by Bill Snyder

Researcher says bad battery design, manufacturing errors led to Note7 debacle

Sep 16, 2016
Consumer Electronics

Samsung and a U.S. safety commission have recalled a million Note7 phones amidst concerns that their batteries are dangerously flawed. One researchers suggests the problems are directly related to poor battery design and Li-ion manufacturing issues.

samsung galaxy note7 note 7
Credit: REUTERS/Kim Hong-Ji

We all want our smartphones to be lighter, thinner and more powerful. At the same time, we want them to run longer.

Smartphone, laptop, and tablet designers do their best to deliver all of that, but those contradictory demands may make it harder for manufacturers to build safe batteries. This issue may well be a root cause of the frightening series of fires caused by malfunctioning batteries in Samsung’s new Note7 smartphone, according to Hector Abruña, the director of the Energy Materials Center at Cornell University and an expert on lithium ion (Li-ion) batteries.

“There has been a push to thinner and lighter batteries that also pack the most ‘juice,'” Abruña said. “This, however, can give rise to the safety problems that Samsung has encountered.”

Those problems are quite serious. Samsung acknowledged that at least three dozen Note7s have reportedly caught fire, injuring a number of people.

The U.S. Consumer Product Safety Commission (CSPC) late Thursday issued an official recall of 1 million Samsung Galaxy Note7 smartphones. The recall is necessary because the Note7 “presents such a fire hazard,” said Elliot Kaye, who chairs the organization.

Note7 battery’s dangerously flawed design

Samsung wanted to build “a thinner club sandwich,” which is to say a battery made of a number of layers, Abruña said in an email exchange. “Batteries for cell phones are made by stacking the electrodes in a manner akin to a large ‘club sandwich,’ in which anodes (negative electrode) and the cathodes (positive electrode) are kept apart using layers of separators,” Abruña said. “In an effort to minimize weight and volume, Samsung used a separator that was too thin, and this gave rise to shorts which made the batteries get very hot and fail catastrophically.”

Poor battery design is more serious than a manufacturing defect that may result in a few bad batches of batteries. The problems caused by the poor design were apparently exacerbated by manufacturing errors, as well. “There was also an issue with quality control in which the layers (anode/separator/cathode) were not properly aligned so that the anode and cathode came in contact, again giving rise to shorts,” Abruña said.

Abruña’s analysis is somewhat similar to information Samsung provided to the Korean Agency for Technology and Standards, according to Like Abruña, Samsung believes the negative and positive poles of the batteries came into contact and shorted out. It isn’t clear if Samsung believes a design flaw is also at fault, or if the problem is merely a manufacturing slip up.

Li-ion batteries inherently flawed?

A larger issue exists here is well, and it speaks to the safety of numerous digital devices.

The batteries in the Note7, like nearly all of the batteries in consumer electronics devices, are Li-ions. During the past year, numerous reports have surfaced about Li-ion batteries overheating and sometimes catching fire. “In essence, all Li-ion batteries are inherently unstable,” Abruña said. “However, they can be made to operate safely by appropriate design and control electronics.” 

These issues needed to be researched, researched well, and research soon. Samsung also has to let consumers know if other devices it sells contain batteries with similarly flawed designs.

I’m not about to ditch my many Li-ion-powered devices, but if I owned a Note7, I’d stop using it and exchange the phone immediately.