■ Technology Overview
The demand for high-energy and high-safety lithium batteries has surged in the electric vehicle and lectronic product markets. The international carmaker Tesla held the Battery Day on September 15, 2020. During the conference, Tesla stated that the pace of global sustainable energy development is too slow, and electric cars are still too expensive. Therefore, a large number of inexpensive batteries is needed to achieve global electric transportation and sustainable energy use. In order to produce a large number of cheap batteries, Tesla has set production capacity targets of 100 GWh by 2022 and 3,000 GWh by 2030. Tesla is innovating in five areas: new battery design, new cell factory configuration, anode material, cathode material, and cell vehicle integration. In an effort to reduce battery costs and increase range, Tesla plans to replace graphite with silicon-base material for the anode material and eliminate cobalt in favor of a nickel-rich cathode. However, our laboratory focuses on developing functional interface layer technologies for high-energy battery design, which involves modifying the cathode and anode electrode materials to increase working voltage and reduce irreversible effects for improved battery energy density. This includes surface chemical modification of highvoltage cathode material, modification of high-capacity graphite anode material, and the use of composite silicon-carbon material.
Our laboratory focuses on developing functional interface layer technologies for high-energy battery design. We use various techniques such as mixing, shelling, and coating for cathode material modification to reduce structural phase transformation and prevent the dissolution of transition metal ions(Mn+). This approach enhances battery safety by preventing thermal explosions in the battery. We also modify silicon-based anodes through functional interface layers to suppress the negative effects of volume expansion and improve cycling properties and mechanical strength.
To further improve battery safety, we have developed a ceramic-coated separator layer and an organicinorganic composite (Thermal Tolerance Coating, TOC) coating with ion conduction and lithium supplementation. We also employ a high-temperature separator technology to enhance its electrical performance and value.
The UC layer with current interruption function is another safety feature interface technology developed. This layer prevents external short circuits and overcharging conditions by rapidly increasing the resistance and ultimately resulting in a state of disconnection in the event of a high-temperature danger.
In addition, we have developed a high-performance composite electrolyte technology for quasi-solidstate electrolytes, which achieves good ionic conductivity, high-temperature stability, and easy processing
properties. This technology enables customization of thin batteries to meet the specific product electrical and size requirements of different customers, creating dedicated thin batteries that are more lightweight, compact, and suitable for flexible and foldable designs.
▣ Development of High Energy Density Batteries - Functional Interface Layer Technology Description
▣ Printable polymer thin-film battery technology
• Features of high-performance electrolyte technology include:
‐ High conductivity
‐ Good thermal stability
‐ Low interfacial impedance
‐ Good electrochemical stability
‐ Continuous roll-to-roll printing technology for electrolyte production
• Features of Flexible Ultra-Thin Battery Technology:
‐ High flexibility
‐ Thin thickness (<0.5mm)
‐ Simplified manufacturing process
Industrial Technology Research Institute (ITRI)