Sony has announced that it's entered into negotiations to sell its battery business to Murata, a Japanese components company that plans to use the purchase to expand its energy operations. Financial details of the deal aren't yet available; binding agreements are set to be made by October, and the transfer should be completed by the end of March, regulators permitting.

The sale is expected to include the Sony Energy Devices Corporation subsidiary as well as Sony's manufacturing operations in China and Singapore, though certain products like Sony's branded USB chargers and alkaline batteries will remain under the company's umbrella.

Sony's battery business is a part of its Devices division, which also includes image sensors and other components. While image sensors are generally thought of as one of Sony's more profitable fields in the past few years, battery sales have been lagging, and the company took out a 30.6 billion yen (271 million US dollars) impairment charge on the division at the end of the last financial year.

The decision isn't surprising and fits within CEO Kaz Hirai's ongoing efforts to divest Sony of divisions that aren't performing well or key to the company's strategy, but it does mark an end to yet another mini era for the storied Japanese giant. Sony was a pioneer in the field of battery technology, most notably bringing the first ever commercialized lithium ion battery to market in 1991; it's now hard to imagine a world without them.