rechargeable lithium ion batteries are everywhere– electronics, tablets, laptops, cars and pretty much every single cell phone. and most of the time, these lithium batteriesare incredibly safe. as long as the lithium fail-safes are in place. fail-safes... that work.
Android TV q3, samsung just, voluntarily, recalled an estimated2 million galaxy note 7's as a safety precaution. since some of the batteries are explodinginside the phone. obviously, random explosions are not a featurethat most people look for when purchasing a cell phone.
so lets take a look at the note 7 and assesswhy it might spontaneously combust. during charging, the phone is protected bymultiple fail-safes. first off you have the part the plugs intothe wall; the charger, and the cable. if the charger is faulty, or not designedspecifically for the phone, it can effect the safety of the battery. it can destroy the battery's protection circuitwhich ill show you in a second. the charging port is also a fail-safe as well. it tries to do its best to protect the phoneand the battery from faulty chargers and incorrect electrical flow.
but as a last resort, the battery also hasits own fail-safe built in. here is where the battery plugs into the motherboard to receive its juice and supply the phone power. then we have this circuit board; also calledthe protection circuit, at the top of the battery. this controls the flow of electricity andthe temperature of the lithium. all lithium batteries should have a variationof this board. it makes sure that the battery does not overcharge, and it has a thermal fuse of sorts will blow if the temperature gets too hot,thus protecting the lithium inside from rapid
unplanned catastrophic dis-assembly. the body of the battery is typically two layers. the anode and the cathode, which are separatedby an electrically conducting fluid. this is oily and smells surprisingly of burntskittles. the combination of these elements allow yourphone to charge and function as long as the battery protection circuitry is working correctlyand the electricity and temperature of the lithium are regulated. if it is not regulated correctly during charging,the lithium will react violently. so if we look at one of the exploded phones...we can easily see which of the fail-safes...
is failing at being safe. the charging port sits here inside of thephone. there are no burn marks near the port, orwhere the port connects to the motherboard. but we do see some scorching where the batterysits. not where it plugs into the main board whichwould be about here. but it explodes in the center of the battery. around the battery hole in the thick aluminummidframe. so on this particular exploded note 7, allof the connections are good, its just the battery itself isn't behaving.
tesla cars are also powered by lithium batteries,and the model s had a small issue at the beginning of production where the batteries on the undercarriagecould get punctured by derbies on the road... which could cause the lithium battery underthe car to explode. tesla corrected this problem by adding a titaniumpuncture proof under-plate to the model s. the note 7 batteries are definitely not beingpunctured internally. since there is nothing to poke them on theinside as you can see from my teardown video. it sits on smooth aluminum. so since the note 7 battery isn't being punctured...that narrows us down to overcharging, shorting, or impurities in the battery itself.
a small metal impurity in the lithium couldshort it out. personally, i think the problem has to dowith the little circuit board failing at the top of the battery during charging. from what i have read about the people whohave complained publicly about their note 7 exploding, the phone was charging when ithappened. the phone starts charging... the tiny regulatordoesn't do its job and the battery enters into a thermal runaway and the voltage regulatorcant stop the chain reaction. since this particular note 7 battery isn'tplugged into the phone right now, my tweezers are acting as the other possible failure point;a metal impurity in the manufacturing of the
battery; that could possibly short out thebattery. all of this smoke and fire would be underextreme pressure locked inside of your water tight note 7, the more pressure there is..the bigger the explosion. remember this only happens on a very smallnumber of devices. so far its only happened on 35 phones outof 2 million. so, ya definitely take advantage of the recall,but also feel free to use your phone as normal in the meantime.... just don't set it on yourlap while its plugged into the wall.... and maybe take a fire extinguisher with you tobed... just in case. my instagram followers saw the results ofthis combustion before the video was posted
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