Lithium-ion advancement
#1
02-09-2007, 10:39 AM
Join Date: Oct 2005
Location: Huntsville, AL
Posts: 5,613
Lithium-ion advancement
http://www.edn.com/article/CA6407156.html
Until today, I didn't know the failure mechanisms of the LiON battery fires. Needless to say, this is important to future hybrid and electric cars using LiON battery technology.
Bob Wilson
Originally Posted by Margery_Conner
Lithium-ion advancement improves safety and energy density
. . .
Matsushita, which most people know better by its brand name, Panasonic, recently announced an advancement in lithium-ion cells that the company claims will make lithium-ion battery packs safer and slightly increase energy density, or the battery’s capacity for power.
. . .
According to Rory Pynenburg, PhD, applications-engineering manager at lithium-battery-pack-design house Micro Power, battery manufacturers have been cramming more battery-active materials into the same cell dimensions. To achieve that task, they’ve had to compromise the thickness of the separator layer between the anode and cathode. The separators are polyolefin, typically a polyethylene with about 40% void volume. “The downside of using polyethylene is that, at about 93 to 98°C, the separator softens, and it can allow penetration by contaminants, leading to a short, says Pynenburg. “In pure polyethylene, it will start off with a pinhole penetration and then rapidly widen out, increasing the anode-to-cathode contact area, and you end up in a thermal-runaway situation.” In layman’s terms, this “situation” translates to a fire.
. . .
According to Pynenburg, Panasonic’s improvement was the introduction of ceramic material, a metal oxide, that goes between the separator and the electrodes—the anode and cathode. “It’s shrouded in a bit of mystery as to whether [Panasonic is] coating it onto the electrodes or onto the separator,” he says. “But the metal oxide does greatly increases the thermal stability, so that if there is a penetration through the separator, it stops there, and you don’t get the thermal-runaway situation.” The polymeric separator is still present, but Panasonic has added a heat-resistant layer. . . .
. . .
Matsushita, which most people know better by its brand name, Panasonic, recently announced an advancement in lithium-ion cells that the company claims will make lithium-ion battery packs safer and slightly increase energy density, or the battery’s capacity for power.
. . .
According to Rory Pynenburg, PhD, applications-engineering manager at lithium-battery-pack-design house Micro Power, battery manufacturers have been cramming more battery-active materials into the same cell dimensions. To achieve that task, they’ve had to compromise the thickness of the separator layer between the anode and cathode. The separators are polyolefin, typically a polyethylene with about 40% void volume. “The downside of using polyethylene is that, at about 93 to 98°C, the separator softens, and it can allow penetration by contaminants, leading to a short, says Pynenburg. “In pure polyethylene, it will start off with a pinhole penetration and then rapidly widen out, increasing the anode-to-cathode contact area, and you end up in a thermal-runaway situation.” In layman’s terms, this “situation” translates to a fire.
. . .
According to Pynenburg, Panasonic’s improvement was the introduction of ceramic material, a metal oxide, that goes between the separator and the electrodes—the anode and cathode. “It’s shrouded in a bit of mystery as to whether [Panasonic is] coating it onto the electrodes or onto the separator,” he says. “But the metal oxide does greatly increases the thermal stability, so that if there is a penetration through the separator, it stops there, and you don’t get the thermal-runaway situation.” The polymeric separator is still present, but Panasonic has added a heat-resistant layer. . . .
Bob Wilson
#2
02-10-2007, 09:18 AM
Re: Lithium-ion advancement
Bob, I'm sure you've heard of Altair NanoSafe batteries, where they claimed they've already eliminated this problem by eliminating the separator.
http://www.altairnano.com/documents/...nder060920.pdf
http://www.altairnano.com/documents/...nder060920.pdf
#3
02-10-2007, 10:43 AM
Join Date: Oct 2005
Location: Huntsville, AL
Posts: 5,613
Re: Lithium-ion advancement
Hi,
I was aware of their announcements and just checked their web site. They still don't make or sell batteries but they do make a number of interesting metal-oxides.
I was mostly interested in details about the failure mechanism. It is the low temperature plastic that is the problem. Since Panasonic makes a lot of LiON cells, I suspect we'll see their improved cells pretty soon.
Has Altair signed an agreement with some battery manufacturer to make their cells?
Bob Wilson
I was aware of their announcements and just checked their web site. They still don't make or sell batteries but they do make a number of interesting metal-oxides.
Bob, I'm sure you've heard of Altair NanoSafe batteries, where they claimed they've already eliminated this problem by eliminating the separator.
http://www.altairnano.com/documents/...nder060920.pdf
http://www.altairnano.com/documents/...nder060920.pdf
Has Altair signed an agreement with some battery manufacturer to make their cells?
Bob Wilson
#4
02-10-2007, 12:33 PM
Re: Lithium-ion advancement
I'm not sure where I read it from, but Altair produce the titanate nano powder here in the US, ships it over to Asia somewhere to manufacture the battery, then ships the batteries back to the US.
I think Phoenix cornered their battery EV application for 3 yrs, but I wonder about smaller applications like laptop (which could make laptop batteries last longer the the laptop themselves!). I dont think they're making any other battery except for those in the Phoenix cars right now.
I waiting for the day when they can make these batteries for cheap.
I think Phoenix cornered their battery EV application for 3 yrs, but I wonder about smaller applications like laptop (which could make laptop batteries last longer the the laptop themselves!). I dont think they're making any other battery except for those in the Phoenix cars right now.
I waiting for the day when they can make these batteries for cheap.
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