Lasers are used in manufacturing and operating electric vehicles (EVs), including for cutting, marking, and welding components in the drivetrain and battery pack and in heads-up displays (HUDs) and LIDAR. This FAQ begins with a review of how lasers help to make EVs, looks at how they are used in HUDs, and closes with a brief review of the various LIDAR configurations that rely on lasers.
In high-tech manufacturing environments, like those used to make EVs, lasers are widely used for marking components for traceability and fast precision cutting to support high-quality assemblies. Laser welding combines the precision and low heat loading of the welding site.
Laser welding and surface treatments are used in various EV assembly operations and are especially useful for fabricating battery cells and packs. They produce smooth edges and surfaces that improve cell performance. Infrared (IR) and ultraviolet (UV) nanosecond pulsed lasers are used to cut and clean foils for the anode and cathode.
Lasers with a wavelength of about 1 nm are used for welding copper power connections. Metals like steel and aluminum (not copper) efficiently absorb that wavelength with little heat generation. Other laser technologies and wavelengths are used to weld dissimilar metals together.
Heads-up displays (HUD) and copy machines
A HUD can project information on a vehicle’s windshield directly in the driver’s line of sight, reducing the need for the driver to divert attention from the road ahead. By minimizing a driver’s eye movements, HUDs also mitigate driver fatigue, making for a safer driving environment.
In one case, a HUD was implemented using laser scanning technology developed for copy machines (Figure 1). The original copy machine technology has been refined and adapted for automotive HUDs by adding micro-lens technology and a two-axis MEMS mirror to reliably produce high-quality images. The resulting HUD images have bright colors that create high contrast with the background, making the information easy to view.
Figure 1. Projector module for laser scanning HUD. (Image: Ricoh)
In the future, it’s expected HUDs will overlay alerts and other information in real-time over the environment a driver is viewing through the windshield, creating an augmented reality (AR) experience and further enhancing the utility of the HUD. HUDs based on laser scanning technology produce higher contrast images with a broader range of colors. They’re perceived as brighter than thin film transistor (TFT) liquid crystal display (LCD) based HUDs.
LiDAR uses and types
LIDAR — Light Detection and Ranging — is another useful technology based on lasers. By using lasers with varying wavelengths and pulse widths from nanoseconds to several microseconds, LIDAR can be optimized for long-range, short-range, and nearby sensing (Figure 2):
- Long-range LIDAR has a range of 200 m and is used to detect objects in front of the vehicle. It detects pedestrians, emergency braking, and collision avoidance systems.
- Short-range LIDAR ranges from about 10 to 50 m and can scan the area around the vehicle to identify and differentiate between objects.
- In-cabin sensing can monitor driver attention and detect potential distracted or drowsy driving. It can also be used for gesture recognition for controlling systems like navigation or communications.
Figure 2. Different LIDAR designs are optimized for varying scanning distances. (Image: Lumentum)
LIDAR can be based on mechanical systems or solid-state designs. Mechanical systems require high-quality optics and a rotating assembly to produce a wide field of view. They tend to be bulky and more costly than solid-state LIDARs and are used in applications that benefit from a high signal-to-noise ratio. The most common solid-state LIDAR implementations are based on time-of-flight (TOF) measurements or Doppler technology. Common TOF LIDAR approaches include:
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- Flash LIDAR uses wide-area laser pulse illumination and an array of photodetectors to capture the image distance and the intensity of the reflected light as a single image.
- Microelectromechanical systems (MEMs) LIDAR uses MEMs mirrors that direct the LASER beams to scan the surroundings to build an image.
- Optical phase array LIDAR uses a series of laser beams staggered in time and steered in different directions to scan the surroundings and create an image.
Frequency-modulated continuous wave (FMCW) LIDAR is based on the Doppler effect instead of TOF and measures the change in the frequency of the returned laser beam to estimate the position and velocity of objects.
Summary
Lasers are used in EV production and operation. They make EV production more precise, efficient, and reliable, and HUDs and LIDAR make EV operation safer and more convenient.
References
- An Introduction to Automotive Lidar, Texas Instruments
- Automotive LiDAR and In-Cabin Sensing, Lumentum
- Laser technology for the EV industry, Chutian Laser
- Projection Unit for Laser scanning HUD, Ricoh
Images
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