NGK’s NAS batteries long recovery

Facts

  • September 21, 2011 : Fire incident at the Tsukuba Plant, Joso City, Ibaraki Prefecture, Japan
  • September 22, 2011 : announcement of the event on NGK’s website
  • October 5, 2011 : fire authorities confirmed that the fire had been extinguished
  • October 25, 2011 : NGK requests all NAS batteries facilities to be stopped or to restrict their usage (after agreement with NGK)
  • October 28, 2011 : All shipments are officially postponed & business forecast is revised
  • November 24, 2011 : NGK publishes a Q&A on its website
  • June 7, 2012 : NGK explains the causes of the fire incident and countermeasures
  • From June 2012 : upgrade of existing batteries facilities
  • October 2012 (?) : batteries production resumed

Small cause, big effects

After months of silence, NGK finally communicates on June 7th, 2012, about the NAS battery fire incident. The cause: a single faulty cell. One of 15,360 cells composing a 2 MW block. The solution: safety enhancement. No need for design change. Big incident, easy solution.

Countermeasures

Since June 2012, existing NAS batteries facilities are, one after the other, upgraded to safety enhancement, by implementing following measures to prevent the spread of fire in modular batteries :

  • Fuses between battery cells
  • Insulation boards between blocks in battery modules
  • Anti-fire boards above and below battery modules.

The two first measures requires about 6000 battery modules from 174 locations in Japan, France, Germany, UAE, UK and USA to be collected in NGK facilities in Japan and then shipped back.

Along with additional safety measures (improved fire monitoring system, installation of fire extinguishers and fire-prevention equipment), as well as facilities organisation improvement (setup of a fire-fighting structure on site and of a fire evacuation route, with guidance system).

Production of new batteries 

New batteries would be produced at the earliest in October 2012. Business development perspectives are nevertheless maintained, mainly because NGK niche market is waiting for their batteries. unless GE’s Durathon shows up…

Gauthier Dupont
Dupont Energy Consulting GmbH

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