Remember when you used to buy a dry car battery, get it home, add the acid. Wait awhile and add the water, then check the water level in the battery once a month? I miss the danger of playing with battery acid.
.
Those where safe.
Why Some Lithium-Ion Batteries Explode
Real-time images have captured the chain reaction that causes lithium-ion batteries to explode.
The process can occur in just milliseconds: Overheated battery modules create a domino effect, producing more and more heat, and the battery explodes. But it turns out that not all batteries are equally likely to fail, according to a new study published today (April 28) in the journal Nature Communications.
"The presence of certain safety features can mitigate against the spread of some of this thermal runaway process," said study co-author Paul Shearing, a chemical engineer at the University College London in the United Kingdom. Those features include mechanical supports inside the battery, Shearing said.
The results suggest some ways to make rechargeable lithium-ion batteries safer, the researchers wrote in the paper. [
9 Odd Ways Your Tech Device May Injure You]
Rechargeable batteries
Lithium-ion batteries are the workhorses of modern-day gadgets; they're found in everything from smartphones to jumbo jets to the
Tesla Model S. They are typically made with two layers of material, called the anode and the cathode, separated by an electrically conducting fluid.
Lithium ions start off in the cathode, a layer of material that, in laptop and cellphone batteries, typically includes cobalt, manganese, nickel and oxygen. When the batteries are charged, electricity drives the lithium ions from the cathode, across an ion-filled electrolyte fluid, and into the anode, which is made of stacks of graphite. As the battery drains, the lithium ions return from the anode back into the cathode. The batteries typically come in cells; a laptop battery may have three or four cells, whereas a Tesla Model S may have thousands, Shearing said.
Chain reaction
Hundreds of millions of lithium-ion batteries are produced every year, and catastrophic failure, such as explosion or melting, is rare, Shearing said. Still, there have been 43
product recalls for defective lithium-ion batteries since 2002, according to the U.S. Consumer Product Safety Commission.
Batteries can blow up or melt when internal electrical components short-circuit, when mechanical problems crop up after a fall or an accident, or when they are installed incorrectly, Shearing said. But at the heart, all of these failures occur because one portion of the battery gets too hot and can't cool down quickly enough, creating a
chain reaction that generates more and more heat.
"It's kind of this snowball process that we call thermal runaway," Shearing told Live Science.
During thermal runaway, the miniature battery modules can melt, giving off heat, and the electrolyte material between the anode and the cathode may even boil, Shearing said.
http://www.livescience.com/50643-watch-lithium-battery-explode.html
Why lithium batteries keep catching fire
IN THE past year rechargeable batteries containing the element lithium have been in the headlines for all the wrong reasons. Investigators in Japan are investigating why
a lithium-ion battery overheated on a Boeing 787 Dreamliner at Narita airport. Last year
Boeing grounded its entire fleet of the next-generation plane after the lithium batteries on two of the aircraft caught fire. (The 787s returned to the air after being fitted with a modified system to protect the aircraft against battery fires.) Tesla, a maker of electric cars, performed a remote software update to its
Model S luxury cars after two fires, which were blamed on road debris damaging the undertray containing the vehicles' lithium batteries. Lithium batteries are widely used because of their high energy density: in other words, their ability to store a lot of energy in a lightweight, compact form. But they have a tendency to cause expensive machinery to go up in smoke.
http://www.economist.com/blogs/economist-explains/2014/01/economist-explains-19
Lithium
Like all alkali metals, lithium is highly reactive and flammable.
Because of its high
reactivity, lithium never occurs freely in nature, and instead, only appears in
compounds, which are usually
ionic.
Lithium reacts with water easily, but with noticeably less energy than other alkali metals do. The reaction forms
hydrogen gas and
lithium hydroxide in aqueous solution. Because of its reactivity with water, lithium is usually stored under cover of a hydrocarbon, often
petroleum jelly.
https://en.wikipedia.org/wiki/Lithium
I used to make metallic sodium (alkali metal) bombs. It reacts with water in an exothermic reaction (heat) producing hydrogen gas which ignites due to the heat of reaction. Flushing metallic sodium down the toilet causes an explosion and fire. Oh those youthful days in Chem Lab at the University.
Instead, we have lithium batteries that explode and catch fire. Who knew? Anyone that has taken freshman chemistry knew.
