IBM has filed a lawsuit against a company that sells replacement laptop batteries over the Internet, claiming that the batteries are knockoffs that have a tendency to catch fire.

In court papers filed last week, IBM says that Shentech.com is "offering counterfeit IBM products which pose a substantial threat to the safety of the consuming public."

IBM says it discovered the alleged counterfeits after Shentech sold what was supposed to have been a genuine IBM laptop battery to a consumer in Ohio. The battery caught fire and damaged the buyer's IBM Thinkpad. IBM says it learned the battery was a fake after investigating the incident and tracing the battery to its source.

IBM says it subsequently bought 12 IBM laptop batteries from Shentech's Web site. "Each battery was analyzed. Each battery is a counterfeit product," IBM said in papers filed in U.S. District Court in Northern Ohio.

IBM is asking the court for an order that would prohibit Shentech from claiming that any of the products it sells are made by IBM. The company is also seeking unspecified, "treble" damages, or $1 million for each instance of counterfeiting by Shentech.

In an unusual step, IBM is also asking the court for an order that would expedite discovery and prohibit Shentech from destroying any evidence related to the case.

"Counterfeiters are notorious for poor record keeping and for abandoning businesses at the first hint that the genuine manufacturer is taking steps to enforce its rights," IBM says.

The risk that Shentech will destroy evidence related to the case "is grave," IBM adds.

A woman who answered Shentech's sales phone on Wednesday said Shentech executives were not immediately available for comment.

According to the company's Web site, Shentech is based in Queens, New York, and has been in business since 1999. As of Wednesday, it was still offering products billed as IBM laptop batteries, along with a host of other computer peripherals, for sale on its site.

Shentech.com is registered to an individual named Charlie Shen, according to Internet records.

IBM sold its PC business, including the Thinkpad brand, to Lenovo in 2005. Counterfeit or not, Thinkpad batteries have in the past been prone to overheating. IBM and Lenovo in 2006 announced a joint recall of more than 160,000 laptop batteries because they posed a fire risk.