Sodium-sulfur battery – Wikipedia, the free encyclopedia

A sodium-sulfur battery is a type of battery constructed from sodium (Na) and sulfur (S). This type of battery has a high energy density, high efficiency of charge/discharge (89—92%) and long cycle life, and is fabricated from inexpensive materials. Because, however, of the operating temperatures of 300 to 350 °C and the highly corrosive nature of the sodium polysulfides, such cells are primarily suitable for large-scale non-mobile applications such as grid energy storage…

NaS Battery Development in Japan

TEPCO(Tokyo Electric Power Co.)/NGK(NGK Insulators Ltd.) consortium declared their interest in researching the NaS battery in 1983, and have become the primary drivers behind the development of this type ever since. TEPCO chose the NAS battery because all its component elements (Sodium, Sulphur, Ceramics) can be abundantly found in Japan. First large-scale prototype field testing took place at TEPCO’s Tsunashima substation between 1993 and 1996, using 3 x 2MW, 6.6kV battery banks. Based on the findings from this trial, improved battery modules were developed and were made commercially available in 2000. The performance of the commercial NAS battery bank is as follows:

1. Capacity : 25 - 250 kW per bank
2. Efficiency of 87%
3. Lifetime of 2,500 cycles (at 100% DOD - depth of discharge),
or 4,500 cycles (at 80% DOD)

[1] (Source in Japanese)

As of 2008, sodium-sulfur batteries are only manufactured by one group, the NGK/TEPCO consortium, which is producing 90MW of storage capacity each year. ^[2]

There is currently a demonstration project using NGK Insulators’ NAS battery at Japan Wind Development Co.’s Miura Wind Park in Japan.^[3]

Japan Wind Development has opened a 51 MW wind farm that incorporates a 34 MW sodium sulfur battery system at Futamata in Aomori Prefecture in May 2008. [2] ^[2]

There are already 165MW of installed capacity base in Japan alone as of 2007, and NGK has just announced plan to expand its NAS factory output from 90MW a year to 150MW a year. [3] (Source in Japanese, but with some pictures)

Xcel Energy has announced that it will be testing a wind farm energy storage battery based on 20-50kW sodium-sulfur batteries from NGK Insulators Ltd of Japan. The 80 tonne, 2 semi-trailer sized battery is expected to have 7.2MW-hours of capacity at a charge and discharge rate of 1MW. ^[4]

Sodium-sulfur battery – Wikipedia, the free encyclopedia.