All-solid-state batteries, a distant goal but desperately close

Preface:

At present, the so-called [on-board] solid-state batteries on the market are actually still in the [semi-solid-state] development stage.

However, it is worth noting that some car companies, for various reasons, choose to use other names to refer to [semi-solid-state] batteries. This practice has sparked controversy and discussion about [semi-solid-state] and [all-solid-state] in the public opinion field.

Many companies release updates on solid-state battery layout

Currently, more than ten companies have publicly announced their plans to mass-produce solid-state batteries.

These companies include domestic companies such as CATL , BYD , NIO, Xpeng, SAIC, GAC, Changan, Dongfeng, etc., as well as well-known car companies in the international market such as Toyota, Nissan, BMW, Honda, Volkswagen, and Mercedes-Benz.

Based on the plans of these companies, mass production of solid-state batteries is expected to begin as early as 2026 and at the latest in 2030.

Among them, SAIC Group plans to install semi-solid-state batteries on models such as Zhiji, Feifan, Roewe, and MG in 2025, and it is expected to sell more than 100,000 new energy vehicles with a range of more than 1,000 km throughout the year .

In addition, Toyota Motor plans to achieve mass production and practical application of solid-state batteries from 2027 to 2028;

Companies such as Xpeng Motors, Changan Automobile, and Nissan have also stated that they will launch mass-produced models equipped with solid-state batteries in 2027.

In terms of technology research and development, Tianci Materials has formulated technical plans in the field of semi-solid and solid-state batteries and has begun to lay out related patents, demonstrating the company's foresight and strength in the research and development of solid-state battery technology.

Oriental Electric Heating pointed out that the pre-nickel-plated materials they produce can be used in cylindrical batteries with different dielectric forms, including solid-state batteries, demonstrating the company's innovation capabilities and market adaptability in the field of materials.

Zhenhua Technology also stated that they are closely following the development trend of solid-state batteries, and have carried out related research and development work and have made significant progress.

It is hard to tell whether a solid-state battery is real or fake

The development of solid-state battery technology is a gradual evolutionary process, and it is difficult to achieve leapfrog development. Its development process can be divided into three key stages:

① Change the electrolyte from liquid to solid, remove the diaphragm, but keep the positive and negative electrode material system unchanged;

②Replace the negative electrode material with metallic lithium to significantly increase the energy density of the battery;

③Replace the positive electrode material and use a high-density material that does not contain lithium ions. The core difference between solid-state batteries and liquid batteries is that the electrolyte is replaced with a powdered electrolyte.

Although all-solid-state electrolytes have problems such as low electrical conductivity and poor stability of the electrode and electrolyte interfaces that have not yet been fully resolved, semi-solid-state batteries, as an intermediate solution to all-solid-state batteries, have received widespread attention in the industry.

Solid, quasi-solid and semi-solid, the classification standard is the content of liquid electrolyte, liquid (25wt%), semi-solid (5-10wt%), quasi-solid (0-5wt%) and full solid (0wt%) (wt% is mass percentage), that is, it is below 10wt% to enter the threshold of semi-solid.

In terms of electrolyte selection, there are currently three main routes to choose from: sulfide, oxide and polymer.

Taking into account the difficulty of preparation, cost and comprehensive performance, oxides are considered to be the solid electrolytes that are easiest to mass-produce.

Therefore, Qingtao Energy, which provides batteries for Zhiji, currently launches products that adopt the oxide route.

Some professionals predict that all-solid-state batteries are expected to be industrialized by 2030.

In addition to the automotive field, all-solid-state batteries will also have a positive impact on consumer electronics, low-altitude flight and other fields, especially the trillion-level eVTOL market, which has more stringent requirements for long-range flight.

However, in automotive-grade scenarios, an optimal balance needs to be achieved between technology, cost, and market demand.

In the future, it may stop at quasi-solid-state form (400Wh/kg).

If the capital market focuses too much on distant concepts and ignores the actual progress of industrialization, all progress may become slow.

At present, the development difficulty of all-solid-state batteries is still higher than that of semi-solid-state batteries.

Therefore, downstream new energy vehicle manufacturers have adopted semi-solid-state battery solutions as a transition and are planning to gradually achieve the transformation to all-solid-state batteries.

In this process, special attention should be paid to avoid using the name of solid-state batteries to confuse the concepts of all-solid-state batteries and solid-liquid hybrid batteries.

BYD and CATL did not [join in the fun]

CATL and BYD have not carried out large-scale publicity activities in the field of solid-state batteries.

BYD's core focus this year is the release of its second-generation blade battery .

They plan to test-install all-solid-state lithium batteries in 2025 , and expect to launch a new pure electric platform and model equipped with all-solid-state lithium batteries in 2026 .

Although CATL has not yet released semi-solid and all-solid-state batteries, they have launched a condensed state battery. The characteristic of this battery is that the electrolyte has an adhesive form.

Although it belongs to the category of solid-state batteries, it does not belong to the classification of semi-solid-state or all-solid-state batteries, but is a relatively unique technical path.

It is worth noting that BYD and CATL's R&D work has not fallen behind.

The reason why they keep a low profile on solid-state batteries is mainly because they have invested a lot of money in liquid lithium battery production lines.

To ensure profitability, these production lines need to reach a certain production scale to reduce average costs.

Since the liquid lithium battery production line has just been put into operation, the sunk costs are high, making it difficult for the two companies to easily change their strategies in the short term.

Therefore, even though progress has been made in the development of solid-state batteries, they choose to remain cautious to avoid a premature change in market trends.

Industrialization goal is far away due to technology and cost

Although solid-state batteries have significant advantages in theory, they have not yet been able to completely replace liquid batteries.

This is mainly because breakthroughs in solid-state battery technology still require more efforts and its mass production process faces many challenges.

The development of solid-state batteries involves three technical routes, including the oxide route, the sulfide route and the polymer route.

However, there are still many basic scientific problems that need to be solved, such as the significant difference in ion diffusion rate in solid electrolytes and liquid electrolytes, and the difficulty in maintaining good contact at the solid-solid interface.

These issues need to be solved after breakthroughs are made at the scientific and technological level before we can further consider industrialization.

In terms of technology, core issues such as the solid-state electrolyte ion transport mechanism, the lithium dendrite growth mechanism of the lithium metal negative electrode, and the runaway failure mechanism of the multi-field coupling system are still the main obstacles to the development of solid-state batteries.

In addition, mass production of solid-state batteries is extremely difficult, which mainly involves high material costs and complex manufacturing processes.

If the cost cannot be effectively reduced, the market competitiveness of the product will be seriously affected, thus hindering the process of industrialization.

Solid-state batteries also face many obstacles in terms of large-scale production technology.

For example, the preparation of ultra-thin solid-state films with uniform conductivity, the electrode winding method to achieve qualified standards for surface capacity and density, and high-temperature sintering of oxides, all these problems need to be gradually solved during small-batch trial production.

A Japanese company report said that the cost of solid-state batteries may be twice that of liquid batteries.

This estimate may be based on the purchase price in the Japanese market, but in the Chinese market, the ratio may be different.

On the application side, although some manufacturers have begun to choose semi-solid-state batteries in the short term, there are still many difficulties for the rapid promotion and scale-up of the industry.

Among them, technical and safety issues have not yet been fully resolved, which further increases the difficulty of solid-state batteries replacing liquid batteries.

Ending:

Currently, the generally accepted view in the industry is that the high production cost of solid-state batteries and the immature technology together limit the development of their commercial applications.