20-07-2013, 04:32 PM
(This post was last modified: 20-07-2013, 04:43 PM by camallison.)
I have followed the development and deployment of lithium batteries with interest over the years. Does anyone remember the fire aboard the MIR space station when Foale, the Brit, had to evacuate to a Soyuz escape capsule with the other crew. That was a lithium module fire and the flame was apparently 6 feet long! Not nice when there is a vacuum on the other side of the module wall it is playing against.
In the European Spacelab programme, lithium was a banned substance in any equipment deployed, including lithium (Tadiran) standby batteries in systems with volatile memory. The company I was working with at the time had a contract to supply a piece of control equipment to the German scientific module. In its normal form, our equipment had Tadiran batteries to support the volatile memory - taken off for flight and replaced by a battery with another chemistry.
In 2001, I visited the Mitsushima works of Mitsubishi Chemicals and also their Yokohama laboratories. The visit was to look at progress with their development of lithium ion battery chemistry. As you well know, these batteries don't like overcharging or short-circuit discharging and are prone to catching fire. We performed some testing in fire-proof cells built out of furnace bricks with fire-proof glass windows let into the sides.
The tests involved overcharging one of their batteries and, in the cell next door, overcharging a competitor's battery (Sony). The Mitsubishi battery swelled to about 30% bigger than normal. The Sony battery suddenly spouted a flame around 6 feet long and 2 feet wide at its widest. That battery was the one being fitted at that time to Sony-Ericsson mobile phones as standard.
Shortly afterwards, the Sony-Ericsson battery was subject to recall and all were replaced.
The chemistry of lithium ion batteries is such that this can happen whatever protection they put in and the only solution is to guard against it. I did some calculations at the time and reckoned that lithium ion batteries have a higher potential energy density (explosive power) than Semtex!
My own personal feeling is Boeing have gone one step too far in putting these batteries in aircraft as there will always be this inherent problem.
Colin
In the European Spacelab programme, lithium was a banned substance in any equipment deployed, including lithium (Tadiran) standby batteries in systems with volatile memory. The company I was working with at the time had a contract to supply a piece of control equipment to the German scientific module. In its normal form, our equipment had Tadiran batteries to support the volatile memory - taken off for flight and replaced by a battery with another chemistry.
In 2001, I visited the Mitsushima works of Mitsubishi Chemicals and also their Yokohama laboratories. The visit was to look at progress with their development of lithium ion battery chemistry. As you well know, these batteries don't like overcharging or short-circuit discharging and are prone to catching fire. We performed some testing in fire-proof cells built out of furnace bricks with fire-proof glass windows let into the sides.
The tests involved overcharging one of their batteries and, in the cell next door, overcharging a competitor's battery (Sony). The Mitsubishi battery swelled to about 30% bigger than normal. The Sony battery suddenly spouted a flame around 6 feet long and 2 feet wide at its widest. That battery was the one being fitted at that time to Sony-Ericsson mobile phones as standard.
Shortly afterwards, the Sony-Ericsson battery was subject to recall and all were replaced.
The chemistry of lithium ion batteries is such that this can happen whatever protection they put in and the only solution is to guard against it. I did some calculations at the time and reckoned that lithium ion batteries have a higher potential energy density (explosive power) than Semtex!
My own personal feeling is Boeing have gone one step too far in putting these batteries in aircraft as there will always be this inherent problem.
Colin
