Validating EV Battery Performance Remains Critical

Article By : George Leopold

EV manufacturers scramble to develop in-house test and design validation capabilities, including for testing batteries...

Tesla’s bid to control its entire electric vehicle design and production cycle with the introduction of a “tab-less” battery cell and other innovations also represents a scaling problem that will require stringent testing of the central power component of EV designs.

As the power source for all other EV components, validating battery performance remains critical as innovators like Tesla seek to ramp operations around new battery technologies that promise to increase range and power density. Test engineers also predict design and chemistry innovations like Tesla’s will have a ripple effect on battery management systems (BMS) and the subsystems they increasingly control.


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For example, they point to designs based on Volkswagen Group’s ID.3 battery. “Audi had a lot of issues with the ID.3 platform because they were introducing this new requirement on all the subsystems on the car to ask permission of the BMS,” said Jeffrey Phillips of National Instruments’ Transportation Business Unit.

That introduces another layer of design complexity during system integration and testing. Hence, vendors like National Instruments assert that Tesla’s battery innovation will increase the need for rigorous test and validation as EV architectures are centered on battery management.

Whether Tesla has confronted those design verification challenges is unknown. What the EV maker did reveal during its “Battery Day” in September was a novel tab-less battery design said to yield five times more storage capacity, a six-fold increase in power and a 16 percent increase in range. The company is promoting the battery prototype as a way of pricing EVs in the same range as gasoline-powered cars.

battery testing
Elon Musk unveils his “tab-less’ battery. (Source: Tesla)

The larger cells (46 by 80 millimeters) would also become the hub for future Tesla designs, managing power distribution to virtually all vehicle subsystems. That ambitious design approach presents new testing and design validation challenges, experts note.

Tesla said its battery design eliminates tabs that connect battery cells and allows them to discharge, thereby eliminating a weak point in current battery designs.  The larger, cylindrical cell design actually creates a shorter electrical path. Along with greater energy density, the tab-less batteries are forecast to halve manufacturing costs—if and when Tesla moves from prototype to full-scale production.

The trick will be validating the new battery design during testing as Tesla attempts to scale manufacturing, Phillips said. Battery testing alone can take months, he added.

“The concept of building and maintaining your own test system, designs and architecture so that you can make your changes is a concept that’s still fairly new to automotive,” said Phillips. Among the reasons is that auto makers have their own integrated supply chain and usually work with test providers who are focused on automotive applications.

“It’s been a fundamental shift for a lot of companies,” Phillips added in an interview.

Tesla’s approach could mean designing a new test system from scratch to account for I/O and other vehicles requirements, according to Phillips.

National instruments, its automotive test business thriving as EV makers struggle to validate designs, stresses modularity and flexibility in its automotive test regime. Its PXI test system encompasses a software stack incorporating programming languages like Python and C and another layer connecting systems with systems.

Those and other automotive test platforms must account for the growing complexity of EV designs that will incorporate 5G wireless for self-driving, data security and infotainment systems — upgrades increasingly controlled by the battery management system.

“There’s so much unknown” about how these subsystems will interact, Phillips said, and car manufacturers can count on increasing complexity as EV architectures are built around battery innovations.

The goal is “safe production of automotive components at scale,” Phillips stressed. That’s “the next inflection point for Tesla,” he adds, a safe and reliable design that is within Tesla’s reach if the car maker succeeds in harnessing its entire design and production workflow, beginning with the power supply.

Tesla founder Elon Musk “has rethought the whole integration chain,” Phillips said, taking a holistic approach that includes in-house production of long-range batteries, a move Phillips notes could also have wide-ranging consequences for power storage on an emerging smart grid.

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