Why do smartphone batteries explode?

Posted on Posted in Tech-'o'-Mania

Hello guyzz!! Today let’s talk about the thing that you have almost all the time nearby you in your hand or in your pocket. Can u make a guess of what I’m talking about right here right now.. Yeah!! you guyzz are so closer. Hey! you got me , Yeah I’m talking about that Apple, Samsung that you have in your hand right there. Smartphones, may be called as a life in itself, one can live without air, water, food but can’t without a smartphone. One can do anything to have the latest and hi-tech one with the special effect camera and the quality speakers with crystal clear sounds. Sorry if I’ve missed something. But to be very true, for me a smartphone is like someone special who’s always with me 24×7 either in my good times or in my hard times.

But smartphones are becoming a sign of danger these days and people have to be stay aware while using their devices. You might heard the news about Samsung Galaxy Note 7 smartphone explosions. This news left the millions, billions of users shellshocked which also affected the mindsets of users for the use of smartphones. This also led to the huge loss to the company. So why these phones explode?? Is there something wrong with the phone?? Is it because of the company’s carelessness?? Millions of questions start arising among the world population to find out the reasons behind this. Let us find out why these smartphones batteries explode? First of all let us find out what is the thing “Battery”? Batteries are small containers of chemical energy. When a smartphone is plugged into the mains, electricity is used to reset a chemical reaction within the battery, transferring electrons from the negative anode to the cathode – the positive end of the battery.

Once charged, the battery can then create electricity by driving electrons through a circuit, in this case a smartphone, to the anode and will continue to do so until all of the electrons contained within the battery have transferred to the anode or a built-in switch disconnects the battery. Inside a typical battery you have an anode, a cathode and electrolyte – something for the positive ions to travel through.

Lithium-ion batteries found in most smartphones and electronics have a metal oxide cathode made of a cobalt, nickel, manganese or iron mix, a porous graphite anode that holds lithium ions within it and a lithium salt electrolyte. Positively charged lithium ions travel through the electrolyte from the anode to the cathode driving electrons through the smartphone as required and back to the anode.

(Src: media.indiatimes.in)
(Src: media.indiatimes.in)

The major limiting factor for batteries is their energy density. A battery can only generate as much electricity as its chemical components can store energy. Everything that is not the active material within the battery is effectively dead weight, including the casing, the controller chips, the wires to carry the current out – they all add weight but not power.

A typical lithium ion battery within a smartphone has an energy density around 150 Watt-hours per kilogram (Wh/kg). While Lithium ion battery energy density has improved since its introduction in the early 1990s, it is held back by its construction and chemistry.

The only way to immediately increase a smartphone’s battery life with current technology is to increase the power efficiency of the smartphone’s electronics and increase the size of the battery – but thinner and thinner smartphones demand thinner and thinner batteries.

Battery life doesn’t stay constant for the entire life of a smartphone – it diminishes slowly over time, as the battery is discharged and recharged. This is because the chemical reaction that produces the electricity causes thin layers of lithium to be laid down on the electrodes, which reduces the amount available to generate electricity and increases the internal resistance of the battery. The higher the resistance the harder the battery has to work to maintain a usable voltage and so the amount of power it can produce per charge decreases.

As you guyzz have already read above Lithium batteries , commonly used in smartphones, have two electrodes on opposite sides and lithium ions move from one electrode to another during charging. Both the electrodes should never touch and to prevent this from happening, battery makers insert separators in between. In case of Samsung note 7, the separators were reportedly flawed and the two elctrodes touched leading to explosion.

cdwefwe400Samsung, on its U.K website, released a statement confirming that at least 35 cases of phone explosion have been reported. They said that the batteries combusted due to a “very rare manufacturing process error” where the anode and cathode touched. Most of the times, phones or other devices explode because of errors in the charging process. The batteries rely on a software which basically instructs them how much the batteries should be charged and how fast. When there is an error in these set protocols, it can destabilise the chemicals inside the batteries. Lithium reacts with pretty much everything, by the way, so destabilised chemicals cause a chain reaction known as a “thermal runaway”. Thermal runaway can lead to fire or explosions.  Shoddy manufacturing of devices can also be blamed for the explosions. Sometimes scraps of metal or other objects find their way inside the battery when the phone is being made, which ends up setting off a thermal runaway.

Overheating can also be a reason. Many phones nowadays are completely made of metal (because, who likes plastic anymore, right?) which makes the phone even hotter. Many phones also send you a notification about needing to cool down when it gets too hot. Batteries can also heat up and fail when they’re charged too fast or kept in charge for way too long.

Dropping your device could also affect the way your phone behaves. Sometimes, the impact causes the separator between the anode and the cathode to break, and you know what happens when the anode and cathode react with each other.

What is the future of battery technology?

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Solid state batteries are one possible future, where the liquid electrolyte in the battery is replaced by a solid substance, which will provide significant safety improvements. “The main advantage of solid state batteries is that you can go back to using lithium as the anode material, which has really good power and energy density, but wasn’t safe with liquid electrolytes,”. Solid-state batteries will remove the need for the porous carbon anode and therefore removes more of the weight from the battery that doesn’t contribute to generating power. Metal air batteries, using zinc, lithium or aluminium are also on the horizon, but are 20 years away from being available in a commercial application.

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