Composite current collector is a new type of current collector material for power batteries, with a sandwich like sandwich structure. The middle layer is a conductive plastic film made of polymer insulating resin PET/PP and other materials. The two sides of the conductive film are made of metal aluminum/copper with a thickness of about 20-80nm by magnetron sputtering/vacuum evaporation, respectively, to produce a composite current collector.

Lithium batteries have been widely used due to their high energy density, excellent cycling performance, and high discharge rate. However, the current collector positive electrode of conventional lithium-ion batteries usually uses metal aluminum foil, and the negative electrode usually uses metal copper foil. However, once a short circuit occurs inside the battery, the current cannot be cut off, which ultimately leads to heat accumulation and causes thermal runaway. The safety issues caused by thermal runaway are very obvious.

In recent years, researchers have adopted a new type of current collector to replace conventional metal current collectors. This type of composite current collector usually uses non-conductive polymer films as substrates, and a layer of metal is deposited on both sides of the substrate through vacuum evaporation, electroplating, and other methods. For example, metal aluminum is plated on both sides of PET (polyethylene terephthalate) film as the positive electrode current collector, and metal copper is plated on both sides of PP (polypropylene ester) film as the negative electrode current collector. These composite current collectors have improved the safety performance of the battery to a certain extent, while also reducing the weight of the current collector and further increasing the weight energy density of the battery. Based on the above advantages, composite current collectors are widely used in the manufacturing process of lithium batteries.

As a professional expert in lithium battery welding solutions, DeepSource seized the opportunity and actively carried out technological innovation based on years of experience. They have successively developed a series of ultrasonic roller welding machine models and the current slitting roller welding and coating integrated machine, mainly used for welding composite current collectors, to assist lithium battery manufacturers in achieving rapid product launch and profitability.

Composite current collector roller welding sample - aluminum