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Steel specification for battery contact

2005

I work for a product design firm and I'm currently working on a battery powered device for outdoors use. The product is fairly low volume but high unit price.

I'm using a stamped metal bracket to retain a spring that contacts the negative terminal of the battery. The bracket has a small tab that will fold over the bottom coil of the spring. The tab will be deformed by hand with a small punch. The other end of the contact is used to attach to a PCB. The connection is made to the contact via a solder terminal. The contact does not see any deformation during use. It could be exposed to a corrosive environment, but the exposure will be minimum.

I'm considering 1010 CRS, 1/4 hard, with electroless nickel plating. I'd like some opinions on whether this is the optimum solution.

Johnnie Carnes
Product Development - Raleigh, North Carolina

It may work for a time depending on voltage and amperage but it may fail eventually. Critical contacts must be plated with a metal that does not tarnish, such as gold or palladium.

Guillermo Marrufo
Monterrey, NL, Mexico
2005

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2005

The ductility of EN is only about 1-1.5% at best. When you deformed the tab, the cracking will break leaving cracks through the coating to the steel. If there is moisture present, a galvanic cell will exist between the EN and steel, which will cause some rusting around the cracks. The rusting probably will not cause a part failure but will result in staining in the area of the tab.

Electrolytic sulfamate nickel is another alternate. Its ductility is quite high and it should not crack during deformation of the tab. However, sulfamate nickel's coating thickness will not be uniform like EN.

Ron Duncan [deceased]
- LaVergne, Tennessee
It is our sad duty to note Ron's passing on Dec. 15, 2006. A brief obituary opens Episode 13 of our Podcast.

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2005

You may want to try to use...

NICOR, electro-plated-nickel strip + diffusion anneal. Nickel layers diffuse into the based metal-EN10139 DC04/LC.

Nickel layers are not easy to crack/peel off after forming or welding.
Also, providing a better corrision resistance than regular preplating nickel strip.

Lee
- Taipei, Taiwan

Ed. note: Thanks, Lee. But we must have your full name on future postings.