LETI: The First in Russia System for Automated Welding of Lithium-Ion Batteries Was Developed at LETI

The device using spot welding technology can quickly and safely assemble lithium-ion batteries into a single array of various sizes.

Lithium-ion batteries are a type of electric battery actively used in consumer electronics and electric vehicles today. In particular, cylindrical battery assemblies are used to power laptops, electric scooters, cars, and buses. 18650 batteries are the most common, and they look like ordinary disposable batteries. Arrays of various sizes (one needs three batteries to power a laptop and several dozen batteries for a scooter) are connected using nickel tape.

Assembling lithium-ion batteries into a single structure cannot be done by soldering, as this process takes a relatively long time (several seconds or longer), during which the battery can overheat and fail. Therefore, the main method is spot welding using nickel tape. It has high productivity (several hundred connections per minute) and does not overheat the batteries since the elements are heated in a third of a second. However, equipment for this technology is not produced in Russia.

“We have developed the first domestic spot welding plant that can quickly and reliably connect cylindrical lithium-ion batteries into single arrays.”

Vladimir Evstratov, Engineer of the Department of Electrical Technology and Converter Engineering at LETI.

The device has two configurations. The one with batteries assembled manually can be used in domestic conditions. Besides that, LETI scientists have developed a device for automated welding of arrays consisting of many lithium-ion batteries. The functional prototype has a working area of ​​40×40 cm. However, using a universal approach to writing a program code used at ETU “LETI,” the development can be scaled up and used in larger working areas to assemble batteries of any configuration on an industrial scale. Both types of spot welding devices use nickel tape to connect the batteries.

“Our ultimate goal is to introduce the development to companies that assemble and restore batteries. Today, they use foreign analogs of spot welding devices. Our development is cheaper and more compact. We expect that in the future, the implementation of such a system will significantly increase labor productivity in the field of assembling lithium-ion batteries,” noted Vladimir Ishin, Deputy Head for Academic Affairs of the Department of Electrical Technology and Converter Engineering at LETI.

The project was supported by a grant from the Youth Contest of Innovative Projects of St. Petersburg Electrotechnical University “LETI” in 2021.