Abstract: As the capacity requirements of power equipment continue to increase, there are higher expectations for improving the energy density of lithium-ion batteries. Portable devices, especially smartphones, tablets, and laptops, all require lithium-ion batteries that are small in size and have long standby times.
As the capacity requirements of power equipment continue to increase, there are ever-growing expectations for improving the energy density of lithium-ion batteries. Portable devices, especially smartphones, tablets, and laptops, all require lithium-ion batteries that are small in size and have long standby times. Lithium-ion batteries, which are lighter, smaller, have higher output voltages, and higher power density, are also being developed for use in other power devices, such as energy storage devices, power tools, and electric vehicles. Therefore, developing high-energy-density lithium-ion batteries is an important research and development direction for the lithium-ion battery industry.
Background of the development of high-voltage lithium-ion batteries
In order to design high-energy-density lithium-ion batteries, in addition to continuously optimizing space utilization, improving the compaction density and capacity of battery anode materials, and improving the positive and negative electrode active materials by using highly conductive carbon nanotubes and polymer binder content, the operating voltage of lithium-ion batteries is also an important way to improve the energy density of batteries.
The cutoff voltage of lithium-ion batteries has gradually increased from the original 4.2V to 4.35V, 4.4V, 4.45V, 4.5V, and 5V. Among them, the 5V Nickel-Manganese lithium-ion battery has excellent high energy density and high power, making it one of the important development directions in the field for future new energy vehicles and energy storage. With the development of power technology, high-voltage, high-energy-density lithium-ion batteries will gradually move out of the laboratory and serve consumers.
Current Status of High-Voltage Lithium-ion Battery Applications
High-voltage lithium-ion batteries generally refer to batteries with a charging cutoff voltage higher than 4.2V. For example, the cutoff voltage of lithium-ion batteries in mobile phones has evolved from 4.2V to 4.3V, 4.35V, and 4.4V (Xiaomi phones, Huawei phones, etc.). Currently, 4.35V and 4.4V lithium-ion batteries are already in use on the market, and 4.45V and 4.5V lithium-ion batteries are also gaining popularity, indicating that the market is gradually maturing.
Domestic and international manufacturers of mobile phone batteries and other digital electronic products are moving towards high-voltage lithium-ion batteries. High-voltage, high-energy-density lithium-ion batteries will bring a larger market to high-end mobile phones and portable electronic devices. Cathode materials and electrolytes are key materials for improving the high-voltage performance of lithium-ion batteries.
As voltage increases, some safety features of high-voltage lithium-ion batteries decrease during use, thus limiting their widespread adoption in electric vehicles. Currently, the main cathode materials for electric vehicle batteries are ternary lithium batteries and lithium iron phosphate batteries. To improve energy density and meet demand, high-nickel cathode materials such as 811NCM and NCA, high-capacity silicon-carbon cathodes, or improved battery space utilization are generally selected to enhance energy density and battery life.
