05/13/2025 | Industries & applications

Steel strip for battery casings: suitable for deep drawing and corrosion resistant

The cylindrical casings of commercially available batteries, such as those used in remote controls, are manufactured on state-of-the-art deep-drawing lines at high speeds of over 1,000 units per minute. This is done using cold rolled steel strip that is specifically designed to be suitable for deep drawing. If the battery casing also has to have a well-adhering, corrosion-resistant nickel coating, the material needs to possess even more highly specialized properties. Custom-developing highly specialized material solutions of this kind for customers is one of Waelzholz’s areas of expertise.

Battery cell housings need to be resistant to corrosion. For this reason, the finished casings are plated with nickel after forming. To make the production of battery casings more efficient by eliminating the costly and time-consuming step of piece finishing, Waelzholz offers cold rolled steel strip coated on both sides with an adhesive nickel layer over its entire length. “We have many years of extensive expertise in the production of materials for demanding deep-drawing processes,” explains Thorsten Köhler, head of Materials Technology and Quality Assurance at Waelzholz in Hagen, Germany. “This is why we can also fulfill special requests such as an additional corrosion-resistant nickel layer for such a specific challenge.”

Inspection of the distribution of nickel and iron elements at 2500:1 magnification | Via EDS (energy-dispersive X-ray spectroscopy) analysis using Waelzholz’s own scanning electron microscope, the materials experts can precisely inspect the distribution of elements in the transition area of the nickel-coated and heat-treated steel strip. In this process, the EDS image processing software clearly visualizes the different chemical elements (with nickel appearing green and iron appearing red). This makes it possible to immediately determine whether the diffusion process was successful.

Nickel layer optimized for the deep-drawing process

What initially sounds simple actually requires in-depth expertise, as materials engineer Robert Golla from the Hagen site in Germany reports: “The challenge is ensuring that the nickel layer adheres so firmly that it doesn’t crack during the subsequent deep-drawing process.” To achieve this, a special routing is used in the heat treatment process after the nickel layer has been applied to the steel strip. This routing increases the rate of diffusion of the nickel, causing it to penetrate into the material and therefore better adhere to the surface of the steel strip.

Development expertise and worldwide availability

“Our particular strength, in addition to delivering products of the highest quality, is our ability to quickly implement special customer requests, such as the development of a material with a nickel coating that is suitable for deep drawing,” reports Köhler. This is helped by the fact that Waelzholz not only has many years of experience but also uses state-of-the-art materials analysis equipment such as a scanning electron microscope. As Köhler explains: “After a test routing, the results of a material analysis are available to us almost immediately, enabling us to rapidly proceed to the next development steps.” In this way, the available equipment accelerates the company’s own development processes, which, according to Köhler, offers a major advantage for customers: “Time to market is what it all comes down to. Many of our customers operate in highly dynamic industries and want to bring new ideas to market as quickly as possible. We use all the means at our disposal to help them achieve this.”

These means include Waelzholz’s global presence with locations on four continents. Customers with worldwide operations have access to Waelzholz’s extensive development expertise from almost anywhere. They also benefit from redundant manufacturing processes for products like nickel-coated, cold rolled steel strip suitable for deep drawing.