Nickel Strip Current Capacity Calculator | BatteryPackCalc

How to Use the Nickel Strip Calculator

Choose the strip material — pure nickel or nickel-plated steel — then enter the strip's width, thickness, and length in millimetres and the current it has to carry. The tool first works out the cross-section as width × thickness: a common 8 mm × 0.15 mm strip is 1.2 mm². Continuous ampacity is that cross-section times a conservative current density of 6 A/mm² for pure nickel (4 A/mm² for plated steel), so the 1.2 mm² strip is rated for about 7.2 A continuously, with a short-duration peak of 8 A/mm² giving roughly 9.6 A.

Resistance is calculated from the material resistivity and geometry as ρ × length ÷ cross-section. A 20 mm length of that 1.2 mm² pure-nickel strip (ρ = 6.99×10⁻⁸ Ω·m) comes to about 1.17 mΩ. At its 7.2 A rating the voltage drop is current × resistance ≈ 8.4 mV and the heat dissipated is I²R ≈ 0.06 W — small per strip, but it adds up across dozens of interconnects and concentrates exactly where the strip meets the cell terminal. That is why longer or thinner runs, which raise resistance, run hotter for the same current.

Free-air ratings rarely apply inside a real pack. The derating field applies an IEC 60287-style temperature factor — 1 − 0.8 percent per °C above 25 °C, floored at 0.5 — multiplied by a bundling factor (use about 0.7 for an enclosed pack, 1.0 for open air). The 7.2 A strip in a warm, enclosed build is realistically good for closer to 5 A continuous. When a single layer falls short, run two stacked layers, use thicker stock, or add a copper-nickel sandwich. Sizing a strip too thin makes it behave like an unintended fuse: it overheats, damages the cell's seal, and can trigger thermal runaway.