Driveline Electrification Technologies

28 Jul 2020

Developing Testing for a Changing Industry

How will new powertrain electrification technologies perform as they age? What are the most cost-effective strategies for optimizing each system? And how can further improvements be made through integration of systems and more effective management of their interfaces? If the sale of electric vehicles is to accelerate to meet government and industry targets, these questions must be addressed quickly.

For electrified powertrains, much of the testing roadmap is new and there are many unanswered questions that require a fresh approach. For test engineers, more is required than new techniques: understanding of the design challenges, the component interactions and the subtly different drive cycles of these next generation vehicles is important. Test technologies must evolve at the same pace as new EV powertrain technologies, and they must be adaptable to unique, continuously developing requirements.

E-Machines

Like most engineering systems, e-machines can be optimized for cost or performance. Unlike mature technologies, the ability to achieve both together to meet the needs of volume markets is in its infancy. Test operations must be explored across all likely operating conditions, from extreme heat to extreme cold, dust, salt, vibration and driver abuse. E-machine technology can be facilitated by progress in testing techniques for the following:

• Very high-speed operation
• Very high wheel torque with aggressive transients
• Thermal management including hot spot mitigation
• Integrated cooling loops with different media
• Migration from three phase operation to six or nine phases
• New magnetic materials and their impact on efficiency and durability
• New e-machine architectures

Power Electronics

It is likely that this technology will become more common thanks to its ability to enable more efficient motors and to reduce the packaging and cooling requirement of the power electronics. To enable progress in power electronics, developing these test techniques will be key:

• Flexibility to address voltages from 48 V to beyond 1,000 V
• Scalability to address future power increases
• Thermal management using a choice of media
• Migration from three phase operation to six or nine phases
• Fast integration of prototype control software
• Very high-speed data collection
• Comprehensive understanding of EMC issues

Whole Vehicles, Transmissions, and Drivelines

Transmissions and drivelines are another area where there is growing diversity of technical solutions. Transmissions may be standalone or integrated with the e-machine, which may be standalone or integrated with the inverter or axle. Multispeed transmissions are already being introduced for high performance electric vehicles and will soon cascade into higher volume sectors and commercial vehicles. Testing for whole vehicles, transmissions and drivelines should include the following:

• Drive cycle analysis including torque pattern characterization
• Noise, vibration and harshness
• System and subsystem efficiency
• Lubrication and cooling system losses
• Fast integration of prototype control systems and software
• Very high-speed data collection
• Precise analysis of component performance
• Comprehensive understanding of EMC issues

Batteries

It is generally agreed that Li-ion batteries will dominate the current vehicle design cycle, as well as the next, partly because they are the most attractive energy storage technology, but also because they are also the most understood; a key factor in a market where the speed of new model introduction is critical. Li-ion batteries will require substantial improvements in charging rates and useable power density. Key to achieving this (in addition to improved cell chemistries) will be progress in control strategies, thermal management and cell diagnostics. As such, the following testing should be used:  

• Cell, module and pack level capability
• Cycle life analysis including the impact of thermal cycling regimes
• Hybrid pulse power characterization
• Thermal management using a choice of media
• Climatic conditioning and rapid temperature change
• Fast integration of prototype BMS and control software
• Physical robustness and safety
• Electrical abuse and safety
• Very high-speed data collection
• Comprehensive understanding of EMC issues

As electric vehicles continue to evolve, it is important that testing techniques also change and grow.  Learn more about each of these areas, their testing needs and our capabilities by downloading our white paper.