Pure Nickel Strip for Battery Welding: The Key to Safe & Efficient Power Packs

A pure nickel strip is a flat, thin metal conductor composed of 99.6% or higher nickel content. It’s commonly used to create connections between individual cells in a battery pack through a technique called spot welding.

Unlike nickel-plated steel strips, which are cheaper and often used as substitutes, pure nickel strips offer superior performance and long-term stability, especially in high-drain or high-capacity battery applications.

Why Use Pure Nickel Strips for Battery Welding?

Here are some key reasons why pure nickel is preferred in battery welding:

1. Excellent Electrical Conductivity

Nickel is a good conductor of electricity. Pure nickel ensures minimal voltage drop and efficient power transfer between battery cells, which is vital for performance and safety.

2. High Corrosion Resistance

Nickel naturally forms a passive oxide layer, making it highly resistant to corrosion, even in humid or chemically reactive environments. This is crucial for the durability of battery packs.

3. Superior Weldability

Pure nickel strips bond seamlessly during spot welding. The uniform melting point and thermal conductivity allow for clean, strong welds that do not damage the battery terminals.

4. Low Internal Resistance

Low resistance is critical in preventing heat buildup during charge and discharge cycles. Pure nickel helps maintain thermal stability and prevents battery overheating.

5. Longevity and Safety

Pure nickel does not degrade as quickly as nickel-plated alternatives. It maintains its properties over thousands of cycles, reducing the risk of weld failure and increasing overall battery safety.

Common Applications

Pure nickel strips are widely used in:

• EV battery packs
• Power tools (like cordless drills)
• E-bikes and scooters
• Solar power storage units
• DIY battery projects (18650 cells, 21700 cells, etc.)

How to Identify Pure Nickel vs Nickel-Plated Steel

Because of cost differences, some suppliers sell nickel-plated steel strips as "nickel"—but there’s a difference.

Here’s how to tell them apart:

• Weight Test: Pure nickel is slightly lighter than steel.
• Spark Test: Grinding a pure nickel strip will show fewer sparks compared to steel.
• Magnet Test: Steel is magnetic; pure nickel is weakly magnetic or non-magnetic.
• Saltwater Test: Dip both strips in saltwater for a few days. Steel will rust; pure nickel won’t.

Always verify the purity before using the material in critical applications.

Standard Sizes & Thickness

Common sizes of pure nickel strips for battery welding include:

• Width: 5mm, 7mm, 8mm, 10mm
• Thickness: 0.1mm, 0.15mm, 0.2mm

The right size depends on the battery cell size, current load, and application.

Tips for Spot Welding Pure Nickel Strips

• Use a pulse spot welder for clean and controlled welds.
• Adjust the pulse duration and power level according to strip thickness.
• Clean battery terminals before welding.
• Ensure good surface contact and pressure during welding.

Conclusion

If you’re assembling high-quality battery packs, pure nickel strips are not optional—they’re essential. While they may cost a bit more than alternatives, the performance, safety, and reliability they offer make them worth every penny.