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The BYD Seal uses the company’s LFP battery cells and is built on the electric platform 3.0. (BYD)

WCX 2023: New Chinese EVs feature ASSB tech

Advanced semi-solid-state batteries are a leap toward fully solid-state cells, notes Autodatas analyst.

By the end of 2023 there will be 10 Chinese electric passenger vehicles using advanced semi-solid-state batteries (ASSB) — an industry-first application for EVs and a milestone for vehicle electrification, according to Paul Haelterman, North American VP at Autodatas, a vehicle benchmarking and research firm. It’s “a huge step for the industry’s production pursuit of all-solid-state batteries,” Haelterman told SAE Media ahead of his presentation on China’s EV market at SAE’s WCX 2023 in Detroit.

A semi-solid-state battery can be one in which one electrode does not contain a liquid electrolyte and the other electrode does. Or it can be a battery in which the mass or volume of the solid electrolyte in the monomer accounts for half of the total mass or volume of the electrolyte in the monomer. Some battery experts view semi-solid-state as a compromise technology, offering a faster route to scale but heavy and requiring more volume, according to experts.

The EV models coming in China will have an estimaged driving range of 1000 km (621 miles) and a battery recharge time of 10 minutes to achieve 80% state of charge, Haelterman said. “These EVs will also have 10x the cycle life of current lithium-ion batteries,” he added. More changes will materialize with all-solid-state batteries as ASSB utilize 25% of the total lithium used in current EV batteries use and do not contain cobalt, Haelterman noted.

China is the global EV battery technology leader right now, Haelterman asserted. The country’s battery industry Ied by Contemporary Amperex Technology Company (CATL), largest EV battery producer in the world. In 2022, CATL’s Yibin plant in China’s southwest Sichuan Province was certified as the world’s first zero carbon battery factory.

Passenger EV sales are on a major upswing in China, whose population exceeds 1.4 billion (and recently lost the most-populus-nation crown to India). In 2022, China’s EV market share tallied 31%, vastly more than the approximately 5.5% in the U.S. “More EVs were sold in China last year than the rest of the world combined,” Haelterman noted. The 6.8 million-plus EVs sold reflected an astonishing jump of 80% from 2021 to 2022.

“There’s a very strong collaborative relationship between universities, government, and the auto industry, which means there’s a lot of R&D work being done to further China’s overall macro-economy,” Haelterman explained. Six vehicle models from Chinese automaker BYD were among the top 10 best sellers in China last year. SAIC-GM-Wuling Automobile Co. Ltd. also had an EV in the top 10 as did Guangzhou Automobile Group (GAC).

Two Tesla produced EVs (Model Y and Model 3) were also on the top 10 list. “The vast majority of EVs being made in China are competitive with the best that Tesla can produce,” Haelterman said. Tesla, the U.S. EV market share leader, manufactures and sells EVs in China, the U.S. and Germany.

With sales of more than 475,000 units in 2022, BYD’s Seal sedan was the top seller among all EVs in China. The car rides on a vehicle platform the company calls 3.0. The Seal’s lithium-iron-phosphate (LFP) battery system has a 150-kW capacity, 310 kW torque and 1.63 kW/kg power density, the company claims. It weighs 114.6 kg (252.6 lb).

“BYD integrates the [Blade] battery pack into the vehicle’s floorpan, so it’s actually part of the vehicle structure.” Haelterman said. [See "BYD's Blade Runner" from October of 2021.] The battery’s upper shell is used as the floor with carpet attached to it. The lower floor’s ring panel is mated to a sealing strip above the battery to create a cabin seal.

A teardown of the Seal sedan by Autodatas using digital scanning of components and material analysis, showed that the integration of Seal’s electric drive system substantially improved versus the 2.0 electric platform used by BYD’s Han EV sedan. The Han EV reached the marketplace three years earlier than the Seal. Seal’s next-generation structure is 17.4 kg (38.3) lb. lighter.

Seal’s 8-in-1 electric powertrain, a world-first application, includes the motor, motor controller, reducer, onboard charger, DC converter, high-voltage distribution box, battery management system, and vehicle controller, Haelterman explained.

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