In order to pursue technological differences and get rid of the involution situation, the symbolic significance of solid-state batteries has been greater than the actual significance, and the solid-state battery technology that survives in the imagination is only a "venture investment" at present.
Text丨Zhijia.com Wang Xin
Editor|The little pig demon on Langlang Mountain
Solid-state batteries were once known as the holy grail in the field of power batteries, and every once in a while there will be a round of industry and capital carnival.
Today, solid-state batteries are no longer a chemical problem, and can even be called a philosophical problem until a precise conceptual specification has been made.
Since March 25, Liu Tao, co-CEO of Zhiji Automobile, announced that the "quasi-900V ultra-fast charging solid-state battery" equipped with the Zhiji L6 can achieve a range of more than 1,000 kilometers, a new round of solid-state battery publicity war has begun.
Lithium battery start-ups Tailan and GAC Haobo subsequently released solid-state battery products, among which GAC marked the words "all-solid-state" in the promotional poster, and claimed to use the third-generation sponge silicon anode and high-capacity solid-state cathode technology.
Li Jin, head of GAC Aion battery R&D, introduced that the energy density of the all-solid-state battery can reach more than 400Wh/kg, which is more than 52% higher than the current mass production of liquid lithium-ion batteries, and the mass energy density is increased by more than 50%, which can easily achieve a range of more than 1,000 kilometers.
Feng Xingya, general manager of GAC Group, said that the all-solid-state battery technology will be mass-produced in 2026 and will be the first to be applied to its Haobo models.
This is the first solid-state battery product to give a clear mass production landing timetable.
It seems that this solid-state battery, which has been in the concept stage for a long time, has ushered in a breakthrough period?
However, Zhiji's solid-state battery was questioned as soon as it was proposed. Qingtao Energy, the manufacturer of the battery, said that the battery is a semi-solid-state battery.
According to Li Zheng, general manager of the supplier Qingtao Energy, the "solid-state battery" still needs liquid components to wet the pole piece to facilitate the movement of electrons between the pole pieces, but the mass of the "wetting agent" accounts for about 10% of the battery as a whole, while the data in ordinary lithium-ion batteries is about 15%. The electrolyte content was reduced by 5%.
According to the different electrolytes, the academic community divides batteries into liquid batteries, semi-solid-state batteries (electrolyte content accounts for 5%-10%), quasi-solid-state batteries (electrolyte content accounts for less than 5%), and all-solid-state batteries (excluding electrolyte).
Besides, is the energy density of 400Wh/kg really worth applauding?
At the Shanghai Auto Show a year ago, CATL released a condensed matter battery, which was called the first power battery used in the aviation field by CATL, and its battery cell energy density reached an astonishing 500Wh/kg (see "CATL Completes the Fatal Blow to Fuel Vehicles Today"), but the so-called condensed matter is still a liquid battery, not a solid state.
In contrast, although the index of 400Wh/kg is denser than many liquid batteries in mass production today, it does not break through the ceiling of liquid batteries.
As for whether solid-state batteries are about to be mass-produced and end consumers go on the market, Zhijia.com consulted CATL's engineers, who said that Zeng Yuqun recently pointed out from the side that some of the current problems of solid-state batteries are CATL's current true views on solid-state batteries:
"There are three technical routes for solid-state batteries, namely the oxide route, the sulfide route, and the polymer route. At present, there are still many basic scientific problems to be solved, such as the difference of order of magnitude between the ion diffusion rate and the liquid electrolyte in most solid-state electrolytes, and the difficulty of maintaining good contact between the solid-solid interface. ”
Although CATL has maintained a high investment in solid-state battery research and development for many years, it has not released a timetable for possible mass production, and at present, the companies on the market that claim to have mass-produced solid-state batteries have a very small number of companies such as Funeng Technology, Ganfeng Lithium, Weilan New Energy and Qingtao Energy, among which Weilan delivered only 0.8GWh of semi-solid-state batteries last year, and the production capacity provided is quite limited.
In terms of performance indicators, the semi-solid-state batteries that are now mass-produced and installed, whether it is NIO's 150KWh battery or Zhiji L6's semi-solid-state battery, have an energy density of about 350Wh/KG, which is less than 20% higher than the highest level of ternary lithium batteries.
This is of course progress, but there is still a long way to go from the capital speculation and the solid-state batteries expected by the industry.
Today's discussion of power batteries is just as good as whether autonomous driving should take a leapfrog route to L5 in one step, or a gradual route from L2 to L5.
For now, though, true solid-state batteries are not yet possible.
01.
Why do solid-state batteries catch fire?
It is undeniable that solid-state batteries are expected to be the key to success in next-generation battery technology, and have been pushed to the height of strategic industries by various countries.
Unlike the lithium-ion batteries and lithium-ion polymer batteries commonly used today, a solid-state battery is a type of battery that uses solid electrodes and a solid electrolyte.
Solid-state batteries and graphene batteries have been considered to be the ones that can inherit the status of lithium-ion batteries in recent years, as the scientific community believes that lithium-ion batteries have reached their limits. Solid-state lithium battery technology uses glass compounds made of lithium and sodium as conductive substances to replace the electrolyte of previous lithium batteries and greatly improve the energy density of lithium batteries (see "Smoke and War of Solid-State Batteries" for details).
Especially when it comes to security.
The safety of liquid batteries has been criticized by everyone, the electrolyte is very flammable at high temperature or severe impact, and lithium dendrites will puncture the film under high current, resulting in short circuits, and sometimes the electrolyte will also undergo side reactions or decomposition at high temperatures.
The thermal stability of liquid electrolytes can only be maintained up to 100°C, while oxide solid electrolytes can reach 800°C and sulfides and halides can reach 400°C. The oxidation stability of the solid state is also higher than that of the liquid state, and the impact resistance is much higher than that of the liquid state due to the solid form.
Ma Xin, a partner of Tailan New Energy, told Zhijia.com: "The traditional liquid battery, in fact, should be close to the ceiling from the perspective of the industry. ”
Just imagine, in the hot weather in summer, or when the chassis is bumped by external forces, the safety of the power battery cannot be guaranteed.
Various manufacturers are also making efforts at the battery cell level.
For example, do some treatment on the battery pack, such as heat dissipation, monitoring and monitoring, and add some means to the shell to prevent it from being pierced by external forces. If you want to make a substantial breakthrough at the battery cell level, the solid-state battery industry is generally optimistic about the landing direction.
At present, solid-state batteries have not achieved an energy density that exceeds that of liquid batteries, but theoretically solid-state batteries can achieve a high energy density. Because solid-state batteries do not need to be wrapped in liquid to prevent leakage like liquid batteries, they can be stacked in series like bricks, which saves a lot of shells, wrapping films, heat dissipation materials, etc., and the mass energy density and volume energy density can be greatly improved, and the single module level is improved at the same time.
The goal of solid-state batteries is to eliminate separators and liquid electrolytes, and the biggest point of divergence is that the material routes of solid-state electrolytes are different.
Materials can be divided into four categories: oxides, sulfides, polymers, halides. Each of these four types of electrolytes has different physical and chemical properties, which determine the difficulty and future market position of R&D, production and industrialization.
The semi-solid-state battery will go through the stage of semi-solid-state battery in the middle of the liquid state, and the most applicable stage is the oxide path, because the ionic conductivity is in the middle, and there is the best electrochemical stability, mechanical stability, thermal stability and cost advantages, which can make the semi-solid-state battery replace the current liquid battery more quickly, so as to gradually give full play to the advantages and cost performance of the solid-state battery, which is certain.
02.
Solid-state batteries still exist in the lab
The production process, cost and quality control of all-solid-state batteries are the biggest challenges.
Not long ago, NIO, which tested semi-solid-state batteries live-stream, revealed that the price of a 150kWh semi-solid-state battery alone was close to 300,000 yuan.
In fact, the world's first all-solid-state battery was born as early as the 90s of the last century, but its production cost is much higher than that of liquid batteries. If you want to make an all-solid-state battery, all the production equipment and process links are different from the current liquid battery, which means that the entire production line needs to be restarted.
The replacement rate of production equipment is large, and the cost of all-solid-state batteries is significantly higher than that of existing liquid batteries. Solid-state technology is difficult to integrate and develop, and requires high technical capabilities. Therefore, the current industrialization needs to be combined with the liquid lithium-ion battery system and process, and the introduction of semi-solid-state lithium batteries is more suitable for the current industrialization, and gradually develops to quasi-solid-state and all-solid-state lithium batteries.
The high cost of solid-state batteries is also mainly reflected in the solid-state electrolyte and positive and negative electrodes.
At present, the solid electrolyte is difficult to be lightened and thinned, and the price of some rare metal raw materials used is high, the oxide electrolyte contains zirconium, the sulfide electrolyte contains germanium, and the high-activity cathode and anode materials used for high energy density are not yet mature, and the price of copper-lithium composite belt is about 10,000 yuan/kg.
This has led companies to directly slow down the goal of solid-state batteries.
As early as 2018, Volkswagen began to deploy solid-state batteries, spending $300 million to become the largest shareholder of QuantumScape. At that time, the agreement signed between the two parties was that QuantumScape would supply solid-state batteries for Volkswagen's electric vehicles in 2025, which could more than double the range of the electric golf to 750 kilometers.
However, Jagdeep Singh, CEO of QuantumScape, said that although the company's previous delivery of small-batch solid-state batteries passed the loading acceptance, it does not mean that it has been successful, because how to ensure the quality control of mass production is a difficult problem, after all, this is not a mass production table, and if the battery has a problem, it will be a big problem.
Almost every few years, Toyota releases news of new advances in solid-state batteries. However, it also said in December last year that it would postpone mass production from 2027 to after 2030 due to "challenges in technology development."
Nissan Motor is the first automaker to announce the mass production of solid-state batteries, and plans to launch electric vehicles equipped with solid-state batteries by 2030. However, even if solid-state batteries have been developed, trial production will not begin in small batches until 2025, and they will not be available until 2028 at the earliest.
Companies have chosen to retain a small amount of liquid electrolyte on the grounds that although they are inferior in performance compared to all-solid-state batteries, semi-solid-state batteries have a significant improvement in energy density and safety compared to traditional liquid batteries.
At the same time, investor enthusiasm is not as positive as in previous years, with global venture capital deals for solid-state battery companies falling 72% in 2023 to $146 million, the lowest in nearly five years, according to financial data and software analytics firm PitchBook.
Jeff Peters, a partner at investment firm Ibex Investors, said, "Investors' interest in solid-state batteries has waned, and they are questioning whether the risks of solid-state batteries are worth it." ”
How far is a true solid-state battery?
Please savor this passage - at the beginning of this year, the revised draft of the "Lithium Battery Industry Standard Conditions (2024 Edition)" to solicit opinions from enterprises added product performance requirements for solid-state batteries: the energy density of solid-state single batteries ≥ 300Wh/kg, the energy density of battery packs ≥ 260Wh/kg, the cycle life ≥ 1000 times and the capacity retention rate ≥80%.
This is not a definition of a solid-state battery, but rather a requirement for its high performance.
Ouyang Minggao said at a forum this year: "There is a great possibility of a breakthrough in the industrialization of all-solid-state batteries around 2030, and China's battery industry needs to sound the alarm." ”
He also made it clear that "all-solid-state batteries are recognized as one of the preferred solutions for next-generation batteries, and have been included in the development strategies of major countries such as China, the United States, the European Union, Japan and South Korea, and have also become the key commanding heights of next-generation battery technology competition." ”
Is the semi-solid state an all-solid? Zhijia.com consulted a number of industry insiders on this and found that everyone's views are rational and conservative:
Wang Zidong, former director of the National 863 Electric Vehicle Major Special Power Battery Test Center, believes that it is difficult to achieve the mass production time of solid-state batteries within a window of 5 years.
He said that the possibility of mass production of all-solid-state batteries before 2026 is very small, if it can be made in batches to achieve the energy density of 400Wh/kg, it is not considered a high level, and the current all-solid-state batteries have not really been made, and now the cost will be reduced by 35%, which is not very reliable.
A R&D engineer at CATL believes that there are many technical difficulties to be broken through in solid-state batteries, and this question is a long way to answer, and the electrolyte, anode material, interface, and production process all need to be solved urgently. At present, many scholars and experts are studying this problem, and these problems cannot be solved in a short time.
03.
Solid-state batteries, do domestic car companies really need them?
However, the tug-of-war between car companies has essentially accelerated the development of solid-state batteries.
At present, the domestic market is mainly driven, and the solid-state battery subsidy policy has not yet been introduced, so there is a high probability that the semi-solid-state battery technology will be focused on in the short term, and the sulfide route will be laid out at the same time.
Looking back on the development of China's solid-state batteries - since 2020, mainland has listed solid-state batteries as a key development object in the industry for the first time and proposed to accelerate the process of R&D and industrialization, and achieved a breakthrough in loading for the first time, but the energy density is only at the level of 260Wh/kg;In 2023, it is proposed to further strengthen the research on the solid-state battery standard system, and at the same time achieve an energy density of 360Wh/kg in this year, becoming the first year of industrialization, and it is expected to achieve large-scale production in 2024.
At present, manufacturers such as Weilan New Energy and Qingtao Energy, as well as traditional lithium electronic battery companies such as CATL, Ganfeng Lithium, BYD, etc., all have layouts in sulfides, oxides and polymer electrolytes.
It is reported that domestic car companies are actively cooperating with solid-state battery rookies, such as NIO cooperating with Weilan New Energy, BAIC, SAIC, and GAC investing in Qingtao Energy.
In addition, the joint research and development of car companies and battery factories has become a mainstream solution for the layout of solid-state battery technology, but now it is still overseas car companies that are in the leading position.
Among them, Japanese automakers have an earlier layout, driven by policies, and joint research and development with battery companies, while European and American automakers have invested in start-ups.
One of the reasons for the overall overseas layout is that it can preemptively bet on all-solid-state battery technology with large subsidies.
For example, with the support of the system of joint research and development between Japanese car companies and battery factories, the local government has provided financial support of more than 200 billion yen (about 10 billion yuan), and strives to achieve the commercialization of all-solid-state batteries by 2030, with an energy density target of 500Wh/kg.
The South Korean government provides tax credits to support the research and development of solid-state batteries, and the power battery giants jointly promote it, aiming to develop a commercial technology with an energy density of 400Wh/kg from 2025 to 2028 and complete the installation of vehicles by 2030.
Among European countries, Germany has the largest investment in R&D layout. In the United States, funded by the Department of Energy, start-ups have led R&D and reached cooperation with many car companies, aiming to achieve an energy density of 500Wh/kg by 2030.
Under the temptation of powerful performance, even if it is difficult to overcome solid-state battery technology, there will always be people who will bow down to the game and gnaw hard bones.
Therefore, the industry pays attention to the latest progress of solid-state batteries, and also needs to look more at China, Japan, South Korea and other countries.
At present, batteries still account for the majority of the cost of a new energy vehicle, about 30%, and are the primary consideration for car companies when controlling profit margins.
According to a research report recently released by RMI, a global energy think tank, the cost of batteries is likely to drop significantly in the next few years. According to the report, battery costs could fall to $32/kWh~$54/kWh by 2030. The company also said that the top-of-the-line battery energy density will reach 600Wh/kg~800Wh/kg.
RMI claims in the report that this goal will be achieved due to increased battery energy density, lower battery costs, and exponential growth in battery demand. Since lithium-ion batteries were introduced in 1991, every doubling in battery production has reduced battery prices by 19%.
RMI analyzed the total demand for all battery applications, including consumer electronics, and observed that the average cost of battery production had fallen by 199% for every increase in battery production since 1991. Over time, the cost of batteries will continue to fall.
If solid-state batteries reach the "Scaling Law" moment in technology and cost one day, and the performance can be greatly improved, it will not only be used as a "enjoyment" for high-end models, but can be installed on more low-end models to achieve technical equality. This is also the expectation of car companies and consumers.
However, each car company is equipped with semi-solid-state batteries, and the average real cruising range is about 600km/h. Even so, there are already several car companies that have advertised that the maximum range can reach 700km/h.
In order to pursue technological differences and get rid of the involution situation, the symbolic significance of solid-state batteries has been greater than the practical significance, and the solid-state battery technology that survives in the imagination is only a "venture capital".