noncontact sensing technologies.”