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Will batteries still explode like LiPo batteries?
by op00to 3y ago
Will batteries still explode like LiPo batteries?
- galangalalgol 3y agoWell there wouldn't be fires that produce toxic fumes and burn even under water, but if the coil fractured in an accident all that energy would be released in a tiny fraction of a second instead of a combustion event that takes time. That seems bad...
- yetihehe 3y ago> all that energy would be released in a tiny fraction of a second Probably along with a large electromagnetic pulse...
- ben_w 3y agoNecessarily with a large EMP, as the energy is stored in the magnetic field. Fortunately the energy density[0] is comparable with rubber bands[1] and supercapacitors[1], so while the EMP is large, it's not terrifyingly large. [0] at least according to wikipedia, 4-40 kJ/kg: https://en.wikipedia.org/wiki/Superconducting_magnetic_energy_storage https://en.wikipedia.org/wiki/Superconducting_magnetic_energ... [1] 1.6-6.6 kJ/kg and 10-30 kJ/kg respectively: https://en.wikipedia.org/wiki/Energy_density https://en.wikipedia.org/wiki/Energy_density
- galangalalgol 3y agoThe energy density isn't the scary bit, the power density is. The referenced paper in that Wikipedia article indicates ~10^5 higher power density than li-ion. So while it stores 10x less energy than li-ion it dumps it so much faster. The difference between a combustion and a detonation if you will. I'm guessing the vicinity of the thing would get turned to plasma.
- ben_w 3y agoA very small and localised plasma near the normal conductors that suddenly experience a rapidly decaying magnetic field; but the total energy is still (relatively) low compared to, say, the thermal heat capacity of the air of about 1.3 kJ/K/m^3.
- almostnormal 3y agoThat energy density number likely includes the cooling system.
- galangalalgol 3y agoThat is what I thought too, but reading the paper referenced it seemed like they only included the coils, not even the support structure to keep them from collapsing. But it wasn't that clear. Edit: they were clear that the limiting factor on energy and power density was the forces exerted on the coils.
- deleted 3y ago[deleted]
- amluto 3y agoNo, they’ll explode unlike LiPo batteries. LiPo batteries merely catch fire. An electromagnet, superconducting or otherwise, has large internal forces. If the support structure lets go, it will move. And, if part of the circuit becomes non-conducting, an inductive kickback will occur, generating enough voltage to (initially) sustain the original current. You could cut a Li-ion battery in half, and the two halves will continue to store their chemical energy, at least until they burn up. If you cut an inductor in half (which is what this type of energy storage device is), that energy will dissipate very quickly whether you like it or not.
- mmis1000 3y agoA battery that transform all energy it stored into heat sounds more like a bomb instead. Imagine someone accidentally heat up the 'super-conductive' battery to the point that it is no longer super-conductive.
- deleted 3y ago[deleted]
- jacquesm 3y agoThat goes for any sufficiently dense energy storage system, including most batteries. Imagine someone accidentally shorted out a car battery with something that can withstand a few thousand amps. (Come to think of it, a room temperature superconductor would do nicely for that purpose...).
- sudosysgen 3y agoI did something similar once with a high power lowish voltage battery array - my soldering iron's shroud literally vaporized with a deafening bang before even triggering the fuse.
- jacquesm 3y agoRi of those is typically 1 Ohm or thereabouts, which at 500 A develops 500W in the battery itself and a large multiple of that in your 'load' (in this case your soldering iron :) ). When working with large battery arrays I use tools that are taped in all the way except for the business end, just in case. All you need to do is drop a wrench in the wrong spot and it's party time.
- Timon3 3y agoA colleague recently showed me the coil of a broken superconducting magnet after it quenched. There was an easily visible rip in the structure, even though the whole thing was enclosed. It must have at least had enough kinetic energy to tear the metal apart.
- jacquesm 3y agoI've had a relatively small (about 2" x 2" x 1") ceramic magnet explode on me. The shrapnel was embedded deep into the adjacent wall.