Market status and development analysis of China's solid-state battery industry in 2021

Solid-state batteries are the future development direction of lithium batteries . On January 9, 2021, NIO released a new electric sedan model ET7 that uses a solid-state battery with a high energy density of 360wh/kg, which attracted the attention of the industry.

NIO's new models sparked a surge in interest in solid-state batteries

On January 9, 2021, NIO released a new electric sedan model, the ET7. One of the highlights is that the ET7 uses solid-state battery technology, with an ultra-high energy density of 360wh/kg and a range of more than 1,000 kilometers. The energy density of the solid-state battery used in the new NIO "ET7" model exceeds that of the BAIC EU260, BAIC prototype, and Nezha U. The new NIO "ET7" model has once again ignited the popularity of solid-state batteries.

Solid-state batteries are the future development direction of lithium batteries

Solid-state batteries refer to lithium-ion batteries that use solid electrolytes . They are essentially lithium batteries , with only the electrolyte and separator replaced by solid-state battery materials. Compared with traditional lithium batteries, solid-state batteries have higher energy density and stronger safety, while overcoming the problems of poor stability and low charging efficiency.

From the perspective of the development path of lithium battery technology, all-solid-state is the future development direction of lithium battery. The energy density that liquid lithium batteries can achieve is close to the limit. The energy density of all-solid-state lithium batteries has the potential to exceed 500wh/kg.

Current stage

At present, all-solid-state batteries are divided into three major technical paths, namely polymer all-solid-state batteries, oxide all-solid-state batteries and sulfide solid-state batteries. Polymer all-solid-state batteries can withstand high voltages and have good safety, but the electrolyte sheets are prone to brittle cracks, the interface resistance is high, and it is difficult to manufacture large-capacity batteries. Oxide all-solid-state batteries are basically adapted to high-voltage ions and have the highest conductivity, but the solid-solid contact continues to deteriorate and they are air-sensitive (high cost). Sulfide solid-state batteries are easy to process and can be used to prepare large-capacity batteries, but the temperature range is narrow, generally between 60 and 85 degrees Celsius.

It will take time for solid-state batteries to be commercialized

However, the global solid-state battery technology is still immature. Solid-state batteries have the problem of solid-solid interface contact, large internal resistance, and poor cycle performance and rate performance. Compared with liquid electrolytes, the conductivity/lithium ion mobility of solid electrolytes is 1-2 orders of magnitude lower, the conductivity is low, and the impedance of the whole battery is large, resulting in poor cycle performance and rate performance. The electrode material expands during charging and is frustrated during discharge. The contact between liquid electrolyte and electrode (liquid-solid) is relatively good, while it is difficult for solid electrolyte and electrode (solid-solid) to maintain long-term stable contact, and the possibility of rupture or separation of the solid electrolyte is increased, and the battery internal resistance is large.

At the same time, there are many processing steps for solid-state batteries, and there is a problem of difficult processing technology. Sulfide solid electrolytes have strict requirements on the production environment and need to be isolated from water and oxygen. The processing technology and large-scale mass production technology have not yet been solved. On the other hand, the production cost of solid-state batteries is mostly the production process cost. According to data from the International New Energy Network, the production process cost of solid-state batteries accounts for more than 50%, while the production process cost of lithium-ion batteries is only 20%-30%; the cost of precious metal nanosilver required for large-scale production of silver-carbon layers is relatively high. Therefore, it will take some time to achieve the commercialization of solid-state batteries.

Many global participants

At present, research institutions and enterprises in China, the United States, Japan, South Korea, the United Kingdom and other countries are actively developing solid electrolytes. The solid-state battery companies that have deployed are divided into three categories: one is entrepreneurial companies, such as QuantumScape, Solid Power, and Prologix, battery companies such as CATL and Samsung SDI, and car companies such as Toyota. These companies also choose different technology systems. Bollore and IMEC choose solid polymers; TDK (MLCC) and Prologix choose oxide systems; QuantumScape takes into account the three major technology systems; CATL chooses sulfide systems. However, overall, the global mass production of all-solid-state batteries is expected to be at least after 2025.

Car companies enter the market by investing in lithium battery manufacturers

In recent years, my country's automobile companies have invested in lithium battery manufacturers to deploy solid-state batteries. For example, BAIC, SAIC, and GAC have successively participated in the financing of Qingtao Energy, and FAW participated in the D round of financing of Prologix Energy in April 2020.

In any case, the new model ET7 released by NIO has further increased the attention paid to solid-state batteries. It is worth looking forward to the mass production of solid-state batteries by lithium battery manufacturers after 2025.