What is an e-Axle?

An eAxle is a drive unit that integrates into an axle structure the main components necessary to propel a vehicle using an electric motor as the main power source, such as a battery electric vehicle (BEV). eAxle mainly consists of a gearbox, a motor and an inverter. eAxle’s gearing is designed to handle high motor torque and high amounts of brake regeneration, and can be adapted to fit various needs based on a vehicle’s application, duty cycle, and regional requirements and duty cycle

The integration of the key components in one structure makes the entire unit smaller and lighter, generating various benefits such as space saving, lower power consumption, and lower cost.¹

What powers an e-Axle?

eAxles take energy from battery-powered motors, which commonly use lithium-ion (Li-ion) batteries. Axles typically have one motor but, depending on how large the axle is, may have two to ensure they can deliver a sufficiently high level of energy. The latest generation of eAxles have components like the motor and transmission incorporated into one, which can weigh much less as a whole than the three separate parts.

Which motors do e-Axles use?

eAxles can be powered by a range of different motor types. Some options include:

• Permanent magnet synchronous motor – PMS motors are well suited to high-performance settings thanks to their high power density and efficiency.
• Induction motor – Even though they’re comparatively low cost, and considered to be a simple and durable option, induction motors have lower efficiency and power potential.
• Switched reluctance motor – Using reluctance torque, switched reluctance motors can offer high motor-drive efficiency in a simple, low-cost motor, though they have lower torque capacity.

Electric powertrains (ePowertrains) typically have one of three motor placements: placing the motor directly into the axle, using a centralized drive solution or opting for a centralized motor with a gearbox. Opting for an integrated eAxle can reduce drag, making a vehicle more streamlined and preventing excess energy consumption.²

Using fuel cells to power e-Axles

Like batteries, fuel cells are also a sustainable power source for zero-emissions vehicles. To explain the technology in the simplest terms, a fuel cell has two electrodes – a negative electrode (anode) and a positive electrode (cathode) – that sit on either side of an electrolyte. The anode is fed with an energy source, which in a hydrogen fuel cell is hydrogen, and a catalyst separates the molecules into protons and electrons. The result is electricity and harmless emissions in the form of water and heat.

A hydrogen-powered fuel cell produces low or no emissions (depending on the electricity source powering the electrolysis). Hydrogen is shaping up to be a sustainable alternative for the future; while the infrastructure isn’t quite there to make hydrogen-powered vehicles a viable option at present, the technology is rapidly advancing. It’s anticipated that hydrogen-powered vehicles could be on the roads and rails en masse by 2030.

The benefits OF AN e-Axle

eAxles could be vital in helping businesses transition from a fossil-fueled fleet to hybrid or fully electric vehicles. However, the benefits of installing an eAxle go far beyond its carbon reduction potential. These modern components come with lots of advantages, including:

• Better fleet serviceability as eAxles can be easier to integrate into a vehicle and reduce the number of separate parts.
• Potential for higher driveline efficiency with reduced gear losses.
• Increases lifespan and reduces maintenance of brakes through regenerative braking.
• Condense components usually spread throughout the entire chassis into a more compact axle.
• Frees up space to place batteries inside the frame rails in the chassis’ most protected spot. And, if more range is needed, additional batteries can be added outside the frame rails instead of conventional fuel tanks – further reducing the vehicle’s reliance on fuels.
• Reduces noise pollution because the vehicle is quieter when running.
• Facilitates an enjoyable driving experience with instant torque response.

Sources

¹The eAxle: a core component in electric vehicles

²Everything you need to know about eAxles