On November 13th in Shenzhen, OFweek China's high-tech industry portal (OFweek lithium grid hosted) a successful lithium battery event - "OFweek 2018 (3rd) China Power Battery Summit Forum!" The summit brought together people from the positive and negative poles, separators, electrolytes, batteries, PACK, equipment, machine factories and other lithium-ion industry chains. Together with experts from academia and research institutes, the focus will be on the development and future trends of the power battery market. "Power cell technology innovation and application" two themes, from the power battery market, development, safety research, manufacturing process and cost, technology innovation and R & D and other aspects of in-depth discussion, sharing and exchange of the latest research results at home and abroad And technical experience, aiming to promote the cooperation and development of industry and technology. Among them, at the power battery summit forum, Mr. Liu Wei, R&D director of the Dazu Laser New Energy Equipment Division, delivered a wonderful speech entitled "Power Cell Laser Welding Quality Improvement and Quality Inspection".
Laser welding is an important process in battery manufacturing
"The laser welding process has become an important process in battery manufacturing." At the beginning of the speech, Liu Wei focused on the guests.
Laser welding is the only non-contact, high-precision and high-efficiency welding method; it can economically and quickly weld and seal battery structural parts. Laser processing usually includes laser cutting, laser welding, laser surface treatment and so on. In the entire power battery manufacturing, including the core, module and pack, there are about 19 main component parts to be welded, among which: 11 welding must be laser welded at present; 5 welding may use laser welding; 3 welding will not Use laser welding. In the square-shell battery, laser welding is required for the sealing nail, the cover plate assembly and the sealing; in the cylindrical battery and the module, the laser welding portion is required to have a tab, a cap, a bus bar and the like.
"Battery leakage may cause short circuits between the batteries in the module, which may cause high temperature fires and other accidents. The presence of cracks and holes in the battery is a potential factor for the failure of the weld seal."
Failure of the collection line terminal may result in failure of voltage acquisition and temperature collection, which may cause the battery to overcharge and cause fire or explosion.
Laser welding quality improvement and testing
"Process innovation can effectively improve the quality of welding. In fact, the more complete the preliminary verification work, the stronger its process capability." Liu Wei stressed. In order to highlight the impact of process innovation on welding quality, Liu Wei cited examples to illustrate.
In the aspect of module side plate welding, the aluminum alloy profiles (end plates) and plates (side plates) of the power battery modules are used as the module outer frame structural members, and the welding quality is good or bad, which determines the rigidity of the overall structure of the module. Different welding results can be obtained by using different welding heads and processes, and side-plate laser welding has also developed a variety of processes. The ordinary welded joint has a porosity of 10%, the double beam welded joint has a porosity of 3%, and the oscillating spot welded joint has a porosity of only 1%. More and more advanced laser welding equipment and processes continue to improve the quality of welding and reduce the porosity.
In addition, cell sealing laser welding is an important process in battery manufacturing, which greatly affects battery yield. At the same time as the welding speed of the battery core is getting faster and faster, it is also necessary to ensure the weld seam performance such as weld consistency. A variety of laser welding sealing processes have thus been derived. Among them, the fiber laser is oscillating at high speed, the weld is smooth and the consistency is good. The oscillating head has a repairing effect on the explosion point as the welding frequency increases.
Han's Laser New Energy Division: Strong Lithium Manufacturing Capabilities
As the finale of his speech, Liu Wei revealed the current situation of the Dazu Laser New Energy Equipment Division to the guests present. Dazu Laser has opened up the closed-loop industrial chain of battery process equipment through the strategic layout of "combining vertical and horizontal". At present, Han's laser can provide complete line equipment, including stirring, coating, die cutting, winding, battery assembly, cell periphery welding, liquid injection, module assembly, PACK assembly, etc. Core automatic assembly line, aluminum shell module automatic intelligent assembly line system. Showcasing the strong manufacturing capabilities of the Dazu in lithium battery in addition to laser welding.
