Sanyo started producing NiCd batteries around 1964, and NiMH batteries from 1990 acccording to wikipedia.
On October 4, 2000 Sanyo acquired the NiMH battery business from the Toshiba Group.
And on April 27,2001 established the subsidiary Sanyo Energy in Takasaki, Gunma, Japan called officially Sanyo Energy Takasaki Co. Ltd.
In April 2003, they merged with Sanyo Energy Kaizuka Co, and changed their name to Sanyo Energy Twicell Co. Ltd
This is quoted from their own words: "The word Twicell comes from the desire to be a company that allows twinkling employees (Twinkle), twisted (Twine), twice the power (Twice) to be demonstrated."
On November 14, 2005, Sanyo released eneloop which became a registered trademark by Sanyo. They were being produced in the Takasaki plant.
In 2006 eneloop universe was established, which would produce all kinds of gadgets including portable solar panels.
The eneloop battery line-up expanded with the production of C and D size batteries.
On december 2009 Panasonic completed a 400 billion yen ($4.5 billion) acquisition of a 50.2% stake in Sanyo, making Sanyo a subsidiary of Panasonic.
The first eneloop limited edition (eneloop tones) were produced.
Sanyo Energy Twicell Co., Ltd. and Sanyo Energy Tottori Co., Ltd. shares were transferred from Sanyo Electric, and renamed their company names to FDK Twicell Corporation and FDK Tottori Co. Ltd. Panasonic kept buying their eneloop batteries from this company.
Eneloop XX came on the market as a High capacity eneloop cell, that would have a higher capacity as standard eneloops, but with a lower cycle life.
June 2010: eneloop announced the production of Eneloop Lite batteries, which have a lower capacity than standard eneloops but can be be charged more times, and are less prone to increased internal resistance. Good for low drain devices.
April 26, 2013, eneloop officially became a Panasonic brand. By doing this, the trademark of the SANYO brand in Japan was terminated.
Panasonic started producing eneloop batteries in China. The "made in China" eneloops are available tin the Asian market, including New Zealand and Australia. The Made in Japan batteries for the Japanese -, North American- and European market.
Panasonic celebrated they shipped 400 million eneloop batteries worldwide.