It's time to cool down the frenzy over solid-state batteries.

Have you recently been bombarded with news about "solid-state batteries"? Headlines like "A 100-kilogram battery pack will be able to run 1000 km in the future", "Solid-state batteries will be installed in vehicles by 2027", and "Chinese research institutions have made significant breakthroughs in the field of solid-state batteries" have been everywhere. Even CCTV has joined the reporting fray...

In the capital market, the solid-state battery index has almost doubled in half a year. For ordinary consumers, the recent spate of electric vehicle spontaneous combustion accidents has also led to a growing call for the installation of solid-state batteries in vehicles. Many people might be wondering, if I buy a car now, will I end up regretting it by 2027?

Calm down! A few days ago, Academician Ouyang Minggao poured cold water on the hype surrounding solid-state batteries. He said, "Currently, there are high expectations for all-solid-state batteries, and some consumers are even waiting for them. In fact, this is misleading. We still have a series of scientific and technological problems to overcome."

So why are solid-state batteries suddenly in the spotlight again? How far are they from becoming a reality? Can they really reshape the entire automotive industry landscape?

Why are solid-state batteries popular again?

Let's first explain what solid-state batteries are.

You can think of the lithium batteries currently used in our mobile phones, computers, and electric vehicles as a "sandwich cookie". The two outer "cookies" are the positive and negative electrodes of the battery, while the middle layer of "cream" is the liquid electrolyte - its job is to allow ions to move back and forth between the positive and negative electrodes.

The problem lies with this "cream"! It is sensitive to impact and heat, and can easily catch fire and "self-ignite" with a little stimulation. Moreover, this layer of "cream" takes up a lot of space in the battery, affecting both the battery's range and size.

So how do solid-state batteries solve these problems? It's simple - replace the dangerous "cream" with a "jelly" or a "compressed biscuit", that is, a solid electrolyte. With this change, the battery immediately "evolves": it becomes safer, has a higher energy density, and can be made smaller and lighter.

We know that China currently leads the world in liquid battery technology. CATL and BYD are the two dominant players, together accounting for about 70% of the market share. However, overseas competitors are intensively investing in solid-state battery research in an attempt to "overtake on a curve".

For example, Toyota plans to launch its first mass-produced vehicle equipped with all-solid-state battery technology as early as 2027; Samsung SDI's solid-state battery technology focuses on the sulfide route and plans to achieve mass production by 2027; Mercedes-Benz has started road tests of its test vehicles equipped with new solid-state batteries.

Facing this situation, China naturally feels a sense of "crisis". The government is also rapidly increasing its investment, pouring real money into the basic research and development of solid-state batteries!

Data shows that 2024 was a milestone year for China's solid-state battery development. Since the second half of the year, the number of solid-state battery patents applied for in China has been three times that of Japan. In February this year, eight government departments, including the Ministry of Industry and Information Technology, clearly listed solid-state batteries as a key research and development direction. Domestic automakers and battery giants have all jumped into the fray, and a "race for territory" around solid-state batteries has already begun.

For example, CATL's research and development team for sulfide all-solid-state batteries has expanded to 1,200 people, and the energy density of the announced 20Ah sample has reached 450Wh/kg; Xinwangda recently announced the launch of its all-solid-state battery, "Xin·Bixiao", with an energy density of up to 400Wh/kg. It is expected to build a 0.2GWh polymer solid-state battery cell pilot production line by the end of 2025; Guoxuan High-Tech's all-solid-state Jinshi battery is currently in the pilot mass production stage, and the design work for a 2GWh mass production line has been initiated...

Guoxuan High-Tech's all-solid-state Jinshi battery

On the practical application front, automakers such as BYD, SAIC, GAC, Changan, and Geely have all announced the implementation timelines and technological breakthroughs of solid-state batteries, accelerating the push towards mass production and vehicle installation.

This makes it seem that solid-state batteries are getting closer to us, but in fact, that's not the case.

Challenges in industrialization

Many experts have stated that the so-called solid-state batteries currently being discussed are mostly "semi-solid" or solid-liquid hybrid batteries, which are an extension of liquid batteries. The energy density of such batteries launched by some companies ranges from 260 to 360Wh/kg, and they are in the transitional stage from liquid batteries to all-solid-state batteries.

A few days ago, the "Roadmap 3.0" released by the Society of Automotive Engineers of China set the tone for solid-state batteries. It is expected that they will enter "small-scale" industrialization by 2030. Chairman Zhang Jinhua even admitted that whether the energy density can reach the expected 500Wh/kg remains to be seen.

Ouyang Minggao also admitted that although there have been many breakthroughs in the research of solid-state batteries, there is still a large gap between the progress in materials science and the actual products. As for when the ideal energy density of 500Wh/kg can be achieved, the roadmap says 2030, but that is the technical roadmap, not the product roadmap, let alone the commercial roadmap. He believes that it is more realistic to achieve industrialization around 2035.

Why are experts so cautious? Four "harsh realities" are in plain sight:

Firstly, the technology is not mature enough. CATL has publicly stated that if the technical and manufacturing maturity of solid-state batteries is rated on a scale of 1 to 9, with "1" representing the initial stage of research and "9" representing full maturity for large-scale production, the current industry is at a level of "4".

Secondly, the cost problem remains severe. Data from research institutions shows that the unit cost of all-solid-state batteries is currently as high as 1,200 yuan/kWh, more than three times that of liquid batteries. The high cost makes solid-state batteries uncompetitive in the market.

Thirdly, the supply chain is still immature. The entire supply chain for solid-state batteries, from materials to equipment, needs to be re-established. Moreover, with the lack of a unified technical route (sulfide, oxide, polymer, etc.) and industry standards, it is difficult for upstream and downstream enterprises to cooperate, resulting in high coordination costs. Without a complete supply chain, large-scale mass production is difficult to achieve.

Finally, we should not overestimate the capabilities of solid-state batteries. At a recent industry forum, Wang Fang, the chief scientist of the China Automotive Technology and Research Center, said, "Although the safety margin of solid-state batteries is indeed wider than that of liquid batteries, once the margin is breached, the consequences could be more severe than those of liquid batteries."

Ouyang Minggao also admitted that there is no such thing as an absolutely safe battery, just as there is no absolutely safe self-driving car. There are always exceptions. All-solid-state batteries are designed to improve the safety of high-energy-density ternary batteries to the level of lithium iron phosphate batteries.

Ouyang Minggao, an academician of the Chinese Academy of Sciences and a professor at Tsinghua University

Conclusion

In the future, emerging fields such as drones and humanoid robots are most likely to be the first to adopt solid-state batteries. These fields are less sensitive to price and can quickly verify the value of the technology. As the industrial chain matures and costs decrease, solid-state batteries will gradually enter the automotive industry.

The birth of great things often involves challenges and hardships. Academician Nan Cewen of the Chinese Academy of Sciences once said that research pursues a 1% possibility, while the industry requires 99% or even 100% reliability. This means that from the laboratory to industrialization, we need to overcome many difficulties and gradually improve the technology until it is mature and fully controllable.

As for whether solid-state batteries can really reshape the industrial landscape, in fact, solid-state and liquid batteries are complementary. As Ouyang Minggao said, in the future, while we will develop high-energy-density all-solid-state batteries, lithium iron phosphate batteries will still be around for a long time. I think they will remain in use for at least 30 years.

This article is from the WeChat public account “Autostinger” (ID: autostinger), written by Peng Fei and published by 36Kr with permission.