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Making Safer Lithium-Ion Batteries
itwbennett writes "Exploding iPhones may be a thing of the past. Researchers at Taiwan's Industrial Technology Research Institute have developed a new polymer, STOBA (that's self-terminated oligomers with hyper-branched architecture to you and me), that is added to the cathode material inside a lithium-ion battery to keep them from overheating. 'Fires or explosions in these batteries are caused by short circuits,' said Wu Hung-chun, a researcher at ITRI, explaining that even minor mishandling such as dropping the handset could result in damage causing a short circuit. 'The technology is ready for lithium-ion batteries used in electronic devices, mobile phones, laptops,' said Wu. And ITRI has started testing STOBA on electric car batteries."
We looked at using these kinds of batteries for an engineering applicant for a client, so one of our engineers got a sample package of different sizes and shapes of batteries along with a handy CD of what you could and could not do with them. Unfortunately, the application involved possibly putting a battery on the end of an armature to power a light, something the disc explicitly warned against NOT doing -- it came with a nice set of exploding battery clips. Our client saw those and promptly refused to carry a cell phone in any piece of clothing attached to his body from there on it. I think his laptop no longer ever rested on his lap, either...
it's not just discharge rate. it's pure energy density.
ni-hm just can't store as much energy compared to lithium ion for the same size. The new hybrid Ni-HM probably has a far lower discharge then lithium-ion but that still doesn't solve the problem of lack of energy capacity. People want things to run long on a single charge (like laptops lasting 2 hours vs laptops lasting 4 hours). Most low drain devices where battery energy discharge would matter generally aren't on the radar for most people since charging within a few weeks span is simple compared to charging every few hours which is annoying and impractical.
The additive is usually in the separator that keeps the lithium and cathode apart (which you want to do). When the battery overheats the separator breaks down and disables the battery, this has been used where I work for over 20+ years, and is in no way new tech. Putting the same thing in the cathode is like putting a guard rail on the very edge of a cliff instead of 15-20 ft from a cliff, it may stop small shorts that slowly develop in the battery, but a major short, or hole in the separator will melt down and become quite dangerous before the cathode is even involved. Plus, how hot before this effect happens? Cathode is heat treated at over 650F, I sure hope it doesnt take that much to trigger this new substance.
Im ok..