Copper foil is an important basic material for lithium-ion batteries. It serves not only as a carrier for negative electrode active materials, but also as a negative electrode electron collector and conductor. Its role is to gather the current generated by the battery active materials to generate a larger output current. Copper foil is used as the negative electrode current collector material in lithium batteries, accounting for about 8% of the cost of the battery cell. The thinner the lithium battery copper foil, the greater the effect on the energy density of the battery. Copper foil is thinner, lower cost, and higher performance. The direction of technological upgrading.
1. The industrialization of composite copper foil is imminent
Composite copper foil is a new type of micro-nano material with a "sandwich" structure, dedicated to solving the safety problem of thermal runaway of lithium batteries. The middle layer of the composite copper foil is a polymer material with a thickness of 3.6-6 μm, and the upper and lower surface layers are copper-plated layers with a thickness of 1 μm, which can realize the function of the negative electrode collector and make up for the defects of the current traditional electrolytic copper foil materials.
The middle layer of the composite copper foil is a polymer material with a low melting point, which can act as a fuse blowing function when heat accumulates, blocking the heat source generated by the internal short circuit, preventing the battery from igniting and exploding, and effectively improving the safety of the lithium battery.
In addition to effectively improving the safety performance of lithium batteries, composite copper foil also has the following outstanding advantages:
1. Low cost: The cost of polymer materials in composite copper foil is low, and the amount of copper used is small. In the case of large-scale mass production, the production cost is far lower than that of traditional electrolytic copper foil;
2. High energy density: The polymer material in the composite copper foil has a low density, which can greatly reduce the weight of the lithium battery current collector, thereby increasing the weight energy density of the battery.
3. Long life: polymer materials have a lower elastic modulus than metals, and the cycle life of batteries can be increased by 5%.
The technical barriers in the composite copper foil industry are relatively high. At present, composite copper foil still has equipment and process bottlenecks and downstream lithium battery supporting bottlenecks. With the continuous technology research and development, equipment transformation, production line debugging, and trial production trial verification , It is expected that the composite copper foil is expected to achieve batch commercial application in the next two years.
2. Guangteng micro-nano composite copper foil is about to be mass-produced
In September 2022, the first phase of Jiangxi Guangteng Micro-nano Materials Co., Ltd. was completed and has entered the trial production stage. After mass production, it is expected to have an annual production capacity of 14 million square meters of micro-nano composite copper foil (corresponding to a lithium battery with a capacity of about 1GWH). It is currently a large-scale lithium battery composite copper foil manufacturer in China. After the first phase of production is successfully put into operation, the company will gradually expand its production scale. It is planned that the annual production capacity will reach more than 50 million square meters by the end of 2023 (corresponding to lithium batteries with a capacity of about 3GWH).
It is understood that Chairman Lin Tengguang, the founder of Guangteng Micro-Nano, has been deeply involved in electrolytic copper foil for many years, and has many years of rich industry experience in the supply chain, production process and market client demand of traditional copper foil. In 2019, Chairman Lin Tengguang gathered elites in the electrolytic copper foil, flexible circuit board and shielding material industries, established a professional core team, and began to explore the production process and market application prospects of micro-nano composite copper foil. After more than two years of research and precipitation, in July 2021, Jiangxi Guangteng Micro-Nano Materials Co., Ltd. was established, focusing on the research and development and production of micro-nano composite copper foil materials, and officially entered the composite copper foil industry.
At present, there are mainly two-step and three-step processes for composite copper foil in the industry. Guangteng adopts the mainstream two-step process, that is, first uses the vacuum magnetron sputtering method to metallize the surface of the non-metallic polymer material, and then uses the electroplating method to thicken the metallized polymer material. At the same time, the company is also developing a one-step electroless plating process, hoping to improve the production efficiency and yield rate of micro-nano composite copper foil by reducing production links.
Chairman Lin Tengguang said that because composite copper foil can fundamentally solve the safety problem of lithium batteries, the industry has broad prospects and is a once-in-a-lifetime opportunity; however, there are many challenges in the industry at this stage, such as low production capacity and low yield rate. The material supply chain is immature, and the production process is still in the basic stage. To achieve economically beneficial large-scale production and high yield, it is still necessary to continuously optimize equipment and processes during trial production.
The requirements of end customers for composite copper foil are close to those for traditional electrolytic copper foil, and the product structure and process flow of composite copper foil are similar to those of flexible circuit boards and shielding materials. Experts in electroplating technology have entered the trial production stage in the early stage, and samples of products have been sent to a small scale, maintaining close technical exchanges with customers, and striving to achieve large-scale mass production by the end of 2022.
With an open and integrated attitude, Guangteng Micro-Nano will actively conduct in-depth technical exchanges with experts in the industry, be inclusive, and continue to develop in depth in the field of composite copper foil production and application.