Japanese automaker Nissan's blueprint for solid-state batteries (ASSB) is gradually becoming clear. Kazuhiro Doi, Nissan's vice president of advanced battery research and development, said: "All-solid-state batteries can change the game in the electric vehicle industry. ”
On April 11, Nissan officially announced a pilot production facility for stacked soft-pack all-solid-state battery cells, planning to build a production line and put it into use in 2024, and officially put into operation in 2028. Nissan's all-solid-state battery pilot production facility is located at the Nissan Automotive Research Center in Kanagawa Prefecture, Japan, and the project aims to further promote the development and application of all-solid-state batteries.
Previously, Nissan's Solid-State Battery Feasibility Study Laboratory was conducting small-scale, hand-made battery experiments. At present, the laboratory can only produce about 50 four-layer soft-pack solid-state batteries per month, while an electric car alone needs about 5,000 soft-pack solid-state batteries. Therefore, the construction of large-scale battery production facilities is crucial to the commercialization process of its solid-state batteries.
Image source: Nissan official website
In the "Nissan Vision 2030", Nissan plans to build a solid-state battery pilot plant in Yokohama, Japan, by fiscal year 2024. By fiscal 2026, a total of 2 trillion yen (about 112.8 billion yuan) will be invested to accelerate the transformation of electric technology. At the same time, Nissan plans to achieve large-scale mass production of solid-state batteries in fiscal 2028, and launched the first electric model equipped with an original all-solid-state battery in the same year.
Nissan has promised to bring lighter, smaller, and more energy-dense solid-state batteries to market within six years, and believes that this breakthrough will help the company launch electric models in segments such as pickup trucks, large SUVs and even sports cars, and improve the competitiveness of electric models.
Kunio Nakaguro, Executive Vice President of Nissan Motor Company and responsible for R&D and product development, said: "Through extensive R&D efforts, Nissan Motor is actively involved in the research and development of molecular-grade battery materials and the development of safe and high-performance electric models, leading the development of electro-drive technology. At the same time, Nissan Motor uses electric models as energy storage batteries to support the development of the city. ”
Nissan's solid-state battery has an energy density close to twice that of a conventional lithium-ion battery, and at the same time has excellent charging and discharging performance, charging time is one-third of that of lithium-ion batteries, and reduces the amount of expensive rare metals, effectively reducing battery costs.
According to the plan, by fiscal year 2028, the all-solid-state battery can reduce the battery cost to $75 per kWh (about 477 yuan), and further reduce it to $65 per kWh (about 414 yuan) in the future to achieve cost parity for electric vehicle models and fuel models. It is understood that the current cost of ternary lithium batteries has exceeded 1,000 yuan per kWh.
Kazuhiro Doi said, "Solid-state batteries are twice as dense as current lithium-ion batteries, so they are like a more dangerous potential bomb." In the event of a major accident, solid-state batteries could be even more catastrophic than current batteries. But he also firmly believes that Nissan can now overcome such safety issues, as well as other key challenges that make it difficult to deliver solid-state batteries.
When producing solid-state batteries, a series of strict standards are required. First of all, the slurry must be beaten very finely to maximize the conductivity of the battery. Second, the cathode-electrolytic-anode layer must be precisely arranged. In the process, Nissan must also increase the speed of all procedures in order to achieve mass production.
"These programs are all about precision, but precision is also related to production costs and speed." Kazuhiro Doi said, "This is a more complex process than traditional lithium-ion batteries. ”
In recent years, Nissan Motor has actively cooperated with scientists and universities in battery materials, process design, and test design, and has made technological breakthroughs in six major areas: cathode materials and structure, computational material science, protective layer, precision mixing process, material surface coating, and maintaining interface stability.
In terms of cathode material and structure, Nissan uses fibrous adhesives instead of traditional adhesives, so that the movement of lithium ions of the cathode active is not hindered, and the cell impedance is greatly reduced. At the same time, the cell impedance can be further reduced through the precision mixing technology of the positive electrode active substance and the solid electrolyte.
The researchers found a material that can inhibit the formation of twig crystals, which can avoid short circuits in the battery caused by twig crystals. They also invented a design that allows the electrolyte and electrode to expand and contract repeatedly without separating, further improving safety. On top of that, according to Kazuhiro Doi's team, they've cracked the puzzle of fast charging at low temperatures.
Nissan Motor, one of the first companies to independently develop in-vehicle lithium-ion battery technology, has been exploring for 30 years to date, with the goal of reducing battery costs by more than 65% by 2028 (compared to the second-generation Nissan Leaf).
Nissan pioneered the relatively inexpensive Nissan LEAF in 2010, which currently sells more than 500,000 units worldwide and has not had any major battery accidents. Although the battery technology used in this model is different from that of solid-state batteries, some technologies are common to all types of batteries, such as lamination technology for battery cells.
Nissan LEAF electric vehicle (Nissan LEAF)
In addition, Nissan Motor co., Ltd. announced on April 9 that it is working with NASA to develop a new all-solid-state battery to replace the traditional lithium-ion battery as a battery for 2028 product launches and 2024 pilot plants. This all-solid-state battery is stable enough to even be used in pacemakers. It is only half the size of the current battery and takes only 15 minutes to fully charge.
Nissan and NASA will create a "raw materials information platform" that can search the agency's vast battery database for effective material combinations. Simulate the effects of hundreds of thousands of material combinations through artificial intelligence, avoiding as many rare metal materials used in existing batteries as possible. Through its partnership with NASA, Nissan believes it can find the optimal chemical composition formulation for the cathode and anode of solid-state batteries faster, and the research time will be shortened from 5-20 years to 2-3 years.
Solid-state batteries are becoming one of the most promising power battery technology routes in recent years. Major automakers around the world are developing all-solid-state batteries, including Nissan's local rival Toyota Motor, Germany's Volkswagen, and the United States' Ford Motor, General Motors.
Among them, GM has also cooperated with NASA to build a lunar rover in the Apollo mission. General Motors also recently announced that it and Honda motor vehicles are working together to develop the next generation of electric vehicles. Volkswagen is working with startup QuantumScape to develop solid-state batteries. Last year, Ford established a $185 million research center for developing and manufacturing solid-state batteries.
In the face of a growing number of competitors in the field of solid-state batteries, Nissan believes that going it alone and independently researching and developing has more advantages than cooperation, at least in the early stages. Commenting on external suppliers, Kazuhiro Doi said: "They don't have the mature technology to work with automakers like us. ”
Nissan wants to control know-how in areas such as solid-state battery design and manufacturing, rather than necessarily the chemical composition of the raw materials themselves. "This will be our core competency in the solid-state battery space," Kazuhiro Doi expressed confidence in the future of Nissan's solid-state battery, "We are currently talking about the R&D process, so there is no 100% confidence." But as long as we work hard, we can do it. ”
Although solid-state batteries remove the liquid electrolyte of traditional lithium-ion batteries, it is still inevitable that some expensive rare metal materials, such as cobalt and nickel, are inevitable. Kazuhiro Doi said Nissan is also insisting on exploring cobalt-free cathodes, possibly using abundant and inexpensive sulfur or manganese as cathode materials. On the anode side, Nissan said it sees potential for silicon-based or lithium metal compounds.