The solid-state battery arms race starts quietly

The solid-state battery arms race starts quietly

This article is from the WeChat public account: Brocade (ID: jinduan006) , author: Zhiyong, head picture from Pixabay

In the past few years, the technology of power batteries has advanced by leaps and bounds, but the hidden dangers and mileage anxiety are still the “curse” that it is difficult to get rid of. At the same time, solid-state batteries have become the new darling of the industry amidst disputes and doubts. With the entry of various giants, the future of solid-state batteries has gradually become clear.

On January 9 this year, NIO (NYSE:NIO) released a high-profile 150kWh solid-state battery pack with an energy density of 360Wh/kg on NIO Day. The NIO ET7 sedan equipped with this battery pack will have a battery life of more than 1000km, which is impressive. .

The popularity of NIO has not subsided. On its Power Day on March 15th, Volkswagen Group stated that it will focus on the development of solid-state battery technology in the future, and Volkswagen directly throws out the goal more simply and rudely: it is expected to start using solid-state batteries in 2025.

In April, the unwilling BMW Group also gave a plan for solid-state batteries: it plans to launch a prototype car equipped with solid-state batteries by 2025 and achieve mass production by 2030.

Not only car companies, but power battery giants are also unanimously deploying solid-state batteries: CATL has invested 3.3 billion to build a 21C innovation laboratory for the research and development of next-generation batteries such as metal lithium batteries and all-solid-state batteries; LG Chem said it will be in 2025. To realize the commercialization of all-solid-state batteries between 2010 and 2027; Panasonic plans to launch an electric vehicle using solid-state batteries in 2025.

For a time, solid-state batteries became an invisible battlefield for industry giants. Why are solid-state batteries so attractive, and what is the current development progress?

1. Solid-state batteries have become a high ground for giants

01 What is a solid-state battery?

Solid-state batteries sound mysterious, and it is simple to understand with traditional liquid lithium batteries, because their working principles are the same. Traditional liquid lithium batteries are also vividly called “rocking chair batteries” by scientists. The two ends of the rocking chair are the positive and negative poles of the battery, and the middle is the liquid electrolyte and the diaphragm. The lithium ion is like an “athlete”. The athlete runs back and forth on the two ends of the rocking chair, and the battery charging and discharging process is completed.

When it comes to solid-state batteries, the “athlete” still runs back and forth between the positive and negative ends. The difference is that the sports venue is replaced with a solid electrolyte from a liquid electrolyte. In addition, the solid electrolyte also plays the role of separating the positive and negative electrodes, that is, it acts as a separator, so the solid-state battery no longer needs a separator.

In terms of composition structure alone, solid-state batteries are simpler.

The solid-state battery arms race starts quietly

Figure 1: The difference between solid-state batteries and liquid lithium-ion batteries, source: Internet

Let’s talk about the classification of solid-state batteries. Solid-state batteries are divided into three routes: polymer, oxide and sulfide according to their electrolyte. This part will be analyzed in detail below.

The solid-state battery arms race starts quietly

Figure 2: Main types of solid electrolytes, source: Tianfeng Securities

02 Solid state battery VS liquid lithium battery

Compared with liquid batteries, solid-state batteries have advantages mainly in safety and energy density.

Let me start with the most concerned security issues. Nowadays, the development momentum of electric vehicles is strong, and the sales of electric vehicles have repeatedly reached new highs. However, the safety hazards of batteries have always been the “Sword of Damocles” hanging on the heads of electric vehicles. For example, last year Weimar Motors had four spontaneous combustion accidents in more than a month, which once aroused everyone’s concerns about the future of electric vehicles.

In fact, the potential safety hazards of electric vehicles should be counted on the head of the liquid lithium battery. Once the battery is squeezed or impacted, it will cause the diaphragm to rupture, causing a short circuit between the positive and negative electrodes. At the same time, a large amount of heat is generated inside the lithium battery, and the flammable organic solvent in the liquid electrolyte is added.

Car companies and power battery companies have been doing their best to improve battery safety performance. For example, adding flame retardants to the electrolyte; optimizing the BMS thermal management system; using high-strength, high-temperature-resistant battery diaphragms, but it is a pity that the symptoms cannot be cured.

But solid-state batteries are expected to completely solve the safety problem. First of all, the positive and negative electrodes of solid-state batteries are not prone to short-circuit phenomenon. Secondly, the solid electrolyte is not only non-flammable, non-volatile, and even high temperature resistant. The battery will not catch fire or explode under the same extreme conditions.

Let’s talk about the energy density of the battery, which is the problem of mileage anxiety. Although the cruising range of mainstream electric vehicles can reach more than 500km, high-end models can even exceed 700km. However, in actual use, this battery life is to be discounted (the so-called operating mileage) , and, unlike fuel vehicles, most electric vehicle owners will not drive the car until the battery is 10% remaining. Recharge.

To solve the mileage anxiety can basically only rely on the energy density of the stack battery. According to the “Energy-saving and New Energy Vehicle Technology Roadmap”, the energy density target of power batteries in 2025 is 400Wh/kg, and the target in 2030 is 500Wh/kg. If you want to achieve the goal of 2030, the existing liquid lithium battery technology route may be difficult to shoulder. It is difficult to break the energy density ceiling of 350Wh/kg alone, but the energy density of solid-state batteries can easily exceed 350Wh/kg.

The solid-state battery arms race starts quietly

Figure 3: The current energy density level that liquid lithium batteries can achieve, data source: First Electric, Shen Wan Hongyuan

It should be noted in advance that the energy density of the battery depends on the positive and negative materials. If the liquid electrolyte is simply replaced with a solid electrolyte, if the existing positive and negative materials are not changed, the result can only improve the safety of the battery, but not the energy density of the battery. Therefore, solid-state batteries need to support the innovation of positive and negative materials.

Speaking of cathode materials, current power battery companies are developing towards high nickel. From the ternary 5 series to the ternary 8 series, the nickel content becomes higher, but the stronger the battery activity, the more unstable the inside of the battery will naturally be, and the safety issues mentioned above become more prominent. Although the current Sanyuan 8 Series has a high energy density, it is not used on a large scale. The mainstream of the main engine factory installation is to use the 5 Series power battery. There is also a cost factor, which is not discussed here.

Thanks to the high safety of solid-state batteries, the positive electrode of solid-state batteries does not need to stop with 8 series materials, and can even dry to 9 series (ultra-high nickel) . The energy density of the positive electrode link can reach 700Wh/kg, which will be a qualitative leap. .

Look at the negative electrode material. In fact, there is a consensus in the industry on the upgrade route of anode materials, which is to upgrade from the current graphite anode to the lithium metal anode. Among the currently known negative electrode materials, the energy density that the lithium metal negative electrode can achieve is the highest, and its gram capacity is more than 10 times that of the graphite negative electrode in the current liquid lithium battery.

The question is, if the lithium metal negative electrode is so good, why don’t the existing power batteries use it? The crux of the problem is still in the liquid electrolyte. The lithium metal negative electrode basically cannot exist stably in the liquid electrolyte, and the two will react violently, which can be described as “incompatible with fire and water.” But in solid-state batteries, they can coexist harmoniously.

In a nutshell, it is the solid-state battery that gives new positive and negative materials a lot of room.

In addition, it is worth noting that liquid lithium batteries often need to encapsulate the single cells before connecting them in parallel and then in series. If you want to save the process and directly connect them in series, the positive and negative electrodes will be short-circuited. Since the solid-state battery does not contain liquid inside, there is no short circuit problem, and can be directly assembled in series. In addition, liquid lithium-ion batteries need a cooling system to prevent the temperature from becoming too high during use. For solid-state batteries, because of their high safety, a cooling system can be simplified or even not required. Therefore, in the actual mass production of solid-state batteries, the component cost will be lower, and the entire production process will be simpler.

The solid-state battery arms race starts quietly

Figure 4: Comparison of preparation processes between liquid lithium-ion batteries and solid-state batteries, source: Everbright Securities

Rather than saying that solid-state batteries are “subverting” liquid lithium batteries, solid-state batteries are an upgraded version of liquid lithium batteries.

03 Xia Yu sees each other, both long and short

Since solid-state batteries are so good, why don’t car companies rush to “upgrade” them and use traditional liquid lithium batteries? The reason is that the replacement of liquid electrolyte with solid electrolyte solves some of the problems, but also brings new troubles. Before the solid-state battery is officially mass-produced, there are still several key issues that need to be overcome.

First, the ionic conductivity of the solid electrolyte is low. The so-called ionic conductivity refers to the smooth movement of lithium ions in the electrolyte.

The conductivity of solid-state batteries is generally lower than that of liquid ions. For example, polymer electrolytes have ionic conductivity that is even orders of magnitude worse than that of liquid ions. It is equivalent to the increased resistance of the “athlete” running, and the speed is much slower than before, and even the resistance is too great, and it is a bit unable to run.

The solid-state battery arms race starts quietly

Figure 5: Comparison of conductivity between solid electrolyte and liquid electrolyte, data source: collated by Damask Research Institute

Second, the interface impedance between the solid electrolyte and the electrode is relatively large.

The traditional liquid electrolyte is in solid-liquid contact with the positive and negative electrodes, and the interface has good wettability. It can be said that it is “closely connected”, and there is no large impedance between the interfaces. However, the solid electrolyte and the positive and negative electrodes are in solid-solid contact, and the contact effect is much worse, so the transmission resistance of lithium ions between the interfaces is greater. This is like the “athlete” who used to run on a flat track, but now it is replaced by a bumpy mud road. Naturally, it is not possible to perform at a real level.

Because of the low conductivity and high interface impedance of solid-state batteries, the transmission efficiency of lithium ions inside the battery is too low, which affects the fast charging capacity and cycle life of the battery, and at the same time, the battery capacity cannot be released normally.

The solid-state battery arms race starts quietly

Figure 6: The effect diagram of the interface contact between solid-state battery and liquid battery, data source: collated by Jinshen Research Institute

Considering the current technological level, it is still difficult for many companies to realize all-solid-state batteries in one step, and then take a “three-step” route from semi-solid, quasi-solid, and all-solid. The NIO solid-state battery mentioned at the beginning of the article is actually a semi-solid battery.

The solid-state battery arms race starts quietly

Figure 7: “Three-step” roadmap for solid-state batteries, source: Everbright Securities

The third point is the high cost.

Oxide and sulfide electrolytes are porous ceramic materials. The characteristic of the material is that it is brittle. It is very difficult to process it into a very thin electrolyte, and it will break if it is careless. Even if it can be processed, the existing process level and equipment capabilities, the yield of the finished product is not much better.

And solid-state batteries are still far from mass production, not to mention the supporting industrial chain. A large part of the reason why traditional liquid lithium batteries can continue to reduce costs in the past few years is the synergy of the industrial chain. Currently, the cost of solid-state batteries is still high.

2. Players from all walks of life enter the game, mass production is still in the long run

The technical bottleneck of solid-state batteries has not been broken, and industrialization has to face many problems, but it does not affect the enthusiasm of players from all walks of life.

For car companies, the starting point is much more complicated. First of all, it is certain that electric vehicles are the future of automobiles, and traditional car companies are eager to transform. Batteries are the core of electric vehicles, and car companies naturally hope to be in their own hands. Car companies have been “stuck” by power battery companies for a long time, so how can they be willing to be constrained again? Solid-state batteries are a great opportunity to regain the initiative, which is why Volkswagen, Toyota, and other fuel vehicle giants deploy solid-state batteries.

For power battery companies, on the one hand, solid-state batteries can solve their long-standing problems of safety and energy density, and the temptation is huge. It is no exaggeration to say that whoever masters solid-state battery technology in the future can give pointers. Therefore, not only CATL and LG, but also second-tier battery companies such as BYD and Guoxuan Hi-Tech have all laid out solid-state batteries. On the other hand, under the existing liquid lithium battery route, domestic second-tier battery companies have been suppressed by the Ningde era. Even with BYD with a “blade battery” in hand, it is difficult to shake the status of the Ningde era. With solid-state batteries, everyone has the opportunity to stand on the same starting line.

Throughout the global participants, different companies “believe” in different solid electrolyte routes: domestic companies dominate the oxide route, European and American companies prefer the polymer route, while Japanese and Korean companies are more keen on the sulfide system.

The solid-state battery arms race starts quietly

Figure 8: Overview of key global solid-state battery companies, source: Qianzhan Industry Research Institute

01 Polymer faction

The polymer electrolyte route is the first solid-state battery route to be applied.

As early as 2011, the French company Bollore launched a solid-state battery using polymer electrolytes. Unfortunately, the ionic conductivity of the solid-state battery at room temperature is too low. It is necessary to equip the battery with a heater, and the energy density can only achieve 100Wh/kg, which is basically It has no commercial value.

Since the problem of low conductivity of polymer electrolytes has been difficult to solve, mainstream solid-state battery companies still focus on oxide electrolyte and sulfide electrolyte routes.

02 Oxide Faction

The comprehensive performance of the oxide faction is the best among the three solid electrolyte routes. The most representative ones are Jiangsu Qingtao, Taiwan Huineng and overseas QuantumScape.

Jiangsu Qingtao is a typical start-up company established in 2016. Compared with power battery companies, there is no technical baggage, and progress has been smooth. Qingtao has built the country’s first mass-produced solid-state lithium battery production line in November 2018, and it has been officially used in special power supplies, high-end digital and other fields. Last year, a new energy prototype equipped with Qingtao’s solid-state power lithium battery was successfully rolled off the assembly line at BAIC, and Qingtao’s phase 1 1GWh solid-state power battery project has been officially put into production.

Compared with Qingtao, Taiwan Huineng has a clearer plan for the future of solid-state batteries. In 2013, Huineng realized the commercial mass production of solid-state lithium batteries for the consumption of lithium batteries. In 2019, Huineng cooperated with Weilai to customize the production of “MAB” solid-state battery packs (semi-solid) . According to its plan, semi-solid lithium-ion batteries will reach a production capacity of 1GWh in 2021 and mass production of all-solid-state batteries in 2024.

Peripheral player Ganfeng Lithium, although it is a lithium material company, has also made a lot of layout on solid-state batteries. According to the information disclosed in the 2020 annual report, Ganfeng Lithium has invested in the first and second generation solid-state lithium battery research and development pilot production lines, but they are still in the mixed solid-liquid electrolyte stage, and the energy density cannot exceed 300Wh/kg. Ganfeng Lithium Battery has been deploying the third generation of solid-state lithium batteries based on metal lithium anodes, and the energy density will exceed 400Wh/kg in the future.

Finally, I will talk about QuantumScape, a key investment company of the Volkswagen Group. It went public in November last year through SPAC. It is the only listed company in the industry with solid-state batteries as its main business. 

According to the information published on its official website, QuantumScape has technically broken through the bottleneck of the low ion conductivity of solid-state batteries. The fast charging speed even exceeds that of traditional liquid lithium batteries. The fast charging can achieve 80% charging in 15 minutes. At the same time, the energy density, cycle life, In terms of safety, they are significantly better than existing liquid lithium batteries.

But what it shows is only the test result of the single-piece laminate, not the effect of being installed on the car. After all, this is still a laboratory product, and there is still a gap between mass production. According to QuantumScape’s prospectus, the company will establish a 1GWh trial production line in 2024 and test it on Volkswagen to achieve commercial mass production of its solid-state batteries.

The solid-state battery arms race starts quietly

Figure 9: QuantumScape’s solid-state battery fast charging performance, source: QuantumScape official website

03 Sulfide faction

The sulfide electrolyte is actually derived from the oxide electrolyte. Considering the low conductivity of the oxide electrolyte, scientists replaced the oxygen element in the oxide electrolyte with sulfur. Because the electronegativity of sulfur element is smaller than that of oxygen element, it is less bound to lithium ions, which is conducive to obtaining more freely moving lithium ions. Simply put, the sulfide electrolyte has a higher ionic conductivity, which can reach a level close to that of a liquid lithium battery system.

However, the sulfide electrolyte solves the problem of ionic conductivity, and it also brings another difficulty. Because the sulfide electrolyte is sensitive to air and is extremely prone to adverse reactions, the production of sulfide electrolyte has harsh environmental requirements and is a big test for equipment. , The result is extremely high production costs.

The fastest progress in the sulfide route is Japan’s Toyota.

At present, Toyota has more than 1,000 patents in the field of solid-state batteries, ranking first in the world. In July last year, the general manager of Toyota’s automotive battery business revealed that Toyota had successfully manufactured solid-state batteries as planned and installed them on concept cars. It is expected to be officially mass-produced in 2025.

Finally, it is worth talking about the Ningde era in China. As early as 2016, CATL announced its research and development path on sulfide solid-state batteries. However, the information about its solid-state battery has been kept secret, and the public information is quite small. It was not until January this year that it took the initiative to disclose “a solid electrolyte preparation method” and “a sulfide solid electrolyte sheet and its preparation method”. For solid-state battery related patents, the patent abstract shows that the above-mentioned patents aim to improve the conductivity of solid electrolytes and reduce the impedance of the solid-solid interface, which is the short-board problem of solid-state batteries mentioned above.

CATL has not disclosed the mass production time of solid-state batteries. In the past year, CATL has frantically increased its power battery production capacity. The announced long-term planned total production capacity is close to 500GWh, and some production capacity has been scheduled after 2025. It is speculated from this point that Ningde’s solid-state batteries are also not the focus of mass production in the short term.

The solid-state battery arms race starts quietly

Figure 10: Ningde era’s public patents on solid-state batteries, source: Qichacha

Three, the unfinished end

It is undeniable that the rapid development of power battery technology has contributed to the development of electric vehicles. As the penetration rate of new energy vehicles continues to increase, the market has higher and higher requirements for power batteries, and traditional liquid lithium batteries with obvious shortcomings are difficult to adapt to the future rhythm.

As the industry-recognized next-generation battery route, solid-state batteries can perfectly solve the shortcomings of traditional liquid lithium batteries. Enterprises at home and abroad have high hopes for them and have accelerated the development of solid-state batteries, hoping to seize market opportunities.

Nowadays, solid-state batteries have made a lot of substantial progress, but technology and cost are still the two big mountains blocking the road to solid-state battery industrialization. These cannot be surpassed in the short term. Refer to the plans of mainstream solid-state battery companies, and mass production time is common. After 2025, the industrialization of solid-state batteries is estimated to be 10 years from now.

Looking back at history, 10 years is actually not a long dimension. Ten years ago, China’s pure electric vehicle sales were less than 10,000 units. By 2020, China’s pure electric vehicle sales have exceeded 1 million units. Nowadays, under the optimism of the industry and the layout of various companies, the industrialization process of solid-state batteries is expected to develop beyond expectations. While waiting for solid-state batteries, we also have confidence.

For the players who have ended, the problem that has to be faced is that the industrialization of solid-state batteries will reshape the existing lithium battery supply chain, such as diaphragm and liquid electrolyte companies. If they cannot transform and upgrade in time, they will face “subversion”. ending.

Written at the end, the development of technology has always blossomed. In addition to solid-state batteries, the future road to electrification will also include hydrogen fuel cells. Although there are also many difficulties in industrialization at this stage, it can still be seen that it has a broad development space in the fields of heavy trucks and aviation in the future. Regarding the research on hydrogen fuel cells, the Damask Research Institute will discuss it in a follow-up article.

This article comes from WeChat public account: Brocade (ID: jinduan006) , author: Zhiyong

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