They don’t hover, but they do explode unexpectedly.
As if the world’s strangest and most weirdly-popular new transportation device didn’t attract enough attention already, it’s starting to appear that hoverboards have a tendency to unexpectedly catch fire,
Unfortunately, one charging two-wheeler caused an entire house to burn down in Louisiana within the last month. A similar situation occurred in Gulf, Shores, Alabama. Another Louisiana hoverboard exploded under the same circumstances earlier this week, though members of the household were luckily able to control the flames. A gyroboard caused major damage to a New York home within the past few days and a scooterboard caught fire in a mall in Washington this week (and it wasn’t even plugged in!).
The prevalence of these issues have led to a nation-wide ban on the devices by major airlines.
So why does this keep happening? Because charging so often has a major role in the explosions, people are assuming that the issue must be with the hoverboard’s lithium-ion batteries. It’s not that lithium-ion batteries tend to explode; your smartphones mtablets, laptops and electric car all utilize ithium-ion batteries. It’s just that in the hoverboard’s case, the batteries are prone to defects and generally tucked in one of the foot rests.
Professor Materials Science & Engineering at Carnegie Mellon University Jay Whitacre explained that likely the problem has to do with the less expensive hoverboard brands using low-quality lithium batteries. With the holiday season rapidly approaching, plenty of shoppers will prefer to purchase a cheaper hoverboard for their children or spouses, especially if they can’t afford an $1000+ self-balancing board.
“There are a lot of factories in China that now make Li-ion batteries, and the reality is that the quality and consistency of these batteries is typically not as good as what is found in top tier producers such as LG or Samsung,” explained Whitacre. “There are known as ‘low-cost li-ion batteries’ by most in the industry; they are not knockoffs or copies but are instead just mass-manufactured cells.
Fires can occur in hoverboards powered by these batteries in a variety of different ways. The nature of any transportation device doesn’t lend itself well to faulty batteries; the little vehicles can be expected to collide with hard surfaces at some point and potentially damage the battery in that way. If the battery is then defective in such a way that it is more susceptible to being punctured than its engineers expected, it can cause a sizable explosion.
In addition, a short circuit can occur if a cheaper battery’s separator isn’t correctly aligned between the battery’s cathode and anode. There could also be small holes in the separator as a result of metal impurities. Either way, a short circuit can occur that could then lead to the device lighting on fire.
“If there is an inherent defect in the cell, it will go off at some point,” summed up Whiacre. “Small defects in the manufacturing materials steam lead to the plus/minus sides of the batteries being shorted with each other after a small amount of use. When this happens, especially when the batteries are charged, a lot of heat is generated inside the cells and this leads to electrolyte boiling, the rupture of the cell casing, and then a significant fire.”
And not just an ordinary fire; the fire created by a malfunctioning lithium ion battery is extremely difficult to control. The batteries are full of highly flammable electrolytes that burn fast and hard when they make contact with the air. Add onto that the fact that common cathode materials present in the battery then turn into additional oxygen sources to fan the flames and you’ve got a huge problem on your hands.