EV tire enhancements to help secure future

EV tire enhancements to help secure future

AKRON — Fast forward to the International Tire Exhibition & Conference in 2040, and it is predicted that the world will peak with near 100 million new vehicles sold — and more than half of those are predicted to be some type of electric vehicle.

As such, engineers, compounders and raw material providers need to address the changing technological landscape for EV tires today, and do so within a number of parameters, including rolling resistance, noise, weight, wear and grip.

"There is so much activity and development that has been going on for sometime now," said Christine Domer, general manager of Akron Laboratories and Tire Services for the Akron-based Smithers, a third party testing and consulting group. "If our projections are correct, this is an exciting time to be in tire development. I am excited on what's coming in the next 20 years."

Ms. Domer, who has 30 years experience in raw materials, compounding, reinforcement and processing in both the tire and non-tire markets, offered her predictions on the EV market, the drivers of this burgeoning automotive space and performance thresholds that will be required of tires in the future. She spoke at the virtual ITEC Sept. 16.

Ms. Domer noted that Smithers' EV market report was completed pre-COVID, and that there will be shifts and delays because of the pandemic. But those research and development delays are not expected to last for long as OEMs and aftermarket customers also have their eyes firmly locked on the EV horizon.

"There will be shifts in projections because of that, but we expect EVs to be at the forefront in the push for green technology, and carbon emission effects on the environment," she said.

And EV penetration is expected to happen rapidly over the next decade, with "really high growth," Ms. Domer said.

By segment, Ms. Domer said tire demand in the EV market — encompassing hybrids, plug-ins and fuel cell EVs — will be led by passenger cars and light goods vehicles, with a 36% continuous annual growth rate by 2028.

Broken down, Ms. Domer said 19.9 million tires in these segments were sold in 2018, compared to a predicted 422.4 million units being sold in 2028. Within the passenger car and light vehicle segment, that translates to $1.4 billion in sales in 2018, and a predicted $29.6 billion in sales in 2028.

Following this EV segment will be a 29% CAGR for EV truck tires and a 19% CAGR for EV bus tires by 2028, Ms. Domer said.

"We are looking at really high growth in all three segments," she said.

Full EVs are expected to dominate the vehicle sales market in the next decade, followed by hybrids and slightly softer growth for plug-in hybrids and fuel cell EVs.

Market drivers

The drivers of growth in the EV space are as varied as the geographies in which the tires will be sold, Ms. Domer said.

By 2030, Ms. Domer said more than 50% of the global population is predicted to be living in or around urban areas — in large cities, or just outside these epicenters.

Directly related to urbanization are the motivating factors of pollution and congestion; infrastructure development with the advent of charging stations; battery technology and range improvements; and aggressive regulatory requirements, more so in China than in any other region right now, Ms. Domer said.

She said that by 2040, China will be looking at 70% of its vehicles sold being EVs, while the U.S. is predicted to have a 60% customer base for EVs. India, with its dense populations and comparatively few environmental regulations, is expected to have a 30% market share in EVs.

In all three regions, Ms. Domer said, 2025 is where the curve starts to rise rapidly in the sale of EVs and hybrids.

And EV tire performance requirements also will be varied and challenging for tire designers and engineers, with an emphasis on fuel efficiency and rolling resistance (as compared to internal combustion engine tires).

"EV tires are not expected to be significantly different, but there will be a big emphasis on rolling resistance," Ms. Domer said, noting that the last big technological change in rolling resistance came with Michelin's patent on silica technology 27 years ago. "And this will come possibly at the expense of other design parameters."

Noise reduction also will have a much greater impact in the design of EV tires, as the cabins are quieter in EVs than in internal combustion engine vehicles. Other parameters that will see a greater emphasis in EV tire design include grip, load bearing, wear, torque (generated by the battery), air retention and extended mobility.

"This, again, is a really challenging time, but it is also a time for opportunity in the tire value chain," Ms. Domer said. "Noise is a big one where lots of technologies are being analyzed."

Ms. Domer cited Continental's work with its ContiSilent tire; Michelin's work with noise reduction technologies like foam inserts; and other tire makers' work with performance resins to treat grip and wet traction properties without sacrificing rolling resistance.

Tire makers also are analyzing inner liner technologies for durability and extended mobility (puncture resistance).

"They are looking at high tenacity with lower weights with EV development, and there is so much more to be had and discovered in the coming years," she said.

All in the design

When it comes to designing tires for the EV market, Ms. Domer cited Smithers' tire analysis report, published every month since the company's inception in 1925 for the U.S., Europe and emerging growth markets.

Tire design metrics analyzed between EV and non-EV tires include ISO rolling resistance (fuel efficiency), use of tread compounds, din abrasion, mold-related items, tread width, inner liner gauges, weight, belt widths and angles, and total center tread gauge.

"There is a lot to be mined when it comes to EV tire analysis today," Ms. Domer said, adding that EV tires often use the best technologies available.

And as OEMs make the switch to EV tire technologies, Ms. Domer said that means greater use of sub-treads, the need for lighter weights and lower rolling resistance, and the use of greener tread compounds.

One of the dominant trends is the use of silica compounded with SSBR. Silica silane has shown to have better rolling resistance and wet traction while showing about the same performance properties in abrasion resistance, versus standard carbon black compounded with SSBR in those same analytics, she said.

"There is a large challenge in performance requirements, since fuel efficiency and rolling resistance, along with noise, are much more important," Ms. Domer said. "We will continue to watch these things as we go along. This hopefully gives you a flavor of what we are seeing. There are a lot of challenges to overcome by 2040 if we are to be surpassing internal combustion engine tires, and there is a lot of development to be done to bring these technologies quickly to market.

"COVID may have slowed us down, but we don't expect it to slow us down for long."