Date: 2025-09-19 hits: 102
A recent financial forecast from a laser equipment manufacturer revealed a significant shift in the consumer electronics supply chain.
According to Lianying Laser, orders for its small steel-cased battery welding equipment for consumer electronics applications reached 400 to 500 million RMB in the first half of 2025 alone. Orders are expected to continue to grow in the second half of the year, potentially reaching 600 to 800 million RMB in confirmed revenue for the full year.
A company executive bluntly stated, "Subsequently released new mobile phones will essentially use small steel-cased batteries, and our equipment will be involved."
This prediction reflects a key shift in Apple's product strategy. Following Apple's initial introduction of steel-cased batteries in the iPhone 16 Pro, market sources indicate that all four models of the iPhone 17 series, to be released in 2025, are expected to utilize this technology.
This marks the evolution of mobile phone battery packaging along the path of "soft-pack winding, soft-pack lamination, and steel-cased lamination."
In the consumer battery sector, the steel-cased trend has already begun. Samsung is actively developing its "SUS" (SUS) The "CAN" stainless steel casing solution is planned for use in flagship smartphones starting in 2026.
Meanwhile, market sources indicate that Highpower Technology has secured a share of battery supply for Meta's next-generation AI glasses, projecting a 30% to 40% share of shipments in the third and fourth quarters of 2025. With increasing production capacity and yield, its share is expected to rise to 50% by 2026, making it the primary supplier.
Highpower Technology has already established a dedicated square steel casing lamination line in its Tonghu Industrial Park to meet the mass production needs of AI terminal devices.
Other battery companies have also responded quickly. Zhuhai Guanyu announced plans to invest approximately 2 billion RMB to build a new steel casing battery mass production line using its existing factory.
The company explained the motivation for this strategic move in its semi-annual report: "Compared to traditional polymer soft-pack batteries, steel casing batteries offer greater flexibility in form factor design, enabling better adaptation and optimized utilization of internal device space, thereby increasing battery capacity." It can be seen that a structural change in batteries driven by both demand and technology is accelerating, and its impact has far exceeded consumer electronics and extended to the field of power batteries with strict requirements on cost and safety.
How Steel Cases Solve the iPhone's "Slimming" Challenge
For consumer electronics like smartphones, the core value of steel-cased batteries lies in their superior physical properties, enabling them to achieve both higher performance and enhanced safety within an extremely thin and light body.
First, structural strength allows for design freedom. Supply chain sources indicate that the battery in the ultra-thin iPhone 17 series may be as thin as 2.5mm. As a sturdy, independent unit, the high strength of the steel case directly enhances the overall body's resistance to bending.
This means the battery itself can become part of the body structure, reducing reliance on an internal midframe or additional support components, creating the foundation for a slimmer and more robust design.
Second, irregular molding improves space utilization. With space being at a premium within mobile phones, and foldable screens and ultra-thin devices being two of the latest trends, batteries with [shaped] or other irregular shapes are a natural choice.
Steel can withstand more complex stamping and welding processes, perfectly supporting irregular battery designs. By utilizing the corners of the device, the steel-cased laminated battery significantly improves space utilization. Test data shows that Apple's steel-cased laminated battery technology improves space utilization by 18%, and the iPhone 16 Pro model using steel-cased batteries has a 9% increase in capacity. Improved heat dissipation is another key advantage. The steel casing has superior thermal conductivity to the aluminum-plastic film of traditional soft-pack batteries, more effectively transferring heat generated by the battery cells to the device's midframe. This enables the battery to support higher charge and discharge rates, reducing heat loss and ensuring stable processor operation under high loads. It's also worth noting that steel-cased batteries are actually driven by global policy trends. Regions like the EU are increasingly emphasizing the removability of batteries in electronic products. Soft-pack batteries are easily punctured during disassembly, posing a safety hazard. The rigid, stable structure of steel-cased battery cells makes battery replacement safer and easier, complying with regulatory requirements.
The "rigid demand" for large cylindrical and other power batteries: cost, safety, and system-level optimization.
In the power battery sector, the application logic of steel casings differs from that of consumer electronics. Its core drivers are cost, safety, and deep integration with vehicle structures.
Cost advantage is its most direct appeal. ThyssenKrupp's Selectrify project research shows that a battery casing made of high-strength steel, while weighing the same as an aluminum casing, can save up to 50% in costs. This is undoubtedly a significant advantage in the fiercely price-competitive electric vehicle market.
Safety is another core strength of steel. EVE Energy executives once cited data to explain the value of steel casings: the risk of battery failure caused by chassis collisions in electric vehicles leads to higher insurance claims rates than fuel-powered vehicles.
For this reason, the steel casings used in the company's large cylindrical batteries boast a strength of 550 MPa, compared to 95 MPa for square aluminum casings—5.6 times the strength of the latter. This structural strength provides more reliable physical protection for the chassis battery. Furthermore, steel's melting point (approximately 1410°C) is much higher than aluminum's (approximately 610°C), giving drivers and passengers a longer escape time in extreme situations like thermal runaway.
Previously, steel's weight disadvantage was a major obstacle to its application. However, the emergence of new battery structural technologies such as CTP and CTC has provided a breakthrough opportunity.
Tesla's 4680 structural battery pack, for example, features steel-cased cells secured by adhesive, forming part of the vehicle's floorpan. Steel's exceptional strength enables it to function as a structural component of the vehicle body, replacing some crossbeams or reinforcements, achieving system-wide weight and cost reductions.
Notably, steel casings are also essential for high-energy-density chemistries. Silicon-based anode materials undergo significant volume expansion during charging and discharging. The strong mechanical restraint of steel casings effectively suppresses this expansion, ensuring the stability of the battery structure and its cycle life.
Zhuhai Guanyu and realme recently jointly announced their 100% all-silicon anode battery technology, mentioning the need for module-level steel casing technology for subsequent mass production.
Manufacturing upgrades make steel-cased batteries possible.
The large-scale application of steel-cased batteries relies on simultaneous breakthroughs in manufacturing, particularly welding, stamping, and materials science.
Laser welding is a key bottleneck. High-speed rotation, in particular, demands even higher welding precision. Laser welding can easily cause the nickel plating on the casing to fall off, making it more susceptible to rust.
Lianying Laser's "high-speed turret welding technology," developed for 4680 large cylindrical batteries, utilizes a proprietary turret mechanism and on-the-fly welding technology, effectively addressing the challenges of welding precision and automation under high-speed rotation.
The company has completed laser process development for the entire process, from structural components to cell assembly, for both large and small steel-cased batteries.
Daz's steel-cased cam-turret 4695 cylindrical battery assembly line not only offers high flexibility and operability, but also allows for multiple welding processes by simply changing welding stations, significantly improving production efficiency.
The operating efficiency of the steel-cased cam-turret 4695 cylindrical battery assembly line is 150ppm. The stamping process, especially for large cylindrical batteries, presents equally significant challenges.
Industry insiders point out that stretching the casing height from 65mm to 135mm or even higher represents a significant technological leap. Because steel has a much higher yield strength and hardness than aluminum, and its plasticity is much lower, greater stamping force is required to achieve the same deformation.
This significant stamping force introduces two major risks: first, mold deformation can easily occur, compromising machining accuracy; second, the pre-nickel plating layer is inherently fragile and can easily crack if improperly processed, thereby reducing the battery's corrosion resistance.
Therefore, large cylindrical batteries like the 46 series require the use of precision stamping machines with long strokes, achieving deep drawing through a multi-station, step-by-step process. This places a significant strain on the equipment's accuracy and stability.
Faced with these challenges, some manufacturers have found solutions by leveraging their cross-industry experience. For example, Suzhou Slake Precision Equipment, with extensive experience in can manufacturing, has introduced its key DWL (Draw and Wall Thinning) process to battery case production.
This process features a single station where the workpiece passes through multiple dies with decreasing inner diameters, achieving multi-stage stamping and forming in one step. This highly efficient process provides a key solution to addressing yield and efficiency issues in the production of large cylindrical steel cases.
Finally, breakthroughs in the localization of high-strength pre-nickel-plated steel strip as a core raw material have ensured cost reduction and supply chain security.
Pre-nickel-plated steel strip is a core material for high-end battery cases and has long relied on imports. On a technical level, ensuring steel maintains sufficient strength and ductility without cracking under extreme stamping and stretching conditions remains a core challenge plaguing the industry.
For example, the 40160 steel (160mm high) for large cylindrical deep-drawn battery casings developed by China Baowu Group for a leading domestic new energy company addresses this significant material challenge.
The height increases by only 20mm from 140mm to 160mm, but the deep-drawing ratio increases dramatically from 3.5 to 4, resulting in a surge in tensile deformation of over 20%, making it highly susceptible to cracking due to stress concentration. Previously, the industry yield rate was less than 30%.
In May 2025, the company successfully rolled off China's first roll of large cylindrical deep-drawn battery casing steel. Tests were conducted on 0.3mm thick pre-nickel-plated steel coils, demonstrating that key performance indicators such as stamping formability and coating adhesion exceeded expectations. Furthermore, Jiangsu Weijinmai's 1 billion yuan pre-nickel-plated battery case steel project was approved in July, signaling the rapid expansion of domestically produced high-performance battery steel.
The industrialization of steel-cased batteries isn't the triumph of a single technology, but rather the result of simultaneous advancements in design on the demand side and materials, equipment, and manufacturing processes on the supply side.
We are currently seeing early signs of a multi-pronged convergence: terminal designs are evolving, materials are addressing shortcomings, and equipment is being deployed. Whether this transition from "multi-site pilots" to "large-scale commercial use" within the next two years will depend on the coordinated maturity of these three links.
