Running on sunshine: Bridgestone outfits first commercially available solar car

NASHVILLE, Tenn.—The world's first commercially available solar-powered vehicle won't just run on sunlight. It'll run on Bridgestone's custom-engineered Turanza Eco tires, to be exact.

The tire maker established its exclusive partnership with Netherlands-based mobility innovator Lightyear to engineer tires specifically for its Lightyear One vehicle. That plan between Bridgestone and the makers of the world's first long-range solar electric vehicle is expected to result in the vehicle being commercially available in Europe later this year.

The Lightyear One is designed for sustainability, using a large solar roof to charge the battery. This, the auto maker said, minimizes carbon dioxide emissions and the charging needs of the user while maximizing efficiency.

The first Lightyear One model with Bridgestone tires will be produced in a limited volume, according to a company spokesperson. However, consumers can reserve one of these long-range solar electric vehicles now, with deliveries expected in summer 2022. Lightyear One's first exclusive model is expected to include just under 950 vehicles. Once mass market models are produced, they likely will come with a purchase price well below $58,000, starting in 2024.

Up to 100,000 vehicles are projected to be made by 2025.

According to company spokespersons from both Bridgestone and Lightyear, discussions for this partnership began as early as 2018 when the tire manufacturer's global CEO approached Lightyear. Bridgestone was the perfect partner, Lightyear said, not only because of the expertise it brought to the table, but also because it was willing to work on a project that offered a comparative lack of initial tire volume.

The foundation for the Lightyear-Bridgestone partnership was laid when professionals from the two companies worked together in the Bridgestone World Solar Challenge, a 1,900-mile race across the Australian Outback that pushes the limits of technological innovation and solar-powered mobility. Bridgestone has been collaborating with Lightyear and experts at research universities at this challenge for eight years. Solar Team Eindhoven, the predecessor of Lightyear, won the Bridgestone World Solar Challenge's Cruiser Cup four consecutive times, from 2013-19.

European market
Mobility is undergoing a rapid shift toward EVs, and electrification is accelerating on a global scale. Bridgestone's spokesperson indicated that it sees EVs as a huge opportunity to reduce carbon dioxide emissions and make mobility more environmentally sustainable, particularly with 20 percent of new car sales in Europe in 2025 expected to be EVs. Still, there are many barriers to overcome before a fully electric future can be realized.

Recent research from Bridgestone found that, despite 50 percent of European drivers considering purchasing a fully electric vehicle, 37 percent are still skeptical. Concerns include the high acquisition cost of EVs (57 percent), range anxiety (50 percent) and insufficient charging networks (50 percent). This latest challenge is being addressed by the EU "Fit for 55" package, which is requiring member states to expand charging capacity in line with the expected zero-emission car sales, and to install charging and fueling points at regular intervals on major highways.

Lightyear One addresses these concerns by offering a range of 450 miles, while being up to three times more energy-efficient versus alternative electric vehicles currently on the market. And Bridgestone said its tires can help with that, too.

The Turanza Eco is designed with very low rolling resistance, which helps to boost range when compared to alternative Bridgestone EV-specific tires. Further, Bridgestone said it improved the tire's silica dispersion through a new mixing technology, resulting in a 10 percent overall reduction in the tire's weight per vehicle without sacrificing wear or .

Overall, designing a tire for a solar-powered electric vehicle requires much of the same innovation built into traditional EV tires, Bridgestone said. For the Lightyear One project, Bridgestone focused on:

• Optimized contact pressure distribution for increased wet performance and traction;
• Optimized geometric tire shape to enhance footprint for high performance;
• Customized pattern design to ensure optimal wear performance;
• Usage of new 3D sipes technology to reduce rolling resistance—improving battery range—and extend tire life; and
• New generation tread compounds utilizing the latest mixing technology to obtain lower rolling resistance and better wear resistance.

What EVs demand
An electric vehicle's tire load is due to higher mass and torque levels that an EV requires, according to a Bridgestone spokesperson. Treadwear for EV tires is significantly impacted because the vehicles are relatively heavy but unable to accelerate quickly. Bridgestone's tire requirements take this weight and torque trade-off into account, then includes the added trade-off of "grip vs rolling resistance" to the mix, the spokesperson said.

In partnership with leading EV manufacturers, Bridgestone manufactures industry-leading sustainable tire technologies that meet the specific requirements of EVs, such as low rolling resistance, weight to maximize battery range, wear resistance, noise and more.That commitment is one the company is actively marketing. Its spokesperson said Bridgestone EMIA, the company's sustainable mobility and advanced solutions subsidiary, commits more than 30 percent of its tire development resources to the creation of OE fitments for EVs. These tires currently represent 11 percent of Bridgestone EMIA's total OE lineup for passenger cars—rising from just 4 percent in 2019. This figure is expected to eclipse 20 percent in 2024.

Bridgestone's spokesperson reiterated the company's commitment to shaping a sustainable and efficient future of mobility. As a result, its EMIA subsidiary has identified features that its tires must have:

• Low rolling resistance tires that save battery life and address range anxiety concerns. Over the past four years, the rolling resistance of Bridgestone EMIA's replacement tire portfolio for passenger cars has been reduced by an average of 15 percent.
• Excellent handling and control, short braking distances and exceptional grip in all weather conditions to address safety-related issues due to the increased weight and higher torque of EVs.
• Higher wear tolerance as tires are susceptible to irregular wear due to the increased vehicle weight and high torque of EVs. Over the past four years, the average wear mileage of Bridgestone's replacement tire portfolio for passenger cars has increased by 15 percent.
• Decreased noise for driver comfort, which is required due to EV engine noise being almost non-existent, and tire noise therefore being more apparent.