11 Nov

Is your storage battery chemistry safe?

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Before I begin a discussion concerning lithium ion battery safety, I would like to assure the reader that modern lithium ion batteries are considered safe and that thermal related failures are rare. Having said that though, certain battery chemistries are inherently safer than others and that will be the primary topic of my post. An energy dense cobalt based lithium ion battery that might be ideal for an electric vehicle, might not necessarily be the safest choice for a residential or small commercial energy storage installaion.

Lithium ion batteries were first introduced to the market back in 1991. These early offerings utilized the metallic form of lithium which possessed a very high energy density. Unfortunately along with the high energy density came a higher propensity for thermal runaway. Thermal runaway in lithium ion battery is a rapid, exothermic reaction that causes the cell to self destruct, The hotter the cell gets the more reactive the remaining lithium in the cell becomes. The heat from a single cell in thermal runaway can propagate to neighboring cells in the battery back resulting in the release of noxious gasses, fire and even the possibility of explosion.

Following the catatrophic failure of several of these earlier metallic lithium based battery designs, the industry shifted to a non mettalic lithium ion alternative. This new design offered lower energy density than metallic lithium but provided better thermal stability.

Today there are several different types of lithium ion battery chemistries available on the market.

1. Lithium Colbalt

2. Lithium Manganese Oxide LiMn2O4

3. Lithium Iron Phosphate LiFeO2

4. Lithium Nickel Manganese Cobalt Oxide LiNiMnCoO2

5. Lithium Nickel Cobalt Aluminum Oxide LiNiCoAlO2

6. Lithium Titanate Li4Ti5O12

When it comes to cost, specific energy, thermal stabilty, lifespan, power density and safety, each battery chemistry offers advantages and disadvantages. For example, while Lithium Colbalt LiCoO2 and Lithium Nickel Cobalt Aluminum Oxide LiNiCoAlO2 offer increased specific energy, they score lower on safety.

See UPS jet crash involving shipment of lithium ion batteries 

Also see this video depicting this explosive failure of lithium ion batteries 

On the other hand, while Lithium Iron Phosphate LiFeO2 may offer lower specific energy, which by the way is not a critical consideration for stationary energy storage applications, they do offer an exceptionally high safety rating.

While residential energy storage systems do come equipped with both active and passive cooling systems as well as a built-in BMS (Battery Management System), it is this author's opinion that it is best to start with a battery chemistry that is inherently safer and less dependent on these external safety systems should those safety systems fail. https://vimeo.com/144190533

Read 408 times Last modified on Thursday, 12 November 2015 11:03


There are many different storage battery chemistries on the market. Make sure that the chemistry that you choose is safe.