(New throughout, updates prices, market activity and comments) LONDON, March 5 (Reuters) - Nickel edged up on Friday as buyers sought to pick up bargains after two days of hefty losses, though prices were still set for their steepest weekly fall in almost a decade after a major supply deal undermined expectations for shortages. The metal is mainly used in stainless steel, but demand for battery grade nickel for electric vehicles is expected to boom in as the world moves towards a lower-carbon economy. Benchmark three-month nickel edged up 1.5% to $16,390 a tonne by 1700 GMT, but was still on track for a weekly loss of about 11%, its biggest since September 2011. Nickel fell when Tsingshan Holding Group said it would supply battery grade nickel to two Chinese companies, undermining expectations for a shortage of “Class 1” nickel that had underpinned prices. “The selloff was pretty ferocious, I’m sure people have had to cover positions and it makes sense to buy on the dips in some markets,” said Citi analyst Oliver Nugent. He added that expectations of more supply from Tsingshan’s conversion technology was “shooting down the bull case for nickel”. Nickel hit its highest since May 2014 at $20,110 a tonne on Feb. 22. On the Shanghai Futures Exchange (ShFE) nickel ended 7.8% down at 121,750 yuan ($18,763.10) a tonne. ING analyst Wenyu Yao said metals markets were in a “consolidation phase” after pressure from a stronger U.S. dollar in the past few sessions. POSITIONING: The LME net speculative long had contracted to 10% of open interest on Wednesday from a year-to-date high of 33% on Feb. 25, according to estimates by broker Marex Spectron. TCs: Spot treatment charges for copper concentrate in top copper consumer China AM-CN-CUCONC slumped to their lowest in more than 10 years on Friday, according to data from Asian Metal, underscoring how tight the feedstock market is for smelters. OTHER METALS: LME copper fell 0.1% to $8,992 a tonne, aluminium gained 0.8% to $2,171, zinc was flat at $2,750, lead lost 0.4% to $2,007 and tin jumped 2.9% to $24,280 ($1 = 6.4888 Chinese yuan renminbi) (Reporting by Zandi Shabalala Additional reporting by Mai Nguyen Editing by David Goodman, David Evans and David Gregorio)