Superbattery fiction and reality: gimmick or disruptive technology?

Tesla CEO Elon Musk recently announced on Twitter that Tesla will release an "industry-disruptive" power battery product on "Battery Day." The industry believes that this product is "Super battery".

Barring any unexpected events, Tesla’s “Battery Day” event will be held on September 22 at Tesla’s California factory. Previously, this event had been postponed repeatedly due to the epidemic.

According to foreign media reports, Tesla will announce the details of its "million-mile" battery at the "Battery Day" event. The "Million Mile" battery uses a new generation of monocrystalline NCM (nickel, cobalt, manganese) 523 cathode and a new advanced electrolyte to enable electric vehicles to last 1 million miles (approximately 1.61 million kilometers).

Coincidentally, not only Tesla has sounded the clarion call to attack super batteries, but also OEMs such as Volkswagen and General Motors, as well as domestic and foreign power battery companies such as CATL, Honeycomb Energy, LG Chem, and Samsung SDI, have launched a battle against super batteries. Among them, LG Chem, which has become the world's largest power battery company by virtue of its orders from Tesla, announced on September 17 that it will split the company's power battery business unit in December this year and name it "LG Chem" LG Energy Solutions.

A Korean battery industry insider told China Business News that this is mainly due to LG Chem’s capital needs in battery research and development and production capacity expansion, of which super batteries have become an important part. As of the first quarter of 2020, LG Chem's total borrowed cash has exceeded 11 trillion won, a significant increase from 8.41 trillion won at the end of 2019. The above-mentioned industry insiders revealed that LG Chem’s borrowed cash remained at a stable level of 2 trillion to 3 trillion won before 2017. Since the “super battery” concept was proposed in 2018 and the power battery market continued to expand, this amount has increased every year. Nearly doubled in growth.

Power batteries are known as the "heart" of electric vehicles. Various companies have deployed heavy forces in this field, and a tough battle is inevitable. However, the industry has different opinions on whether super batteries are a gimmick or a real technological change.

Super battery wearing a "veil"

What exactly does a super battery look like?

At present, super batteries are still more at the conceptual level. Companies that break into the super battery field often only give simple "km" and principle information.

For example, Tesla issued three patent documents in September last year, December and April this year, respectively describing the material formula, discharge cycle and number of charge and discharge. The company said that there are revolutionary changes in its technology, but it does not require fundamental changes in ternary lithium or lithium iron phosphate materials, so the room for cost increase is relatively limited. As for the details of the "super battery", this is yet to be disclosed by Tesla on the 22nd of this month.

In addition, Ningde Times also revealed not long ago that it will launch batteries with a total cycle charging range (total mileage) of up to 2 million kilometers and a lifespan of 16 years. It is currently accepting orders and producing them. CATL claims that the biggest feature of the long-life batteries developed by CATL is its unique "self-repairing long-life technology", which can be used in both lithium iron phosphate batteries and ternary lithium batteries. Therefore, compared with the technology of competing companies, Has cost advantage. However, CATL is also vague on the details of super batteries.

Because of this, the industry is full of curiosity about the upcoming reveal of Tesla’s super battery.

Wu Hui, general manager of the research department of Ivey Economic Research Institute, said in an interview with China Business News that it is impossible to judge whether this technology is breakthrough based on a million-mile battery life. If an electric vehicle is equipped with 100 kilowatt-hours of electricity and has a cruising range of 700 to 800 kilometers, it can reach Tesla's goal of one million miles after 2,000 cycles.

Wu Hui said that if Tesla will adopt the single crystal NCM 523 rumored in the industry, this material is a relatively mature material system, and its gas production, thermal stability and cycle performance are better than the polycrystalline NCM 523 material. It has more advantages, but its capacity is lower than that of polycrystalline NCM523 material. Therefore, single crystal NCM523 material is more suitable for applications in fields that do not have high requirements for rate performance but have high requirements for cycle performance. In addition, Tesla will use advanced electrolytes, possibly solid-state electrolytes, so this super battery may be a solid-state battery or a semi-solid-state battery.

He also analyzed and pointed out that it is meaningless to talk about the battery life of electric vehicles. It depends on how much electricity the car is loaded with to talk about single cruising range and cycle life. The cost of installing more batteries will definitely be higher. The high cost is not because the unit price of the battery is high, but because the car is equipped with more batteries. Therefore, in essence, to improve the battery life, the energy density of the battery must be increased, and you cannot rely on installing more batteries.

Xuan Yangguo, an academician of the Korean Academy of Engineering and a professor at Hanyang University, told China Business News that the life limit of power batteries is mainly at the two levels of cell material and cell design. Therefore, by improving the structural design to make the battery stable and not jump rapidly, or directly introducing new cell materials to improve the initial capacity and the stability of the positive and negative electrode materials, these are the two core routes to improve the battery life. Most of them Super batteries often choose from these two routes.

Facing multiple bunkers

After years of hard work, the technology of power batteries has improved significantly and the cost has dropped significantly. Previously, the cost of power batteries accounted for as high as 50%~60% in the cost of electric vehicles, but now the proportion in many electric models has dropped to 30% or even lower. At the same time, the comprehensive cruising range of electric vehicles has generally been concentrated below 300 kilometers before, and now many models have exceeded 500 kilometers or even higher.

However, in the battle for power battery technology, OEMs and power battery manufacturers have to face many barriers such as cost and safety. Whether it is Tesla and Panasonic internationally, or domestic companies such as BYD, CATL, NIO, and GAC New Energy, they have all been involved in accidents where batteries caused new energy vehicles to catch fire. Currently, data from the national regulatory platform shows that since 2020, 54 domestic new energy vehicles have caught fire.

Can Tesla's super battery solve safety and cost problems and smoothly advance the commercialization process?

Since the beginning of this year, what has attracted much attention is that CATL, which has entered Tesla’s battery supplier list, has been accused of having safety risks in its NCM811 batteries to some extent. This is due to the fact that GAC New Energy’s flagship pure electric model Aion S, which uses NCM811 batteries from CATL, suffered three spontaneous combustion accidents this year. In this regard, GAC New Energy insiders said in an interview with China Business News that the first spontaneous combustion accident has been basically identified. The fire was caused by the relatively violent collision of the car. The subsequent two fires are still under investigation with the battery supplier. The reason will be announced in time once the reason is found out.

In an interview with a reporter from China Business News, CATL insiders responded that the battery cells for GAC New Energy Electric Vehicles are supplied by CATL, and the battery packs used in GAC New Energy Electric Vehicles are partly produced by itself and partly by Ningde. Courtesy of The Times. Exactly which link caused the safety hazard is still under joint investigation with GAC New Energy.

The so-called NCM811 battery refers to a ternary lithium battery with a ratio of nickel, cobalt, and manganese in the cathode material of 8:1:1. The NCM811/graphite system battery cell launched by CATL in 2019 has a single energy density of more than 240Wh. This is more than 40% higher than the density of lithium iron phosphate batteries, and more than 15% higher than the general ternary lithium battery. Increasing the energy density of battery cells can help increase the energy density of battery packs, thereby increasing the vehicle's cruising range. In addition, some people in the industry have estimated that the cost per watt hour can be reduced by 8% after using ternary batteries produced with 811 materials into battery packs.

NCM811 batteries are becoming one of the key research directions for global power battery companies. However, due to safety issues, LG Chem and SKI originally planned to launch NCM811 batteries for electric vehicles in 2018, but they were later postponed. Currently, NCM811 prismatic and soft-pack batteries have not been widely promoted internationally.

As a new type of NCM811 technology, its application difficulty is multi-dimensional. The first is battery cell production. NCM811 material is restricted by factors such as its high nickel content, high residual alkali on the surface, and poor thermal stability. It poses a great challenge to cathode material manufacturers and battery companies. The production and manufacturing environment and technical level of the battery have put forward higher requirements; secondly, the safety of the battery is a systematic project. Due to the changes in the performance of the individual units, the modules, systems and even the entire vehicle should be designed in a targeted manner. The production process also needs to increase its requirements. Therefore, the large-scale commercialization of NCM811 batteries is still subject to certain limitations.

CATL's NCM 811 battery reduces the proportion of cobalt by increasing the proportion of nickel and reduces the production cost of the battery. However, the greater the proportion of highly active nickel in power batteries, the thermal stability of the cathode material is relatively reduced. When the battery encounters high temperatures, Thermal runaway may easily occur due to impact such as external force. After multiple fire incidents occurred in electric vehicles equipped with CATL's NCM 811, there are rumors that CATL has basically rejected the NCM811 route, which has accounted for 20% of its power battery market, and will turn to NCM523 batteries with lower energy density. In this regard, the above-mentioned insiders of CATL said that this rumor is untrue. There will be challenges in the development of new NCM811 technology, but they will not give up just because of difficulties. This is one of the weapons to deal with advanced battery technologies such as Japan and South Korea in the future. First, we will continue to overcome difficulties and continuously improve NCM811 technology.

New technologies often encounter unknown challenges. Can the Tesla super battery, which is about to be unveiled, break through many barriers such as safety and cost and trigger changes in the power battery industry?

Wang Fan, a researcher in the power battery industry, is studying the reliability of different types of batteries. To this end, he is conducting research and experiments on battery life in various regions with different climates across the country. He said that the performance stability of the battery is mainly based on whether the electrolyte and the separator layer between the cells are stable, and he found that some early cheap power batteries appeared on some super batteries called "dream batteries". Situations that occur, such as different weather conditions that affect battery life.

Wang Fan believes that even the NCM 811 battery, which is more concrete than super battery technology and has nearly three times more patents, has caused the power battery industry to think deeply and make continuous improvements due to several spontaneous combustion cases, so super batteries are relatively abstract. Based on the concept of globalization, whether its safety performance is guaranteed still needs more verification.

Since Tesla has not announced the specific materials and composition of the super battery, it is temporarily difficult for the industry to estimate its cost, but it is generally believed that the cost is bound to increase. In addition, whether the "super battery" has commercial value has also been questioned. Liu Miao, a teacher at the School of Automotive Engineering at Shanghai University of Engineering and Technology, said in an interview with China Business News that the "three-electric system" represented by batteries is indeed the core component of many new energy vehicles, but considering the actual use of a new energy vehicle The lifespan is far from as simple as a battery component.

Liu Miao mentioned that just like the "barrel effect", a car is a system made up of many parts that work together, and each part is connected like a gear. Therefore, the overall life of the car does not depend on the component with the longest life, but on the Parts with the shortest life span.

For example, the warranty period of the motor cable board that connects the battery and the motor is generally only a few years, which is far shorter than the designed service life of the super battery. Liu Miao said that if the life of this kind of accessory is to be greatly improved, it will be difficult unless the material is completely replaced. In his view, even if super batteries are technically achievable, other components of new energy vehicles do not have the same long service life, which means that the actual value of super batteries is not as great as advertised.