{"id":12880,"date":"2023-11-08T09:00:16","date_gmt":"2023-11-08T09:00:16","guid":{"rendered":"https:\/\/blog.ophiropt.com\/?p=12880"},"modified":"2026-03-25T14:26:30","modified_gmt":"2026-03-25T14:26:30","slug":"laser-applications-in-ev-car-batteries","status":"publish","type":"post","link":"https:\/\/www.ophiropt.com\/blog\/laser-applications-in-ev-car-batteries\/","title":{"rendered":"Laser Applications in EV Car Batteries"},"content":{"rendered":"\n

Electrical cars are all around us.
The power source of an electrical car is its Li-ion battery pack. One of the most important parameters for a battery pack is its charge capacity per weight in kWh\/kg.  This means that battery and car makers want to put in as many \u2018battery cells\u2019 (the basic Li-ion unit that stores charge) as possible, and get rid of anything else, such as metal parts that house together several cells in a \u2018module\u2019, or several modules in a pack, or the battery pack entirely (i.e. going C2V or \u2018cell to vehicle\u2019).<\/p>\n\n\n\n

\"Electrical<\/figure>\n\n\n\n

What has that got to do with lasers?<\/h4>\n\n\n\n

Moving away from a modular approach (cells, modules, battery\npack) means that servicing or fixing the battery of an EV car is almost\nimpossible, and therefore the reliability, safety, and structural integrity of\nthe battery must be very high. That is where laser processes come into play.<\/p>\n\n\n\n

There are several processes in the manufacturing of the battery pack in which lasers can be used to improved reliability and throughput.
Let\u2019s look at several examples<\/p>\n\n\n\n

Cutting, cleaning, and welding at the cell level<\/h4>\n\n\n\n

The battery cell is made of three thin foils, anode foil (usually aluminum), separator foil (polypropylene or polyethylene) and cathode foil (usually copper). The anode and cathode foils are coated with a mixture of an active material, conductive agent, and binder. The foils are wound together to make the cell, a positive and negative metal tab is attached to the anode and cathode, and a liquid electrolyte is poured into the cell. <\/p>\n\n\n\n

\"Cutting,<\/figure>\n\n\n\n

Modern Li-ion battery factories work in a roll-to-roll\nprocess, i.e. processing long rolls of the foils for coating, drying, and\ncutting, before the foils are packed into individual cells. <\/p>\n\n\n\n

High-power (100\u2019s W) nanosecond pulsed IR and UV lasers are commonly used\u200b to cut the foils, clean, and weld the tabs to the anode and cathode. These laser processes have a big advantage over other processes, as they create smoother edges and surfaces which reduce the risk of lithium dendrite formation, a common cause of Li-ion battery failure.<\/p>\n\n\n\n

\"Welding<\/figure>\n\n\n\n

Welding battery pack frame and power harness<\/h4>\n\n\n\n

The battery frame holds the cells, modules, coolant lines\nand power harness. In the C2V concept, this can be a part of the vehicle\nchassis. Laser welding can produce strong and reliable joints. Traditionally,\nkilowatt class fiber lasers at a 1 micron wavelength are used. While\nefficiently absorbed by aluminum and steel, this wavelength is not absorbed by\ncopper, which is used in the power connections. Recently, green (515-535nm,\nfrequency doubled fiber lasers), and blue (450nm direct diode laser) high-power\nlasers are making their debut, in order to improve the throughput of copper\nwelding. Good welding of different metals is always challenging. A new approach\nto solving this problem is to control the shape of the laser spot, such as\nusing two spots with different size and power. <\/p>\n\n\n\n

Applications currently in research <\/h4>\n\n\n\n

In addition to current laser applications in battery manufacturing, there are also several applications currently in research. Let\u2019s consider a few: <\/p>\n\n\n\n