Flowers and saliva fly together, research and development of solid-state batteries is a "gamble"?

Economic Observation Network reporter Zhou Ju

The automotive industry's attitude towards solid-state batteries is polarized. On the one hand, Us electric vehicle startup Fisker said it would abandon solid-state battery research and development, pouring cold water on this new project. Late last year, Fisker founder Henrik Fisker said in an interview, "Solid-state batteries are one of those technologies where you feel like you've done 90 percent and are almost there, and then you realize that the remaining 10 percent is a lot more difficult than the previous 90 percent." So now, we're completely abandoning solid-state batteries because we really can't land on the ground. ”

Prior to this, Fisker had been working on solid-state batteries for several years and planned to carry solid-state batteries on one of its new cars, but eventually jumped the ticket and later decisively abandoned the solid-state battery project.

But on the other hand, automobile companies represented by Nissan, Toyota, Honda, etc., have launched a continuous attack on solid-state batteries. On April 8, Nissan Held an All-Solid-State Battery Technical Briefing, making it clear that it will establish its first all-solid-state battery pilot plant in Yokohama, Japan, in 2024, and that the first mass-production vehicle equipped with solid-state batteries is expected to be brought to market in 2028.

In fact, in addition to Japanese car companies, major automakers such as Volkswagen, Ford Motor, and General Motors are conducting research and development of all-solid-state batteries and have successively announced mass production schedules.

Some car companies resolutely turned around, and some car companies rushed to attack, why is the attitude of car companies so different on solid-state batteries? Where are the difficulties in mass production of all-solid-state batteries and whether they can be broken through, these have become the focus of attention in the industry.

"Solid-state batteries are definitely the future development trend of lithium-ion batteries, but at present, there are still many scientific problems in all-solid-state batteries that have not been solved, such as interface problems, electrolyte cost problems, positive and negative electrode material matching problems, etc., at least 5-10 years of technological breakthrough time, and there is no potential for industrialization in a short period of time." Shao Yuanjun, research director of the Chinese Academy of Sciences Venture Capital Management Co., Ltd., told the Economic Observer Network reporter.

Mei Songlin, a senior analyst in the automotive industry, also said, "Solid-state batteries are still far from being installed, and some are optimistic about 2025, but some are expected in 2030." Therefore, solid-state batteries are a strategic long-term investment for car companies. Only a very small number of car companies invest in solid-state batteries as strategic technologies and strategic competitive advantages, which require sufficient capital, technology research and development capabilities, and especially patience and control of uncertainty. ”

It is worth noting that Shao Yuanjun pointed out that in the context of the establishment of a mature industrial chain of existing liquid lithium-ion batteries and the performance to meet the needs, the existing advantageous industries have little demand for subversive technologies with great uncertainty about solid-state batteries, and the research and development of solid-state batteries is more of a bet on new entrants or enterprises seeking transformation.

All-solid-state battery: "Thorny Rose"

All-solid-state batteries have become the research and development goals of car companies, mainly because it has some advantages in terms of light weight, long mileage, fast charging speed, and safety.

Compared with liquid batteries, solid-state batteries bear the brunt of their advantages in light weight and high energy density. "One of the advantages of all-solid-state batteries is that the energy density per unit weight is high, and the weight of solid-state batteries is much lighter than that of liquid batteries, which reduces the loss of endurance." Nissan pointed out at the press conference that the energy density of Nissan's solid-state battery is expected to reach 1000Wh/L, and in the case of the same volume, the cruising range will be twice that of liquid batteries.

At the same time, solid-state batteries can exert fast charging performance to a greater extent. The average charging power of current fast-charging facilities is around 150kW, but Nissan has a target value of 350kW for charging power in its solid-state battery charging facilities. It is reported that Nissan has completed the measurement of the charge and discharge performance of the 1000Wh/L-class electrode, and can charge from 15% to 80% in 15 minutes at 25 °C, and the charging time can be shortened to 1/3.

In addition, solid-state batteries are considered to be less affected by temperature, so they perform better at low temperatures, which can solve problems such as the decline in vehicle mileage in winter to a certain extent. At the same time, it can avoid the lithium ions of the liquid battery from generating lithium dendrites during repeated charging and penetrating the battery separator to cause spontaneous combustion, and the safety is improved.

However, the mass production of all-solid-state batteries, which seems to be almost "perfect", also faces many difficulties, mainly reflected in the difficulty of manufacturing and high cost.

The head of Nissan technology said at the meeting that there are still many technical problems in the current all-solid-state battery from large-scale mass production and loading. First of all, at the technical level, solid-state batteries need to be evenly stacked with multi-layer cells, and once the force between each layer is uneven or the volume change caused by battery charge and discharge is not fully considered, it will lead to local accumulation of charge, which may cause a short circuit when serious.

In addition, affected by external factors such as the ongoing conflict between Russia and Ukraine, the price of cobalt and other metal materials currently used to make electrodes soar, making the already high manufacturing cost of solid-state batteries worse. According to reports, Nissan's current important research direction is to develop manganese and other relatively inexpensive alternative materials, hoping to reach a future cost of $75 per kilowatt-hour.

But Shao Yuanjun said that all-solid-state batteries can not completely avoid the current shortage of materials, the cost is still very high. "The positive and negative electrodes of [solid-state batteries] are still those (materials), that is, the replacement of EC DMC and lithium hexafluorophosphate with more complex sulfides or oxides, which will involve elements such as La and Ge. The price of sulfides is now calculated in grams and is very expensive. Shao Yuanjun pointed out that the future of all-solid-state batteries is basically used in high-end models that are not bad for money.

It is worth noting that solid-state batteries will also have certain safety risks. According to Nissan, due to the higher energy density of solid-state batteries, once the internal sulfide is mixed with foreign matter or in contact with air, it is easy to form highly toxic flammable gases such as hydrogen sulfide, which in turn triggers an explosion.

"Solid-state batteries are twice as densely energy-dense as current lithium-ion batteries, so they're like a more dangerous potential bomb." In the event of a major accident, solid-state batteries could be even more catastrophic than current batteries. Kazuhiro Doi Kazuhiro Doi, Nissan's vice president in charge of advanced battery research and development, said. This requires more comprehensive safety verification for solid-state batteries.

Will semi-solid-state batteries be in place?

The current mass production time for all-solid-state batteries in the industry is also expected to vary greatly. According to the data, the earliest to achieve mass production is Volkswagen, which invested in the American power battery company Quantum Scape, a joint venture to develop solid-state batteries, and plans to mass-produce in 2023. It is worth noting that Fisker is also one of the shareholders of Quantum Scape, and whether Fisker's abandonment of solid-state battery research and development means that the company's solid-state battery mass production time is variable.

Toyota plans to start mass production of solid-state batteries from 2025, and the mass production time of Nissan is 2028, and BMW is more cautious and plans to mass-produce them in 2030. Fisker founder Henrik Fisker said last year that solid-state batteries will take at least 7 years from any form of mass production. Shao Yuanjun believes that the mass production of all-solid-state batteries is at least 10 years later.

At present, the mass production of solid-state batteries should basically be in 2025 and beyond. Market research firm Yole Développement (Yole) expects solid-state battery commercialization to begin around 2025, with small-scale mass production even ahead of schedule. This is a relatively long time, but also to the development prospects of solid-state batteries add a lot of variables.

In China, some car companies have said that they will launch semi-solid-state batteries, which is considered to be a transitional form to all-solid-state batteries. It is reported that Weilai Automobile and Weilan New Energy cooperation, the former of the Weilai ET7 will be equipped with the latter research and development of hybrid solid-state battery, the semi-solid-state battery is expected to start mass production at the end of this year or the first half of next year, a single charge endurance of 1000 kilometers.

"Compared with all-solid-state batteries, domestic solid-state batteries generally use a solid-liquid mixed state route, and there is a certain liquid in the battery, which is more realistic." Solid-liquid hybrid batteries can be understood as an upgrade of liquid batteries rather than a subversion, and there is a certain improvement in energy density and safety under the condition of controllable cost. Shao Yuanjun pointed out that if the solid-state battery meets the demand in performance, it will not necessarily need an all-solid-state battery.

Because of the high investment and cost of research and development of solid-state batteries, it may face certain challenges in the market. "Consumers may pay 10% more to choose to increase the safety factor of the battery from 90% to 99%, but they will not necessarily spend 5-10 times the cost to choose a 100% safe all-solid-state battery." Shao Yuanjun told the Economic Observer Network reporter. At the same time, it pointed out that the current solid electrolyte material basically does not have the ability to work at low temperatures, which is still the short board of solid-state batteries, and the safety performance cannot be 100% guaranteed.

For the high cost of solid-state batteries, Nissan officials revealed at the analysis meeting that it will reduce the manufacturing cost of solid-state batteries to 75 US dollars (about 477 yuan) / kWh in 2028, which is equivalent to the current cost of liquid lithium-ion batteries. But Shao Yuanjun said, "The all-solid-state battery is now telling stories in theory, and the actual product performance is not certain." ”

So which of the car companies that develop all-solid-state batteries is the most likely to achieve mass production? Shao Yuanjun said, "Toyota is doing it faster, Japan has lagged behind China and South Korea in the liquid battery industry, and can only seek other opportunities, similar to fuel cells, this bet on solid-state batteries is also like gambling." Shao Yuanjun said.