The future of smartphones: fireproof batteries
A charred Galaxy Note 7
As technology progresses, mobile devices become more and more powerful and capable. But with the increased power, also comes a greater need for higher capacity batteries, capable of sustaining the needs of their host devices.
As of late, however — meaning the last couple of years — there has been a growing number of reports about smartphones, and other mobile devices, bursting in flames while charging, or much worse, while on their owner. Most notably, last year the Samsung Galaxy Note 7 faced a global recall due to a still-mysterious defect that caused many units to catch fire, forcing the Korean tech giant to pull its latest flagship from the market. If there is a bright side to this whole fiasco, it would be the fact that major tech companies and researchers alike have taken note and are working toward preventing such issues in the future.
To tackle the problem, researchers from the Stanford University have developed a Li-ion battery with a “nonwoven electrospun separator with thermal-triggered flame-retardant properties”, or in layman's terms, a battery with a de facto fire extinguisher built-in. While the concept is not exactly new, previous attempts have resulted batteries with significantly reduced performance. This one, on the other hand, performs just as well as it would without the new fireproofing system, claims Prof Yi Cui, the project's lead scientist.
Schematic of the new separator with thermal-triggered flame-retardant properties. The separator is composed of polymer microfibers with a flame retardant encapsulated in their core. When triggered by a high temperature build-up in the battery, the polymer shell melts and releases the chemical, thus effectively supressing the ignition and burning of the electrolytes.
The Stanford-developed battery employs a plastic fiber separator that keeps negative and positive electrodes away from each other, infused with a compound called triphenyl phosphate, which has flame retardant properties. If the battery reaches a temperature of 150 °C, the separator melts and releases the phosphate. The Stanford University research team claims that this method of dealing with overheating batteries can extinguish any flames within 0.4 seconds, which is mighty impressive.
While it will be some time until this method, or a similar one, is successfully employed in mass produced Li-on batteries, it's still reassuring to see that scientific researchers are constantly working on ways to solve overheating problems, or at least battle the consequences thereof.
On a semi-related note, LG has promised that the battery of the upcoming LG G6 won't overheat, thanks to a system of copper heat pipes that will drive heat away from the battery. To learn more about that, check out our story on LG's fireproof battery.