Can solid-state batteries defeat the Ningde era?

Can solid-state batteries defeat the Ningde era?

"Charging five minutes and you can talking for two hours", the toxicity of this slogan is comparable to "Melatonin". Today, this slogan also has a car industry version - "charge one minute, battery life for 800 kilometers."

In early 2018, foreign media released a message, electric car brand Fisker applied for a solid lithium battery patent, the maximum life of 800 kilometers, charging only 1 minute.

With the retreat of new energy vehicles and batteries, the price of lithium batteries has been declining, and the gross profit margin of battery companies has been declining. At the same time, the lithium batteries that most companies have developed at present have not been able to improve substantially, eliminating the electric vehicles. "Mileage worry."

Therefore, the all-solid-state battery with an energy density of three times that of the ternary lithium battery came into being, and it was only able to defeat the Ningde era.

Since 2017, companies that have developed solid-state batteries have sprung up, and all-solid-state batteries have become a research hotspot for companies.

Recently, the German Volkswagen Group confirmed that it has invested 100 million US dollars to QuantumScape jointly develop solid-state batteries. "We will join forces with Volkswagen as a vehicle production specialist and QuantumScape's experience as a leader in solid state battery technology to accelerate the commercialization of QuantumScape solid state battery products," said Axel Heinrich, head of research at Volkswagen Group.

In the current various new battery systems, solid-state batteries use new solid-state electrolytes to replace current organic electrolytes and separators, with high safety, high volumetric energy density, and different new high-energy electrode systems (such as lithium-sulfur systems, metals). The air system, etc., has a wide range of adaptability and can further improve the mass energy density, which expected to become the ultimate solution for the next generation of power batteries, causing widespread concern among many research institutes, startups and some car companies in Japan, the United States, and Germany.

What is an all-solid battery?

As the name implies, all materials in the battery are in solid form, without liquid or liquid. It should note that because lithium-ion batteries are the most common batteries in our daily life, we usually use all-solid-state lithium-ion batteries as the representative of all-solid-state batteries by default. Therefore, the all-solid-state battery mentioned in this article is the default solid-state lithium ion. Battery.

According to Prof. Li Hong and Prof. Xu Xiaoxiong, who are leading the research on solid-state batteries in China, all solid-state batteries will undergo three stages: semi-solid (2018), quasi-solid (2020) and all-solid (2022). ).

At present, a semi-solid state technology realized, that is, a solid electrolyte used as a protective layer of the negative electrode metal lithium while assisting a liquid electrolyte. However, all-solid-state batteries are still in the experimental stage of the laboratory and cannot commercialized.

As mentioned at the beginning of the article, all solid-state batteries have many advantages over traditional lithium-ion batteries.

Small size

The volumetric energy density of a battery is a very important reference data. According to the application field, the requirements from high to low are consumer electronics>home electric vehicle>electric bus.

In traditional lithium-ion batteries, it is necessary to use a separator and an electrolyte, which together account for nearly 40% of the volume and 25% of the mass of the battery. If they are replaced by solid electrolytes (mainly organic and inorganic ceramic materials).the distance between the positive and negative, electrodes can be shortened to even a few to a few tenths of a micrometer, so that the thickness of the battery can be greatly reduced.

This means that after using an all-solid-state battery, the car no longer carries a battery as heavy as its own weight and runs on the road.

2. High security

For electric vehicles, the safety of the battery is extremely important. The self-ignition accident of new energy vehicles has not stopped, even Tesla, the highest end of the global new energy vehicle, is not immune.

Conventional lithium-ion batteries are extremely prone to heat due to abnormal organic conditions such as long-term charging and internal short-circuiting due to the organic liquid electrolyte used, resulting in swelling, spontaneous combustion or even explosion of the electrolyte. Many inorganic solid electrolyte materials are non-flammable, non-corrosive, non-volatile, and have no leakage problems. The polymer solid electrolyte has a significantly improved battery safety compared to a liquid electrolyte containing a flammable solvent.

3. High energy density

Solid electrolytes generally have a wide electrochemical window, just like a small frame, so more high-voltage cathode materials can installed. Coupled with the small size and stability of solid-state batteries, battery management can simplified and the energy density will naturally increase.

At present, the energy density of all-solid-state batteries is about 400Wh/Kg, and the estimated maximum potential value is 900Wh/Kg, which has more than 100% room for improvement.

The high energy density means that the battery's endurance enhanced. One of the factors currently plaguing the advancement of electric vehicles is that the current battery life cannot be broken. If you achieve an all-solid-state battery, you can eliminate the "mileage anxiety". Even if it charged for one minute at the beginning of the article, it is not impossible to end the 800 kilometers.

Not all solid-state batteries can "step into the sky"

Despite the many advantages of all-solid-state batteries, it is not so easy to get out of the lab.

The first is that the interface impedance of the all-solid-state battery is too large. The interface between the solid electrolyte and the electrode material is in a solid-solid state, so the effective contact between the electrode and the electrolyte is weak, and the transport kinetics of ions in the solid matter is low.

The second is the charging problem. For electric car owners, they do not want to waste more time on charging. However, if you use an all-solid-state battery, it is more difficult to charge quickly.

The impedance and conductivity of the battery show that the internal resistance is large, which will hinder the charging, and because the internal resistance is large, energy loss will occur during the charging process. This part of energy waste cannot ignored. In addition, the material of the all-solid battery may expand or contract during the charging and discharging process, resulting in easy separation of the interface.

The most important cost issue follows this. Cost is the biggest factor preventing commercialization.

At present, the electrolytes of all-solid-state lithium batteries mainly have two major systems, organic and inorganic, and the cost is generally high. In particular, complicated processes such as CVD/PVD prepare many inorganic batteries, and the production (deposited film) is slow and expensive. The single cell has a small capacity and is often only suitable for batteries for small electronic devices, let alone for automobiles.

In addition, the solid-state battery preparation process is not mature enough, and battery, usage data collection is not comprehensive. Only in the electrolyte manufacturing of all-solid-state batteries, the technical immaturity of the two core problems of solid-solid interface optimization is enough to make the cost of solid-state batteries high.

In addition, all-solid-state batteries have not yet reached commercialization on a large scale.

At the same time as the solid-state battery heat in the capital market this year, the industry is amazed; most people say that it is too early to commercialize solid-state batteries.

Li Wei, a researcher at the Institute of Physics of the Chinese Academy of Sciences, said that in order to commercialize solid-state batteries, there must be sufficient technical reserves and R&D teams, because a lithium battery technology generally requires at least 15 years of development time.

Wang Rongjin, a partner of Jinbang Capital, who is investing in lithium battery, told the Daily Economic News that most of the R&D personnel he has contacted are pessimistic about solid-state batteries and believe that it is difficult to commercialize in the short term.

Even as early as 2010, Toyota introduced electric vehicles that use solid-state batteries and have a range of up to 1,000 kilometers. However, Toyota's staff also admitted that Toyota's all-solid-state batteries are still in the laboratory stage.

Li Wei described the current commercialization of solid-state batteries as "the so-called all-solid state only sees the concept, but does not know the performance; only heard of security, but no safety test report." He said that from the public data, there is no systematic data release for solid-state batteries, and fuel cells have system data such as the size, power and life of the stack. If these data made public, this technology is mature.

Indeed, to date, many car companies have indicated that they have made some moves in this regard, but none of them actually gave data.

Domestic and foreign giants have laid out

Although for large-scale batteries, large-scale commercialization in the car is not the topic of the current, but many car companies, battery suppliers, etc. have made great efforts in this regard. Leading companies in the battery industry such as Toyota, Panasonic, Samsung, Mitsubishi and the domestic Ningde era have actively deployed the reserve research and development of solid-state batteries.

Relatively speaking, the technology maturity is higher, and the technology is deeper. It belongs to Bolloré of France, Sakti3 of the United States and Toyota of Japan. These three also represent the typical technology development direction of the three solid electrolytes of polymers, oxides and sulfides.

Bolloré, which is famous in Europe, uses a polymer electrolyte system, and Samsung uses a sulfide electrolyte system. German auto parts giant Bosch (BOSCH) acquired the US battery company "Seeo" in 2015. Bosch and Seeo then established a new plant with the famous Japanese GSYUASA Battery Company and Mitsubishi Heavy Industries, focusing on solid-state anode lithium-ion batteries.

In the field of automotive batteries, Japanese companies have been at the forefront. It has already accounted for 70% of the global market share as early as 2013, but by 2016, this figure has fallen to 41%. At present, the Japanese government hopes to regain market dominance by increasing the research and development of all-solid-state batteries.

In May 2017, the Japanese Ministry of Economic Affairs announced that it will invest 1.6 billion yen to jointly develop solid-state batteries, such as Toyota, Honda, Nissan, Panasonic, GS Yuasa, Toray, Asahi Kasei, Mitsui Chemicals, and Mitsubishi Chemical. It hoped that the goal of 800 kilometers would achieved in 2030.

Toyota also announced cooperation with Panasonic to develop solid-state batteries; BMW announced cooperation with SolidPower to develop solid-state lithium batteries; Bosch and Japan's famous GSYUASA (Tangshhao) battery company and Mitsubishi Heavy Industries jointly established a new factory, focusing on solid-state anode lithium-ion batteries; domestically, it has not largely abandoned by foreign countries in this regard.

Before the official development of solid-state batteries, the Ningde era conducted research on global solid-state battery companies and determined their own development direction. In October 2016, Dr. Liu Na, Ningde Times New Energy, introduced the layout and research and development path of the Ningde era in the field of polymer solid-state lithium metal batteries and sulfide solid-state batteries.

Moreover, in the development process of Ningde era, it is also concerned about the manufacturing of solid-state batteries. The completely manufacturing process of solid-state batteries is different from the traditional lithium-ion manufacturing process and new equipment and new processes needed. Therefore, the development of the process also carried out in the Ningde era. .

In addition, in 2017, Guoxuan Hi-Tech, which has already begun to develop solid-state batteries and solid electrolytes, revealed that the company is developing next-generation power battery production, technology in the United States and Japan according to product requirements for cooperation with international first-line vehicle brands. With production equipment, related products will use semi-solid battery technology. Companies will also pay close attention to the development and industrialization of upstream key raw materials, including solid electrolytes.

In March 2018, Guoxuan Hi-Tech said on the investor interaction platform that the company's semi-solid battery technology is currently in the laboratory-to-laboratory conversion phase.

With the rapid development of electric vehicles around the world, all-solid-state batteries can rapidly improve the endurance of automobiles, which is undoubtedly an inevitable direction for the future development of batteries. Under the dual influence of "double-point policy" and subsidies, it means that the competition in the battery industry will become more intense, forcing these companies to focus on the next generation of battery technology, solid-state batteries or better. Select.

In addition, the investment and financing of solid-state batteries has objectively promoted the research and development of solid-state batteries, stimulating the industry and the field, and promoting the industry's emphasis on solid-state batteries.

However, regarding to conductivity, cell rate, battery preparation efficiency, and cost control of solid electrolytes, all solid state batteries are still have long way to go.

The page contains the contents of the machine translation.