11
Nov
Is your
storage battery chemistry safe?
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Is your storage battery
chemistry safe?
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 LiCoO2
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
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Last modified on
Thursday,
12 November 2015 11:03
