Old Version
Cover Story

Amped for Change

The race is on to develop a new generation of solid-state batteries, which are safer and more energy efficient than liquid lithium-ion batteries. At stake is the total structure of the electric vehicle, along with other industries

By Xie Ying , Chen Weishan Updated May.1

Fifteen people died in a fire at a residential building in Nanjing, capital of Jiangsu Province on February 23. Fire authorities said it was caused by an electric moped catching fire for unknown reasons. It was parked with dozens of other mopeds in an open area on the first floor of the apartment block.  

As e-scooters have become increasingly popular in China, the number of fires they cause is growing. Data from the National Fire and Rescue Administration showed that in 2023, it received 21,000 reports of fires caused by electric scooters, 17.4 percent more than in 2022. Most were related to battery failure.  

Battery failures after crashes are also a leading cause of electric vehicle (EV) fires. In June 2023, six people were killed when an electric car caught fire after a crash in Hangzhou, Zhejiang Province. Rescuers told media that the fast-spreading fire from the batteries prevented them from rescuing the victims.  

The most common battery used in e-scooters and EVs is a liquid lithium-ion (Li-ion) model, consisting of four parts: the anode, the cathode, a gel-like electrolyte to support the transfer of current and a separator to prevent short circuits. If these batteries sustain serious damage, are punctured, overcharged or overheated, the chemicals, in a process called thermal runaway, can ignite or explode. The electrolyte liquid is also explosive and can ignite upon oxygen contact. Other causes can be manufacturing defects if poor quality materials are used.  

Solid-state batteries are thus regarded as a solution to increasing the safety of electric vehicles. Using solid electrodes and electrolytes, these batteries are inflammable and stable. They are much less volatile and have a much higher energy density, with little risk of explosion or fire. 
Yet still, enterprises worldwide are devoting efforts to produce new generation Li-ion batteries, even as solid-state technologies continue to develop. This is particularly important not only to Chinese consumers, but also for Chinese manufacturers to keep their lead in the global supply of electric vehicles and batteries. Given this, it is regarded as one of the sectors that represent the new quality productive forces that China is pursuing.  

‘Taming Monsters’ 
Liquid Li-ion batteries for electric cars and consumer electronics are dominated by two battery types. The first is the nickel-cobalt-manganese battery (NCM), which offers high energy levels, but is less stable and more prone to thermal runaway due to the materials it contains. The other is the lithium iron phosphate (LFP) battery, which is cheaper and safer with a longer life cycle, but offers a lower energy density.  

In 2019, several spontaneous combustions of electric cars caused public worries about the safety of Li-ion batteries. According to media reports, the cars all had NCM batteries which have a much lower autoignition temperature of 200 Celsius compared to about 500 Celsius for LFP batteries.  

Yu Huigen, president of Beijing WeLion New Energy, a unicorn company engaged in solid-state battery technologies, compared batteries’ anodes and cathodes to two monsters which liquid electrolyte can only try to “tame.”  

“It’s very difficult for liquid electrolyte to ‘tame’ 80 percent nickel content [in a liquid battery], but a semi-solid state battery can ‘tame’ 90 percent of nickel,” he told NewsChina.  

A semi-solid battery involves a mix of both solid and gel-like electrolytes.  

According to Yu, NCM liquid batteries, restricted by the materials used by anodes and cathodes, can generally reach an energy density of 260-280 watt-hours (Wh) per kilogram – the amount of energy a battery can store with respect to its mass – close to the upper limit of the energy density of liquid batteries (300 Wh/kg), while solid-state batteries can break the upper limit.  
Solid-state batteries are much safer, as they support a higher working temperature, about 80 Celsius, 25 degrees higher than that of liquid batteries.  

Solid-state batteries are the answer to consumer concerns over EV safety, Yu said, pointing to decreased risk of combustion while supporting long-range travel, even in low temperatures where chemical substances are less active.  

For example, a semi-solid Li-ion battery used in a NIO ES6 vehicle which supports a normal range of 700-800 kilometers can ensure a range of around 600 kilometers in cold weather. WeLion works closely with NIO, a well-known Chinese electric car brand.  

In December 2023, NIO founder and president Li Bin drove 1,044 kilometers from Shanghai to Xiamen, Fujian Province, in a NIO ET7 equipped with a 150 kWh semi-solid-state battery pack on a single charge.  

Although a few EVs with liquid lithium batteries can theoretically reach a range of 1,000 kilometers, it is at the cost of increased energy consumption, meaning packing more batteries in the car and sacrificing efficiencies for increased weight.  

Given solid-state batteries support materials offering higher energy density, they can achieve the same range with fewer batteries, which saves energy.  

“For every 100 kilograms less a car weighs, it means 3-10 percent less energy consumption,” Yu said.  

“A range of 1,000 kilometers is actually a starting point for semi-solid-state batteries whose theoretical energy density could be higher,” Yao Meng, R&D director of EnPower, a Chinese company engaged in solid-state battery technologies, told NewsChina.  

Cost is Key 
Most of the technologies related to solid-state batteries are still in the R&D phase, as scientists have to tackle an array of problems, such as increasing conductivity of solid materials and improving the contact surface between solid electrolyte and electrodes.  

Cost is another key issue.  

According to Zhong Liang, a senior battery development director at Guangzhou-based automaker Xpeng, semi-solid batteries cost twice that of liquid batteries, which is why they are only used in high-end cars.  

According to Zhu Guannan, deputy director of the International Engineering Institute under Gotion High-tech, which develops Li-ion batteries in Hefei, Anhui Province, for liquid batteries, higher battery capacity usually brings higher cost. An NCM battery which contains 80-120 kWhs of electricity costs more than an LFP battery which contains around 40-60 kWhs of electricity.  
To better balance energy and cost, a new battery based on a Li-ion model has emerged – the lithium manganese iron phosphate (LMFP) battery, which replaces some iron used in the cathode with manganese.  

LMFP batteries have a higher energy density than LFP batteries, and are safer than NCM batteries, while the cost lies between the two. Zhu believes that LMFP batteries have diverted EV makers’ attention from developing solid-state batteries, mainly due to cost reasons, as LMFP batteries will approach the same capacity as NCM batteries, but at a lower cost.  

“LMFP materials have existed for two or three decades, and LMFP batteries are being produced now at a time when the market values cost reduction more [amid the economic slowdown],” Zhu said.  

Another battery industry insider who refused to reveal his name told NewsChina that he feels auto manufacturers’ interest in solid-state batteries is changing with the market environment.  

“One year ago, some battery producers sent semi-solid-state samples to car manufacturers, who showed strong interest in the new product and even proposed a radical route to application. However, because automakers are under increasing pressure to cut costs since the latter half of 2023, their attitude toward solid-state batteries turned from enthusiastic to cautious,” he said. 

Interviewed experts agreed that the final cost of solid-state batteries will be much lower than expected, due to increasing the amount of nickel in the battery, whose price is only one-fifth that of cobalt. However, it has to be premised on mass production when the technology is mature, and when battery producers have more room to negotiate the cost of raw materials with suppliers.  

“The cost of Gotion High-tech’s semi-solid battery is now 5-10 percent higher than that of an NCM battery because we haven’t yet achieved mass production of silicon which we use to make anodes. When we scale up production, the cost of a battery will reduce by more than 50 percent to be similar to the cost of graphite now,” Zhu said. Graphite is the material used to make cathodes in liquid batteries.  

Li Zheng, general manager of Qingtao New Energy, another Chinese unicorn developing solid-state batteries, told Electric Vehicle Observer in an interview in August 2023 that the cost of Qingtao’s second-generation solid-state battery will be 10-30 percent less than that of liquid batteries, and that of the third generation, which is expected to launch by 2027, will be 40 percent less than liquid batteries.  

International Race 
When BYD Auto took an interest in the Li-ion battery industry in the early 21st century, it was in its infancy. But developing generations of new battery technologies has in turn promoted the development of the whole EV industry. In 2023, BYD reportedly exported 243,000 electric passenger cars, 334.2 percent more than that in 2022.  

Solid-state batteries for EVs, though not yet in mass production, will be a chance to restructure the electric car industry as liquid Li-ion batteries have done, according to industry insiders.  

Japanese enterprises are pioneers. As early as 2010, Toyota announced a four-layer all-solid-state battery. In October 2023, Toyota and Idemitsu Kosan, a Japanese company engaged in petrochemical technology, announced a cooperation plan for mass production of full-solid-state batteries with commercialization by 2027-2028.  

In April 2023, rival Honda announced a plan to invest in semi- and full-solid-state batteries. Honda said it expects the technology to be adopted in EVs after 2025.  

According to Japanese media Nikkei, Japan is a world leader in the number of patents related to solid-state batteries, with Toyota holding over 1,300 patents, followed by Panasonic and Idemitsu Kosan.  

South Korea is not far behind. Samsung SDI has announced a plan to develop large full-solid-state batteries before 2025 and mass production by 2027. In the US, a number of startups are engaged in solid-state batteries.  

In January 2024, ProLogium, a battery manufacturer in Taiwan, announced the launch of the world’s first Giga-level plant for solid-state Li-ion ceramic batteries for mass production.  

Three years before, ProLogium had already established an industrial base in Hangzhou, Zhejiang Province with investment of 38 billion yuan (US$5.3b) for the production of solid-state batteries. In May 2023, ProLogium announced a plan to build a gigafactory for solid-state batteries in Dunkirk, France which is scheduled to go into mass production by the end of 2026.  

These developments have triggered hot discussion in China as many netizens questioned whether Chinese mainland enterprises which had taken the lead in liquid Li-ion batteries are already lagging behind on solid-state batteries.  

But according to interviewed experts, Chinese mainland enterprises are working hard to develop solid-state batteries. CATL, China’s leading Li-ion battery supplier, released its R&D roadmap for sulfide solid-state batteries in 2016. In May 2023, CATL was reported to have accomplished the first batch of solid-state battery samples and plan to go into mass production by 2030. Qingtao New Energy reportedly launched its solid-state battery production line in late 2018 with an annual output of 0.1 GWh, the figure of which raised to 1 GWh by 2020. In August 2023, Qingtao tested its first semi-solid-state batteries jointly developed with SAIC Motor, a leading Chinese automaker, in cars. The tested car, according to the Electric Vehicle Observer, carries a battery pack of 368 Wh/kg power density and reached a maximum range of 1,083 kilometers, with a 400 kilometer increase in range for every 10 minutes of charging.  

Mass Production 
Different from many overseas enterprises that focus largely on technological research and development, Chinese mainland enterprises also emphasize industrial applications.  

“China’s industries with complete upstream and downstream supply chains give more advantages in responding to new technologies. China is very powerful at industrial transformation. NCM and LFP batteries weren’t invented in China, but China is advantaged at industrial application,” Yao told NewsChina.  

To shorten the commercialization of solid-state batteries, Chinese enterprises opted to first apply semi-solid-state batteries, which they believe will in turn promote the technological development of solid-state batteries.  

“Semi-solid-state batteries now compete with liquid NCM batteries in the mid- to high-end EV markets,” Zhu Guannan said, adding that the vehicles are expected to support a range of 600- 800 kilometers on a single charge.  

“We estimate there will still be big demand for LFP batteries. Fifty percent of power batteries and 80 percent of storage batteries will still use LFP batteries,” Yao said. “So, Chinese enterprises will continue to try to grab the market for [liquid] Li-ion batteries as well as an advantage in developing semi-solid-state batteries, where it will be easy to shift production of liquid batteries to semi-solid-state batteries at a controlled cost,” he added.  

Yu agrees. He believes solid-state batteries will not completely replace liquid batteries and the key problem is to find suitable applications for solid-state batteries.  

To control the cost of solid-state batteries, NIO has launched a battery change service, which is much easier to promote than buying a whole new car. “NIO’s future task is to further reduce the cost of semi-solid-state batteries to be within 10 percent higher than the cost of an NCM battery. As output rises and the cost of cathode materials reduces, we expect the cost to drop in line with a liquid battery,” he said.  

“At that time, semi-solid-state batteries will rather become a choice to reduce the cost of a whole car as they will require fewer batteries,” he added, predicting that the turning point will occur in 2026.  

According to Yu, WeLion’s task this year is to satisfy NIO’s demands for semi-solid-state batteries, then in 2025, they will partner with two more car manufacturers. “NIO now has more than 2,000 battery change stations. During holidays, some car owners rent semi-solid-state batteries that contain 150 kWhs of electricity,” he said.  

On May 31, 2023, Qingtao signed a partnership agreement with SAIC Motor to equip 100,000 new energy cars with semi-solid-state batteries by 2025.  

“The growth in the production output of semi-solid-state batteries will be faster than expected, and we plan to establish a production line of 10 GWh before 2025,” Yao told NewsChina, revealing that EnPower has put into use a 0.3 GWh production line and in 2024, they will build a 2 GWh line at home and another 0.2 GWh line in the US. Both will go into production this year. 

Yao argues that the commercialization of solid-state battery technologies will not be limited to EV batteries.  

“We have to research market segments and find out those where liquid batteries can’t provide enough support and users are more tolerant of high costs... and we can also commercialize solid-state battery technologies in stages, such as the technologies that optimize the contact surface between the electrolyte and electrode,” he said.  

According to Yao, EnPower is entering the drone market, as semi-solid-state batteries suit the need for high energy density. Given drone batteries are very small, manufacturers are not so price sensitive as car manufacturers.  

But Yu is looking to the stars. “Future manned spaceships which require very high energy density can only be supported by full-solid-state batteries,” he said.  

At the end of 2023, industrial analysts EVTank predicted that solid-state batteries will take up 10 percent of the total market share of Li-ion batteries by 2030, most of which will be semi-solid-state batteries. In January when a platform for integrating the research and production of solid-state batteries was established, Ouyang Minggao, deputy director of China Electric Vehicles 100, which researches electronic vehicles, predicted that full-solid-state batteries will account for 1 percent of the market by 2030, a rate he believed high enough to bring subversive change to the battery industry. 

Technicians work on WeLion’s production line for semi-solid-state batteries (Photo Courtesy of WeLion)