Fudan participates in the research and development of new materials to improve the safety of new energy vehicles and installs nano "armor" on battery separators
There are frequent battery spontaneous combustion accidents in new energy vehicles. On the 28th, at the 2024 Zhongguancun Forum Annual Meeting, an "interfacial super-assembled carbon nanocomposite" developed by Zhongpo New Materials and Fudan University for battery separators was released. This new separator material may significantly improve the safety of new energy vehicle power batteries.
Yu Jie, general manager of Zhongpo New Material Technology Co., Ltd., said that there are four parts inside a lithium battery: positive electrode, negative electrode, electrolyte, and separator. During the use of the battery, some of the lithium ions in the electrolyte are reduced to lithium on the electrode surface, forming a deposition of dendritic crystals - lithium dendrites. Lithium dendrites are the biggest safety hazard in car batteries. Their growth may pierce the separator and directly connect the positive and negative poles of the power supply, causing a short circuit and spontaneous combustion. In addition, it will also reduce battery capacity and shorten battery life.
"Using super-assembly two-phase polymerization technology to synthesize a functional silicon-polymer carbon nanocoating on the surface of the original separator, it can effectively inhibit the formation of lithium dendrites and greatly improve battery safety." He said.
The battery separator covered with a special coating is like wearing a nano-armor. According to reports, after modifying the current commercial PP separator through interfacial super-assembly technology, the thickness of the separator only increased by 10-20 microns, and the macroscopic morphology did not change significantly; but the physical and chemical properties were greatly improved, in terms of elastic modulus, electrolyte adsorption capacity, The ionic conductivity and lithium ion migration number have been significantly improved.
"Before modification, lithium ions pass through the separator in a disordered state; after modification, the intermolecular force causes the lithium ions to appear in an ordered state, just like lining up, and then pass through the separator." Yu Jay said. This significantly improves battery safety and longevity. "The material cost increases by about 10%, and the service life increases by about 50%."
In addition, the performance and stability of lithium-ion batteries are effectively improved. After 1,000 cycles at 25°C, the Coulombic efficiency of the modified product increased from 67% to 85%; after 150 cycles at 45°C, this data increased from 10% to 93%.
According to reports, the two core patents for this new material come from the team of Kong Biao, executive vice president of the Shandong Research Institute of Fudan University and director of the Shandong Provincial Laboratory of Green Chemicals and Functional Materials. The technical level has reached an internationally leading level. Currently, the two parties are cooperating to develop a new mesoporous silica separator based on super-assembly technology, which is expected to completely replace the current PP separator and greatly increase the service life of automotive lithium batteries.