It has been asked, why change to new battery technology (Li-Ion) when old (Ni-Cd) seemed to cause few problems? The answer is a combination of different advantages of Li-Ion over Ni-Cd:
1. Ni-Cd contains cadmium, which is very toxic to the environment, therefore during the last decade or so banned from practically all applications.
2. Ni-Cd is two-three times heavier.
3. Ni-Cd is more maintenance intensive, and has shorter life.
4. Ni-Cd needs maintenance even when stored as a "spare part".
Pretty sure, there will never again be a new airliner design with Ni-Cd batteries. On the other hand existing airliner types will at relevant opportunities be updated to have Li-Ion batteries, just like newbuilt 747s some 35 years ago had its main battery changed from Lead-Acid to Ni-Cd.
Here is what I wrote yesterday; apparently not everybody bothered to read it first time around..
Lead-acid (e.g. car battery, invented 1859) >> Ni-Cd (1899) >> Ni-MH (1989) >> Li-Ion (1991)>> Li-Ion polymer (1997) >> (?? - next generation)From left to right you get more capacity for less weight. You also get increasing cost.
Up until 2008 Ni-Cd & Ni-MH were the go to solution for torches, radios, electric drills, etc.
Since 26th September 2008 an EU directive has banned ALL manufacturers/distributors from importing Ni-Cd batteries into Europe.
Of course China/eBay are not necessarily bothered by such things, and you can still buy Ni-Cd and import them yourself.
Ni-MH are still the first choice today for most domestic applications, whereas Li-ion are most probably what you will find in high value goods such as your laptop, and mobile phone. Indeed, some of you may remember a bit of an issue with spontaneous combustion and the Samsung Galaxy Note 7.https://en.wikipedia.org/wiki/Samsung_G
So, why is nobody mentioning Ni-MH? (apart from myself).
In domestic applications, for AA size batteries, the best Ni-Cd was typically 700 mAh; the best Ni-MH is around 2500 mAh i.e. around 3½ times the capacity, with lower toxic problems, much better shelf life, and better energy density.
If Boeing are having problems with Li-Ion, they do not need to revert all the way back to Ni-Cd for a safer solution
However, as Li-ion batteries are in normal day-to-day usage around the world, it might just be that Boeing are stretching the parameters on these batteries one step too far. Or they need to source from a new supplier with better Quality Control.
Last edited by SheikhDjibouti
on Sun Dec 03, 2017 6:10 pm, edited 1 time in total.
There are two things that happen when you get old.
1. You start to lose your memory.
2. What was I saying again?